耕作方式与秸秆还田对冬小麦–夏玉米轮作系统中干物质生产和水分利用效率的影响

为探讨黄淮海地区一年两熟制下土壤耕作方式与秸秆还田相结合的适宜模式,2010—2012年进行了两年度的田间试验,研究不同处理对冬小麦–夏玉米轮作系统干物质生产和水分利用效率的影响。通过比较常规耕作+秸秆还田、常规耕作+无秸秆还田、深耕+秸秆还田、深耕+无秸秆还田、深松+秸秆还田、深松+无秸秆还田6个处理,发现深松(耕)与秸秆还田可以增加冬小麦和夏玉米的农田耗水量,降低休闲期农田耗水量,提高作物叶片相对含水量、净光合速率、蒸腾速率和茎秆伤流量,促进植株干物质积累,进而提高作物籽粒产量和水分利用效率。耕作方式与秸秆还田对冬小麦和夏玉米的干物质生产和水分利用效率存在显著交互作用。与常规耕作+无秸秆还田相比,深耕+秸秆还田和深松+秸秆还田处理的作物干物质积累量分别提高19.3%和22.9%,周年作物产量分别提高18.0%和19.3%,水分利用效率分别提高15.9%和15.1%,且两处理无显著差异。因此认为,与本试验相似环境条件下,宜在秸秆还田的基础上配合深松或深耕。

Effects of Tillage and Straw Returning on Biomass and Water Use Efficiency in a Winter Wheat and Summer Maize Rotation System

Straw returning to the field has been carried out in Huang-Huai-Hai Plain for ten years. In a consecutive two-year field experiment from 2010 to 2012, the effects of conventional tillage (CT), deep tillage (DT) and subsoiling (SS) on dry matter accumulation and water use efficiency were tested in a winter wheat–summer maize rotation system for setting up a tillage practice suitable for straw returning. The results were obtained from the comparison among six treatments, including CT+AS (all straw returning), CT+NS (no straw returning), DT+AS, DT+NS, SS+AS, and SS+NS. Under straw returning condition, either DT or SS practice increased water consumption amount during winter wheat or summer maize growth period but decreased it during fallow period. In addition, relative water content, net photosynthetic rate (P_n), transpiration rate (T_r) of leaf, and bleeding sap in stalk were also increased in both crops, leading to more biomass and higher water use efficiency together with increased grain yields in winter wheat and summer maize seasons. The effects of interactions between soil tillage (DT or SS) and straw returning on dry matter accumulation and water use efficiency were significant in both crops. Compared with conventional tillage under no straw returning, DT and SS under straw retuning resulted in increased dry matter accumulation (19.3% and 22.9%, respectively), annual crop yield (by 18.0% and 19.3%, respectively), and water use efficiency (by 15.9% and 15.1%, respectively). The difference of the effect between DT and SS under straw returning was not significant. Therefore, we recommend DT or SS practice in straw returning field under the environment similar to that of this experiment.