不同耕作措施对麦田土壤碳储量和作物水氮利用效率的影响

为了探索耕作措施和秸秆还田对麦田土壤碳氮水的动态变化的影响,在田间定位试验的基础上,通过深耕(T1)、深耕+秸秆还田(T2)、浅耕(T3)、浅耕+秸秆还田(T4)4种不同耕作方式处理,对麦田碳储量、土壤含水量、全氮含量以及作物水氮利用效率的变化进行了研究。结果表明,秸秆还田在不同时期对土壤碳储量有一定的影响,与播前土壤有机碳储量相比,0~20 cm土层各处理在越冬期有较高的有机碳储量,20~40 cm土层则于拔节期有机碳储量达到最大值,40~60 cm土层除T1处理,其他处理皆为拔节期最大。综合来看,在整个生育期有机碳储量均表现为秸秆还田处理大于秸秆不还田处理。深耕处理提高了小麦生育前期的土壤含水量,T2处理的作物耗水量比T4处理高4.2%;秸秆还田提高了作物的水分利用效率,T2的水分利用效率、灌溉水利用效率分别比浅耕加秸秆还田高24.9%,27.6%。除开花期,T1处理的植株含氮量高于浅耕处理,T2处理能够显著提高冬小麦氮素积累量,较不还田处理提高了44%;T1处理的氮素利用效率比浅耕处理高57.2%。秸秆还田处理在生育前期抑制了小麦的生长,但后期促进了植株干物质量的积累。秸秆还田有利于穗粒数的提高,从而提高产量,T2处理较T3处理产量提高了22.1%,较T1处理增产6.7%;T1处理较T3处理增产14.4%。因此,秸秆还田和深耕有助于提高土壤碳储量,提高水分和氮素利用效率,进而提高作物产量。

Effects of Different Tillage Methods on Carbon Storage of Soil and Utilization Efficiency of Water and Nitrogen in Wheat

Based on a long-term field experiment,the effects of different tillage measures on the carbon storage of soil and the utilization efficiency of water and nitrogen in wheat were studied.Four models were designed:deep tillage(T1 ),deep tillage plus straw returning(T2 ),shallow tillage (T3 ),and shallow tillage plus straw returning (T4).The results showed that straw returning had a certain infuenceron soil carbon accumulation.Compared with the organic carbon storage before sowing,it was higher at winter stage in 0 -20 cm soil,reached to the highest at jointing stage in 20 -40 cm,and also had the maximum value at jointing stage in 40 -60 cm except T1 treatment. During the whole growth period,the organic carbon storage was generally higher in straw returning treatment than in no straw returning.T1 treatment increased the soil water content in early growth stage of wheat.The crop water con-sumption of T2 treatment was 4.2% higher than that of T4 treatment.Straw returning could increase the water use efficiency of wheat.The water use efficiency and irrigation water use efficiency of T2 were 24.9% and 27.6% high-er,respectively,than that of T4.Except in flowering stage,the nitrogen content of plant was higher in deep tillage than in shallow tillage.And T2 treatment could significantly improve the nitrogen accumulation of wheat,44% high-er than that of no straw returning.Deep tillage increased the nitrogen utilization efficiency by 57.2% compared with the shallow tillage straw returning treatment inhibited the growth of wheat in early growing stage,but promoted the dry matter accumulation in later growing stage.Straw returning could increase the grain number of wheat,so as to raise the grain yield.The grain yield of T2 was 22.1 % higher that of T3,and 6.7% higher than that of T1 ,while it was 14.4% higher in T1 than in T3.The results suggested that straw returning and deep tillage could increase the carbon storage of soil,improve the use efficiency of water and nitrogen,and then increase the grain yield of wheat.