CORN (Zea mays)

Importance and grain composition:

Corn is the most important annual fodder in this country. About 90% of maize is grown for silage that is the main energy component of roughage for cattle used at present. It is also used for so called divided harvest two-phase harvest (CCM and LKS silages and preserved high moisture grains).

The remaining 10 % is corn grains production. Corn grains are used in the food industry, for feeding farm animals and for industrial processing. Corn meal and grits are intended for human nutrition, they are used e.g. for production of corn flakes. Sweet corn is also popular. It is harvested between milk and wax maturity and eaten raw, cooked or preserved, either kernels of whole young cobs. A popular delicacy is pop corn. From corn kernels, alcohol, starch and invert sugar are made, and from corn germs oil is obtained. Corn grain is suitable feed for all farm animal species, particularly for fattening animals.

The corn grain has the highest energy value of all the cereals. It has a high content of nitrogen–free extract (about 70%), with a high proportion of starch. It also contains up to 5% fat. Fat consists mainly of unsaturated fatty acids, linoleic acid and oleic acid. There are small amounts of palmitic and stearic acid. A high content of unsaturated fatty acids renders fat prone to oxidation. Therefore corn meal in which fat is easily accessed by external influences, should not be stored for a longer period of time. The composition of fatty acids influences texture of body fat, making it softer. This does not matter in beef and sheep tallow and poultry fat, but it does in swine lard. Therefore it is recommended to withdraw corn in the end of fattening period in swine.

Corn has a low content of crude protein, about 9-9.5% only. Reserve protein zein (prolamin) and glutenins prevail that have a low biological value, low lysine and tryptophane contents. Crude fibre content is low, about 2%. Mineral content is also low (about 1.4%), compared with other cereals. Calcium content is very low. Yellow grain varieties have higher contents of b-carotene (provitamin A) and contain also other yellow pigments – xantophyl and zeaxanthin. These pigments cause yellow colour of fat (undesirable in lard) and egg yolk.

Cultivation requirements:

Corn is a thermophilic plant. An optimum temperature for growth and development of generative organs is 20-24 ˚C, the growth stops at 5-6 ˚C. In the period of intensive growth (springing to milk maturity) it has a high demand for moisture. Requirements for soil are much lower than those for warmth. Corn requires structural soils with neutral reaction, heavy and cool soils are not suitable. In the crop pattern corn is usually included after cereals that are relatively good previous crops for corn. Corn tolerates being grown in the same field for several successive years. However, it is not recommended to grow corn in one field for more than five years in the row because this can lead to weed infestation. For corn fertilizing usually organic fertilizers are used, it is one of the most suitable crops for slurry utilization.