Friday, 1 February 2013

down on the farm

Many people go out of their way to buy organically grown produce because of the guarantee that such produce is free from pesticides, but there are other benefits that are often overlooked or not understood. In particular, the use of synthetic nitrate fertilizers is banned under Soil Association rules in the UK, and probably by other accreditation bodies elsewhere, because this has an important effect on the uptake by plants of trace elements from the soil. All nitrates are extremely soluble in water and therefore dissolve preferentially; as a result, trace elements are not taken up by a crop that is fertilized in this way, and its nutritional value is thereby reduced.

There are two main strands to the practice of organic farming: crop rotation, which includes the planting of legumes, and soil conditioning. Legumes such as clover have nodules on their roots that are home to colonies of nitrogen-fixing bacteria, so when the crop is ploughed back into the soil at the end of the growing season, this becomes a vital source of nitrogen given the prohibition on synthetic nitrates. Animal manure provides an additional nitrogen source, but this material also has an important effect on soil condition.

Soils vary considerably depending on the underlying bedrock, the use to which land is put and the materials that are added, but all soils are complex ecosystems that need to be managed carefully. Soils that have a low organic content (humus) do not retain moisture efficiently, while soils with a high content of clay minerals easily become waterlogged. It follows that soil health depends on having plenty of humus, so that air can enter the pore spaces between soil grains and thus support the bacteria and small invertebrates (earthworms, burrowing insects, etc.) that are essential if the organic material is to decompose, making nutrients available to the growing crop. Roots also need air to function properly, so soil condition is of crucial importance whatever the crop.

An often neglected aspect of sustainable arable farming is composting, although ploughing unwanted plant material back into the soil is a viable alternative. However, the best way to deal with organic waste is to place it in a compost heap, where it will decompose aerobically, with the aid of invertebrates and micro-organisms that invade from the underlying soil, to form a material rich in humus that can be added to the soil.

Pests are dealt with in organic farming by introducing natural predators, which commercial pesticides are likely to kill in addition to the target pest. Another useful technique is intercropping: for example, planting pungent herbs such as rosemary and sage among rows of carrots deters the carrot root fly, the larvae of which can devastate a carrot crop. Ensuring that plants are healthy makes it less likely that they will be seriously affected by fungal infections and other plant diseases. The end result is foodstuffs that are healthier to eat and contain more trace nutrients than the same foods produced by conventional means, which in addition to being less nutritious are often completely lacking in flavour.

However, there is one major drawback to organic farming: crop yields are lower, and with the world’s population already approaching unsustainable levels, this is not a problem that can be ignored. The choice is therefore between producing less nutritious food in greater quantities and organically grown produce, which costs more and can feed fewer people. This begs an unavoidable question: is it socially responsible to insist on buying organic produce when the priority should be to feed everyone, not just those who can afford the higher prices that come with lower yields?

10 comments:

  1. Wasn't there a time when people were more responsible for feeding their own families from their own organic backyard gardens? Is it possible for each high rise community in Hong Kong to have their own gardens? Why does it seem that growing real, life-giving food is not a priority in many places? Maybe it is a sign that as humans in general, our priorities are out of place.

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    1. Hi Matteo. High-rise housing estates in Hong Kong do have gardens, but they are ornamental gardens. You wouldn’t believe the quantity of grass clippings, hedge trimmings and other organic material that is collected, from this source and from public parks, river banks and motorway embankments, and it all goes into landfill!!! I maintain a compost heap at my house in the UK, and I’d love to have one here in Hong Kong, but I have nowhere to put it.

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  2. Wow, I've learnt so much just by reading this post. I honestly didn't know there was so many factors in regards to soil, but then again why would I? The vast majority of the worlds population live in cities. Therefore the consumers of veg/meat etc have no idea of the practicalities of growing things, keeping, slaughtering animals etc.

    I would like to eat more organic foods but can't afford it. I do make sure that my eggs are organic though, and I'm always ready to snap up any bargains. Great Post.

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    1. Soils are an entire scientific discipline by themselves Rum, and there is certainly more to maintaining a healthy soil than most people realize. And if I’ve been able to broaden your understanding of why organic food is better to eat, then this post has been successful. I think you’ve already realized that hens allowed to roam freely produce tastier eggs than battery hens.

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  3. I only recently watched Ken Burns' The Dust Bowl, which made me realize that I never really appreciated the amount of human suffering caused by those man-made dust storms. Great post, Dennis. At 64, am I too old to be a student in your class?

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    1. Bruce, at 64, you’re a mere youngster (I’m 66). And you’re only too old to learn something new if you think you’re too old.

      By the way, the natural climate of US dust-bowl country is semi-arid, so the ‘Dust Bowl’ was always a disaster waiting to happen.

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  4. Great post, Dennis. I buy local organic everything, for all the reasons you mentioned above. I'd much rather support sustainable independent farming than the wasteful, irresponsible American food industry.

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    1. Quite right too Kris! The food industry is only interested in making money, not in promoting the health of its customers.

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  5. OK Dennis,
    Have had some issues posting, so we'll see how this goes-

    Yes, the whole organic thing certainly is interesting. I believe we do have a resposibility to feed the world. It seems to me that having food to put in your family's mouth is a good start to being an environmentalist.

    Sustainability is the answer, but am always careful not to preach when in poorer countries. Probably careful when visiting any country I guess. That said, we `Westerners' must get our own houses in order first.

    I'm not even going to start on the subject of World population growth & organized religion.

    Cheers,
    ic

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    1. Ian, I agree that preaching to poorer countries is well out of order unless the developed countries put their own houses in order first. We could start by factoring in the cost to the environment of growing fruit and vegetables ‘out of season’ and of importing foodstuffs that appear to be cheaper only because the environmental costs are not factored into the price paid by the consumer.

      Best not to get me started on the subjects of population growth and organized religion either Ian, although both are significant variables in the overall equation.

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