Text b CropRequirements

The grain crops in general are rather heavy uses of the mineral elements. Unlike the legumes they cannot fix the nitrogen and for their best development use large quantities of nutrients. The elements most extensively used in the production of the grains are nitrogen, phosphorus, calcium and potassium. Magnesium is of considerable importance, but relatively small amounts are required. With the exception of soybeans, the grain crops as a whole are not high in their content of nitrogen, yet when considered on an acre basis the requirements are great. The seed is very rich in phosphorus, and we might therefore expect grain crops to respond to phosphorus-bearing fertilizers. Considerable calcium is found in the leaves of the grain plant and it is believed to be essential to root development. Potassium is known to be very necessary to the metabolism of crops. The grain crops on the whole remove large quantities of plant nutrients from the soil.

The grain crops take large quantities of nitrogen, phosphorus and potassium from the soil. Lesser amounts of calcium and magnesium are required. Even a crop like alfalfa requires considerable plant food, while buckwheat requires much calcium for its straw.

In general, corn removes relatively more from the soil than the other grain crops. It is evident that corn requires a soil of high fertility. As a rule, corn is given the choice place in the rotation in order to provide it with the best possible opportunity to produce well. Flax, wheat and barley are generally given more favourable places in the rotation than rye, oats or buckwheat. Of the latter three crops rye is often grown on the poorer soils because of its ability to yield well rather adverse conditions. Buckwheat is a more specialized crop and usually is given a better spot than rye or oats. As indicated earlier, the oat crop is frequently grown primarily because if fits into many types of rotation and serves well as a companion crop for small seeded legumes and grasses.

17. Find in the last paragraph of the text the sentences about the elements that are most extensively used in the production of grains.

18. Skim the text again and say:

1) which elements cereal crops consume in greater amounts and which in less amounts;

2) which of the crops remove more nutrients from the soil;

3) which of the crops produce good yield even under unfavorable conditions;

4) what crop may be a companion crop and may be included into many types of crop rotations

19. Work in pairs, ask each other 3 questions on the text and answer them.

20. Translate text C using a dictionary.

Text C

Having suggested light to medium textured soils for maize, it must also be stressed that organic status and fertility should be high.

The maize land should be free draining in order that as much of the heat as possible is employed in raising soil temperatures and removing excess of soil moisture. The soil should be naturally free draining to enable a full rooting system to develop in a plentiful supply of oxygen.

Maximum yields are believed to be obtained between pH 4 and 9. Some scientists believe maize to be successfully cultivated on the moderately acid soils (pH 6-7 as optimal). Others say that maize growing can be successful under alkaline conditions provided there are no serious deficiencies of the micronutrients.

Applications of fertilizers. It has been suggested that phosphate and potash should be applied to the land well in advance of drilling and the nitrogen incorporated into the seedbed just prior to drilling, otherwise much of it would be lost by leaching.

One should remember that germination is much retarded by fertilizers in contact with the seed.

Cultivation. With a more extensive and deeper rooting system than the other cereals, maize will require deeper ploughing, cultivation and seedbed to obtain maximum growth. Autumn ploughing is advisable on stronger soils and it may be left until the early spring when textures are light. Cultivations which follow should be to a depth of 4-5 inches. They kill the weeds after germination; inter-row cultivation can follow crop emergence to obtain further weed control. Chemical means are often preferred. Seedbed should be uniform and fine to obtain a quick germination and to assist the action of herbicides in their control of weeds.