氮肥和接种根瘤菌对豌豆/玉米间作产量和水分利用效率的影响

Effects of nitrogen fertilizer application and rhizobial inoculation on yield and water use efficiency of pea/maize intercropping system

豌豆/玉米间作是河西绿洲灌区面积最大的间作模式,也是当地重要的高产高效种植模式之一。针对目前氮肥过量施用和豆科作物生物固氮被忽视的实际,2011年和2012年在甘肃省武威市凉州区进行了豌豆/玉米间作大田试验,研究不同施氮量下,豌豆接种根瘤菌对豌豆/玉米间作体系作物籽粒产量和水分利用效率的影响,旨在为河西绿洲灌区豌豆/玉米间作体系节肥、高产的氮肥用量和接菌增产作用提供理论依据。结果表明:施用氮肥对豌豆产量影响不显著。接种根瘤菌后单作豌豆比不接菌处理两年平均增产12.7%,间作豌豆产量比单作两年平均增产61.1%,间作豌豆接种根瘤菌比不接菌两年平均增产4.8%。单作豌豆以施氮量75 kg(N)·hm-2接菌处理的产量最高,达到2 735 kg·hm-2;而且在此施氮量下接菌比不接菌两年平均增产达22.8%。施用氮肥对玉米的增产效果显著,施氮量在300 kg(N)·hm-2时单作玉米产量为14 394 kg·hm-2,间作比单作两年平均增产61.8%;间作豌豆带接菌较不接菌玉米两年平均增产3.3%。土地当量比在不同施氮量和接种根瘤菌的条件下都大于1。豌豆水分利用效率随施氮量增加而减小,最大值为不施氮的12.9 kg·mm-1·hm-2;玉米水分利用效率随施氮量增加先增大后减小,以施氮量300 kg(N)·hm-2处理为最高,达25.0 kg·mm-1·hm-2。综上所述,在豌豆/玉米间作体系中,玉米高产、高水分利用效率的施氮量为300 kg(N)·hm-2,豌豆高产高效的施氮量为75 kg(N)·hm-2。在大田生产中,接种根瘤菌对豌豆和玉米增产作用明显。

Pea/maize intercropping has been a vital crop production mode in irrigated areas of Hexi Corridor in Gansu Province.However, there some problems of heavy fertilization and symbiotic N2 fixation neglect have persisted in local crop production in the region. Thus field trials were conducted in Wuwei City of Gansu Province in 2011 and 2012 to study the effects of nitrogen fertilization and rhizobial inoculation on crop yield and water use efficiency of pea/maize intercropping system. The work aimed to determine an optimal nitrogen fertilizer application and rhizobial inoculation so as to save fertilizer and increase yield of pea/maize intercropping system. The results showed that while nitrogen fertilization had not significant effects on pea yield, yields ofmonocropped and intercropped pea increased on average by 12.7% and 4.8%, respectively, after inoculation. Yield of intercropped pea increased by 61.1% on average compared to that of monocropped pea. Yield of monocropped pea was highest（2 735 kg·hm^-2）under nitrogen fertilizer rate of 75 kg·hm^-2 with inoculation. Under nitrogen fertilizer rate of 75 kg·hm^-2, pea yield increased by22.8% on average after inoculation. The effect of nitrogen fertilization on maize yield was significant. Yield of monocropped maize under nitrogen fertilizer rate of 300 kg·hm^-2 was 14 394 kg·hm^-2 and yield of intercropped increased by 61.8% compared with that of monocropped maize. Yield of maize intercropped with rhizobium-inoculated pea belt increased by 3.3% on average, compared with that intercropped with non-inoculated pea belt. Land equivalent ratio was larger than 1 under different treatments. The water use efficiency of pea reduced with increasing nitrogen fertilizer application, with the maximum value（12.9 kg·mm-1·hm-2） appearing under zero-N fertilizer use. Water use efficiency of maize first increased and then latter decreased under increasing nitrogen fertilization rate, with the maximum value（25 kg·mm-1·hm-2） appearing under nitrogen fertilizer dose of 300 kg·hm^-2. From the above results, it was recommended that the rate of nitrogen fertilizer application in maize for high grain yield and high water use efficiency was 300 kg·hm^-2 in pea/maize intercropping system. Then the recommended rate of nitrogen fertilizer application in pea for high grain yield and high water use efficiency was 75 kg·hm^-2 in pea/maize intercropping system. In filed production, pea yield significantly increased by the inoculation of rhizobia.