宁南山区马铃薯燕麦间作系统氮素互作机制及施肥调控研究

Potato industry as one of the special advantage industries can promote peasant income increase and rural economy development in the mountainous area of southern Ningxia. However, continuous cropping obstacle has been one of the main restriction factors in potato industry. Potato/oat intercropping is beneficial to overcoming continuous cropping obstacles and increase farmers’ income. Nitrogen is the largest nutrient input in agricultural production. It is important to quantify the nitrogen requirement characteristics and mechanism of nitrogen interactions in potato/oat intercropping system, thereby to enhance yields, nitrogen fertilizer use efficiency and agricultural sustainability. In this project, the pot, field and 15N micro-plot trials were conducted to study the effect of nitrogen rate on crop yield, quality and the accumulation of mineral N in soil, analysis the differences of nitrogen uptake, utilization and interactions between potato and oat, and investigate the fertilizer-N translation and movement characteristics in potato/oat intercropping system. The objective is to definite the characteristics of nitrogen uptake and utilization, effect of nitrogen fertilizer and the mechanism of nitrogen interactions in potato/oat intercropping system. The results would provide theoretical basis and technical support for scientific fertilization and continuous production of intercropping potato in the mountainous district of southern Ningxia.

马铃薯是宁夏南部山区农民增收的特色优势产业，然而因规模化种植带来的连作障碍问题已经严重影响到当地马铃薯种植业的可持续发展。将优质杂粮作物燕麦纳入马铃薯种植制度，发展马铃薯燕麦间作，有利于解决马铃薯连作障碍，促进农民增收。氮是农业生产中投入最大的养分资源，掌握马铃薯燕麦间作系统中氮素养分的互作关系与机制，对于确定间作马铃薯合理施肥技术，提高产量和肥料养分利用效率具有重要的理论意义和应用价值。因此，本项目采用田间定位试验、根系分割盆栽试验与15N示踪技术相结合的方法，研究不同施氮水平下马铃薯燕麦间作系统中作物的产量、品质和土壤无机氮累积效应，分析马铃薯燕麦对氮素吸收利用的差异以及种间互作效应，并探讨间作系统中肥料氮的转化和运移规律，明确肥料氮的行为和去向，揭示间作系统中作物氮素吸收利用规律、氮素养分互作机制，并进行施肥调控，为宁南山区间作马铃薯科学施肥和持续生产提供理论依据与技术支撑。

为了探讨间作和施氮对宁南山区马铃薯、燕麦氮素吸收、积累与转运及产量品质的影响，以宁夏南部山区主栽马铃薯品种‘青薯9号’和燕麦‘燕科1号’为供试材料，研究结果如下：.1、间作和施氮可促进马铃薯、燕麦植株氮素吸收、分配与积累，交互作用在生长后期对氮素积累的影响显著，连续几年均以施氮150 kg·hm-2和225 kg·hm-2促进效果显著。间作和施氮更有利于马铃薯氮素收获指数、氮肥生理利用率、氮肥利用率的提高，显著降低氮肥偏生产力，施氮150 kg·hm-2效果最佳且种植模式和施氮水平对氮素利用率的影响显著。 .2、间作和施氮改善了马铃薯、燕麦耕层土壤的全氮、硝态氮、铵态氮含量，提高了土壤理化性状，可以实现土壤和植株的氮素平衡。间作和施氮对0-40 cm的耕层土壤氮素含量变化影响显著，块茎形成期土壤全氮、硝态氮、铵态氮含量均以单作马铃薯较高，耕层以施氮150 kg·hm-2和225 kg·hm-2较高，间作模式下硝态氮含量增幅较大，后期马铃薯吸收速效性氮能力强于燕麦，马铃薯土壤氮残留量低于燕麦。.3、基施和追施肥下，间作和施氮处理马铃薯、燕麦各器官对15N积累量、Ndff、肥料氮和土壤氮的吸收能力均有所不同。单作基施处理下肥料氮对马铃薯、燕麦生殖器官的全氮量的贡献较高，追施间作处理肥料氮对马铃薯块茎全氮量的贡献高，燕麦追施下对生殖器官的贡献弱于营养器官。单作和间作模式下基施，马铃薯块茎、燕麦叶15N积累量最高，在施氮225 kg·hm-2处理下积累量最大。.4、马铃薯燕麦间作优势明显，且燕麦的营养竞争能力要强于马铃薯。间作和施氮能促进马铃薯产量、品质提升，经济效益明显。单作和间作模式下马铃薯产量随施氮量的增加呈先增加后降低趋势，施氮150 kg·hm-2马铃薯产量（33635.10 kg·hm-2--36796.05 kg·hm-2）及经济效益（23478.45元/ hm2--24546.75元/ hm2）最佳。.研究成果丰富了宁南山区马铃薯间作理论，为当地间作马铃薯科学施肥和持续生产提供理论依据与技术支撑。