| A long-term practice of applying single soil rotary tillage pattern in this area causes soil compaction,poor ability of retaining rainwater and providing nutrition.The experiments of CRS(continuous rotary tillage and straw returning),CSS(continuous subsoiling and straw returning),CDS(continuous deep tillage and straw returning),DS/RS(rotary tillage in first year,deep tillage in second year,again deep tillage followed by alternating the next year and straw returning),DS/RS/RS(deep tillage in first year,rotary tillage in second year,rotary tillage in third year,again deep tillage followed by alternating the next year and straw returning)and CDNS(continuous deep tillage and straw removed)were conducted in Luoyang and xinxiang before sowing winter wheat,and different rotational tillage and straw returning on soil bulk density,ratio of soil solid-liquid-gaseous,soil available nutrition,soil organic carbon storage,soil total nitrogen storage,soil enzyme activities,soil respiration rate,nutrient absorption,crop economic benefits and carbon footprint were analyzed.The results showed that:1.Rotational tillage patterns and straw returing decreased soil bulk density and the R value,ratio of soil solid-liquid-gaseous.Rotational tillage patterns mainly decreased soil bulk density in 0-20 cm soil layers,but soil bulk density under straw returing had no significantly different.At 0-20 cm soil layer,compared with CRS,the soil bulk density under CSS,CDS,DS/RS,DS/RS/RS were significantly decreased 7.8%,9.8%,6.9%,5.5% in winter wheat maturing stage,and significantly decreased 8.0%,10.3%,7.5%,6.2% in summer maize maturing stage,respectively.Rotational tillage,straw returning reduced the R value of 0-40 cm soil layer.Compared with CRS,the R value under CSS,CDS,DS/RS,DS/RS/RS were significantly decreased 14.0%,9.0%,12.9%,9.0% in winter wheat maturing stage,and significantly decreased 18.3%,10.1%,15.3%,8.3% in summer maize maturing stage,respectively.Compared to CDNS,the R value of CDS significantly reduced10.8% in winter wheat maturing stage,and significantly decreased 4.6% in summer maize maturing stage.2.Rotational tillage and straw returning improved soil nutrients of surface and subsurface of 0-40 cm soil layer,and the increase trend under DS/RS/RS was obvious.Compared with CRS,soil nutrient contents of CSS,CDS,DS/RS,DS/RS/RS at 0-40 cm soil layer increased by 10.3%,9.3%,11.8%,9.3% in winter wheat maturing stage,and thesummer maize maturing stage increased by 10.9%,10.0%,12.3%,10.9%,respectively.Compared to CDNS,the soil nutrient contents of CDS significantly reduced 10.8% in winter wheat maturing stage,and significantly decreased 4.6% in summer maize maturing stage.3.With increasing cultivation,the soil organic carbon storage and soil total nitrogen storage at 0-40 cm soil layer showed atrend of overall increase.The DS/RS/RS pattern was obvious significantly,but CDNS showed a trend of overall decrease.Under straw returning,DS/RS/RS was the most of the soil organic carbon storage and soil total nitrogen storage at0-40 cm soil layer,which had no significantly difference with DS/RS,and was significantly higher than CRS,CSS.Compared to CDNS,CDS of the soil organic carbon storage and soil total nitrogen storage increased significantly by 14.0% in winter wheat maturing stage,and significantly increased 16.3% in summer maize maturing stage,4.Rotational tillage and straw returning mainly increased soil enzyme activities at 10-40 cm soil layer.There was a decreasing trend of soil enzyme activities with increasing soil depth and had a significant difference between soil layers.Compared with CRS,soil enzyme activities under CSS,CDS,DS/RS,DS/RS/RS patterns at 10-40 cm soil layer increased by14.7%,25.6%,26.8%,25.6% in winter wheat maturing stage,and the summer maize maturing stage increased by 14.2%,25.2%,25.6%,14.2%,respectively.Compared to CDNS,soil enzyme activity under CDS pattern at 10-40 cm soil layer in winter wheat maturing stage significantly increased by 24.3%,and the summer maize maturing stage significantly increased by 20.8%.5.Rotational tillage and straw returning significantly improved the soil respiration rate and soil heterotrophic respiration rate,and increased the season of winter wheat and summer maize season of CO2 emissions.Under straw returning,the maximum of soil respiration rate and CO2 emissions under different rotational tillage patterns was CDS,followed by CSS,DS/RS,DS/RS/RS,CRS.CDS,CSS were significantly higher than other rotational tillage patterns.Compared to DS/RS/RS,anniversary CO2 emissions of DS/RS increased 4.6%.6.Rotational tillage and straw returning significantly increased the plant nutrient uptake.Compared with CRS,the plant nitrogen absorption under CSS,CDS,DS/RS,DS/RS/RS patterns were significantly increased by 30.6%,16.6%,30.1%,16.6%,and the phosphorus absorption were significantly increased by 24.1%,17.7%,33.0%,17.7%,and potassium absorption were significantly increased by 27.4%,17.0%,30.2%,17.0%.Nitrogen and phosphorus nutrients were mainly distributed by 75.8%,82.1% in grains,respectively,while potassium mainly distributed by 79.0% in the straw.Under continuous deep tillage,CDS of plant nutrient uptake was significantly higher than that of CDNS.7.Rotational tillage and straw returning significantly improved the winter wheat andsummer maize yield and economic benefits.Through comprehensive evaluation and analysis of the winter wheat and summer maize annual grain yield and economic benefits for five rotational tillage patterns in six years,DS/RS/RS rotational tillage pattern was the best,followed by DS/RS.Compared with CRS,the average annual yield of DS/RS/RS,DS/RS,CSS,CDS significantly increased by 19.9%,19.9%,15.7%,12.9%;DS/RS/RS significantly increased the average economic benefits by11.8% than CDS,and significantly increased 34.2% than CRS.Under continuous deep tillage,compared to CDNS,the average annual yield of CDS significantly increased 7.7%,and the annual economic benefit increased 28.0%.8.Rotational tillage and straw returning had a significant impact in farmland carbon footprint.There was a decreasing trend of soil enzyme activities with increasing cultivation in Luoyang and Xinxiang experimental zones.Farming activities were the main factors affecting farmland carbon footprint.The highest proportion in footprint constitute was chemical fertilizer(64.5%),followed by irrigation,diesel oil,seeds,pesticides and manpower.Compared with CRS,CSS,CDS,DS/RS,DS/RS/RS of farming activities increased 17.2 kg CO2-eqhm-2·yr-1,16.8 kg CO2-eqhm-2·yr-1,8.4 kg CO2-eqhm-2·yr-1,5.6 kg CO2-eqhm-2·yr-1.Compared with CRS,carbon footprint of CSS,CDS,DS/RS,DS/RS/RS significantly reduced by 11.5%,10.2%,14.0%,10.2%.CDS in the carbon footprint was lower by 4.5% than CDNS. |
PDF Full Text Request