19 June 2010

Zimbabwe: Let's All Fight Desertification


Harare — CLIMATE change is going to see Zimbabwe become warmer and drier, and the danger of the Kalahari Desert spreading east is real and serious.

So this week's World Day to Combat Desertification is not one of those international days that can be safely ignored. Zimbabwe needs to be in the front line of the battle to stop desertification.

This is going to require changes in how we farm the land, changes in how we regard many natural resources, changes in how we use water and a major cultural change so that we learn to nurture rather than abuse the soil.

The goal has to be producing more food, and better food, while at the same time ensuring that our natural ecosystems are not degraded and that our farm soils are not just protected but can be made better so that future generations can eat as well or better than we do.

Much serious scientific research has been done over the decades, and Zimbabwe has done its share, to ensure this is possible. More needs to be done.

But among this serious scientific research, we sometimes see the output of cranks and faddists, and one such unscientific fad is the idea that "organic" fertilisers are superior to "artificial" fertilisers, which sometimes reaches the dangerous conclusion that "artificial" fertilisers are dangerous.

No known laboratory test can, in fact, tell whether a potassium ion in the soil, or a boron ion or a nitrate ion, came from a chemical made by a living creature or made in a factory from other chemicals. They are identical.

Artificial fertilisers no more cause deserts than organic fertilisers. What causes deserts, besides serious climate change, is bad farming and bad land management.

Most Zimbabwean soils, like most African soils, are very poor in some essential nutrients, are fairly thin, and are vulnerable to severe degradation and even destruction by farmers who do not know how to care for them.

Good farmers do try to make natural ecosystems work for them; they do try to create more complex ecosystems to enhance fertility and improve soils. This almost always requires soil testing and the application of considerable quantities of suitable artificial fertilisers.

Anyone can see this during a short drive into the countryside.

Farmers with adequate finance and knowledge build soils and produce good crops at the same time. Their soils are not exposed; they are covered with plants or mulches. Their crops are dense; their pastures are lush.

Poorly funded farmers, or farmers without the necessary technical knowledge, not only produce a lot less but they frequently destroy soils while doing so. We have all seen the arid cleared fields with only the odd speck of green.

Whatever else accelerates desertification, it is not the application of artificial fertilizer. Indeed it is such fertilisers that allow farmers to grow the trees and other plants that are required to halt the spread of deserts and produce the organic materials that are needed to build soils.

If all Zimbabwean farmers could do what the best of our farmers do, then we would not need to worry about the spread of deserts. We could almost certainly push back the spreading Kalahari. But this will require far more knowledge by many, and far more use of "artificial" fertilisers not less.

The fertilisers will correct the serious nutrient deficiencies. The knowledge will ensure that soils are protected and built up, that the organic content of the often thin and sandy soils is massively enhanced, even if this is just digging in crop residues, a good start although more complex farming operations can do more.

It is not that difficult to enhance soil fertility and improve soils.

We have some farms that have benefited from generations of such work and they are among the most productive in the country. The soils are better now than they were a century ago. And tonnes of fertiliser are applied each decade to each hectare as part of that process.

Zimbabwe almost certainly has to do more applied research, and needs to get the results of this research to more farmers far faster.

We almost certainly have to ensure that agricultural researchers and ecologists work far more closely together, since sustainable farming in effect requires the creation or restoration of complex ecologies.

The "organic" farmers usually have a better knowledge of how to protect and improve soils, which is why their knowledge can be tapped. But they miss the point when they decry artificial fertilisers.

Often, and in Zimbabwe that can mean almost always, artificial fertilisers are essential to start the process of rebuilding soils and creating productive and sustainable farming systems. We need to separate the scientific facts from the fads.

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