线辣椒玉米套作的养分吸收利用及产量优势分析

采用田间微区试验和地下部种间根系分隔技术,研究了施氮肥和不施氮肥两种情况下,线辣椒/玉米套作体系的产量优势,套作与单作在成熟期氮磷钾养分吸收量和利用效率的差异,以及地上部和地下部因素对套作产量优势的相对贡献。结果表明,不论施氮肥与否,线辣椒/玉米套作经济产量和生物产量的土地当量比均大于1,呈现产量优势,但生物产量套作优势比经济产量更明显。套作氮、磷、钾养分吸收总量分别比单作高出16.4%～22.1%、26.1%～30.5%和27.0%～51.5%,而套作的养分利用效率分别比单作降低4.0%～14.1%、4.4%～9.4%和4.3%～15.9%。套作优势在养分资源方面主要是因为吸收量的增加,而非利用率的提高;套作线辣椒的养分收获指数高于单作。不施氮肥时,地上部和地下部因素对套作体系经济产量优势的相对贡献分别为93.2%和6.8%,生物产量优势的相对贡献分别为88.8%和11.2%;施氮肥时,对经济产量优势的相对贡献分别为85.2%和14.8%,生物产量优势的相对贡献分别为84.6%和15.4%。

Studies on Uptake and Utilization of Nitrogen, Phosphorus and Potassium and Yield Advantage in Capsicum/Maize Relay Intercropping System

A microplot experiment and a root barrier technique were employed to investigate the yield advantage of relay intercropping and the absorption and utilization efficiency of nitrogen，phosphorus and potassium by the component crops relay intercropped or monocultured，and the relative contribution of above- and below-ground interactions to yield in the capsicum/maize relay intercropping system with or without nitrogen fertilizer application was also researched. The results showed that the land equivalent ratios（LERs）of both economic yield and biological yield exceeded 1，which demonstrated a significant yield advantage for all the relay intercropping treatments of capsicum and maize. The biological yield advantage was stronger than that of the economic yield advantage. The absorption of nitrogen，phosphorus and potassium by capsicum and maize in the intercropping system were 16.4%–22.1%，26.1%–30.5% and 27.0%–51.5% higher，respectively，than those in the monoculture system. However，the utilization efficiency of nitrogen，phosphorus and potassium in the intercropping system were 4.0%–14.1%，4.4%–9.4% and 4.3%–15.9% lower，respectively，than those in the monoculture system. The relay intercropping advantage on nutrient aspect was mainly due to the increase of nutrient absorption but not the decrease of nutrient utilization efficiency. The harvesting index of relay intercropping capsicum was significantly higher than that of the monocultured capsicum. The contribution of above- and below-ground interactions to the relay intercropping advantage of economic yield were 93.2% and 6.8%，respectively；Nevertheless the values were 88.8% and 11.2% respectively for biological yield in the condition of no nitrogen fertilizer application. While in the nitrogen fertilizer application zone，the contribution of above- and below-ground interactions to the relay intercropping advantage of economic yield were 85.2% and 14.8% respectively，and 84.6% and 15.4% were their relay intercropping advantage of biological yields respectively.