耕作与秸秆还田方式对稻茬麦草谷比及麦秸可收集系数的影响

Effects of Tillage and Straw-returning Modes on Straw-Grain Ratio and Wheat Straw Collectable Coefficient in Wheat-Rice Rotation System

研究了不同耕作（耕翻与浅旋耕）与秸秆还田方式（周年稻秸秆全量还田、麦秸秆全量还田、稻麦秸秆全量还田以及稻麦秸秆不还田）对稻茬麦草谷比和麦秸可收集系数的影响。结果表明，两种耕作处理对稻茬麦草谷比、麦秸垂直空间分布特征以及麦秸可收集系数的影响皆不显著，而不同秸秆还田处理间草谷比差异达显著水平，麦秸垂直空间分布特征及可收集系数未表现出差异。秸秆还田处理增加了单位面积内稻茬麦秸秆产量，秸秆产量高低顺序依次为周年稻麦秸秆全量还田（Srw）〉周年仅水稻秸秆还田（Sr）〉周年仅小麦秸秆还田（Sw）〉周年秸秆不还田（SO），各处理间籽粒产量变化并不显著，因而处理Srw的草谷比显著高于Sw与S0处理。相同留茬高度条件下，麦秸可收集系数在不同秸秆还田方式间没有显著差异，留茬高度分别为5、10、15、20cm时，稻茬麦秸秆可收集系数依次为0．65～0．66、0．58～0．60、0．52～0．54、0．45～0．47。估算一定留茬高度的稻茬麦秸秆可收集系数时可以忽略旋耕整地和秸秆还田方式的短期影响，进一步简化估算参数。

In the typical rice -wheat rotation region of Jiangsu province, the winter wheat variety Yangmai 16 was used to study the effects of 2 tillage measures （ conventional ploughing, shallow rotary tillage） and 4 straw - returning modes [ returning all rice straw to field （treatment St）, returning all wheat straw to field （treatment Sw）, returning all rice straw and wheat straw to field （treatment Srw）, not returning straw to field （treatment SO） ] on the ratio of rice stubble plus wheat straw to grain, as well as the wheat straw collectable coefficient in wheat - rice rotation system. The results showed that there was no significant difference in straw - grain ratio, vertical spatial distribution characteristics of wheat straw, and wheat straw collectable coefficient between two tillage measures. Among 4 straw - returning modes, there was significant difference in straw - grain ratio, but there was no significant difference in vertical spatial distribution characteristics of wheat straw and wheat straw collectable coefficient. All treatments of retur- ning straw to field increased the yield of rice stubble plus wheat straw per unit area, and the straw yield in various treatments re- vealed the following sequence ： Srw 〉 Sr 〉 Sw 〉 SO. However, straw - returning mode had no significant influence on grain yield, therefore the straw - grain ratio in treatment Srw was significantly higher than that in treatment Sw and SO. The wheat straw collect- able coefficient was scarcely effected by different straw - returning modes under the condition of same stubble height. When the height of rice stubble left in the field was 5, 10, 15, and 20 cm separately, the wheat straw collectable coefficient was 0.65 ～ 0.66, 0.58～ 0.60, 0.52 ～ 0.54, and 0.45～ 0.47 respectively.