Text 9A Farm manure
Fertility is one of the most essential properties of the soil, as high crop production always greatly depends on it.
A lot of factors may help to produce soil fertility. A fertile soil is warm, moist and well structured; it is neither too acid nor too alkaline, and contains a great amount of soil nutrients. Since good structure and the supply of nutrients depend on organic matter, one can say that fertility of a soil is greatly affected by the organic matter it contains.
However, plant nutrients are lost from the soil in different ways. To compensate the nutrients the growing crops remove, as well as those lost through erosion and leaching farmers have to use barnyard manure and green manure crops.
Farm or barnyard manure is highly important for growing crops, its value for maintenance of soil productivity having been recognized since early times. Manure can improve the soil that is cropped because it contains such substances as nitrogen, phosphorus and potash. It also adds humus which is the product of organic matter decomposition.
When the soil is low in organic matter, the growing of crops which are to be plowed under may be desirable. Such crops are referred to as1 green manure crops. The aim of growing them is to increase organic matter and nitrogen content of the soil. Cover crops which are used to protect the soil surface should commonly be turned under for green manure, too.
Green manures are primarily used in order to increase the yield of subsequent crops as well as to improve the fertility of the soil, supplying organic matter and thus compensating for its losses through cultivation. The purpose of green manuring is also to prevent the leaching of plant nutrients from the soil during periods between regular crops, and to increase the supply of combined nitrogen when leguminous plants are turned under.
However, it is not always practically possible to increase the organic matter content of a given soil to any considerable extent. The beneficial results often obtained from incorporating a green manure crop arc due to increased availability of soil nutrients rather than2 to an increase in the organic matter content in the cultivated soil.
Notes to the text
1. to be referred to as – называться;
2. rather than – а не.
Grammar and Vocabulary Activities
5. Translate from English into Russian paying attention to the meanings of the to be and to have.
1. We have used these crops as green manure to increase the amount of organic matter in the soil.