晋北半干旱区免耕对玉米光合和蒸腾特性的影响

Effects of No-tillage on the Photosynthesis and Transpiration of Maize in the Semi-arid Area of Northern Shanxi Province

采用田间小区试验,对覆盖免耕、留茬免耕和传统翻耕三种耕作方式下玉米不同生育期土壤温度、土壤含水量以及玉米蒸腾速率和净光合速率进行观测。结果表明:与翻耕相比,免耕可降低0-20cm土层的土壤温度;覆盖免耕玉米地土壤温度的降低幅度较大,而留茬免耕地则较小;免耕对土壤温度的降低作用随着玉米的生长发育而减弱。免耕能够提高土壤含水量,尤其是0-60cm土层。免耕与翻耕相比,在玉米苗期,叶片的蒸腾和光合速率降低,其中覆盖免耕玉米日平均蒸腾与光合速率比翻耕分别降低了8.5%和9.7%,差异显著;留茬免耕略有降低,但差异不显著。在拔节前期,免耕与翻耕田玉米的蒸腾和光合速率无显著差异;在拔节后期、抽穗期和灌浆期,覆盖免耕玉米蒸腾和光合速率均比翻耕显著提高;留茬免耕在灌浆期玉米的蒸腾与光合速率均比翻耕显著提高,其它时期与翻耕差异不显著。

The experiment was carried out in the field with three treatments i.e. conventional till （CT）,non-till with retaining maize stubble （NT） and mulch-till with un-chopped maize straw mulch （MT）.The soil temperature,soil water content,transpiration and photosynthesis of maize in CT,NT and MT were observed. The soil temperature of maize field in no-tillage practices including MT and NT decreased comparing to that in CT. The decrease of the soil temperature was high in MT,and low in NT. The differences of the soil temperature among MT,NT and CT gradually became smaller with the growth of maize. MT and NT could improve the soil water content,especially in 0-60cm depth,comparing to CT. At the seedling stage,the photosynthesis and transpiration rates of maize in MT significantly reduced by 8.5% and 9.7%,respectively,but insignificantly reduced in MT,comparing to CT. At the early jointing stage,the photosynthesis and transpiration rates of maize showed no significant difference among MT,NT and CT. The photosynthesis and transpiration rates of maize in MT were significantly increased at the later jointing stage,the heading stage and the filling stage,respectively while those in NT significantly enhanced only at the filling stage,comparing to CT.