关键词: 秸秆还田, 氮肥, 土壤有机碳, 土壤氮, 小麦(Triticum aestivum L.), 生长特性, 产量

Abstract: To determine the optimal combination of straw returning and nitrogen fertilizer in wheat (Triticum aestivum L.) cultivation within the rice-wheat rotation system of the Jianghan Plain,a field experiment was conducted using a split-plot design. Three straw returning treatments of no straw returning (NSR),half straw returning (HSR),and full straw returning (TSR) were tested. Four N fertilization levels of N0 (0 kg/hm²),N1 (90 kg/hm²),N2 (180 kg/hm²),and N3 (270 kg/hm²) were also applied. The effects of these treatments on soil carbon and nitrogen contents, population photosynthetic parameters, aboveground dry matter accumulation and yield of wheat were studied. The results showed that HSR and TSR combined with N2 and N3 could effectively increase soil organic carbon in 0~20 cm soil layer. HSR combined with N2 and N3 could increase soil total nitrogen content. HSR combined with N3 could increase soil nitrate nitrogen content in the wintering stage. TSR combined with N2 and N3 could increase soil ammonium nitrogen content in 0~10 cm soil layer from the flowering stage to the maturity stage. HSR+N3 treatment significantly increased the flag leaf relative chlorophyll content and population leaf area index of wheat after booting, so that it had higher aboveground dry matter accumulation. Straw returning increased the proportion after anthesis, while the increase of nitrogen application rate increased the proportion of dry matter accumulation before anthesis. Straw returning combined with nitrogen fertilizer significantly affected wheat yield, and the yield of HSR+N3 treatment was the highest. In conclusion, in the Jianghan Plain’s rice-wheat rotation system, half straw returning combined with 180~270 kg/hm² of N fertilizer could maximize wheat yield and effectively improve soil nutrient content.

Key words: straw returning, nitrogen fertilizer, soil organic carbon, soil nitrogen, wheat(Triticum aestivum L.), growth characteristics, yield