夜间土壤增温和免耕对大豆生长及N、P养分吸收利用的影响

Effects of Nighttime Soil Warming and No-tillage on Soybean Growth and the Utilization of N and P

采用田间开放式增温系统在南京信息工程大学试验田设置4个处理：常温＋翻耕（CK）、夜间增温＋翻耕（W）、常温＋免耕（NT）、夜间增温＋免耕（WNT）种植大豆,观测其生物量、籽粒产量和构成因子以及氮（N）、磷（P）累积和转运特征,分析各处理对大豆生长及N、P养分吸收利用的综合影响.结果表明：（1）与对照相比,全生育期内大豆植物生物量在夜间增温（W）下均显著减小（P＜0.05）,降幅为6％～25％.籽粒产量、单株粒数、单株粒重和百粒重均有一定减小,但未达显著水平.分枝期和开花期,植物N素累积量分别下降30％和20％,P素累积量均下降39％.（2）免耕处理（NT）未对大豆籽粒产量及构成因子产生明显影响,但显著降低了植物生物量、营养器官的N、P转运量和转运率（P＜0.01）.（3）增温＋免耕处理（WNT）下,植物生物量和籽粒产量均极显著减小（P＜0.01）,分别降低29％和34％,大豆单株粒数、单株粒重和百粒重分别减小22％、22％和3％.植物成熟期N、P累积量在WNT处理下分别下降20％和22％,显著低于其它3个处理.研究结果表明,夜间增温或免耕单一因素对大豆籽粒产量及产量构成因子的影响效应较小,而夜间增温叠加免耕措施则显著抑制了大豆籽粒产量和N、P素累积量.因此,在夜间土温增高条件下采用免耕措施对大豆生产将产生不利影响.研究结果对未来气候背景下,建立长江下游地区的保护性耕作技术体系具有实践指导意义.

In order to investigate the effects of nighttime warming and no-tillage on soybean growth and its uptake and utilization of nitrogen （N） and phosphorus （P）, field nighttime warming system was designed in trial field in Nanjing University of Information Science and Technology. The experiments were conducted with four treatments, that is, normal nighttime temperature with traditional tillage （CK）, nighttime warming with traditional tillage （W）, normal nighttime temperature with no-tillage （NT）, and nighttime warming with no-tillage （WNT）. The results showed that compared to CK, nighttime warming （W） significantly decreased plant biomass by 6% -25% during the growing season （P 〈 0.05 ） , whereas had little effect on grain yield, grains per plant, grain weight per plant, and 100 - seed weight of soybean. During branching and flowering stages, warming reduced N accumulation by 30% and 20%, respectively, and P accumulation by 39% and 39%. No-tillage had a limited effect on grain yield and yield components, but significantly decreased plant biomass, translocation amounts and efficiencies of N and P （ P 〈 0. 01 ）. Warming with no-tillage （WNT） treatment significantly decreased plant biomass and grain yield by 29% and 34%, respectively （P 〈 0. 01 ）. Moreover, grains per plant, grain weight per plant, and 100 -seed weight of soybean were reduced by 22%, 22% and 3% , respectively, under WNT treatment. Meanwhile, at maturity, N and P accumulations were 20% and 22% lower under WNT treatment than under CK treatment, respectively. Thus, this study indicated that grain yield and yield components of soybean were hardly affected by single factor like either nighttime warming or no-tillage, whereas nighttime warming with no-tillage significantly reduced grain yield of soybean and N and P accumulation. Therefore, it is unfavorable to soybean production by means of no-tillage under climate warming condition.