玉米-大豆间作和施氮对玉米产量及农艺性状的影响

为研究玉米-大豆间作模式和施氮水平对玉米产量、主要农艺性状及生长动态的影响,进行2个种植模式(玉米单作和玉米-大豆间作)和2个施氮水平(0 kg/hm2,150 kg/hm2)的双因素随机区组试验,以期揭示施氮和间作对玉米产量的影响规律,为提高玉米-大豆间作系统产量提供一定的理论依据。研究结果表明:(1)与不施氮相比,施氮显著增加了春秋两季间作玉米产量,分别达到23.81%和40.99%。施氮处理下的间作玉米地上部生物量较不施氮提高了29.91%,单作模式下显著提高了40.34%,两者差异均达到显著水平。(2)与不施氮相比,施氮150 kg/hm2条件下春玉米单作和间作模式百粒重分别提高了18.92%和19.23%,秋玉米单作和间作模式百粒重分别提高了31.03%和32.75%,差异均达到显著水平。与不施氮相比,施氮150 kg/hm2条件下,单作和间作模式均显著提高秋玉米穗长。与不施氮相比,施氮150 kg/hm2条件下,单作秋玉米的穗粗提高了18.67%,差异显著。(3)施氮和间作均能促进玉米干物质累积、提高株高和叶绿素(SPAD值),且表现为施氮效果高于间作效果。总体来看,种植模式和施氮水平对玉米产量、主要农艺性状和生长动态均有一定影响,且施氮效果优于间作效果。由于土壤具有一定的供氮能力,而间作豆科能为玉米供给一定量的氮素,故对于春玉米而言,施氮效果仅在百粒重中表现,随着土壤原有氮素被玉米吸收利用减少后,供氮能力下降,在秋玉米中施氮效果显著提高。

Effects of maize-soybean intercropping and nitrogen fertilizer on yield and agronomic traits of maize

Intercropping, with 1000-year history in Chinese agriculture, is still widespread in modern Chinese agriculture. The environmental resources, such as light, water and mineral nutrients, might be used more efficiently in intercropping than in monoculture by crops, which resulted in greater yield. The interaction among crops in intercropping might help the usage of environmental resources by crops. One of the vital roles of legumes played in cropping systems is their ability to fix nitrogen from air. However, Species of Leguminosae are known as weaker competitors to species of Gramineae. Theconcentration of soil inorganic N following legumes was often higher than that following cereal crops. To study the effects of maize-soybean intercropping and nitrogen levels on corn yield, main agronomic characters and growth dynamic, we conducted a double-factor randomized block experiment of two planting patterns (corn monoculture and maize-soybean intercropping) and two nitrogen levels (0 kg/hm², 150 kg/hm²). The results showed that: cropping patterns and nitrogen levels had no significant effect on the yield of spring maize; the yield of monoculture maize in autumn with N application (150 kg/hm²) was significantly higher than the other three treatments. Comparing to no nitrogen treatment, hundred-grain weight with N 150 kg/hm² increased by 18.92% and 19.23% respectively in the mode of spring maize monoculture and intercropping. In the mode of autumn maize monoculture and intercropping, hundred-grain weight of the treatment with N 150 kg/hm² was significant higher than those of no nitrogen treatments, increased by 31.03% and 32.75% respectively. There was no significant difference in maize hundred-grain weight between intercropping and monoculture under the same N application. There was no significant difference of ear length among the treatments of spring maize. Comparing to no nitrogen treatment, the ear length of autumn maize in the treatment with N 150 kg/hm² in monoculture and intercropping patterns were both significantly improved. On the aspect of ear width, there was no significant difference between the treatments of spring maize; whilte autumn maize monoculture increased by 18.67% under N 150 kg/hm² comparing to N 0 kg/hm². However, intercropping had no significant difference in autumn maize. On the aspect of spike grain number, there was no significant difference between the treatments of spring maize; while autumn maize grain number was significantly higher than the other three under monoculture and N 150 kg/hm². Nitrogen and intercropping both could improve SPAD value and plant height of maize, and promote the maize dry matter accumulation, while there was no significant difference among the treatments. Overall, cropping patterns and nitrogen levels had effects on maize yield, main agronomic characters and growth dynamic. The effects of intercropping were less than nitrogen level, because soil and Leguminosae had a certain capacity of supplying nitrogen for maize. The effects of nitrogen application on spring maize were only presented in the hundred-grain weight. As the nitrogen in soil was absorbed by maize, the nitrogen supporting from soil decreased, leading to the significantly effects of nitrogen application in the autumn maize.