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(无秸秆还田(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。RMW30、RMW50和RMW100处理较RMW0处理土壤容重分别显著降低15.2%、11.7%和17.9%,土壤孔隙度则分别显著增加18.4%、13.7%和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,且孔隙均匀性和孔隙间连通性明显改善,RMW100和RMW50处理对土壤大孔隙组成的改善优于RMW30和RMW0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,RMW50和RMW100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%和23.6%。RMW50与RMW100处理土壤物理特征接近,与RMW0和RMW30处理在PC1和PC2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%和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,宜因地制宜进行还田量选择。
【Objective】The aim of this study was to ascertain the effects of straw returning quantity on the soil physical characteristics and to establish a recycling model for planting by-products,so as to provide a scientific basis for the utilization of straw resources in the central hilly area of Sichuan basin.【Method】Herein,based on long-term field trials(2006-present)using a combination of in situ monitoring and computed tomography microscanning (CT), the effects of different amounts 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 were examined.【Result】(1) Straw returned to the field could significantly improve soil permeability, water holding capacity and hydraulic conductivity, and the improving effect increased significantly with the amount of straw returned to the field. Compared with RMW0, soil bulk density under RMW30, RMW50, and RMW100 reduced significantly by 15.2%, 11.7%, and 17.9%, respectively;whereas, soil porosity under 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 under the RMW30 and RMW0 treatments. The average pore diameter of the RMW100 treatment tended to be larger and inter-pore connectivity was optimal. The homogeneity of the pores under the RMW50 treatment was significantly improved and the pore size distribution was more appropriate than that under other treatments. (3) Compared with 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 under RMW30 treatment. (4) Principal 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 23.6% of the physical properties of the soil, respectively. The physical characteristics under 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. 【Conclusion】On 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.
作者
马胜兰
况福虹
林洪羽
崔俊芳
唐家良
朱波
蒲全波
MA ShengLan;KUANG FuHong;LIN HongYu;CUI JunFang;TANG JiaLiang;ZHU Bo;PU QuanBo(Institute of Mountain Hazards and Environment,Chinese Academy of Sciences,Chengdu 610041;University of Chinese Academy of Sciences,Beijing 100049;Nanchong Academy of Agricultural Sciences,Nanchong 637000,Sichuan)
出处
《中国农业科学》
CAS
CSCD
北大核心
2023年第7期1344-1358,共15页
Scientia Agricultura Sinica
基金
国家重点研发计划(2018YFD0200700)
四川省科技计划(2018SZDX0027)。
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
straw returning
purple soil
winter wheat-summer maize rotation system
soil aggregate
soil pore characteristics
