中国农业科学

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最新录用:秸秆还田量对川中丘陵冬小麦-夏玉米轮作体系土壤物理特性的影响

马胜兰1,2况福虹1*林洪羽1,2, 崔俊芳1唐家良1朱波1蒲全波3
  

  1. 1中国科学院、水利部成都山地灾害与环境研究所,成都 610041;2中国科学院大学,北京1000493南充市农业科学院,四川南充 637000
  • 发布日期:2022-06-22

Effects of Straw Incorporation Quantity on Soil Physical Characteristics of Winter Wheat-Summer Maize Rotation System in the Central Hilly Area of Sichuan Basin

MA ShengLan1,2, KUANG FuHong1*, LIN HongYu1,2, CUI JunFang1, TANG JiaLiang1, ZHU Bo1, PU QuanBo3 #br#   

  1. 1Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041; 2University of Chinese Academy of Sciences, Beijing 100049; 3Nanchong Academy of Agricultural Sciences, Nanchong 637000, Sichuan
  • Online:2022-06-22

摘要: 【目的】探明秸秆还田量对农田土壤物理特征的影响,为川中丘陵紫色土区建立提升土壤质量、高效利用秸秆的种植业副产物利用模式,同时为秸秆资源化利用提供科学依据。【方法】基于田间长期定位试验(2006-至今),采用原位监测和计算机断层微扫描技术(CT)相结合的方法,研究秸秆还田量(秸秆还田(RMW0)、秸秆30%还田(RMW30)、秸秆50%还田(RMW50)和秸秆100% 还田(RMW100))差异对冬小麦-夏玉米轮作体系耕层土壤物理特征的影响。【结果】(1秸秆还田可明显改善土壤透气、持水和导水性能,随秸秆还田量增加改善效果明显增加RMW30RMW50RMW100处理较RMW0处理土壤容重分别显著降低15.2%11.7%17.9%,土壤孔隙度分别显著增加18.4%13.7%21.3%。另外,RMW100处理饱和导水率高达1.62 mm·min-1导水性能优于其他处理。2秸秆还田促进已有孔隙发育成更大孔隙,孔隙均匀性和孔隙间连通性明显改善RMW100处理和RMW50处理对土壤大孔隙组成的改善优于RMW30RMW0处理。RMW100处理平均孔隙直径趋大,孔隙间连通性最优RMW50处理孔隙均匀性明显提高,大小孔隙配比较其他处理更合理。3)与无秸秆还田处理相比,秸秆还田后>2 mm团聚体数量显著增加,0.25—2 mm团聚体数量显著减少,秸秆还田有利于形成土壤水稳性大团聚体,促进中团聚体向大团聚体转变,RMW50RMW100处理改善效果均显著优于RMW30处理。4土壤容重、>0.25 mm团聚体和大孔隙特征是反映石灰性紫色土区耕层土壤物理特征的主要指标,第一主成分和第二主成分对土壤物理性质的解释度分别为57.8%23.62%RMW50RMW100处理土壤物理特征接近,与RMW0RMW30处理在PC1PC2轴上出现明显离散。【结论】川中丘陵紫色土区在产量无显著差异的基础上,不同秸秆还田量对耕层土壤物理性质的影响存在差异,秸秆50%100%还田效果无显著差异,但显著优于秸秆30%还田和不还田处理因地制宜进行还田量选择


关键词: 秸秆还田, 紫色土, 冬小麦-夏玉米轮作, 土壤团聚体, 土壤孔隙

Abstract: 【ObjectiveTo ascertain the effect of straw returning quantity on the soil physical characteristics and establish a recycling model for planting by-products. At the same time, to provide a scientific basis for the utilization of straw resources in the central hilly area of Sichuan basin.MethodHerein, we examined the effects of different amount of straw returned to the field (0% straw returned (RMW0), 30% straw returned (RMW30), 50% straw returned (RMW50) and 100% straw returned (RMW100)) on the physical characteristics at the cultivated soil layer of the winter wheat-summer maize rotation system, based on long-term field trials (2006-present) using a combination of in situ monitoring and computed tomography microscanning (CT).Result(1) Straw returns to the field could significantly improve soil permeability, water holding capacity and hydraulic conductivity, and the improve effect increases significantly with the amount of straw returned to the field . Compared to the RMW0 treatment, soil bulk density in RMW30, RMW50 and RMW100 treatments reduced significantly by 15.2%, 11.7% and 17.9%, respectively. Whereas soil porosity of these treatments were significantly increased by 18.4%, 13.7% and 21.3%, respectively. In addition, the Saturated hydraulic conductivity of RMW100 treatment was as high as 1.62 mm min-1, and the soil hydraulic conductivity was superior to other treatments. (2) Straw returning promoted the development of existing pores into larger ones and significantly improved pore uniformity and connectivity. The RMW100 and RMW50 treatments improved the macropore composition of the soil better than that of the RMW30 and non-return treatments. The average pore diameter of the RMW100 treatment tends to be larger and inter-pore connectivity is optimal. The homogeneity of the pores in the RMW50 treatment was significantly improved and the pore size distribution was more appropriate than that of other treatments. (3) Compared to the RMW0 treatment, the number of >2 mm agglomerates increased significantly and the number of 0.25-2 mm agglomerates decreased significantly after straw returned to the field, which was beneficial to the formation of large soil water-stable agglomerates and promoted the transformation of medium to large agglomerates. Both RMW50 and RMW100 treatments improved significantly better than that of RMW30 treatment. (4) Principle components analysis showed soil bulk density, water-stable aggregate with diameter larger than 0.25 mm and large pore were the main indicators of the physical characteristics of cultivated soils in calcareous purple soils. The first and second principal components explained 57.8% and 23.62% of the physical properties of the soil. The physical characteristics of RMW50 and RMW100 treatments were close to each other, and showed significant divergence from the RMW0 and RMW30 treatments on the PC1 and PC2 axes. ConclusionOn the basis of no significant difference of crop yield in the central hilly area of Sichuan basin, there were differences in the effects of different straw returning quantities on the physical properties of cultivated soil layer, with no significant differences between 50% and 100% straw returning effects, but significantly better than that of 30% and 0% of straw incorporation. The specific straw application rate should be selected according to the local conditions.


Key words: straw returning, purple soil, winter wheat-summer maize rotation system, soil aggregate, soil pore characteristics