小麦大豆间作条件下作物养分吸收利用对间作优势的贡献

Uptake and utilization of nitrogen, phosphorus and potassium as related to yield advantage in wheat/soybean intercropping

采用田间小区试验和田间微区根系分隔试验 ,通过间作与相应单作成熟期氮磷钾养分吸收量和利用效率 (单位养分吸收量所能生产的干物质量 )的比较研究了小麦大豆间作中养分吸收和利用效率的变化。结果表明 ,间作作物氮、磷、钾养分吸收总量分别高出相应单作 2 4 %～39% ,6 %～ 2 7%和 2 4 %～ 6 4 % ;而间作氮、磷和钾的利用效率分别比单作低 5%～ 2 0 %、5%～7%和 6 %～ 32 %。间作优势主要表现在养分吸收量的增加。间作大豆养分收获指数的提高使间作子粒产量优势比生物学产量优势更明显。种间根系分隔微区试验表明 。

Nitrogen, phosphorus and potassium absorption efficiency and utilization efficiency in the intercropping or sole cropping of wheat and soybean were investigated by field plot and microplot experiments. The results showed that nitrogen, phosphorus and potassium uptakes by intercropped species were higher than the weighted means of uptakes by sole cropping species; Increases in N, P and K uptake by intercropped species over sole cropping species were 24%～29%, 6%～27% and 24%～26%, respectively. However, nitrogen, phosphorus and potassium utilization efficiency (kg biomass per kg nutrient uptake) were reduced due to intercropping. The reductions in the N, P and K utilization efficiency of intercropping ranged from 5% to 20%, from 5% to 7% and from 6% to 32%, respectively. Land equivalent ratio(LER) analysis in term of N, P and K utilization efficiency showed that the increase in LER over unity was due largely to a higher total uptake of nutrients by the component crops in the intercropping than by the sole crops. The greater nutrient harvest index of intercropped soybean than that of sole soybean also contributed to the yield advantage. Interspecific root partition experiment demonstrated that interspecific root intermingle also affected nutrient utilization efficiency in intercropping.