浅埋滴灌下尿素减量配施UAN对春玉米根系形态及其生理特性的影响

在内蒙古科尔沁区农业高新科技示范园区，以常规追施尿素为对照，研究浅埋滴灌减施尿素配施尿素硝酸铵溶液（UAN）对春玉米根系、产量及效益的影响。结果表明，适量减施尿素配施UAN能促进玉米根系生长，增强吐丝期和乳熟期根系超氧化物歧化酶（SOD）、过氧化物酶（POD）酶活性，降低丙二醛（MDA）含量，延缓根系的衰老，有利于生育后期产量的形成。各土层土壤铵态氮及硝态氮含量均表现为CK （常规追施尿素）显著高于尿素减量配施UAN处理，UAN能促进根系对土壤氮的吸收利用。减施尿素25%、配施UAN 75 kg/hm²处理（N2U）产量与CK差异不显著，且显著高于减施尿素51%、配施UAN 75kg/hm²（N1U）处理；N2U处理两年的经济效益均最高。浅埋滴灌技术为尿素减量配施UAN玉米的田间作业提供便利，配施UAN、减施尿素是西辽河平原灌区春玉米减氮增效的有效途径。

Effects of Urea Reduction with UAN on Root Morphology and Physiological Characteristics of Spring Maize under Shallow Buried Drip Irrigation

In the Inner Mongolia Horqin Agricultural Hi-tech Demonstration Park, using conventional topdressing urea as a control, studied the effect of shallow burial drip irrigation combined with reduced application of urea combined with Urea Ammonium Nitrate Solution(UAN) on root system, yield and benefit of spring maize. The result showed, appropriate reduction of urea and application of UAN can promote corn root growth, enhance Superoxide dismutase(SOD) and Peroxidase(POD) enzyme activities of root during silking and milking stages, reduce Malondialdehyde(MDA) content, slow down the senescence of the root system, conducive to the formation of yield in the later growth periods. The contents of ammonium nitrogen and nitrate nitrogen in each soil layer showed that CK(conventional topdressing urea) were significantly higher than that of urea reduction with UAN treatment, UAN could promote the absorption and utilization of soil nitrogen by roots. The yield of N2U treatment(reduction of urea by 25%, combined with UAN 75 kg/ha) were not significantly different from that of CK,and they were significantly higher than that of N1U treatment(reduction of urea by 51%, combined with UAN 75kg/ha). N2U treatment has the highest economic benefits in two years. Shallow buried drip irrigation technology facilitates field operations of urea reduction with UAN of maize, combined application of UAN and reduction of urea was an effective way to reduce nitrogen and increase efficiency of spring maize in the irrigation area of Xiliaohe plain.