Water Requirement Regulation And Yield Of Xinjiang Spring Maize With High Yield Of(≥15000 Kg/hm~2) Under The Condition Of Drip Irrigation

【Object】Water requirement characteristics and effects of irrigation quantity on growth, yield and water use efficiency(WUE) of Xinjiang spring maize with high yield of 15000 kg/hm2 were studied by conducting experiments of different irrigation quantities under the condition of drip irrigation under plastic film. Through analyzing the responses of above ground population and distribution characteristics of root biomass to different irrigation quantities, water requirement characteristics of high yield spring maize was revealed and the effective regulation pathway of yield formation was also explored. It will be helpful for providing the theoretical basis and technical support for further improving of maize yield and develop a reasonable irrigation system in Xinjiang. 【Method】This study was conducted in at Yining and Qitai sites from 2013 to 2014 by adopting drip irrigation under plas tic film. Based on the local irrigation quantity of high-yielding maize(T4), four irrigation quantity levels [Yining with 8400m3/hm2(T4),7560m3/hm2(T3),6720m3/hm2(T2), and 5880m3/hm2(T1); Qitai with the 6000m3/hm2(T4),5400m3/hm2(T3),4800m3/hm2(T2) and 4200m3/hm2(T1)] were adopted. Zhongdan909(ZD909), Xianyu335(XY335), KWS1568 were used at Yingning sites; Zhongdan909(ZD909), Liaodan565(LD565), Ningyu721(NY721) were used at Qitai sites. The maize planting density was 12×104 plants /hm2 at each experimental site. The effects of irrigation quantities on water requirement characteristics, growth, yield and water use efficiency(WUE) of Xinjiang spring maize with high yield of 15000 kg/hm2 were analyzed. 【Conclusion】(1) There were significant differences between yields under different irrigation quantities. Results of the two sites showed that yield of most cultivars had no decrease trend except LD565, when the irrigation quantity was reduced to 90% of conventional irrigation quantity(T3). Yield of most cultivars were significantly reduced when irrigation quantity was reduced to 80% of conventional irrigation quantity. Therefore, slightly decreasing the quantity of irrigation had no significant effect on maize yield. Irrigation quantity had no significant effects on the harvest ears but had significant effects on grain weight per ear. Irrigation quantity affected the yield through influencing the grain weight per spike. Irrigation quantity had significant effects on grain number and weight per ear. Further analysis revealed that the row number per ear was not significantly affected, kernels per row was significantly affected because of different bald lengths. Irrigation quantity had significant effect on ear diameter but had no significant effect on the number of rows per ear which showed that ear diameter was affected because of the change of grain volume. Therefore, maize yield was affected because grain weight per ear was significantly affected by irrigation quantity.(2) With increasing irrigation quantity, plant height, stem diameter, ear length, ear diameter, kernels per row showed an increasing trend while bald length showed a decreasing trend. Number of rows per ear was unaffected by irrigation quantity, but the responses of these agronomic traits of different genotypes to irrigation quantity were different. Leaf area, leaf area index and dry matter of maize were positively correlated with the irrigation quantity within the scope of irrigation quota. For some cultivars, when leaf area reached a c ertain level, leaf area index was too large, it would lead to the phenomenon of crown closure. Light could not be transmitted to the lower level of the plant which resulted in reduced photosynthetic efficiency and lower yield. Reducing the irrigation quant ity could promote the growth and development, and structure and function formation of deep root. The root biomass of maize showed a decreasing trend with increasing soil depth. With the reducing of irrigation quantity root biomass decreased.Root-shoot ratio(R/S) increased with increasing irrigation quantity at tasseling and grain fillin g stages, while it showed the opposite trend at milk maturity stages.(3) Irrigation quantity was significantly affected water consumption of maize at different growth stage s. Water consumptions of different genotypes showed significant increasing trend with increasing irrigation quantities at both of the experimental sites. Water consumption showed the trend of sowing to jointing < jointing-filling < grain filling to maturity. Water consumption intensity showed a parabolic trend during the whole growth stage, and the highest peak appeared at the stage of tasseling-filling. Modulus coefficient reached the maximu m at the maturity stage while there was no significant law at other growth stages. Appropriately reducing the irrigation quantity had no significant influence on maize yield. Therefore, the best treatment T3 growth period water requirement of 630.8~670.2mm, reducing the irrigation quantity(reduction of 10 % or 20%), hav e a higher WUE, and can save water 540~1680 m3/hm2 without decreasing maize yield significantly.