The basic operation in the cultivation of maize for grain is deep winter plowing. Spring plowing is not recommended, and if it is necessary, it must be done as soon as possible with the kneading rollers. Spring treatments should start with levelling and harrowing. They are designed to level the field, limit water loss and destroy weeds. Immediately before sowing, the soil should be loosened with the pre-sowing combination to the sowing depth.
Soil fertilization is a very important element in the cultivation of maize for grain. Keep in mind that maize has relatively high fertilization requirements. Depending on the soil fertility, the following fertilization level is recommended for maize: 150 to 200 kg N/ha depending on the assumed yield, 80 to 120 kg P2O5/ha, 140 to 180 kg K2O/ha. The availability of calcium and magnesium is important in maize cultivation. The amount of nitrogen in soil depends on the culture, soil quality and forecrop. When maize is sown after cereals, nitrogen doses should be increased. When maize is grown in fertile soil, a single dose of nitrogen can be applied before sowing in the form of slow-release fertilizers. On poorer soils, it is recommended to divide the nitrogen dose into pre-sowing and late top dressing. Top-dressing maize should be fertilized quite early.
Corn grown for grain is a sparse sowing plant. Therefore, good soil preparation and sowing accuracy are very important, which in the case of maize is optimal between April 20 and May 5. The soil temperature during the sowing period should be at least 8 degrees. This will ensure the maize emerges quickly and evenly. The flowering of the dandelion is a natural indicator of the start of maize sowing. Accelerating or delaying maize sowing is rather inadvisable. Earlier sowing - especially in cold spring - may delay emergence. Delayed maize sowing will always reduce the yield. Sowing depth may vary depending on the type of soil. In heavy soils, the depth of sowing maize should be 3 to 4 cm, while on light soils - 5 to 6 cm. It also depends on the soil moisture in a given sowing year.
A very important element in the cultivation of maize for grain is the appropriate selection of varieties related to the direction of use, as well as their earliness depending on the sowing region. The FAO system divides maize varieties into 9 classes of earliness. Poland was divided into 4 regions. For each of them, the appropriate FAO has been recorded regarding the variety earliness and the possibility of sowing maize:
Another element of the variety selection for grain maize cultivation are the FLINT and DENT hybrids. The mixed varieties of the FLINT type are characterized by a quick initial development, better cold resistance and earlier flowering. FLINT maize perform better in cool and cold spring conditions or in cold and slower heating places. Kernels give up water faster down to a humidity of about 30%, and much slower after reaching this level. This type of maize varieties in grain cultivation are recommended for large farms, where sowing should be accelerated often for organizational reasons. DENT maize varieties are recommended for cultivation in warmer regions, in quickly warming up positions and on lighter soils. The kernels release water more slowly at first, but as a result, throughout the drying process, give up more water than the FLINT varieties, which generally come off the field by 2 to 3% drier.
Maize is a plant where some of the weeds can be mechanically destroyed even before sowing. On the other hand, other features of maize cultivation favor its strong weed infestation. These are mainly a wide row spacing, sparse sowing and vertical plant development. Even under optimal conditions, weeds have very favorable conditions for growth and development. The development of weeds in maize is also favored by cool spring, which delays seed emergence and development. The weeds, on the other hand, only need lower temperatures to grow and develop. Properly performed agrotechnical measures in the spring, before sowing maize, will allow for partial control of weeds that already occur in the field. With regard to chemical weed control, two treatments are currently preferred in the cultivation of grain maize. One is soil treatment, and the other foliar treatment, or the selection and combination of plant protection products so that both treatments are performed together. In the case of a cold spring, the possibility of performing treatments in maize in divided doses should also be considered. This is very important as some of the weeds may emerge later in the maize growing season, which will cause secondary weed infestation. In order for the treatments to be performed in the most optimal manner for maize and with the greatest possible effectiveness in controlling weeds, the development phase of maize and weeds should be taken into account. The exceptions are soil treatments, the effectiveness of which depends mainly on soil moisture. Currently sown maize varieties are resistant to herbicides up to the eighth leaf. Application in later periods may damage the plants as well as inhibit their growth and development. The specific recommendations define the optimal application phases for the individual active substances and should always be followed. In the case of divided doses in the cultivation of maize for grain, dicotyledonous weeds should be as young as possible. Millet weeds are most effectively controlled in the phase from 2 leaves to the beginning of tillering. Common cover shows the greatest sensitivity in the 4 to 6 leaf stage.
In the cultivation of maize for grain, the most dangerous pests include the crops, aphids, thrips and the European corn borer. Agroti and wireworms are known to be harmful. The maize beetle is a species that extends the range of its occurrence and causes considerable losses in maize cultivation. The ability to control maize pests is severely limited due to the withdrawal of certain active substances from the register, and in addition, a suitable sprayer is needed, which will be able to treat later stages of plant development. One of the most important treatments performed in maize is the control of the European corn borer. Depending on the degree of threat posed by the caterpillars, up to two treatments are performed. In highly endangered areas, the first treatment is performed at the turn of the first and second decades of July (these are caterpillars brooding from egg beds), and the second treatment is carried out at the turn of the second and third decades of July (the pest brooding period). As for the control of the maize beetle, the currently registered insecticides only allow the control of beetles. The treatments are performed during their raids. Sometimes even two treatments are performed for effective control.
Corn, both in grain and silage cultivation, has high nutritional needs in terms of microelements. The most important nutrients are: zinc, manganese, boron and copper. Zinc is the most important micronutrient in the cultivation of maize for grain. By taking part in the synthesis of auxins, it stimulates the development of the root system. In order for zinc to fulfill its role, it should be administered early enough. Until the phase of 4 to 5 maize leaves at the latest. Zinc also enhances nitrogen uptake in the critical phase of 5 - 6 leaves, which is when primary cobs are formed. In addition, zinc has an impact on the viability of pollen grains, and during the ripening period, plants rich in zinc assimilate more carbon dioxide and increase the carbohydrate content in grains. Corn likes fertilizing with boron. Boron deficiency during flowering disrupts cob formation and affects the graining of the cob tips. Copper and manganese are important micronutrients in photosynthesis. The most effective method of supplementing microelements in the cultivation of maize for grain is foliar fertilization. It should be remembered that it is a supplementary fertilization in the case of microelements or an intervention fertilization, when we apply foliar macroelements to plants that are not absorbed by the root system. The factor limiting the uptake of macronutrients from the soil may be too low pH, cold spring (mainly phosphorus) and drought. Foliar fertilization, if it is to give the best results, should be done prophylactically, i.e. before deficiencies occur. Often they are still invisible in the appearance of plants, and the processes of their growth and development are inhibited. Moreover, prophylactic foliar treatments make the plants healthy, develop better and are more resistant to all kinds of stress. For foliar fertilization of maize, we can use multi-component fertilizers containing, in addition to microelements, also macroelements. These can be chelated-based fertilizers or those containing plant amino acids. The latter have a much higher concentration of micronutrients and are better absorbed by the plant. In order for the ingredients contained in foliar fertilizers to reach its interior, the liquid drops should stay on it as long as possible. Nutrient supplementation procedures should be performed early in the morning or evening. The optimal air temperature for foliar treatments is 15 to 20 degrees Celsius. We perform only fine-drop treatments so that the working liquid settles on the corn. You also have to remember about the temperature of the water used for the treatments - we cannot bring the plants to thermal shock.
An important element in the cultivation of maize for grain is the optimal and effective harvest time. It is important to choose the moment when the losses will be the lowest during the harvesting process, and the humidity of the harvested grain will reduce the costs associated with drying. The optimal yield when growing maize for grain is obtained when the storage of assimilants in grains is completed. During this time, a so-called black spot forms at the base of the kernel. This means that the kernel has reached physiological maturity. After reaching this phase, the humidity in the kernel fluctuates between 32 and 35%. However, with such humidity, large losses and damage to the maize grain occur during threshing. From that moment on, the conditions favoring humidity will change with each passing day. On the other hand, losses due to the deterioration of the quality of the grain due to the infestation of the fusarium and the dropping of the cob caused by the European grouse and wild game may increase. The weather can also deteriorate. The farmer has to find a balance when choosing the harvest date. Many years of research have shown that it should ideally occur about two weeks after the cocci reach the black spot stage. In this period, between the progressive losses of maize grain due to fusarium, lodging, losses caused by game and threshing losses is the lowest. The thawed maize grain should be cleaned and dried to a moisture content of about 13%. This is the humidity necessary for longer storage of maize grain or for sale as dry maize. When harvesting corn for grain, farmers need to pay attention to the pressure of Fusarium fungi. The critical moment in the cultivation of grain maize for the infestation of Fusarium is the first autumn frost. Although Fusariosis of the cobs causes little loss, it significantly worsens the quality of the grain. In extreme cases, this may disqualify maize grain from being used for feed, and this is the main direction of grain use.
