Abstract: To explore the effects of water and fertilizer addition on wheat biomass in the alfalfa-wheat rotation system,we conducted the experiment in the experiment station of the college of animal science and veterinary medicine,Shanxi Agricultural University,where the winter wheat was sown in 2017 and 2018 after planting alfalfa for 3 years. We carried out water and fertilization addition experiments with water addition for 5 times,and the fertilization addition amounts were 225 kg N·hm^-2 and 150 kg P₂O₅·hm^-2. The results showed that water addition significantly increased winter wheat biomass by 41.0% in 2018,but had no significant effect on it in 2017. Fertilization addition significantly increased winter wheat biomass by 62.0% in 2017 and 50.4% in 2018. The results showed that water and fertilization addition regulated soil moisture,leaf chlorophyll content and photosynthetic rate so that it affected the biomass of winter wheat by influencing the carbon accumulation in winter wheat. In addition,the study found that fertilization effect on winter wheat biomass became weakened following time after its returning green stage. It indicated that introducing alfalfa into winter wheat rotation system could reduce the application of chemical fertilizer by biological means,and then improve the environment.

Key words: Alfalfa, Biomass, Fertilizer addition, Water addition, Winter wheat

摘要： 为探究水肥对草田轮作系统作物生物量的影响，本研究利用山西农业大学动物科技学院试验站紫花苜蓿（Medicago sativa L.）-小麦（Triticum aestivum L.）轮作系统，开展增水（适量补水）和施肥（N 225 kg·hm^-2和P₂O₅ 150 kg·hm^-2）处理的控制试验，动态监测冬小麦生物量和土壤含水量等指标。结果表明：增水处理下，2018年冬小麦生物量提高41.0%（P<0.001），但在2017年不显著；施肥处理下，2017年和2018年冬小麦生物量分别提高62.0%和50.4%（P<0.001）。本研究显示增水和施肥通过调控土壤含水量、叶片叶绿素含量和光合作用速率来改变冬小麦对碳的积累，从而影响冬小麦生物量；冬小麦返青后，随着时间的推进施肥作用减弱。本研究结果说明将紫花苜蓿引入冬小麦的轮作系统有减肥增效以及改善生态环境的作用。

关键词: 紫花苜蓿, 生物量, 施肥, 增水, 冬小麦