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Organic Growing?

Introduction



There is a lot of interest at present in 'organic' farming, driven by an understandable concern for the environment and a wish to eat healthy food. The debate can though sometimes cloud the fact that conventional farming also has a very real concern for these issues. There is a great deal of interesting and important research aimed at finding solutions to the problems associated with growing food on a large scale.

Within our own greenhouse we are able to grow a crop of tomatoes without, in general, any use of herbicides or pesticides. In fifteen years we have only had to spray twice. We can achieve this control by virtue of the advanced growing system which enables us to control the conditions for plant growth closely, enabling us to grow strong and healthy plants - healthy plants have excellent resistance to disease. Occasionally we get minor infestations of white fly or red spider, and these we can control by introducing predator insects into the crop which eat the pests.

In the hydroponic system that we use people are often struck by the absence of soil. Many assume that this should lead to a watery and tasteless final product. This is a natural reaction, and stems from a misunderstanding about how plants grow. Plants do not eat soil. Soil is a complex substrate which holds the water and minerals that a plant needs in order to grow. Of all the dry matter in a plant only 10% comes from the soil, consisting of trace elements such as potassium, calcium, zinc etc. The rest of the dry matter is synthesised from thin air and sunlight, by the process of photosynthesis. This is a truly remarkable process in which carbon dioxide from the surrounding air is transformed into organic compounds within the plant leaf in a matter of seconds.

Plants in a properly managed water culture are able to develop in an entirely normal way. The water contains the nutrients normally found in the soil, and a strong root system is able to take up water, or nutrients, as required. Photosynthesis proceeds as normal. The plants are no more 'watery' than a plant grown in soil.

On the other hand the soil is not simply a passive substrate. It is also teeming with microbial activity which allows for close symbiotic relationships to develop between the plant roots and the surrounding nutrient supplies. Nutrients are often available in forms that first require to be broken down by bacteria before the plant can take them up, and in general this symbiosis is of great value for plants. In hydroponic systems it is now possible to introduce microbes to the root zone so that this activity, not normally associated with water cultures, can proceed as normal. But even without this the plants do not simply take up water in an uncontrolled fashion. Experience shows that the plants take up what they need, resulting in a balanced and healthy plant that can produce fruit of exceptional quality.

All farming consists of growing specially selected hybrid plants in unnaturally dense populations. It is not a natural activity, but has always been a major modification of the environment for the purpose of feeding people. The ethos that we feel is most helpful for the future of agriculture can perhaps be summed up by the search for 'best practice farming'. Many researchers and farmers are engaged in finding the most efficient and friendly methods for producing crops - but this does not necessarily mean adopting the philosophy espoused by the organic movement, which only represents one very particular approach to the problem.

Organic Farming : An Opinion
Underlying the organic philosophy is the notion that there is a ‘natural’ way of farming and an unnatural one. One slogan is ‘Farming as nature intended it’ - an attractive looking statement which though is deeply misleading. First, nature has never produced its own farms. Farming is essentially an artificial manipulation of nature in the interests of providing food. Second it implies that organic farming is natural (and therefore a good thing) whilst conventional farming is not. A little reflection should show that even the most conventional of farms is predominantly governed by the biological activity of the plants, and that even the most organic of farms includes the selection and manipulation of this biological activity.

This is not to deny that there are good ways of doing things and bad ways. In part the organic movement has been impelled by a perception that conventional farming has had too many bad sides to it, such as over use of pesticides and too much reliance on artificial fertilizers to the detriment of soil quality. The organic movement would say, for example, that if care is taken to build up the soil organic matter the resultant plant is healthier and able to draw on a stable store of nutrients without need for applying large quantities of fertilizer. And as for pests, as well as mechanical methods of weed control (such as mechanised hoes), more use could be made up of building up stores of such things as natural predators (like lady birds). A balanced system can result in which reliance on synthetic pesticides is avoided.

One would certainly hope that conventional farming could learn from insights such as these where they prove to be helpful. By pursuing alternative techniques the organic movement helps add to our overall fund of knowledge - there is still a great deal that we all remain ignorant about. But if I may draw an analogy from medicine: complementary (‘natural’) medicine may show us new ways of treating illness, but this does not mean we should decry conventional medicine as wrong. A criticism of organic farming - or rather of its spokespersons - is that too often it is promoted by caricaturing conventional farming and by setting itself up as the true alternative. The proper way forward is for the organic movement not to see itself as the ‘right answer’ but as one part of a wider effort to increase our overall understanding of farming.

Another point of concern is that the organic movement is characterised by what looks worryingly like a fundamentalist and anti-scientific attitude towards ‘chemicals’. The agro-chemical industry has spent much time and money in developing pesticides that are highly specific in what they kill, have low toxicities, and which through extensive testing are shown to be harmless to the environment (in so far as this can be ascertained). The vast majority of these are in fact ‘natural’ chemicals which have been isolated and then made available to farmers. Many plants produce their own pesticides for self-protection. Laurels, for example, produce a herbicide from their roots which is why nothing ever grows under them! Modern day farming can take advantage of this.

But the organic movement casts all this research aside. Instead they permit just a limited range of suitably natural sounding chemicals (such as compounds of copper or sulphur). These chemicals tend to be highly toxic and non-specific in their effects. It was only recently that the Soil Association in the UK banned the use of nicotine, which is a deadly poison. Presumably it was originally permitted because it occurs naturally in tobacco plants. I remember reading with astonishment a book on organic growing which suggested we gather cigarette ends and boil them in water to produce a pesticide. Such chemicals have also never been tested for their possibly longer term detrimental effects. The fact that some of these chemicals have had to be banned illustrates their potentially unpleasant nature. Specially developed pesticides, if used wisely, have a lot to offer and should not be rejected out of hand.

A feature of organic husbandry which is problematic is connected with its use of the ‘ley’ system to fix nitrogen in the soil. After soil has been used for cropping it is put down to something like clover, which is able to capture nitrogen from the air and incorporate it into the soil. The problem is that when this clover ley is ploughed in there is a sudden and considerable release of soluble nitrogen into the soil which quickly leaches away. Nitrogen leaching is the main concern about the (over) use of fertilizers on the land. (Potassium and phosphorus, the other two main ingredients of fertilizer, are much less prone to leaching). A great deal of nitrogen leaching occurred in the second world war when pasture was ploughed up to produce crops. We live near a lake which in summer gets choked with algal bloom. People often assume this is a result of local farmers and their fertilizers, whereas in fact photographs show that the lake has suffered from this bloom for nearly a hundred years - a result of pre-modern farming techniques.

In conventional farming methods have been developed to help reduce this problem of leaching. For example, nitrogen can be applied in small rates at exactly the times that the crop is ready to use it. Slow release forms have been developed in which the nitrogen is provided in a form that is not so readily soluble. Tests can now be made in the field to determine the nutritional requirements of a crop, resulting in precise applications that minimise waste. Again this is not to deny that organic techniques may have something to offer, but we need always to retain a critical eye.

A rather curious aspect of the fundamentalist attitude I mentioned above is found in this consideration of fertilizer. Organic farming is heavily dependent on adequate levels of phosphate in the soil. Phosphate doesn’t leach away and current reserves are actually due to earlier applications of phosphates made by (conventional) farmers. If phosphate levels get too low organic growers are allowed to apply a form known as rock phosphate. Unfortunately this cannot be used on most farms because the soil pH levels in most areas are such that it becomes insoluble. But help is at hand! By a simple manufacturing process we can produce a form of phosphate that is soluble on all lands. Unfortunately this product is banned to organic farmers. Presumably it is not felt to be natural enough.

Finally, I think that we must be cautious over the way that claims for organic farming sometimes become almost ontological and mystical. For example we might imagine a scenario on a conventional farm where a crop is sprayed for protection against a harmful insect. Perhaps this spray kills beneficial predatory insects as well, whilst at the same time the target pest develops a resistance and so flourishes anew. The last state may well be worse than the first and the best thing to do may be to stop spraying altogether. Let us suppose this leads to a build up of the beneficial predatory insects which, in turn, are able to control the harmful pest.

To a greater or lesser extent this type of scenario can in fact occur. But what I call the mystical claim is to say that this is an example of how ‘mother nature’ gets things in balance if only we let her. The belief underlying this is that basically there is a pervasive beneficent ordering in nature which we can make use of. This returns us to the notion of ‘farming in the way nature intended’, as if nature has a blueprint and all we need to do is to find out what it is. It is one thing to say that there are biological cycles that we can make use of, quite another to extend this into a claim about mother nature.

From a publicity point of view the great strength of the organic movement is its appropriation of a terminology that the general public readily responds to. The word ‘organic’ itself sounds wholesome. Similarly for statements about growing the natural way or growing in a sustainable way. It is hard to be against these things! But perhaps such words stand largely for emotive and somewhat undefined claims, and to that extent are a hindrance to proper debate.

Tim Pritchard