Effect Of Different Cultivation Patterns And Zinc Fertilization On The Drought Resistance Of Summer Maize In Arid And Semiarid Region

Water is a kind of most ordinary material in surface of the earth, while it is the most important material, which has very important effect on our life. The soil moisture is one of the essential condition of growth of plant, not only determine the distribution of plants on surface of the earth, but also influence the crops yield and timber's growth. But drought already becomes an important issue which influences the food security in our country. In the northwest of China, the drought has limited the development of local agricultural production seriously. So, in the arid agriculture areas of northwest, how to utilize the limited water resource effectively, improve the moisture utilization of crops efficiency and probe into various effective ways and measures, is becoming the key of improving the drought farmland productivity level. Therefore, a series of researches have been carried out. We have studied the influence of development trends, morphological characteristic, physiological index and yield in different parenting stage of maize under drought condition. In order to offer the basis which adapt and retard the countermeasure of harmful aridity effects, we have studied the influence of zinc absorption of plant under adverse circumstance and influence of moisture utilize of plant when zinc nutritional status. On purpose of explore the way of improving environmental quality and measure of water-saving agricultural suitable for the local climate. The rainfall harvesting planting system has been studied under different cultivation pattern condition. The main results obtained were as follow:(1) Three treatments with different water supply to maize plants before and after blooming was conducted in this experiment, namely, one was adequate water supply condition at the whole growth period; the second was water stress condition before blooming; the third was water stress after blooming. The bleeding intensity, some root growth parameters, root vigor, activity of protective enzymes and malondialdehyde (MDA) were determined at jointing stage, trumpet stage, flowering stage and mature stage. The results obtained were as follows: the anthesis of maize is the key period for senescence starts for root and leaf. For the maize plants under adequate water supply condition, the bleeding intensity, root vigor, catalase (CAT) activity and peroxidase (POD) activity increased gradually from the trumpet stage to following stage, they reached the maximum at atheists, and then they fell. For the maize plants which were grown under water stress before blooming, the root growth was inhibited, bleeding intensity was decreased, and root vigor was lowered. When maize plants were grown under water stress condition after blooming, the anti-oxidizes defense system of former plants was weaken because activity of three protective enzymes dropped greatly. Even adequate water was supplied after blooming; the negative influence of water stress on maize growth before blooming is hard to be eliminated.(2) A pot experiment was conducted in order to research the influence of drought resistant physiological response at the whole growth period of maize after zinc application under adequate water supply condition, mild water stress condition and severe water stress condition. The result indicated that, zinc not only had nutritional functions, but also had the capability to enhance the drought resistance of maize under water stress condition. This kind of drought resistance function of zinc was more obvious under water stress condition. In the key period of blooming, the drought resistance function of zinc from high to low successively was as follows: severe water stress condition>mild water stress condition>adequate water supply condition. However, the way of zinc fertilizer application to strengthen the drought resistance of plant was limited; it is difficult to resume normal growth of crop under severe water stress condition. Therefore, the drought resistance function has regional adaptability and zinc can play a certain role of drought resistance function in arid and semiarid region.(3) The method of chelator-buffering nutrient solution was adopted in this experiment, zinc supply under the three experimental conditions: severe zinc deficiency, mild zinc deficiency, normal zinc supply. Research on influence of drought resistant physiological response at the seedling stage of maize after zinc application under the three equal osmotic potential conditions: drought stress, salt stress, bicarbonate (HCO3-) stress. The results show that, adverse environmental factor decreased the root vigor and CAT activity of maize seedlings when equal osmotic potential conditions, shown as control>salt stress>HCO3- stress>drought stress. The MDA content of plant was raised greatly under HCO₃^- stress conditions, thus the plant suffered from the deepest injure. With the increase of the zinc concentration, root activity, SOD activity, CAT activity and zinc content of blade of maize seedling increased in varied degrees, then MDA content reduced. Therefore, zinc application can really strengthen stress resistance function of crops, but application zinc to strengthen the drought resistance of maize seedling was limited. Compared with various adverse circumstance conditions, the stress resistance function of zinc was more effective under HCO₃^- stress condition.(4) The experiment was conducted in field location experiment of wheat-maize rotation for two years. Foliar Zn application was conducted at the key periods of maize (the seedling stage and florescence stage) in second year. The aims lies in investigating effects of four different cultivation pattern (Conventional, ridge furrow, water saving, straw mulching) on summer maize yield and zinc concentration in grains. The two years of field location experiment shows, the grain yield and biomass of summer maize from high to low successively was as follows: ridge furrow>straw mulching>water saving>conventional. The accumulation of nitrogen, phosphorus and potassium in each organ reached the maximum under the ridge furrow condition. The ridge furrow model promoted every organ to grow and especially promoted the nutriment transfer to the grain after blooming, then influence the formation of yield seriously. In view of condition of applying fertilizer, nitrogen application had obvious effect on the maize yield and could improve the harvest index. The plot yield reduced year by year when without N application continuously. The result shows that, the grain yield, harvest index and zinc accumulation of grain can be increased after spraying zinc at the key period of maize. As a consequence, spraying zinc at the ridge furrow, and nitrogen rate of 120 kg/hm² condition was the ideal combination to raise maize yield and improve the maize quality.