不同耕作方式下秸秆还田对晋中玉米田水分时空分布及产量的影响

为探讨保护性耕作和秸秆还田有机结合对春玉米休闲期蓄水保墒效果、生育期土壤水分时空变化、贮水量季节变化、产量及水分利用效率的影响,设置不同耕作方式(免耕、深松、翻耕)结合秸秆还田(100%秸秆还田、秸秆不还田)6个处理组合,2016-2018年在山西晋中连续2年进行定位试验研究。结果表明:(1)春玉米冬闲期不同耕作处理下土壤贮水量差异显著,且随着时间推移贮水量都有降低趋势,免耕和深松处理分别较翻耕土壤贮水量平均增加10.4,9.3 mm。在玉米的整个生育时期,免耕和深松处理土壤贮水量分别比翻耕提高4.8%,1.2%。(2)平均2年土壤含水量大小顺序为免耕>深松>翻耕,各处理平均土壤含水量分别为23.0%,21.8%,21.5%。丰水年不同耕作方式土壤含水量垂直变化在各生育时期差异较大,干旱年其变化的差异较小。(3)免耕与100%秸秆还田组合下玉米产量和水分利用效率最高,2年平均产量和WUE(水分利用效率)分别为12 679.9 kg/hm²和25.8 kg/(hm²·mm),翻耕与100%秸秆还田处理组合最低。无论是否秸秆还田,免耕和深松处理在春玉米冬闲期土壤蓄水保墒效果、生育期土壤水分状况、产量与水分利用效率均优于翻耕处理;在秸秆还田下免耕和深松耕作方式对玉米田水分的集蓄保用有良好的效果,以免耕秸秆还田效果最佳,可在晋中地区春玉米生产中推广应用。

Effects of Straw Returning on Spatio-temporal Distribution of Water and Maize Yield Under Different Tillage Methods in Jinzhong

In order to explore the effects of combination of conservation tillage and straw returning on water storage during fallow period, temporal and spatial variation of soil moisture during growth period, seasonal variation of water storage, yield and WUE of maize, the located experiment was conducted by setting 6 treatments of different tillage methods (no-tillage, sub-soiling and deep plowing) combined with straw returning (100% straw returning, no straw returning) in Jinzhong of Shanxi from 2016 to 2018. The results showed that:(1) The difference in soil water storage under different tillage treatments during spring maize winter fallow period was significant, and water storage had a decreasing trend along with time delay. The soil water storage of no-tillage and sub-soiling treatments increased by 10.4 mm and 9.3 mm, respectively, compared with deep plowing. During the whole growth stage of maize, the soil water storage of no-tillage and sub-soiling was 4.8% and 1.2% higher than that of deep plowing. (2) The order of average soil water content for two years was no-tillage > sub-soiling > deep plowing, the average soil water content of each treatment was 23.0%, 21.8% and 21.5%, respectively. The vertical variation of soil water content under different tillage methods varied greatly during different growth periods in wet year, and while the variation in drought year was small. (3) The combination of no-tillage and 100% straw returning had the highest yield and WUE of maize, the 2-year average yield and WUE was 12 679.9 kg/hm² and 25.8 kg/(hm²·mm), respectively. The combination of deep plowing and 100% straw returning had the lowest yield and WUE. Regardless of whether straw was returned to the field or not, no tillage and sub-soiling were better than deep plowing on soil water conservation in winter fallow period, soil moisture status in growth period, yield and WUE of spring maize. No-tillage and sub-soiling tillage under straw returning had good effect on water collection and conservation in maize field. The combination of no-tillage and 100% straw returning had the best effect, it could be promoted and applied in spring maize production in Jinzhong area.