缓释复混肥料对马铃薯产量、土壤硝态氮含量及氮肥利用率的影响
Effects of controlled-release compounded fertilizer on potato yield, soil nitrate-N content and nitrogen use efficiency

为探讨青海省山旱区马铃薯发展的新途径，研究了缓释复混肥料对地膜覆盖马铃薯产量、土壤硝态氮含量、硝态氮累积量及氮肥利用率的影响。结果表明：施用1 050 kg·hm-2缓释复混肥（RZ70）处理马铃薯产量最高，为47 240 kg·hm-2；较农民习惯施肥（NXG）处理增产2 175 kg·hm-2，增产率为4.83%；较马铃薯专用肥（MZY）处理增产5 085 kg·hm-2，增产率为12.06%。马铃薯从苗期到成熟期，农民习惯施肥（NXG）和马铃薯专用肥（MZY）处理显著提高了0~100 cm各土层硝态氮的含量，1 050 kg·hm-2缓释复混肥（RZ70）处理显著降低了0~100 cm各土层硝态氮的含量。马铃薯生长季0~100 cm各土层硝态氮含量呈先增加后降低的趋势。硝态氮含量在团棵期出现了一个峰值，且主要集中在20~40 cm土层。随着马铃薯的生长发育，0~100 cm各土层硝态氮含量差异逐渐减小，至成熟期趋于稳定并降至最低。农民习惯施肥（NXG）处理下，马铃薯整个生育期0~100 cm土层硝态氮累积量呈现降低的趋势；除了习惯施肥（NXG），马铃薯整个生育期0~100 cm土层硝态氮累积量与土壤硝态氮含量变化一致。1 050 kg·hm-2缓释复混肥（RZ70）处理下，氮肥利用率最高，达到了53.70%。较农民习惯施肥（NXG），增幅为3.38%~40.85%；较马铃薯专用肥（MZY）施肥处理，增幅为5.01%~33.25%。该结果可为缓释复混肥料在青海省马铃薯种植中的合理施用提供理论依据。
To explore a new way for development potato in arid hill drought regions of Qinghai Province, a field experiment was conducted to assess the effects of controlled-release compounded fertilizer on potato yield, soil nitrate-N content, soil nitrate-N accumulation and nitrogen use efficiency under plastic film mulching condition. The results showed that the highest potato yield was 47 240 kg·hm-2 in 1 050 kg·hm-2 controlled-release compounded fertilizer (RZ70) treatment. Comparing to farmer’s conventional fertilization (NXG) treatment, the potato yield of RZ70 was increased 2 175 kg·hm-2,and the increasing rate was 4.83%. Comparing to special potato fertilizer (MZY) treatment, the potato yield was increased 5 085 kg·hm-2, and the increasing rate was 12.06%. From seedling to mature stage of potato, soil nitrate-N content in depth of 0~100 cm increased significantly under farmer’s conventional fertilization (NXG) treatment and special potato fertilizer(MZY) treatment, whereas, soil nitrate-N content in depth of 0~100 cm decreased significantly under 1 050 kg·hm-2 controlled-release compounded fertilizer (RZ70) treatment. Soil nitrate-N content in depth of 0~100 cm trended as increasing first，then decreasing in the growing season. Nitrate-N content presented a peak in the resettling stage, and mainly concentrated in depth of 20~40 cm. With the growth and development of potato, the difference of soil nitrate-N content in depth of 0~100 cm gradually reduced and stabilized to a minimum level in mature stage. Soil nitrate-N accumulation in depth of 0~100 cm showed a decreasing trend in the growing season under farmer conventional fertilization (NXG) treatment. The changes of soil nitrate-N accumulation in depth of 0~100 cm was similar to soil nitrate-N content, except in farmer conventional fertilization (NXG) treatment. The highest nitrogen use efficiency was 53.70% in 1 050 kg·hm-2 controlled-release