灌水量和种植密度对干热河谷洋葱生物量及养分吸收利用的影响

The Effects of Irrigation Amount and Planting Density on Biomass and Nutrient Absorption and Utilization by Onion in an Arid Warm Valley

【目的】揭示干热河谷水分和密度管理模式的洋葱营养策略和节水减肥增产增效机制。【方法】以黄洋葱为研究对象,设置了3种灌水量(高水:7000 m3/hm2;中水:4550 m3/hm2;低水:3300 m3/hm2)和2个种植密度(高密度:22.12万株/hm2;低密度:11.88万株/hm2),研究其对洋葱生物量、抽薹率、养分吸收利用效率及水分利用效率(WUE)的影响。【结果】灌水量对洋葱WUE和养分吸收利用效率有显著影响,高水处理洋葱具有最高的P、K、Mg吸收效率,低水处理洋葱具有最高的P、K、Mg利用效率和水分利用效率优势。种植密度对洋葱生物量、抽薹率和养分吸收利用效率有显著影响,高密度处理洋葱具有最高N、P、Mg吸收效率;低密度处理洋葱具有最高的N、P、Mg利用效率、生物量和最低抽薹率优势。灌水量与种植密度对洋葱生物量、抽薹率、WUE、养分吸收利用效率及收获指数有明显互作效应;高水高密度处理洋葱N、P、K、Ca、Mg吸收效率显著最高;低水低密度处理洋葱WUE、N、P、K收获指数和Mg利用效率显著最高,抽薹率显著最低,且低水低密度主成分分析综合得分最高。【结论】干热河谷洋葱最佳灌水量和种植密度组合为低水低密度模式。

【Objective】Nutrient uptake and its use efficiency by crops are modulated by many biotic and abiotic factors,and the objective of this paper is to investigate their change in response to planting density and irrigations amount in attempts to provide a guidance to help improve water use efficiency and reduce fertilizer usage without compromising crop yield.【Method】The experiment was conducted in a field in an arid warm valley in Yunnan province,with onion used as the model plant.We compared three irrigation amounts:7000 m^(3)/hm^(2)(I1),4550 m3/hm^(2)(I2)and 3300 m^(3)/hm^(2)(I3),and two planting densities:21200 plants/hm2(D1)and 118800 plants/hm^(2)(D2).In each treatment,we measured the biomass and bolting percentage of the onion,its nutrient absorption and utilization,harvest traits,as well as water use efficiency(WUE)【.Result】Irrigation amount had a significant effect on WUE,nutrient absorption and utilization efficiency.Compared with other irrigation treatments,I1 increased the uptake of P,K and Mg by the crop,but the use efficiencies of these minerals in I3 were the highest.Planting density also significantly affected biomass,bolting percentage,nutrient absorption and utilization efficiency of the crop.Compared with D2,D1 increased the uptake efficiency of N,P and Mg by the crop,whilst their utilization efficiency was higher in the D2.It was found D2 significantly increased the biomass but reduced the bolting percentage of the crop.We found irrigation amount and planting density interactively affected biomass,bolting percentage,WUE,nutrient absorption and utilization efficiency,harvest traits,absorption efficiency of N,P,K,Ca and Mg,with most of these entities peaking in I1+D1.The principal component analysis gave the highest score to I3+D2 followed by I1+D1.【Conclusion】Comparison of various combinations of irrigation amounts and planting densities revealed that I3+D2 was optimal for growing onion in the arid warming valley studied in this work.