Professor – Good afternoon class! We’ve been looking at a variety of the world’s population problems and their possible solutions over our last few classes. And today, I’d like us to take a quick look at one of the solutions to the growing problem of supplying enough food for us all. It’s called “dry land farming.” Have any of you heard of it? Yes, Judy?
Student – I think dry land farming is a set of agricultural practices and agricultural techniques that are used where there is little rainfall.
Professor – Yes! Dry farming should be or needs to be used to produce profitable crops in areas where the rainfall or the snowfall is slight, is erratic, or is very seasonal and is generally less than about 50 centimeters a year. All over the world, there are countries that must use these less than optimal lands to grow their food–the North American prairies, the South American pampas, the Russian steppes, the Middle East. All these areas have marginal rainfall precipitation. Almost half of India’s arable cultivable land, forty-seven out of a total of a hundred and eight million hectares, is dry land as opposed to land fed by adequate rainfall. Originally, these lands were covered with well-adapted grasses but today, much of the natural cover is gone, and these vast plains are seen as, potentially at least, our global breadbasket. Now, dry farming is something that must be practiced in places where the land is inherently only barely suited for food production in the first place. And you can’t make a silk purse out of a sow’s ear. But there’s a number of things you can do that can improve the situation, the conditions for successful farming. Water is of course a key, or the key requirement, and the little precipitation that does fall must be captured and conserved and used sparingly. Providing windbreaks and providing some slight shade and leaving residues from previous crops can often save water, keep it from evaporating so quickly. And weeding can save the water that the weeds would otherwise drink up. In some areas, it may even be feasible to build cisterns so that rainwater can be collected and stored. It brings me to the next point: crop choice. Drought-resistant varieties, heat tolerant varieties, of wheat or corn for instance, must be chosen or developed–varieties that can stand hot, dry conditions and whose seeds will germinate in such adverse conditions and which have growth cycles, life cycles that are fitted to the conditions they must face. With careful attention to these choices and to these practices we’re talking about here, even crops like watermelons have been grown successfully in dry lands. So, conserving carefully, distributing what rainfall is available, and choosing crops that can best tolerate dry conditions are key factors for success. And the soil itself is also a key factor. Dry land soils are, as you might expect, relatively poor in nutrients because dry conditions allow a lot of top soil to be blown away. So the quality of the thin top soils must be preserved and maintained as carefully as possible. The most obvious help here is fertilizers. But other techniques like mulching–putting a protective cover over the field, like all vegetable matter, plants, stalks, and leaves, for example–help solve this problem of soil deterioration. As I said before, dry lands by their nature are not very good, relatively speaking, for growing our food and part of that, is that they are more susceptible to low crop yields or complete crop failures. This is something that dry land farmers must always keep in mind and must always plan for to be ready to deal with. If the year turns ugly, if it is even dryer and colder or hotter than usual, the farmer must be ready and willing to abandon his effort for that year. And in that way, to save his fertilizers and his seeds and his energy. On the other hand, in promising years, where the weather is boding fair, the farmer should be quick to take advantage of it by boosting yields with extra or broader plantings and by extending his growing cycle and so on. With such approaches as these and others we develop, the productivity of such marginal dry lands may be able to help us keep up with our irresistibly growing populations. We can at least take hope in the thought that the natives of the arid American southwest, the Hopi, the Zuni, and the Navajo, survived for hundreds of years on dry land farming in an area with a rainfall was less than twenty-five centimeters a year.
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2. How has the professor mainly organized her lecture?
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3. Mother Nature has produced thousands of species of edible plants. Which of the following plants would probably NOT be feasible for dry land farming?
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4. Which population lived for years surviving on dry land farming?
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5. In which case can dry land farming NOT save the year’s crops?
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6. What does the teacher mean with the phrase ‘you can’t make a silk purse out of a sow’s ear?
