青贮玉米生长、耗水、产量和水分利用效率对水氮供应的响应研究

Response of growth, water consumption, yield and water use efficiency of silage maize to water and nitrogen supply

为探究黑龙港流域典型半干旱半湿润区不同水氮处理对青贮玉米产量和水分利用的影响规律,试验设计灌水量和施氮量2个因素,设置4个灌水水平0.25I(W1)、0.50I(W2)、0.75I(W3)、1.00I(W4)(I为高水处理的灌水量),3个施氮水平(N1:120 kg/hm^(2)、N2:240 kg/hm^(2)、N3:360 kg/hm^(2)),以高水高氮(W4N3)处理为对照,共计12个处理。各小区采用随机布置,于2019年4—8月在河北省巨鹿县开展田间试验。结果表明:轻度亏水(0.75I)、中等施氮量(240 kg/hm^(2))能保证青贮玉米正常生长发育。青贮玉米各生育阶段耗水量由大到小依次为拔节期、抽穗期、苗期、灌浆期,高水高氮的W4N3处理总耗水量最大为492.67 mm,显著高于其余处理。青贮玉米鲜重产量变化范围为59.65~107.49 t/hm^(2),增加灌水显著提高青贮玉米产量,产量随施氮量增加呈先上升后下降趋势。灌水、施氮以及二者交互作用对WUE有极显著影响,其中施氮量为提高WUE的主要因素。W4N2处理WUE最大,与W4N2相比,W3N2处理WUEw仅减少2.57%,差异不显著。轻度亏水(0.75I)、中等施氮量(240 kg/hm^(2))较W4N3处理在鲜重产量仅下降8.68%的情况下,可获得较高的WUE(22.21kg/m^(3)),每亩可节约31.5 m^(3)的灌水量,减小120 kg/hm^(2)的施氮量,采用该方案可达到节水减氮高效目的。

The effects of different water and nitrogen treatments on the yield and water use of silage maize in typical semi-arid and semi-humid area of Heilonggang basin were studied to provide theoretical basis and technical support for determining the water-saving and nitrogen-reducing efficient irrigation and fertilization system of silage maize in this area. Two factors of irrigation amount and nitrogen application amount were set in the experiment design. Four irrigation amount levels were designed as 0.25 I(W1), 0.50 I(W2), 0.75 I(W3) and 1.00 I(W4)(I was the irrigation amount under high water level treatment). Three nitrogen application levels(N1:120 kg/hm^(2), N2:240 kg/hm^(2), N3:360 kg/hm^(2)) were set. There were 12 treatments in total in this study, and the W4 N2 treatment was the control. Each plot was randomly assigned. The field experiment was carried out in Julu County, Hebei Province from April to August 2019. The result showed that mild water deficit(0.75 I) and moderate nitrogen application(240 kg/hm^(2)) could ensure the normal growth and development of silage maize. The decreasing order of water consumption of silage maize in different growth stages was jointing stage, heading stage, seedling stage and filling stage. The total water consumption of W4 N3 treatment with high water and nitrogen was 492.67 mm, which was significantly higher than that of other treatments. The fresh weight and yield of silage maize ranged from 59.65 t/hm^(2) to 107.49 t/hm^(2). Increasing irrigation significantly increased the yield of silage maize, and the yield first increased and then decreased with the increase of nitrogen application rate. Irrigation, nitrogen application and their interaction had significant effects on WUE, and nitrogen application was the main factor to improve WUE. Compared with W4 N2, the WUE of W3 N2 treatment was only 2.57%, and the difference was not significant. Compared with W4 N3 treatment, mild water deficit(0.75 I) and medium nitrogen application rate(240 kg/hm^(2)) can obtain higher WUE(22.21 kg/m^(3)) when fresh weight yield is only reduced by 8.68% compared with W4 N3 treatment. Irrigation amount per mu can be saved by 31.5 m^(3), and nitrogen application rate can be reduced by 120 kg/hm^(2).