施氮对玉米//马铃薯间作作物氮累积和分配的影响

玉米//马铃薯间作在农业生产中占有重要地位。本文通过两年田间试验研究了4个施氮水平[玉米：N0（0 kg/hm2）、N1（125 kg/hm2）、N2（250 kg/hm2）、N3（375 kg/hm2），马铃薯：N0（0 kg/hm2）、N1（62.5 kg/hm2）、N2（125 kg/hm2）、N3（187.5 kg/hm2）]对玉米马铃薯作物产量、生物量和氮在作物籽粒、茎叶和根系的累积和分配的影响。结果表明：玉米//马铃薯有间作产量优势，在4个氮水平下，土地当量比（LER）分别为1.46、1.20、1.04、0.92。随氮水平提高，间作产量优势逐渐下降。各施氮水平下间作玉米籽粒、茎叶和根的氮吸收量平均比单作高39.76%、27.98%、15.36%；间作马铃薯块茎和茎叶的氮吸收量平均比单作低4.14%、24.59%。玉米马铃薯氮吸收的间作优势随施氮水平的提高而降低。间作和施氮对玉米马铃薯各组织中氮的分配比率的影响差异不显著。通过玉米//马铃薯产量和氮肥农学利用率的分析结果表明，间作玉米、马铃薯在低氮水平（N1）就能获得单作玉米、马铃薯常规施氮（N2）或高氮水平（N3）时的产量，因此玉米//马铃薯可有效提高作物产量和氮肥利用效率，降低氮投入。

Effects of Nitrogen Application on Nitrogen Accumulation and Distribution of Crops in Maize and Potato Intercropping

Field experiment was carried out to study the effects of 4 nitrogen (N) levels[maize:N0(0 kg/hm2), N1(125 kg/hm2), N2(250 kg/hm2), N3(375 kg/hm2), potato:N0(0 kg/hm2), N1(62.5 kg/hm2), N2(125 kg/hm2), N3(187.5 kg/hm2)]on the yield, biomass, N accumulation and distribution in grain, stem and leaf, root of crops in maize and potato intercropping. The results showed that the maize and potato intercropping had yield advantages and the land equivalent ratios (LER) of 4 N levels were 1.46, 1.20, 1.04, 0.92, respectively. The intercropping yield advantage decreased with increasing of nitrogen level. The intercropping maize N absorptions of grain, stem and leaf, root were 39.76%, 27.98%, 15.36% higher than monocropping, respectively. The intercropping potato N absorption of tuber, stem and leaf was 4.14%, 24.59% lower than monocropping, respectively. Two years of experiment showed that the intercropping advantage of crop nitrogen absorption decreased with the increasing of nitrogen level. The effect of intercropping and nitrogen fertilizer on nitrogen distribution proportion of organs in corn and potato was not significant. The maize and potato yields of intercropping in low N level can catch up with those of monoculture in conventional or excess N level, so maize and potato intercropping can improve the crop yield and efficiency of nitrogen fertilizer, and reduce the nitrogen fertilizer application.