Symptoms of corn usually have 1-2 panicles, usually one panicle, but in the production process, empty stalks often appear and affect the yield increase. For example, in Kuandian, Yangyan, Benxi, and Huairen in Liaoning Province, the empty stalk rate was 12%-20%, and the 667m2 output was reduced by 50kg. Commonly, there are congenital sterile stalks and non-head stalk-type culms.
In 1994, the empty stalk rate of corn in the suburbs of Beijing was as high as 17.3%, and the empty stalk rate of corn in more than 80% of the city was 2-3 times higher than the average. In many areas, the empty stalk rate is as high as 60%-70%, and individual plots are as high as 90%. Over 20 acres of main cultivars in the city have different degrees of empty stalks. Its characteristics are high in the plains and low in the mountains in the north. There are large differences between varieties, and the occurrence of different plots of the same variety in different regions or in the same region is different.
The cause of congenital infertility, empty stalks, also known as male corn, is caused by internal seed problems. For example, the physiological mechanism of seed declines, the metabolism is disordered, and the transporting tissue is hindered, resulting in that the nutrients in the stem cannot be delivered to the ear, and the young ear buds are not developed due to lack of nutrients, but the tassels are normal. The stalk-type empty stalk is a type of young spikelet on the plant, but no filaments or no grain. The main reasons are as follows: First, the soil is infertile, nutrients cannot meet the requirements for corn growth, reproductive organs cannot be formed, and secondly, the density is too large, the population is covered, the photosynthesis is inhibited, the photosynthetic productivity is low, and the individuals are thin, affecting the development of the ear; Third, management can not keep up with the lack of water and fertilizer in the field, resulting in premature plant failure; Fourth, the emergence of drought before the head of the neck or cold chilling in the middle, affecting or inhibiting the differentiation of young ears, and sometimes ending the development, resulting in empty stalks; Is a mechanical injury or aphids, leafhoppers, ear pests and other insects; six is ​​the choice of varieties of errors, can not adapt to or can not fully adapt to local conditions, affecting the ear differentiation, resulting in empty stalks; seven climate factors. 1 Drought. During the growth period, the drought in June caused a high rate of small seedlings. The vegetative growth and reproductive growth were severely inhibited. The dwarf stems were fine, and it was difficult to achieve normal heading, and the empty culm rate was increased. 2 high temperature. In the five days before and after corn picking and silking, high temperature may reduce pollen viability, affect pollination and seedlings, and have a high emptying rate. 2 rainy, low light. In July and August, the rainy and overcast weather during the draw of spring corn and silking was an important cause of pollination of corn, leading to empty stalks. Eight is a cultivation factor. Seen from the varieties, the occurrence of empty stalks in spring maize was higher than that in summer maize. This was because the summer corn had less influence of high temperature and rain than the spring corn. From the perspective of density and investment, according to the Changping County density test results, the empty stalk rate of spring sowing and summer sowing maize increased with the increase of density, with more than 4,500 per 6677 m2, and the empty stalk rate increased significantly. At present, 4,600 plants have reached the point of density saturation. . Because of the large population of corn in the early growth period, the supply of nutrients is insufficient, it is difficult to achieve Miao Qi, Miao Zhuang, plant individuals are not robust growth, affect the differentiation of male and female ear, resulting in corn empty stalk; Nine is the content of soil organic matter and fertilizer. In the same variety, the empty culm rate with high soil organic matter content is low. The empty stalk rate rises due to insufficient application of fertilizer; ten is the impact of pests and diseases. High temperature, high humidity duration, induced many types of diseases, a wide area, is a serious problem, will also increase the formation of empty stalks.
Prevention and control methods (1) In breeding or introducing maize cultivars, attention should be paid to the study of cultivar adaptability, and varieties suitable for local traits should be selected. For example, the spring maize in the northern mountainous areas of Beijing is dominated by Dandan 13, and the spring corn in the plains is mainly Nongda 60 and Shendan 7. The summer maize in the plain area was dominated by the varieties with good comprehensive, high-yield and stable yield characteristics such as Tang 5, 90-1. In other regions, suitable local varieties should be determined according to local conditions. (2) Under the current local level conditions, the density of 4600 strains per 667m2 has basically reached the population saturation and should not be increased. (3) Adopt new technology of mulching. (4) Promote the use of compost or organic fertilizer made from fermented bacteria, strengthen the return of two straws, and gradually increase soil fertility. It is required to ensure basic fertilization and fertilization at the seedling stage. The plot with high seedling rate should be treated with partial fertilization, and every possible means should be used to reduce seedlings and prevent the formation of empty stalks. (5) Rational rotation, emphasis on soil preparation and sowing quality. To achieve appropriate sowing, appropriate density, and pay attention to the prevention and control of underground pests and aphids, etc. (6) skillfully catch young ear ear differentiation fertilizer, regain chase panicle fertilizer. For example, the mid-late maturing varieties of spring maize have entered the stage of the fetus during the jointing stage of 13-14 leaflets under suitable early sowing conditions. This stage is to determine the size of the spleen and the number of grain rows and grains per row. In the critical period, therefore, reapplying the panicle fertilizer 5-7 days before heading is one of the fundamental measures to achieve large-grained panicles and strive to eliminate empty culms. (7) Spraying corn Zhuang Feng Ling (Jilin City Agricultural Institute) The high-yield planting of middle and late maturity high-yielding maize florets in the differentiation stage, that is, 3-5 days before the tassels are drawn in corn, or several thousandths of tassels To be exposed and not yet exposed, the use of corn Zhuangfengling 27ml, spraying 20kg of clear water once, can reduce plant height, rod position, internode shortening, while improving ventilation and light conditions to prevent lodging, promote female flower development, improve double Bar rate, to avoid baldness, effectively preventing empty stalks and greed, (8) promote the use of "Farmer Po" No. 1 30ml mixed corn seed, so that the Department is well-developed to improve disease resistance, early germination 36 hours. In the corn big bell stage with "farmer" 90m1, spraying 50kg of water, can close the stomata of leaves, reduce water transpiration, improve drought resistance. In addition, it is also possible to spray Wanjiabao 500-600 times solution from corn booting stage to filling stage.
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