两种三熟套作体系中的氮素吸收利用及种间相互作用

Nitrogen Uptake and Utilization and Interspecies Reciprocity in the Two Relay-planting Systems

通过根系分隔盆栽试验,研究小麦/玉米/大豆与小麦/玉米/甘薯两种三熟套作体系的氮素吸收利用及种间相互作用。结果表明:小麦表现为套作优势,两种体系下不分隔的生物产量与吸氮量均高于完全分隔。玉米在"麦/玉/薯"中表现出竞争劣势(Awc>0,NCRwc>0),不分隔的生物产量与吸氮量显著低于完全分隔;在"麦/玉/豆"中表现出竞争优势(Awc<0,NCRwc<0),不分隔的籽粒产量、籽粒吸氮量和总生物产量、总吸氮量均高于完全分隔,且比"麦/玉/薯"高5.62%、59.09%、5.97%、41.18%。大豆虽表现出竞争劣势,但生物产量与吸氮量降低不明显;甘薯具有微弱的竞争优势,但生物产量与吸氮量显著降低,总吸氮量比大豆低53.11%。不分隔时,"麦/玉/薯"中的玉米与甘薯土壤总氮含量比"麦/玉/豆"中的玉米与大豆低3.95%和8.57%。

A root barrier pot experiment was employed to investigate the nitrogen uptake and utilization and interspecies reciprocity of ＂wheat/maize/soybean＂ and ＂wheat/maize/sweet potato＂. The regults showed that wheat exhibited a obvious relay-planting advantage, and in the two systems, the biomass and nitrogen acquisition under without barrier condition were higher than those of under solid barrier. In the ＂wheat/maize/sweet potato＂ system, maize exhibited the competition disadvantage （Aux〈0, NCRux〈0）, and the biomass and nitrogen acquisition under without barrier.condition were significantly than those of under solid barrier. On the contrary, in the ＂wheat/maize/soybean＂ system, maize indicated competition advantage （Aux〈0, NCRux〈0）, the grain yield, the nitrogen acquisition in grain, the total biomass and the total nitrogen acquisition under without barrier were significantly higher than those of under solid barrier, with 5.62%, 59.09%, 5.97% and 41.18% higher respectively than those in the ＂wheat/maize/sweet potato＂ system. In addition, the soybean showed competition disadvantage, hut hiomass and nitrogen acquisition reduced indistinctively. Though the sweet potato exhibited small competition advantage, the biomass and nitrogen acquisition reduced markedly, and the total nitrogen acquisition was 53.11% lower than that of soybean. In the without treatment, the soil total N content of maize and sweet potato in the ＂wheat/maize/sweet potato＂ system, were 3.95% and 8.57% lower than those of ＂wheat/maize/soybean＂ system.