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Nutrient Leaching/Runoff Issues of Both Organic and Conventional Agriculture



The organics movement has been quick to point the finger at conventional agriculture’s role in contaminating ground water and waterways. What they, however, fail to mention is that organic agriculture is also responsible for contaminating ground water and waterways. In fact, research has conclusively demonstrated that while claims are made that organic farming reduces nutrient leaching/runoff when compared to conventional farming this is not the case.



A meta-analysis of European studies comparing organic to conventional agriculture environmental impacts concluded:

 

 “The results show that organic farming practices generally have positive impacts on the environment per unit of area, but not necessarily per product unit. Organic farms tend to have higher soil organic matter content and lower nutrient losses (nitrogen leaching, nitrous oxide emissions and ammonia emissions) per unit of field area. However, ammonia emissions, nitrogen leaching and nitrous oxide emissions per product unit were higher from organic systems. Organic systems had lower energy requirements, but higher land use, eutrophication potential and acidification potential per product unit.”

 

Research by Audun Korsaeth (2008) showed that organic cropping produced significantly lower yields than conventional cropping (“most likely due to sub-optimal plant nutrition and the lack of plant protection in the organic systems”) while at the same time had similar N losses to drainage as conventional arable farming. The research also demonstrated through several models of farming that a conventional system with environmentally sound management had the lowest N loss (runoff/leaching) to food production ratio.

 

Research by Gunnar Torstensson et al. (2006) compared N, P and K leaching in two organic and two conventional systems over a six-year period. One organic system with and one without the addition of animal manure, and in the case of the conventional systems (one with cover crops), both were applied with agrichemical pesticides and fertilizers. The results clearly showed that leaching loads of N were smallest in the conventional system with cover crops; the study concluded that the results clearly suggested that N use efficiency was improved by inorganic N fertilizers.

 

In research by Holger Kirchmann & Lars Bergström (2001) the authors analyzed and compared NO3 N (nitrate nitrogen) leaching from organic and conventional systems. They found that nitrate leaching on average was somewhat lower in organic systems. However, if the different N input intensities and yields were taken into account between the organic and the conventional systems, no difference between leaching loss was found. The research concluded that there was no evidence that organic systems reduced nitrate leaching.

 

In a series of Swedish long-term field trials that commenced in the early 1990s, similar crop rotations in organic and conventional systems were maintained except in years when green manure was grown. N input in the organic systems was close to that of conventional systems.



In these studies, on both a sandy and a clay soil, organic systems had greater nutrient leaching and greater release of N and P to drainage water both per hectare and per unit of harvested N. When comparing the N use in the organic and conventional systems, N uptake through yields and N lost through leaching water were expressed as a percentage of the sum of both. The proportion of the two outputs measured was 35% of N leached and 65% taken up by crops in the organic systems compared to 19% leached and 81% taken up by crops in the conventional systems. The research concluded that if differences between comparative studies caused by different crop rotations and N input intensity can be largely eliminated, leaching of N from organic systems is not lower per unit area.

An ideal agricultural system should both maximize food production and minimize undesirable effects on the environment. On this basis hydroponics, with higher crop yields, no nutrient leaching/runoff where best practice is implemented and up to a 90% reduction in water usage wins hands down over all other systems of horticulture/agriculture.

 

Where Organic Practices Can Make a Difference

 

Having pointed out that from a scientific perspective organic growing methods don’t produce a more nutritious and healthier end product than hydroponically grown plants, one proviso needs to be added and that is certainly some organic practices (at least in theory) aspire to higher ideals over traditional agricultural practices where, among other things, the use of chemical/synthetic pesticides/insecticides, herbicides and fungicides are concerned. Put simply, in organic agriculture potentially toxic/harmful synthetic pesticide, herbicide and fungicide use is not permitted and a product cannot be registered as organic if synthetic pesticides, herbicides and/or fungicides are used.

 

For instance, having cited research that has disproven claims that organic produce is more nutritious and healthier than conventional food, what should be added is that in the case of the British Research, no analysis of the contaminant content (such as herbicide, pesticide and fungicide residues) of organically and conventionally produced foodstuffs was undertaken. This, in my mind, and to be completely fair to the organic movement, was a glaring omission. There is, after all, very little point in discussing the nutritional values of conventional versus organic foods when one food type may be potentially detrimental to your health due to pesticide residues while the other may not. For instance, research in the UK, Europe, North America and elsewhere has consistently shown that synthetic pesticide residues are lower in organic crops than in their conventional equivalents.

 

However, the practice of avoidance/opposition to the use of potentially toxic pesticides and fungicides is also commonly incorporated by many indoor hydroponic growers. In fact, where crops are produced indoors (greenhouses and growrooms) the opportunity for integrated pest management through biological controls etc and pest and fungal spore exclusion through filtering inlet air etc is shown to be far more successful and/or achievable than in outdoor environments where pests and pathogenic fungi (e.g. Botrytis cinerea/gray mold) are naturally present in high numbers.

 

Further, as with the science of mineral nutrition, pesticide and fungicide science is an area that is often greatly oversimplified and/or misunderstood by at least some organic proponents.

 

Organic and Inorganic Pesticides

 

It has been assumed for many years that pesticides that occur naturally (in certain plants, for example) are somehow better for us and the environment than those that have been createdin laboratories by chemists. However, as more research is done into organic pesticide toxicity, this belief has largely been discredited. For instance, nearly 50 percent of the pesticides approved for use in organic farming have failed EU safety tests since the EU’s Plant Protection Products (pesticide) regulations came into force in 1996.

 

Put simply, when you test synthetic chemicals for their ability to cause cancer, you find that about half of them are carcinogenic.  Until recently nobody bothered to look at natural chemicals (such as organic pesticides), because it was assumed that they posed little risk. But when the studies were done, the results surprised many. You find that about half of the natural chemicals studied are carcinogenic as well. This point was summed up well by researchers in California who studied natural and synthetic chemicals in the human diet in 2001 and wrote: “Among the agents identified as human carcinogens by the International Agency for Research in Cancer 62% occur naturally: 16 are natural organic chemicals, 11 are mixtures of natural chemicals, and 10 are infectious agents.”

Therefore, in reality, from a scientific perspective; 1) The biological activity of a chemical is a function of its structure rather than its origin; 2) the biological properties, especially safety, of a chemical depend on its structure and the way in which the chemical is used (i.e. exposure), and; 3) perceived risks are not always consistent with actual risks.

 

Okay, we’re starting to wade into the heady world of chemistry (again) and that is possibly best avoided. My point here is to simply raise the issue that organic (naturally occurring) chemicals can be as toxic as their synthetic equivalents and in many cases more toxic.  This said, a philosophical underpinning of organic growing is to avoid the use of anything that is harmful to the environment and living organisms (e.g. people). While often overly simplified this philosophy has been demonstrated (as a general rule where best practice is concerned) to lead to fewer toxic residues in crops.

 

Therefore, while the use of hydroponic (inorganic) fertilisers does not contribute toxins to plants the inappropriate use of pesticides and fungicides (whether organic or inorganic) does.



Certainly, on this level, the organic approach to producing food is shown to superior to conventional agriculture. I’m perhaps oversimplifying this somewhat because many factors come into play. For instance, some would argue points around safe/acceptable residue limits (maximum residue limits or MRL). Additionally, as previously noted, research has shown that the cancer rates between consumers of organic and conventional produce are the same. This said, that is not to categorically say that there are no associated health risks where pesticides are concerned. As organic bodies have rightfully pointed out, legally defined maximum residue limits are not a guarantee of zero health risk.

 

So, for myself, I tend to err towards the side of caution. If history has taught us anything it is to be sceptical of regulatory bodies and safety claims surrounding pesticides (e.g. DDT), herbicides (e.g. Agent Orange and Paraquat) and fungicides. I.e. what is deemed safe today may not be deemed safe tomorrow. For instance, the latest disaster in a long line of pesticide and herbicide disasters surrounds Monsanto’s Roundup (glyphosate) which for years has been widely promoted with claims to its safety and environmental friendliness.

 

Of the more than two-dozen top herbicides on the market today, glyphosate is the most popular. In 2007, as much as 185 million pounds of glyphosate was used by U.S. farmers, double the amount used six years before.

 

However, a new research report by Anthony Samsel, a retired science consultant, and Dr. Stephanie Seneff, a research scientist at the Massachusetts Institute of Technology (2013) came to some very disturbing conclusions about the weed killer Roundup and its active ingredient glyphosphate.

 

Monsanto has steadfastly claimed that Roundup is harmless to animals and humans because the mechanism of action it uses (which allows it to kill weeds), called the shikimate pathway, is absent in all animals. However, the shikimate pathway is present in bacteria, and that’s the key to understanding how it causes such widespread systemic harm in both humans andanimals.

 

The bacteria in our bodies outnumber our cells by 10 to 1. For every cell in our body, we have 10 microbes of various kinds, and all of them have the shikimate pathway, so they will all respond is some form, at some level to the presence of glyphosate.

 

Glyphosate causes extreme disruption of the microbe’s function and lifecycle. What’s worse is glyphosate preferentially affects beneficial bacteria, allowing pathogens to overgrow and take over. At that point, your body also has to contend with the toxins produced by the pathogens.

 

The research reveals that glyphosate inhibits cytochrome P450 (CYP) enzymes, a large and diverse group of enzymes that catalyze the oxidation of organic substances. This, the authors argue, is “an overlooked component of its toxicity to mammals.” One of the functions of CYP enzymes is to detoxify xenobiotics — chemical compounds found in a living organism that are not normally produced or consumed by the organism in question. By limiting the ability of these enzymes to detoxify foreign chemical compounds, glyphosate enhances the damaging effects of chemicals and environmental toxins that you may be exposed to.

 

Although more research is needed, it now looks as if glyphosate could be potentially linked to a range of health problems and diseases, including Parkinson’s, infertility and cancers.

 

Of course, any talk of herbicide use in hydroponics is misplaced. I.e. because hydroponic systems are separated from the earth/ground there are no weed issues and therefore no need for herbicides. However, you perhaps take my point. What is deemed safe today may not be deemed safe tomorrow and because of this the only guarantee of safety is to avoid the use of synthetic pesticides, herbicides and fungicides altogether. On this level, the organics movement should be applauded… full stop!

 

Pesticide Residues in Organic versus Inorganic Produce

 

The U.S. in 2006 and 2007 used approximately 1.1 billion pounds of pesticides accounting for 22% of the world total. For conventional pesticides which are used in the agricultural sector as well as in industry, commercial, governmental and the home & garden sectors, the U.S. used at total of 857 million pounds, with the agricultural sector accounting for 80% of the conventional pesticide use total.

 

In research conducted by Chensheng Lu et al (2010) forty-six elementary school age children from Georgia and Washington states participated in the study for two to three days. Their parents collected a total of 239 conventional (non-organic) food samples.

 

Nearly one-fifth (20%) of the food samples measured had at least one pesticide. Of those, more than one-quarter contained multiple pesticides in the same food sample. It was also found that many of the food items consumed by the children were also on the list of the most contaminated food commodities reported by the Environmental Working Group.

 

The 2002 through to 2004 annual and quarterly reports from the Pesticides Residues Committee of the UK consistently show that approximately one percent of conventional food samples contain pesticide residues above the maximum permitted levels The annual pesticides monitoring reports of the Food and Veterinary Office of the European Commission also report elevated levels of pesticide residues. Specifically, the 2001, 2002, and 2003 reports (corresponding to a total of approximately 46,000 food samples) show that 3.6, 5.2, and 5.1 percent respectively contained pesticide residues above the maximum residue limit (MRL). Similarly, in the US the 2001 through 2003 annual reports of the Pesticide Program Residue Monitoring of the FDA shows an overall “violative” level of pesticide residues between one and two percent for domestic food samples and between four and six percent for imported food samples.

 

In research conducted by Carl Winter and Sarah Davis (2006) they reviewed America’s largest pesticide database, the USDA’s pesticide data program, which included results of the sampling of 26893 foods for pesticide residues from 1994 to 1999. Nearly 99% of the samples (26591) made no market claim about the method of production, and 73% of these samples contained detectable residues of pesticides. A small number of samples (127) made organic production claims; nonetheless, residues of pesticides were present in 23% of these samples.



Similarly, when the FDA purchased a thousand pounds of tomatoes, peaches, green bell peppers, and apples in five cities in 1999 and tested them for more than 300 synthetic pesticides, they found traces in 25% of the organically labelled foods. This becomes somewhat important also. That is, just because a producer or supplier claims a product is organic and thereby implies that it is grown free of synthetic pesticides this doesn’t necessarily make it so.

 

To be fair to organic growers this could be a combination of spray drift and water contamination from nearby conventional farming. Or, maybe, even a rise in the water table bringing synthetic chemicals used by earlier generations into contact with the roots of now organically grown plants. However, as the production of organic food is becoming more commercial there is economic pressure on growers to supply more produce to get the same amount of income when dealing with larger corporate buyers. This may lead to organic farmers taking short cuts to increase production by using fungicides and pesticides among other non-organic practices.

 

While the Soil Association in the UK runs field tests on farms once yearly, there are serious problems in the North American organics industry. Most notably, the fact that no field-testing is performed to ensure farmers don’t use pesticides. Former United States president Bill Clinton and the America Consumers Union (ACU) advocated field testing in 1997 when the US Department of Agriculture’s (USDA) National Organic Program was first tabled. This said, the organics movement isn’t in a hurry to implement checks and measures and no organic farm in the United States and/or Canada has been field-tested in the last 15 years.

 

USDA administrator Miles McEvoy, promised to change this by testing 10% of American organic farms in 2011, but domestic organic farmers supply only 15% of the American and Canadian market. The other 85% of North American ‘organic’ food is imported from places like China, Mexico and Brazil – countries that will not be subject to the same levels of scrutiny.

 

This situation is not necessarily limited to North America, although the problem does seem worse than in other regions where stricter regulations surrounding pesticide use and more stringent testing is enforced along with less imported product from developing countries is sold. For instance, the European Food Safety Authority (EFSA), in 2008, found synthetic pesticides in a range of organic foods. Organic fruit and vegetables had a generally lower rate of MRL (Maximum Residue Levels) surpluses (1.24% of all organic samples) in comparison to conventionally grown cereals, fruit and vegetables (3.99% of samples analysed).

 

While much of the research we’ve covered compares food sources from crops produced in outdoor settings, pesticide residues from several studies are also shown to be relatively higher in greenhouse hydroponic produce than in outdoor grown organic produce and in other cases higher than conventional produce (dependent on source of research and region). Part of the problem, where greenhouse pesticide residues are concerned, can be directly attributed to greenhouse environments typically having somewhat higher relative humidity than outdoor environments and more ideal temperatures which can play a role in increasing pest pressures. Additionally, pesticides are shown to persist longer in greenhouse environments because they degrade less rapidly due to protection from environmental factors such as rain and UV light. For instance, pesticides may break down faster inside plastic-covered greenhouses than inside glass greenhouses, since glass filters out much of the ultraviolet light that degrades pesticides.

 

This said, hydroponic greenhouses and other indoor environments offer potential well beyond outdoor environments to completely eliminate pesticide use through, among other things, biological controls and exclusion/containment practices. For instance, many hydroponic greenhouse growers in Europe, the UK, Australasia and North America implement practicessuch as biological controls (e.g. bacteria and fungi inoculums to combat pests and pathogens) and/or the use of organic pesticides such as neem and botanical oils to eradicate the need for synthetic pesticides. In other situations greenhouses are designed to exclude pests and pathogenic microorganisms through the use of, among other things, practices such as inlet air filtration and physical exclusion through greenhouse design (e.g. choices in types of glazing and sealing, caulking around service intrusions, insect screens and insect exclusion screened entrance doors).

 

Given growing public concerns around pesticide exposure commercial demand and market pressures for residue free produce will undoubtedly lead the way. As a result, more and more hydroponic greenhouse growers will embrace alternatives to traditional agricultural practices where pesticide use has been, too often, the norm.

Addressing Other Claims

“Chemical” Fertilizers are Radioactive

The following material was inspired after a friend from BC mentioned that he was concerned about the use of inorganic (“chemical”) nutrients/fertilizers because as far as he understood it, inorganic fertilizers are radioactive. I initially laughed at this comment, having never heard before, and then went looking for the source of the information.

 

What I found shocked me. That is, there was information all over the Net that largely originated from a single source, David Malmo-Levine, who writes for Cannabis Culture Magazine, and in January of 2002 went on a mission to demonize inorganic (“chemical” in his words) fertilizers.

 

Subsequently. he has been parroted across the net by multitudes of  article spinners (cut and paste spam artists thinly disguised as experts and authors)  with, among other largely unsubstantiated claims, that it is radioactivity (in the form of polonium-210) caused by the use of agrichemical phosphate fertilizers, not the 70 or so other known carcinogens in the tobacco, all of which are capable of causing cancer on their own, along with numerous carcinogen precursors etc, that is “probably causing 90% of cancer in smokers.”  According to Malmo-Levine this is a fact because the US Surgeon General, C. Everett Koop, allegedly stated this on U.S. National Television at some point during 1990. The only problem being that, other than the fact that this alleged statement is/was not scientifically supported, the Surgeon General in question resigned on October 1 of 1989 – months before he allegedly had a moment of ranting insanity on U.S. National Television. Basically, however, the quality of information went downhill from there.

 

Among other things, Malmo-Levine then promoted carcinogenic organic tobacco as a safe alternative to carcinogenic inorganic tobacco – an act as you’ll come to see, based on his own flawed logic, tantamount to promoting radioactive death to thousands of tobacco smokers. That is, there is every chance that commercially available organic tobacco possesses higher radioactivity values (in the form of polonium-210) than inorganically grown tobacco. Not that this likely matters too much because tobacco without polonium-210 is still deadly. As the American Cancer Society points out:  “All smoke from cigarettes, natural or otherwise, contains many agents that cause cancer (carcinogens) and toxins that come from burning the tobacco itself, including tar and carbon monoxide.”

While the Stanford School of Medicine notes: “Clearly, perceived health benefits of natural cigarettes are still rampant in mainstream popular culture, a dangerous misconception.”

Later that year David Malmo-Levine set out to prove that “chemical” fertilizers are radioactive (possibly as a result of Imperial Tobacco threatening to sue him over his Radioactive Tobacco expose’) and then went live with  “Radioactive Buds?” Now pot, it seemed, according to Malmo-Levine, if grown with “chemical” fertilizers, was radioactive also  (the story first featured on Cannabis Culture Magazine in December of 2002, 11 months after his ‘Radioactive Tobacco’ story). Again, as with his radioactive tobacco lambasting, this largelymisinformed hyperbole was then spammed widely across the internet and taken as fact/proof by many that inorganic fertilizers are highly radioactive stuff and could be causing cancer in pot heads. (Cough! Cough!)

 

Anyway, beyond the hype, let’s take a look at the science.

Are Inorganic Fertilizers Radioactive?

There is some basis to this claim, although it tends to be greatly overstated, misrepresented and/or completely misunderstood by those who typically assert it.

 

This said, it is shown that some inorganic fertilizers potentially have somewhat higher radioactivity levels than organic fertilizers. For instance, agrichemical phosphate fertilizers are shown to possess higher levels of Radium-226 than organic phosphate containing manures. However, where organic phosphate rock fertilizers (e.g. Flouropatite]) are used by organic farmers even higher levels of radioactivity are likely to be present in soils than where agrichemical phosphate fertilizers are used. We’ll cover more on this one shortly.

 

On the points of greatly overstated, misrepresented and/or completely misunderstood; firstly, both organic and inorganic fertilizers are naturally radioactive and, secondly, naturally occurring radioactive materials (NORMS) are found in every constituent of the environment – air, water, soil, food and in humans. There is nowhere on earth that you cannot find natural radioactivity. Our world is radioactive and has been since it was created.

 

For instance, carbon – the key element of organic chemistry and a key element in organic farming, an element that is essential to life, is radioactive. Carbon is the sixth most abundant element in the universe. Carbon-14 is the radioactive isotope of carbon with a half-life of 5,730 years. The amount of carbon-14 in the environment remains constant because new carbon-14 is always being created in the upper atmosphere by cosmic rays. Living things tend to assimilate materials that contain carbon, so the percentage of carbon-14 within living things is the same as the percentage of carbon-14 in the environment.

 

All of us have a number of naturally occurring radionuclides within our bodies. The major one that produces penetrating gamma radiation that can escape from the body is a radioactive isotope of potassium called potassium-40. This radionuclide has been around since the birth of the earth and is present as a tiny fraction of all the potassium in nature.

Potassium-40 (40K) is the primary source of radiation from the human body for two reasons. First, the 40K concentration in the body is fairly high. Potassium is ingested in many foods that we eat and is a critically important element for proper functioning of the human body; it is present in pretty much all the tissues of the body. The amount of the radioactive isotope 40K in a 70kg person is about 5,000 Bq (becquerel), which represents 5,000 atoms undergoing radioactive decay each second. Besides potassium most of the rest of our bodies’ radioactivity is from radioactive carbon and hydrogen.



All food sources combined expose a person to around 40 millirems of radiation per year on average. You’ll note the different forms of radiation measurements – nuclear physics unfortunately is extremely complex (a point too many miss); however, to simplify and explain the different terminology, a millirem is a measurement of the dose of radiation, while a becquerel is the measurement of the amount (measured at rate of decay per second) in a given material/mass.

 

Many foods are naturally radioactive, bananas particularly so, due to high potassium levels and, therefore, the radioactive potassium-40 they contain. The equivalent dose for 365 bananas (one per day for a year) is 3.6 millirems.

 

Anyway, to put things into context, on average our annual radiation exposure from all natural (e.g. cosmic radiation) and man made sources (e.g. pollutants, medical procedures) can be anywhere between, on average, 400-  600 milliRem. This said, the radiation dose for increased cancer risk for 1 in 1000 is stated to be at 1,250 milliRem, while the earliest onset of radiation sickness in a person would require approximately 75,000 milliRem of radiation.



Most radioactive substances enter our bodies as part of food, water or air. Our bodies use the radioactive as well as the nonradioactive forms of vital elements such as iodine and sodium. Radioactivity can be found in all foods and even in our drinking water. In a few areas of the United States, for instance, the naturally occurring radioactivity in the drinking water can result in a dose of more than 1,000 millirem in one year.

 

Coming back to claims of radioactive fertilizers – potassium in fertilizers, whether organic or inorganic, is a source of radionuclides. There are three potassium isotopes: K39, a stable isotope, is the most abundant, at 93.26 % of the total; K41 is next in abundance at 6.73 % and is also a stable isotope. The isotope in question is the radioactive isotope, K40. It is present in all potassium at a very low concentration (0.0118 %). The higher the level of potassium in the fertilizer, the higher the concentration of potassium-40.  Slightly elevated levels of rubidium-87, a pure beta emitter, have also been reported in potassium fertilizers. Rubidium and potassium have similar chemistries.

 

The most problematic source of radioactivity in fertilizers is phosphate rock, mainly due to radium-226 (226Ra). Radium-226 breaks down into two long lived ‘daughter’ elements, lead-210 and polonium-210. Phosphate rock contains radionuclides in concentrations that are 10 to 100 times the radionuclide concentration found in most other natural material, although the average uranium (U) content in phosphate rock is low at 50-200 parts per million (ppm) or 0.005-0.020 percent. For comparison, some Canadian commercial uranium rich ores contain up to 15 percent or 150,000 ppm of U.

 

The problem is that phosphate rock is used as a source of P in producing inorganic phosphorous fertilizers. However, phosphate rock is also commonly used by organic growers as a source of P in organic agriculture. An example would be the use of mined natural rock phosphate which contains phosphorous in the natural mineral form of Flouropatite [Ca5(PO4)F]. Flouropatite is a widely used source of phosphate in organic agriculture. In fact, the use of phosphate rock is seen as a best practice source for P and other macro and microelements by many organic growers. As the Australian Government Rural Industries and Research Corporation states in ‘Fertility Management in Broad-Acre Organic Cropping’:

 

 “Rock phosphate is perhaps the only practical fertiliser that farmers may employ for sustaining soil phosphorus in broad-acre, rain-fed organic agricultural systems, given that superphosphate use is disallowed.” (Evans. J. 2010)

 

On the other hand, phosphate rock is used to produce many conventional inorganic phosphate fertilizers, basically by acid extraction solublising the phosphate ion (PO43-) with sulphuric or phosphoric acid.

 

This is where things get somewhat interesting. The fact is that agrichemical phosphate fertilizers derived from phosphate rock theoretically (very likely) produce far less radioactivity in soils than their organic equivalents (e.g. Flouropatite) when used at volumes to achieve the same levels of available P (ppm) per hectare. This is because treated inorganic phosphate fertilizer has higher % P content than untreated organic phosphate rock. For instance, while the P levels vary in different phosphate rock samples research compiled by the International Atomic Energy Agency (2002) showed variables ranging from 15–17% (Russia, Chile) to 35–36% (Senegal,Togo), with an average of 27% P205. Comparatively, inorganic phosphate fertilizers typically contain between 40 – 50% P205, with more pure products at around 60% P205 or, generally speaking, about twice the P205 as their organic equivalents. Compound this with the fact that organic rock phosphates take a long time to break down into plant available inorganic phosphorous (as a result of soil/microbial interaction); therefore, far higher levels of organic phosphates are needed to achieve the same outcomes. When compared with phosphorus supplied as agrichemical superphosphate, 10 times as much phosphorus as organic rock phosphate may be needed to produce the same yields at low levels of application and 100 times as much at higher levels of application.




Research in Saudi Arabia compared a total of 30 samples: 20 phosphatic fertilizers and 10 organic fertilizers (cow, sheep and chicken) collected from markets and farms. The activities of 226Ra, 232Th and 40K in natural fertilizers (cow, sheep and chicken) were lower than the activities in inorganic fertilizers. The data was compared to available reported data from other countries in literature. The radium-226 in inorganic fertilizer ranges from 100.37 to 161.43 Bq kg−1 and in organic fertilizer ranges from 34.07 to 102.19 Bq kg−1, which in both cases are lower than the safety limit of 370 Bq kg−1. (El-Taher. A. 2012)

 

In other research, uranium (U) concentrations were analyzed in a set of inorganic fertilizers with and without phosphorous (P) and compared to U concentrations in various organic fertilizers (non phosphate rock manures). Mean concentrations between 6 and 149 mg/kg U were found in P containing inorganic fertilizers, while mean concentrations in inorganic fertilizers without P were below 1.3 mg/kg. Mean U concentrations in farmyard manures did not exceed 2.6 mg/kg. As a consequence, an average P dressing of 22 kg/ha P would charge the soil with up to 17-61 g/ha U when added as an inorganic fertilizer but less than 10 g/ha when applied as farmyard manure or slurry. (Kratz. S and Schnug. E. 2006)

Comparison of Radioactivity in Organic and Inorganic Fertilizer Products

The radioactive fertilizer debate amongst the indoor growing community largely stems from a single study conducted by Dr Paul Hornby and David Malmo-Levine. This study was then disseminated and circulated widely with, among other claims:

 

“A recent study shows that many commonly used fertilizers are high in radioactive elements. The study was performed by Dr Paul Hornby, who holds a master’s degree in biochemistry and a PhD in human pathology from the University of British Columbia.

There are different ways of measuring radioactivity. The chart below shows the “counts per minute” (CPM) of radiation detected in each sample. The average for the organic fertilizers was 140, while the chemical fertilizers had an average radiation count of 675, an almost five-fold increase.

The lowest radiation was found in the organic blood meal fertilizers, which emitted only background radiation, the normal low radiation found in most objects. On the other end of the spectrum was the 5-20-20 berry food, with a radiation level about 24 times higher than background.

Numerous studies published in the New England Journal of Medicine and other health, science and radiation journals have indicated that it is the radioactive elements in tobacco which lead to lung cancer (CC#35, Radioactive tobacco). Tobacco is typically fed with high-phosphate, chemical fertilizers, including heavy foliar spraying. All of these factors would produce a high-level of radioactive elements in the tobacco leaf.

Although further research is needed, this study does point the way to some simple harm-reduction techniques for growers. Many growers believe that using organic fertilizers produces a tastier, higher-quality product. This study indicates that they could also be producing a less harmful product than that produced with many chemical fertilizers.”

And so on….

 

Just quickly, to expand on the numerous studies that have indicated it is the radioactive elements in tobacco which lead to lung cancer – this relates to the radioactive element poloniom-210 which some studies have shown could possibly be contributing to, along with the other 70 or so known carcinogens in tobacco, all of which are capable of causing cancer on their own, some role in causing cancer among smokers (albeit, the research could not assess the actual risk).

 

So, let’s analyse the data. (see next page)



See following results:

Organic Fertilizers

Fertilizer Type……………………………………..Radioactivity score

Evergro Specialty Fertilizer……………………..90
Blood Meal 12-0-0

Green Valley…………………………………………….96
Blood Meal Fertilizer
12-0-0

RainGrow Organic Fertilizer…………………….102
Bloom-A-Long
0-12-0

SeaSpray Organic Fertilizer……………………..125
0.5-1.0-0.5

Green Valley Blood and Bone……………………..154
Meal Fertilizer
7-11-0

RainGrow Organic Fertilizer……………………..160
4-2-3

Homestead 100% Organic…………………………..174
Bone Meal
4-14-0

DML Bird Guano………………………………………..178
NPK unknown

Inorganic Fertilizers

Fertilizer Type……………………………………..Radioactivity score
Miracid Soil Acidifier……………………………..248
Plant Food
30-10-10

Shultz All Purpose Plant Food…………………..258
10-15-10

Miracle-Gro For Roses……………………………..285
18-24-16

Green Valley…………………………………………….326
Rhododendron and Azalea Food
10-8-6

Shultz African Violet Plus……………………………..393
8-14-9

 

General Hydroponics……………………………………….400
Flora Grow
2-1-6

Miracle-Gro Water Soluble…………………………….409
Plant Food
15-30-15

Greenleaf Evergreen………………………………………..437
Tree and Hedge Feeder
13-6-7

Stern’s Miracle-Gro……………………………………….538
For Tomatoes
18-18-21

Miracle-Gro…………………………………………………..547
Plant Food Engrais
15-30-15

Greenleaf Shur Gro…………………………………………….672
Soluble Plant Food
20-20-20
Greenleaf Shur Gro…………………………………………….693
Soluble Plant Food
20-20-20

Shultz-Instant…………………………………………………….740
Orchid Plant Food
19-31-17

Shultz Tomato Plus…………………………………………….874
18-19-30

Evergro Fruit Tree…………………………………………….1037
and Berry Food
4-20-20

Osmocote…………………………………………………………..2021
Time Release Fertilizer
18-6-12

Green Valley Berry Food…………………………………….2384
5-20-20

 

Interpreting the Data

There are different ways of measuring radioactivity. These results show the “counts per minute” (CPM) measured with a Geiger counter of radiation detected in each sample. The average for the organic fertilizers was 140, while the “chemical” fertilizers had an average radiation count of 721, a claimed to be five-fold increase. This figure is, however, wrong.

 

Firstly, it is important to note that these tests don’t provide any insight into the type of isotopes being measured and the source of the isotopes. I.e. Geiger counters can detect radioactivity but they cannot tell you which isotope is responsible for it.So, for instance, you’ll note that the organic fertilizers are either extremely low in potassium or possess no potassium at all, while the “chemical” fertilizers typically possess very high levels of potassium. I.e. when combining the total K in the 7 organic fertilizers with known NPK values there is a total of 3.5% v/v K. This equates to 0.5% v/v K average across 7 products. However, when combining the total K found in the 17 “chemical” fertilizers there is 254 % potassium (K = v/v or w/v in the case of one liquid product).



This equates to 14.94% on average across 17 products or 29.88 times the K in the “chemical” fertilizers when compared to the organic samples (factoring in fertilizer sample number differences).



This becomes extremely important in interpreting the data. For instance, when measuring the CPM of potassium salt (food grade) at close distance with a Geiger counter, one-teaspoon worth is likely to register around 80-100 CPM.

 

Therefore, a good deal of the additional CPM registered from the “chemical” fertilizers would be potassium-40 (attributable to the beta and gamma radiation from potassium-40) at levels that wouldn’t pose any risk to people whatsoever. As Dr Cal Herrmann (PhD), head chemist at General Hydroponics, pointed out when discussing the study:

 

“His table shows values of radioactivity for various fertilizers, which seems to be listed in the same order as the potassium content. The organic fertilizers containing little or no potassium list very low in radiation, and the chemical fertilizers containing naturally radioactive potassium give more of the potassium electron-radiation.”

What Dr Cal, perhaps, also should have mentioned, given the General Hydroponics Flora Grow reference at 400 CPM, is that much of this reading is likely related to water. I.e. hydrogen (H), has three naturally occurring isotopes, one of which (tritium) is radioactive, and water has the chemical symbol of H2O. I.e. a water molecule has two hydrogen atoms covalently bonded to a single oxygen atom.

Yet, another factor that is very noticeable (but seems to have been completely overlooked) is that the NPK values of the “chemical” fertilizers, in general, are far higher than the NPK values of the organic products. For instance, when evaluating the NPK averages in the organic fertilizers, of the seven products with known NPK values, excluding the unknown NPK DML Bird Guano a total combined average of 11.85 NPK presents, versus 17 “chemical” fertilizers with an average of 46.41 NPK or 3.916 times more NPK than the organic fertilizers.

 

Given that the research was related to testing the radioactivity of “fertilizers” (i.e. elements such as N, P, and K) this was a significant oversight on the part of the researchers. I.e. it is important to note that when measuring CPM radioactivity of fertilizers, in general, the more the element in question the higher the CPM reading will be. Further, various fertilizers would be expected to emit far higher CPM values of radiation than others. For instance, an N fertilizer with no P and K would emit vastly lower (slightly above background radiation dependent on type of N) levels of radiation than a fertilizer containing P and K (due to the presence K-40 and rubidium-87 in K and radium-226 and K-40 etc in P). Therefore to compare a 12-0-0 organic fertilizer to a 5-20-20 inorganic fertilizer (40 times the P and K) and state that it emitted 24 times higher than background radiation tells us nothing other than 40 times more radioactive material yielded 24 times the radiation which when applying the author’s logic tells us that the “chemical” fertilizer must then be about half as radioactive as the organic fertilizer. Taking a couple of other random samples (one organic and one inorganic) and comparing radioactive values:

 

RainGrow Organic Fertilizer……………………..160
4-2-3

 

And:

.

Greenleaf Shur Gro…………………………………………….672
Soluble Plant Food
20-20-20

 

Okay, so let’s delete the N from the equation. While we can’t be certain there is nil radiation attributable to the N in both samples either way it would be very low. Besides this, P and K are the elements in question. Additionally, with 20 N in the “chemical” sample and 4 N in the organic sample the results will go in favour of the organic sample if N were a source of radiation. Firstly, while the authors of the study seem to be saying that background radiation was 90 CPM this seems highly unlikely given normal background radiation is stated atbetween 25-75 CPM. So, let’s be generous and say 75 CPM at the top end of the range. So, 672 (“chemical fertilizer CPM) – 75 (background CPM) = 597 and 160 (organic fertilizer CPM) – 75 (background CPM)  = 85.

 

Then, 597 (CPM chemical sample less background) divided by 85 (CPM organic sample less background) = 7.96 times the radiation from the “chemical’ sample. However, we have 10 times more P and 6.666 times more K and yet a radiation reading of only 7.96 times more the value. What this really tells us is that when comparing these two samples (variables factored in) the “chemical” sample is emitting lower radiation than the organic sample. The point being, the research methodology is highly flawed and the findings would fail to pass any scientific peer review muster. I.e. in order to conduct an experiment of this nature and give its findings any credibility, at the very least, we would need to have samples of equal numbers (e.g. 10 organic and 10 “chemical) with equal NPK ratios to compare against each other. Further, this would only tell us what fertilizers emitted what radiation (levels) and certainly couldn’t be presented with alarmist information about cancer causing radiation (i.e. polonium-210) without measuring for polonium-210.

 

Therefore, while it is extremely difficult to extrapolate accurate data where so many variables are concerned (a point the researchers seem to have missed completely) in order to establish the true difference in radioactivity values between the organic and “chemical” fertilizers the NPK variables would need to be factored in and what we would be left with would be anywhere between a 1.2 – 1.5 and not a 5 fold increase in radioactivity as has been stated. Again though, we actually have no idea of what isotopes we are dealing with, at what CPM.

 

For instance, I’ve likely been overly generous to the organic fertilizers in not fully accounting for the nitrogen in the inorganic (“chemical”) versus organic fertilizer samples. I.e. soil fertilizers (most of which the inorganic fertilizer samples are) typically use urea (CO(NH2)2 ) as the source of nitrogen, either in full, or part. Urea has two NH₂ groups joined by a carbonyl (C=O) functional group.  Basically, for the purposes of this discussion, the urea molecule has four hydrogen atoms and one atom of carbon, all of which emit radioactivity, and all of which have nothing to do with polonium-210 (the claimed to be deadly isotope in question).

 

In short, while this study has been presented as evidence that “chemical” fertilizers contain higher degrees of harmful radioactive isotopes (cancer causing radioactivity no less) the study fails to demonstrate this because not a single one of these isotopes was actually demonstratively shown to be present. That’s not to say that they aren’t present – they very likely are, at extremely low levels in some samples (both organic and “chemical”?). However, it’s as if the authors are desperately trying to sharpen what can only be described scientifically as a very blunt axe; which is hardly surprising, given that one of the lead researchers, David Malmo-Levine, was nearly a year before the release of this study spreading extremely dubious information about radioactive chemical phosphate fertilizers causing “probably 90% of cancer in smokers.”

 

This claim by Malmo-Levine is somewhat of a distortion of something Jack Herer wrote in the Emperor Wears No Clothes (page 110) where Herer claims: “Former Surgeon General C. Everett Koop said on national television that radioactivity contained in tobacco leaves is probably responsible for most tobacco-related cancer.”

 

Jack Herer cites this event as having occurred in 1990 (as does David Malmo-Levine), which is most unusual given Surgeon General C. Everett Koop resigned as Surgeon General on October 1 of 1989 – months before he allegedly had a moment of insanity on U.S. national television. Not to be too hard on Jack Herer because, let’s face it, the man is a legend to some, having written a seminal text for generations of stoners, but directly following this he makes another statement that looks extremely questionable. I.e. he then adds: “ No radioactivity exists in cannabis tars.” This, simply, is not scientifically supported given that other plants such as potatoes, coffee beans, apples, pears and grapes are all shown to absorb levels of Polonium-210, which is then ingested by humans (most of which – 68-82% – is then eliminated from the body in stool). (Keslev. D, 1973 and others)



Given this, cannabis, as with any other plant, would uptake polonium-210 if present in soils or solution and, much like tobacco, absorb it from other environmental sources (i.e. water and air) meaning that cannabis smokers, as with tobacco smokers, are exposed to levels of polonium-210 that would be found in the smoke stream. While more research is needed, the point really being that these claims have been mimicked/repeated by many and yet they both appear more than questionable.

 

Anyway, putting aside what appears to be two highly questionable claims in a single paragraph of a book that some take as gospel, the structure of a study such as this should be hypothesis, test, conclusion and not conclusion, test, and then distort and aggrandize data/conclusion (no matter how flawed) with, at best, scientifically questionable, at worst, spurious and, arguably, defamatory claims.

 

Unfortunately, this type of scientifically flawed dribble (organic fringe lunatic conspiracy theory) is all too often indicative of the misinformation/disinformation and fear mongering that emerges from some sectors of the organics movement. However, with this in mind, “chemical” radioactive fertilizers causing “probably 90% of cancer in smokers.” is now the thing of ‘urban legend’ (a modern story of obscure origin and with little or no supporting evidence that spreads spontaneously in varying forms and often has elements of humour, moralizing, or horror), taken as fact and spread/amplified widely across the World Wide Web.

Hydroponic Produce Tastes ‘Chemically’

There is some basis to this claim. Where hydroponic produce is not flushed properly the end product does tend to taste “chemically”. However, this is easily avoided through adequate flushing. (See pages….)

 

Other than this, some indoor, under lights hydroponic produce can taste chemically due to the inappropriate use of synthetic pesticides and/or fungicides and/or chemical PGRs (Plant Growth Regulators – subclass, ‘growth retardant’ – such as paclobutrazol which are shown to remain residual in the crop after harvest and which are widely used by some horticulturally challenged, unethical indoor hydroponic growers. As a tip, if any product you are sold tastes chemically don’t purchase from the same source again. If, for instance, the product that you are purchasing is dense and heavy (i.e. weight to volume appears heavier than it should be), low in essential oils and tastes chemically there is a good chance that it has been produced using PGRs. If this is the case you are ingesting poisons (see more about this on page ….) and dealing with highly unethical (or uniformed) people, so exercise your right to shop elsewhere. See lab tests following showing residual paclobutrazol in a harvested, ready for sale product. Thanks to the Werc Shop for the tests.



paclobutrazol_fail



Organic Produce Tastes Better

It has been my experience that taste largely comes down to the genetics of the plant (i.e. I’ve had some very average tasting organic produce and some fantastic tasting hydroponic produce and vice versa). Other than this, taste is an extremely subjective thing – what tastes good to some will not necessarily taste good to others. Taste buds are constantly being replenished, each one lasting on average 5 days, and it’s estimated that we’ve permanently lost half of our taste receptors by the age of 20. Separate receptors for the basic tastes of bitter, sweet and umami (savory) have been found, and the hunt is on for sour. It’s likely that the number of receptors and differences in action of those receptors varies slightly in individuals, so it’s pretty well impossible to get anything substantive out of individual claims that X tastes better than Y.

 

However, scientifically speaking, organic produce has been shown to contain higher levels of phosphorous (P), while conventionally grown produce is higher in nitrogen (N). This could potentially have some impact on taste.

 

That is, the mineral nutrients, potassium (K), by influencing the free acid content and P due to its buffering capacity are shown to directly affect fruit quality (Lacatus et al,1994).

 

Alyson E. Mitchell et al (2007) found flavonoid content in tomatoes seems to be related to available N. Plants with limited N accumulate more flavonoids than those that are well-supplied.

 

Bongue-Bertlesman and Philips found that N-deficient tomato plants had significantly greater flavonoid content in their leaves.

 

Chassy et al (2006) reported significantly higher mean levels of soluble solids, flavonoids, total phenolics, and ascorbic acid in organic tomatoes when compared to their conventional counterparts grown in model plots over a 3-year period.

 

Somewhat contradicting these findings, N has also shown to improve tomato quality and taste. For instance, in research by Yu-Tao Wang et al (2007), it was shown that N increased the flavour of cherry tomatoes; however, the research also noting: Based on contributions of these compounds to tomato flavor, we assume that moderate high N supply improves tomato flavor, whereas excessive N supply can deteriorate it.”

 

One other factor also needs to be considered when discussing the N and P factor and that is, as previously noted, comparing hydroponics to conventional soil growing is often like comparing chalk and cheese. Therefore, findings from soil grown conventional produce when compared to soil grown organic produce may not apply when comparing hydroponic to organic produce.

 

A number of authors have reported that dry matter, sugar, soluble solids, vitamins and carotenoids content in tomatoes; acidity and taste have better marks when grown in hydroponic systems compared to soil. Only very few authors have indicated that soil culture could increase acidity, dry matter, carotenoids and sugar content in tomatoes compared to hydroponic systems.

 

For example, in research conducted by Alicia Marin et al (2008), hydroponically produced sweet red peppers were shown to posess higher concentrations of bioactive compounds (vitamin C, provitamin A, total carotenoid, hydroxycinnamic acids, and flavonoids) than peppers grown under organic and integrated practices.



“Soil-less (hydroponic) peppers showed similar or even higher concentrations of bioactive compounds (vitamin C, provitamin A, total carotenoid, hydroxycinnamic acids, and flavonoids) than peppers grown under organic and integrated practices.”

And:” Irrigation water, manure, and soil were shown to be potential transmission sources of pathogens to the produce. Coliform counts of soil-less peppers were up to 2.9 log units lower than those of organic and integrated peppers.”

Further, the research concluded:

 

“Therefore, in the commercial conditions studied, soil-less culture was a more suitable alternative than organic or integrated practices, because it improved the microbial safety of sweet peppers without detrimental effects on the bioactive compound content.” 

The latter point of improved ‘microbial safety’ also has telling implications when comparing hydroponics to organics. We’ll talk more about this shortly.

 

Other than differences in phosphorous and nitrogen found in organic and conventional produce, there is some evidence that organic food contains less water due to it growing more slowly and therefore the cell texture is more dense, which means its taste potentially is more intense. Although, given dried/dehydrated products (organic or inorganic) this factor would not apply.

 

Another factor re taste could also be that terpenoids and flavonoids in certain plants could be influenced/enhanced by certain agents/additives such as molasses or Jasmonic Acid or Methyl Jasmonate or Triacontanal which some organic indoor growers tend to use. However, terpenoid and flavonoid affecting/enhancing agents can be just as easily used (and often are) by hydroponic growers.

 

In practicality, however (putting aside reams of agricultural/horticultural research), studies have shown that while organic food eaters believe that organic produce tastes better, beyond the anecdotal evidence (i.e. assertions on the part of some in the organics movement), this claim appears highly questionable.

 

For instance, in one study – which the organization behind it (a UK consumer watchdog) admitted was a small-scale investigation – it was found that conventionally grown tomatoes were sweeter, had a stronger flavour and were juicer than organic tomatoes. The tomatoes, were tasted by 194 expert food analysts in a blind taste test. Crucially, they did not know the test was about organic versus inorganic produce.

 

In another UK based study (2002) researchers concluded:

 

“The study found that organic orange juice was perceived as tasting better than conventional orange juice; however, no differences were found between organic and conventional milk. Therefore, it is concluded that the global claim that “organic food tastes better” is not valid, and each product type should be treated separately before a claim can be made.”


In another study (2007), researchers grew side-by-side plots to produce organic and conventional vegetables for consumer sensory studies. In one test, red loose leaf lettuce, spinach, arugula, and mustard greens, grown organically and conventionally, were evaluated for overall liking as well as for intensity of flavor and bitterness. Another consumer test was conducted comparing organically and conventionally grown tomatoes, cucumbers, and onions. Overall, organically and conventionally grown vegetables did not show significant differences in consumer liking or consumer-perceived sensory quality. The only exception was in tomatoes where the conventionally produced tomato was rated as having significantly stronger flavor than the organically produced tomato.



In yet another study by Matthew’s et al (2011) the authors write:

 

“Hydroponic lettuce grown by a local distributor and conventionally and organically field-grown lettuces purchased at local retail stores were compared by descriptive analysis for taste, odor, visual quality and texture… Overall, panel members equally liked the different lettuce samples. The results showed that for each of the five varieties of lettuces, all lettuces were perceived to be equal in their sensory evaluation for those grown locally and hydroponically or purchased from local grocery as organically or conventionally grown.”

In research with organically and conventionally grown ‘Liberty’ apples, over 4 years, internal ethylene concentration, starch pattern index, flesh firmness, soluble solids concentration, titratable acidity, and percent of surface blush of fruit at harvest were shown not to be consistently different. In double-blind triangle taste tests, consumer panelists were able to discriminate between the fruit from each treatment, but in double-blind taste tests, panelists did not consistently rate one group more highly than the other.

 

A series of informal taste tests conducted in 2007 by Stephanie Zonis, an organic food advocate, comparing eggs, yoghurt, cheese, raspberries and peanut butter among other foodstuffs, found mixed results, mostly a tie in each case, though it seems not to have been a blind tasting and was entirely subjective. She showed commendable honesty, concluding:

 

“These tests were not meant to be comprehensive, nor were they carried out under exacting scientific conditions. Other brand choices may have resulted in different outcomes. But I cannot state definitively that organically produced or raised foods taste better (or worse) than their conventionally-produced counterparts. My belief is that anyone who tries to convince you of this is trying to sell you something. Something organic, of course. Any such taste tests or taste claims on fruits and vegetables (or products made from them with no or few other ingredients, such as wine) must be viewed with particular suspicion, as produce varies astoundingly, even within one harvest or from one tree.”

The bottom line – it is unlikely that organic produce tastes better than hydroponic produce, albeit that crop type and growing method (i.e. additives used to enhance terpenoids and flavenoids) may have an influence.

 

So why do so many claim organic tastes better?

 

Well, likely because much of this phenomenon stems from consumers being bombarded with information that organics is healthier, tastier and more nutritious. The power of the mass media (internet and hard marketing) is, after all, a major influencing factor in forming consumer beliefs and opinions.

 

This leads to what psychologists label the ‘ Health Halo effect’. Simply put, the ‘Halo Effect’ is a psychology term used to describe how the perception of one trait can influence perceptions of other traits of an individual or object. For instance, in Cornell University double blind controlled trials (2011) researchers asked 144 people to compare what they believed to be regular and organic chocolate sandwich cookies, plain yogurt and potato chips.



All the products were organic, but they were labeled as either “regular” or “organic.” Participants rated each product on 10 attributes and gave their opinions on taste, perception of fat content, estimation of calories contained and price.

 

Study participants favored nearly all of the health-related taste characteristics of foods labeled “organic,” although they were identical to those labeled “regular”. Other than this, the organic-labeled foods were judged to have an average of 60 fewer calories and yet there was not a single difference between the food groups.

 

Participants were rating the foods based on the preconceived belief that organic foods are healthier, more tasty and more nutritious – preconceived beliefs that have largely been implanted through organic marketing claims (all of which have been largely discredited).

 

An earlier study by scientists at the University of Michigan (2010) came to similar conclusions.

Organics and Food Contamination (e.g. E.coli and Salmonella)

Raw fruits and vegetables can become contaminated with pathogens while in the field, by improperly composted manure, contaminated water, and poor hygiene practices on the part of farm workers.

 

Bacteria pathogenic for humans and animals find their way to the soil, either in the excreta of the hosts or in their remains. As a result, pathogens in soil can be a significant source of produce contamination prior to harvest in both conventional and organic production systems.

 

For example, a study by Oliveira et al. (2010) detected E.coli in 22.2% (16 samples) of organic lettuce and in 12.5% (9 samples) of conventional lettuce.[3]

 

Although the majority of organic food poses no greater threat, some of it can be more dangerous than conventionally grown food because of the way it is grown. Organic farming often uses manure to grow fruit and vegetables. Manure is a natural habitat for bacteria like E. coli O 157, E. coli O104:H4 and Salmonella. Even if food is cleaned properly the bacteria can infect the tissue of the plant making the risks of contracting E. coli far higher.

 

Studies show that farm animal manure or manure slurry may “disseminate, transmit, or propagate” E. coli.

 

For instance, Indira et al. (1998) state:

 

[Quote]

 “The long-term survival of E. coli O157:H7 in manure emphasizes the need for appropriate farm waste management to curtail environmental spread of this bacterium.” (And) “The most significant finding of this work is that E. coli O157:H7 survived for more than 1 year in a nonaerated ovine manure pile that was exposed to environmental conditions. In similar aerated ovine manure and bovine manure piles, the organism survived for 4 months and 47 days, respectively. The finding that E. coli O157:H7 can survive in the environment for a longtime has implications for understanding the ecology of this human pathogen in its ruminant reservoirs and in the farm environment.”

[End Quote]

While Machado et al (2006) note this.

 

[Quote]

“Manure has a beneficial fertilizer value, however, it frequently contains enteric microorganisms and land spreading can lead to pathogen entry into the food chain. Many infection outbreaks have been associated with processed vegetables, directly or indirectly contaminated with animal manure. In this study the presence of total and fecal coliforms in manure (mainly bovine and swine), as well as in soil and rice husks samples revealed that it could be a source of contamination…. the samples fertilized with swine manure showed higher numbers of fecal coliforms than those fertilized with mineral fertilizer.”

 

[End Quote]

In yet another compelling study concerning organic growing practices:

 

[Quote]

“The observation that the prevalence of E. coli was significantly higher in organic produce supportsthe idea that organic produce is more susceptible to fecalcontamination.”

 

[End Quote]

While, Islama et al (2004) have this to say:

 

[Quote]

“Preharvest contamination of carrots and onions with E. coli O157:H7 for several months can occur through both contaminated manure compost and irrigation water.”

 

[End Quote]

And Avik et al (2007) add this:

 

[Quote]

“During the two-year study, less than half of the conventional growers used animal manure for fertilization of their crops, while 70 to 90% of organic and semi-organic farmers applied animalmanure for fertilization. This finding was expected as organic growers are not allowed to use most of the chemical fertilizers that conventional growers can use … Among these two farm types, users of animal waste as fertilizer were at a significantly greater risk of E. coli contamination in their produce compared to those who did not use manure fertilizer.”

 

[End Quote]

Hydroponic Food Safety

Because manures and soils are not used by hydroponic growers, hydroponic growing methods, when handled correctly (e.g. water quality and human handling/hygiene issues factored in), are shown to be superior to organic and conventional growing methods where microbial contaminants (e.g. E.coli and Salmonella) are concerned.

 

For example, Selma et al. (2011) compared microbial contaminants in several lettuce types grown hydroponically and conventionally. The research concluded:

 

“The soilless (hydroponic) system was more effective in controlling microbial contamination as lettuce cultivated in the soilless system had a lower initial microbial load and slower microbial growth during storage. At the end of shelf-life, differences in microbial counts between soil and soilless lettuce were 3 and 1.5 log units higher for lactic acid bacteria and total coliforms, respectively, in soil. This study shows that higher quality and microbiologically safer raw product can be provided by the soilless system as a new growing system although it depends on the genotype and the season.”

Additionally, as previously cited, Alicia Marin et al (2008) concluded from research on Sweet Peppers grown in organic, conventional and hydroponic systems that hydroponically grown peppers showed similar or even higher concentrations of bioactive compounds (vitamin C, provitamin A, total carotenoid, hydroxycinnamic acids, and flavonoids) than peppers grown under organic and integrated practices and “Irrigation water, manure, and soil were shown to be potential transmission sources of pathogens to the produce. Coliform counts of soil-less (hydroponic) peppers were up to 2.9 log units lower than those of organic and integrated peppers.”

 

In other research by Sirsat et al. (2013) comparing Aquaponics to conventional growing methods, the results showed that aquaponically grown lettuce had significantly lower concentration of spoilage and fecal microorganisms compared to in-soil grown lettuce. The study suggested that aquaponic produce may have a lower risk for foodborne illness and an improved shelf-life, due to its low bacterial counts compared to soil grown produce.

 

This said, while the risk of a major foodborne illness being contracted from a clean and well-run hydroponic system is minimal microbial contaminants can be introduced to the system through contaminated water (i.e. water that has been contaminated by faecal matter), contaminated seed, pests and/or unhygienic practices. For instance, research by Belton et al. (1999) found that strains of E. coli were isolated in 14% of leafy vegetables and in 5% of hydroponic herbs, thus indicating there is a small and variable potential risk of hydroponically grown vegetables harboring a pathogen.



Addressing Claims that Organically Grown Plants Can Yield as Much as Hydroponically Grown Plants

Firstly, it is important to note that many attempts have been made to formulate the perfect organic hydroponic nutrient but so far nothing matches the purified mineral salts used in formulating hydroponic nutrient solutions.

 

Other than this, many hydroponic organic formulas sold through stores under the “organic” banner are only part organic (kelp, fish by-product, guano, molasses etc) with the balance of these products being made up from standard inorganic fertiliser components. That is, nutrients that are in many cases passed off as organic formulations would fail to get organic ratings/approval if put to the test. In addition, these fertilisers typically fail to perform as well as their “non organic” cousins and often suffer from pH fluctuations (among other things).

 

In hydroponics minerals are provided to the plant in highly bioavailable form, completely eliminating the need for soil and soil microorganisms to break down mostly non-bioavailable inorganic minerals into readily bioavailable inorganic form. The result is a better optimised nutritional regime and higher growth rates and yields. In hydroponics all the elements can be controlled easily through pH adjustments (optimised pH for uptake), monitoring of EC (nutrient strength) and the provision of the right NPK etc ratios for every stage of the plants life cycle.




In the organic model, soil is enriched with compost, blood and bone, manures and a host of other natural components. These components break down slowly in soil, through a microbial process, at a rate in harmony with the plant’s growth. This of course sounds nice but the level of control through the use of organics is greatly affected and to achieve even close to optimum yields requires a high degree of expertise and soil and/or tissue testing (among other things) to ensure the right nutritional requirements for the crop are met.

 

Other than this, when discussing organic and inorganic soil growing, plant roots require a constant supply of oxygen for respiration. Soil water concentration (SWC) and oxygen availability (AFP – Air Filled Porosity) are critical in achieving optimum yields. Therefore, improving the root environment is an essential part of providing the plant with an optimum environment, and soil is not an easy medium to provide the crop with the ideal combination of moisture, aeration and nutrients. When the moisture content is ideal, the aeration tends to be inadequate, and when the aeration is ideal then moisture tends to be problematic in creating an ideal root zone environment. So, for instance, where moisture content is low and oxygen is ideal, although plants can extract more than the available water, they need to exert extra energy to do so and this restricts their growth.

 

Additionally, soils lock up (bind) certain minerals making it extremely hard to provide an optimized nutritional regime to the plants. For example, because of its particular chemistry, phosphorus, a negatively charged anion reacts readily in soils with positively charged iron (Fe), aluminum (Al), and calcium (Ca) ions to form relatively insoluble substances. The insolubility of the various resulting compounds directly affects the availability of phosphorus for plant growth.

 

Basically, the bottom-line – hydroponics, as a general rule, contrary to claims by some, particularly where non-expert growers are concerned, will outperform organics (yield and quality) every time.

 

Conclusion and Closing Remarks

In many ways. organics is an ideology/philosophy and like all ideologies/philosophies in order for others to adopt it, it must be spread by its believers through verbal, hard media and electronic communications. Other than this, organics is underpinned by another ideology, capitalism, which provides a powerful impetus for the circulation of information that promotes organics over its commercial rivals. The estimated worth of organics on a country-by-country basis are in 2012 the US organic market (food crops, meat, textiles etc) was valued at 81.3 billion, while in 2013, the German and French markets had an estimated worth of euro 6.6 billion, the UK 1.79 billion GBP and the Australian market $655.3 million annually.

 

Comparatively, in 2014 the global hydroponics market was estimated to be worth $24.3 billion or roughly 57 billion less than the U.S. organics market’s estimated worth in 2012 alone. Let’s not lose site of the fact that organics is big business – a business that is highly successful at marketing.

 

Unfortunately, just some of this marketing has in instances purposefully or inadvertently demonized all other forms of food production by applying a wide brush to all inorganic forms of agriculture – whether pastoral farming, broad acre cropping, soil horticulture or hydroponics.  However, like many other forms of marketing the quality of this information varies between fact, not so factual (i.e. perhaps some basis to claims) and absolute fiction.

 

It’s somewhat ironic that while organic marketing groups accuse others of misleading the populace with false information they more so than many others are the guilty party. In short, no, there is no epidemic of cancer, cancer rates are falling dramatically and have been for the past 50 years; no, organic produce is not more nutritious than conventional produce and is very possibly less nutritious than hydroponic produce; no, organic produce is not more tasty – this claim is simply ludicrous when accounting for different tastes; no, inorganic fertilizers do not kill/sterilize soils – at worst, the heavy usage of some inorganic fertilizers temporarily will reduce microbial populations but this has nothing to do with hydroponics; no, inorganic nutrients are not toxins – your plants would be dead without them; and no, inorganic fertilizers are not responsible for 90% of cancer in tobacco smokers …clearly you are on drugs… and so on.

 

Throughout your indoor growing career, particularly on places like forums, you’ll no doubt come across growers who, either because they are ill-informed (i.e. they have embraced organic marketing claims without questioning these claims), or because they have an axe to grind with regards to inorganic methods of agriculture/horticulture (often a combination of both factors) will circulate misinformation to the effect that organics is healthier, more nutritious, better tasting etc. These claims, while often controversial and attacked by other forum members, either purposefully or inadvertently demonize what is undoubtedly the future of environmentally friendly, sustainable food production and, as such, claims to the effect hydroponics results in less healthy and nutritious produce, besides not being scientifically supported, are detrimental to the future of the planet. Paradoxically, of course, these same people would also tell you that the future of the planet is at the forefront of their cause and that is why they are promoting environmentally friendly,sustainable organic agriculture. However, we’ve looked briefly at this claim and what becomes patently obvious is given an ever-increasing world population and ever-increasing pressures on land and water resources, claims to the effect that organic agriculture is environmentally friendly and sustainable when compared to hydroponic food production are fiction.

 

Other claims made on the part of just some in the organics movement, when put under the microscope, as this chapter has demonstrated, are at best highly questionable, at worst little more than commercially driven misinformation/disinformation and, in extreme cases, propaganda (e.g. radioactive chemical fertilizers causing 90% of cancer in smokers).

 

What also needs to be added is that, often, as a response to what can only be called dubious claims on the part of some organic marketing groups others hit back with their own scientifically questionable information.  This actually serves to undermine the credibility of both sides of the debate, although sometimes makes for some very entertaining reading.

 

For instance, on the part of the organics movement, it seems that anytime anyone questions the value of organic farming, invariably organic lobby groups scream fowl and claim the detractor of their methods is working for chemical manufacturers and agribusiness (e.g. Monsanto) or is in league with some shady right-wing US free-market lobby group. On the other hand, at least some of those who question the value of organics come out with their own questionable information and/or forget to mention other important information that may undermine their position. The bottom line is, where the science is concerned, things are not nearly as black and white as some would have us believe and finding the middle ground, between the heckling of two adversarial groups is sometimes not easy. I’ve endeavored, therefore, to present information both for and against. For instance, hopefully it is clear that I myself am a supporter of the organics movement where their views around synthetic pesticides, fungicides and herbicides are concerned. Further, philosophically, organics seeks to take the higher moral ground and sound the alarm where questionable, conventional agricultural practices are concerned (e.g. protestations surrounding GMO crops contaminating non-GMO crops, the widespread decimation of bee populations due to the use of some agrichemicals etc) and certainly they have played an important role in determining and altering future trends in agricultural practices. For this reason, the organics movement should be applauded – they have undoubtedly been on the cutting edge of keeping the more unethical, greed driven agrichemical companies honest.

 

What, however, cannot be denied is hydroponics, when handled ethically and correctly, presents ideals that the organics movement could only dream of. Just some of these being, no nutrient leaching through soils where both organic and inorganic soil farming are shown to pollute ground water and waterways, higher levels of food safety where potentially deadly human pathogens such as E.coli and Salmonella are concerned and far higher yields in given spaces. Due to the latter, hydroponics is shown time and again to leave a lower carbon footprint than both conventional and organic agriculture and with future developments (e.g. more and more hydroponic crops being produced close to or within cities) this cannot be underestimated in terms of tackling global warming. Additionally, hydroponics reduces water usage by up to 90% and this factor in the not so distant future could, arguably, prove to be the make or break for the future of global food security (i.e. the make or break of humanity).

 

However, what seems to happen is that many who compare hydroponics to organics do so in an almost apologist way. Further, others attempt to argue that hydroponics should be accepted as organic if certain parameters are met (e.g. the use of organic fertilizers rather than inorganic fertilizers in hydroponic growing systems). This to me is short sighted (i.e. why would you want to use inferior fertilizers that produce lower yields and potentially act as a source for pathogens?) and plays into the false marketing, fear mongering and hype that has become indicative of just some sectors of the organics movement.

 

Hydroponic food production is vastly superior to organics and, as such, why would we wish to diminish the reputation of the most sustainable, eco-friendly and most food safe and secure method of agriculture by labeling it as organic?

 

What would be more astute is to establish regulatory/certification bodies similar to organic certification bodies and set strict criteria around acceptable and non-acceptable input/growing practices. For instance, the use of synthetic pesticides and fungicides would be out of the question. Hydroponic growers could then become accredited by these bodies where, unlike many organic certification bodies, regular and random testing of produce could take place to ensure that growers are adhering to synthetic pesticide and fungicide free growing principles, meaning consumer exposure to potential toxins is greatly reduced above and beyond the current situation. ‘Certified pesticide free hydroponic produce’ would then become synonymous for sustainable, affordable and safe food. Of course, the odd advertizing campaign to the effect of ‘shit in – shit out’ and/or ‘eat shit and die’ and/or perhaps billboards with something to the effect of a ‘Certified 100% Organic’ symbol with a steaming turd in the centre may help but then that would make us as bad as some of them.

 

Let’s move on…

 

References:

 

Organic food consumption and the incidence of cancer in a large prospective study of women in the United Kingdom; K E Bradbury, A Balkwill, E A Spencer, A W Roddam, G K Reeves, J Green, T J Key, V Beral, K Pirie and The Million Women Study Collaborators; British Journal of Cancer online 27 March 2014; DOI: 10.1038/bjc.2014.148;

 

Shute, T. and Macfie, S.M. (2006) Cadmium and zinc accumulation in soybean: A threat to food safety?

H.L. Tuomisto (2012) Does organic farming reduce environmental impacts? – A meta-analysis of European research

Audun Korsaeth (2008) Relations between nitrogen leaching and food productivity in organic and conventional cropping systems in a long-term field study

 

Gunnar Torstensson et al (2006) Organic and Conventional Cropping Systems in Sweden

Holger Kirchmanna & Lars Bergström (2001) Do Organic Farming Practices Reduce Nitrate Leaching?

Holger Kirchmann and Megan H. Ryan (2004) Nutrients in Organic Farming – Are there advantages from the exclusive use of organic manures and untreated minerals? See also Torstensson 2003b; Lindén et al 1993: Bergström and Kirchmann 1999; 2004: Wallgren and Lindén 1991; Watson et al 1993

S.K. Sahu,  P.Y. Ajmal, R.C. Bhangare, M. Tiwari, G.G. Pandit (2014) Natural radioactivity assessment of a phosphate fertilizer plant area. DOI: 10.1016/j.jrras.2014.01.001

 

[1]N. N. Jibiri and K. P. Fasae (2010) ACTIVITY CONCENTRATIONS OF 226Ra, 232Th AND 40K IN BRANDS OF FERTILISERS USED IN NIGERIA, found in Radiation Protection Dosimetry (2011), pp. 1–6, doi:10.1093/rpd/ncq589

 

Burnett. W. C et al (1988) Release of Radium and Other Decay-Series Isotopes From Florida Phosphate Rock, Florida State University Department of Oceanography, Publication No. 05·016·059

 

David Malmo-Levine Jan 2 2002 , Radioactive Tobacco, Cannabis Culture at http://www.cannabisculture.com/articles/2221.html

 

US Department of Health and Human Services, Surgeon General.Gov at http://www.surgeongeneral.gov/about/previous/biokoop.html

 

Mitchell, A. E. et al (2007) Ten-Year Comparison of the Influence of Organic and Conventional Crop Management Practices on the Content of Flavonoids in Tomatoes

 

Bongue-Bartelsman, M.; Phillips, D. A. (1995) Nitrogen stress regulates gene expression of enzymes in the flavonoid biosynthetic pathway of tomato.

 

Chassy, A. W.; et al. (2006) A three-year comparison of the content of antioxidant microconstituents and several quality characteristics in organic and conventionally managed tomatoes and bell peppers.

 

Yu-Tao Wang (2007) Effects of nitrogen application on flavor compounds of cherry tomato fruits

 

Olle, M et al (2012) Vegetable quality and productivity as influenced by growing medium: a review

Marin, A. et al (2008) Microbial Quality and Bioactive Constituents of Sweet Peppers from Sustainable Production Systems

 

Harry Wallop (2011) The Telegraph retrieved 26/7/14 http://www.telegraph.co.uk/foodanddrink/8340585/Organic-food-less-tasty-than-normal-watchdog-says.html

 

Fillion, L et al (2002) Does organic food taste better? A claim substantiation approach

 

Xin Zhao et al (2007) Consumer Sensory Analysis of Organically and Conventionally Grown Vegetables

 

Matthew T et al (2010) Comparison between Hydroponically and Conventionally and Organically Grown Lettuces for Taste, Odor, Visual Quality and Texture: A Pilot Study

 

Peck, G. M. et al (2009) Maturity and Quality of ‘Liberty’ Apple Fruit Under Integrated and Organic Fruit Production Systems Are Similar

 

Stephanie Zonis (2007) Does Organic Taste Better? Retrieved 26/7/14 at http://www.thenibble.com/reviews/nutri/matter/2007-01.asp
Jenny Wan-chen Lee, Mitsuru Shimizu and Brian Wansink (2011) You taste what you see: Organic labels favorably bias taste perceptions

 

Jonathon P. Schuldt et al (2010) The “organic” path to obesity? Organic claims influence calorie judgments and exercise recommendations

 

M. Oliveira et al. (2010)  Microbiological quality of fresh lettuce from organic and conventional production

Indira T. Kudva, Kathryn Blanch, and Carolyn J. Hovde* Analysis of Escherichia coli O157:H7 Survival in Ovine or Bovine Manure and Manure Slurry

Débora Cabral Machado; Carla Marques Maia; Isabel Dias Carvalho; Natan Fontoura da Silva; Maria Cláudia Dantas Porfírio Borges André; Álvaro Bisol Serafini (2006) MICROBIOLOGICAL QUALITY OF ORGANIC VEGETABLES PRODUCED IN SOIL TREATED WITH DIFFERENT TYPES OF MANURE AND MINERAL FERTILIZER

 

AVIK MUKHERJEE,l DORINDA SPEH,2 ELIZABETH DYCK,2t AND FRANCISCO DIEZ-GONZALEZl* (2003) Preharvest Evaluation of Coliforms, Escherichia coli, Salmonella, and Escherichia coli 0157:H7 in Organic and Conventional Produce Grown by Minnesota Farmers

Mahbub Islama, Michael P. Doylea, Sharad C. Phatakb, Patricia Millnerc, Xiuping Jiang (2004) Survival of Escherichia coli O157:H7 in soil and on carrots and onions grown in fields treated with contaminated manure composts or irrigation water

 

Marin, A. et al (2008) Microbial Quality and Bioactive Constituents of Sweet Peppers from Sustainable Production Systems

 

Sujata A. Sirsat * and Jack A. Neal (2013) Microbial Profile of Soil-Free versus In-Soil Grown Lettuce and Intervention Methodologies to Combat Pathogen Surrogates and Spoilage Microorganisms on Lettuce

 

Belton, D. J. (1999). Food safety and hydroponically cultivated vegetables. NZ Food Monitoring Program, Institute of Environmental Science and Research Limited.