Improving fertility

Naturally good crops will thrive only with proper seed selection, timely seed-bed preparation, weeding and other advanced practices. But good seed varieties will also thrive provided the natural fertility of the soil is maintained or best of all raised. A plant lives through its growth and development. In addition to photosynthesis, where solar light is effective in transforming carbon dioxide into nutrients, the plant must obtain its nutrients from the soil.

In planning a farm or a system of farming for a whole area one has to consider the natural fertility of the soil. For innumerable centuries nature has grown plants and allowed them to decay. This is humus, the chief factor determining the fertility of a soil. And it must be there to produce a good crop, for it is humus which contains the main chemical ingredients necessary for the thriving of plants. But if humus is partly or completely lacking this deficiency has to be compensated.

In terms of chemistry, phosphorus, potassium and nitrogen make up the most important components of a rich soil. Most of the soils that are rich in nitrogen, potassium and phosphorus are productive. If a soil contains a poor amount of these ingredients the deficiency has to be compensated by adding fertilizers or manure.

At the same time soil fertility can also be improved by good crop rotation which prevents exhaustion of soil.

Crop rotation means that crops are grown in definite succession so that a certain crop following in the sequence restitutes to a certain extent to the soil the elements taken away by the preceding crop, so that the ground is never “sick”. Every year the crop sown down on a definite plot and subsequently harvested is replaced by another while the former crop is shifted over to another field. Crop rotations are named after the number of fields or courses that regularly follow one another, each sown to a successive crop; thus, we have four-course, five-course and other multifield systems. Some­times the ground is left to lie fallow to clear the ground from weeds and to accumulate nutritive substances.

The principal advantages of crop rotation are: 1) all plants tend to exhaust the soil, but in different manner, hence a rotation tends to maintain the balance; 2) all plants do not take up the same ingredients in the same proportion from the soil and air thus, crops rich in carbonaceous matter take up relatively small amounts of food from the soil, but large quantities from the air; 3) certain crops help in accumulating humus, such as various grasses; 4) legumes are often sown which enrich the soil with nitrogen.

Of course the rotation system has most frequently to be used together with the application of fertilizers and it sometimes comprises fallow for the ground to rest and be freed from weeds by tillage.

Speaking about crop rotation it is necessary to mention specially catch crops. A catch crop is sown between regular crops. The growth of catch crops in crop rotation is recognized as good farm practice. These comprise peas, beans, alfalfa, red clover which makes a splendid hay because of its, large protein content, white clover, a perennial plant, and soybeans, also rich in protein and fat which make not only an excellent catch crop but also a nutritious household food. They all absorb nitrogen from the air and add it to the soil, thus replacing the nitrogen taken from the soil by other plants.