不同耕作方式对广西蔗田土壤生物性和非生物性孔隙结构的影响

Effects of different tillage practices of soil biopores and non-biopores structures in sugarcane field soils of Guangxi

【目的】探究传统旋耕与粉垄耕作方式对广西蔗田土壤生物性和非生物性孔隙结构的影响,以期为该地区甘蔗生产中合理选择耕作方式提供理论依据。【方法】以蔗田土壤为研究对象,设粉垄耕作20 cm(F20)和传统旋耕20cm(X20)2种处理,于甘蔗伸长期采集土壤样品,测定0~40 cm深度土层的土壤颗粒分布、容重及有机质含量;利用X射线CT扫描技术并结合ImageJ 1.53c及MATLAB 2019a等软件分离获取土壤生物性和非生物性孔隙的二维和三维特征参数,并对2种处理下孔隙结构进行三维重构可视化。【结果】与X20处理相比,F20处理0~40 cm土层的黏粒含量平均值显著降低32.16%(P<0.05,下同),而粉粒含量平均值显著提高12.82%。F20处理0~10 mm孔径范围的二维生物性孔隙数量高于X20处理,二者非生物性二维孔隙数量差异不明显;F20处理的生物性孔隙圆度较X20处理显著提高10.58%。在孔隙三维参数中,F20处理的生物性孔隙连通度较X20处理显著提高67.55%,其余参数均小于X20处理;F20处理非生物性孔隙的孔隙度、弯曲度、连通度和比表面积均低于X20处理,但均无显著差异(P>0.05)。在三维重构图中,X20处理生物性孔隙多分布在0~10 cm土壤表层区域,F20处理的生物性孔隙则在10~30 cm土层中形成了更多向下延伸的连续管状结构;X20处理的非生物性孔隙分布较疏松,F20处理的作物根系主要生长区周围存在较多非生物性孔隙。【结论】粉垄耕作形成的生物性孔隙结构优于传统旋耕,特别是在形成上下连通的生物性孔隙和更密集的非生物孔隙分布方面具有一定优势,可更好地促进水肥运移通道的形成。在广西甘蔗种植过程中,可采用粉垄耕作以有效改善土壤孔隙结构。

【Objective】To investigate the effects of traditional rotary plowing and Fenlong tillage on the biopores and non-biopores structures of sugarcane field soils in Guangxi,which could provide theoretical basis for the rational selec‐tion of tillage practices in sugarcane production in this region.【Method】Using the soil in sugarcane field as object,soil samples were collected during the elongation period of sugarcane using 2 treatments,namely,20 cm Fenlong tillage(F20)and 20 cm traditional rotary tillage(X20),to determine the distribution of soil particles,bulk density and organic matter content of the soil layer from 0 to 40 cm depth.The two-dimensional and three-dimensional feature parameters of soil biopores and non-biopores space were obtained by using X-ray CT scanning technology combined with ImageJ 1.53c and MATLAB 2019a,and the pore structure was visualized by three-dimensional reconstruction under the 2 treatments.【Result】Compared with X20 treatment,the average clay content of 0-40 cm soil layer in F20 treatment was significantly reduced by 32.16%(P<0.05,the same below).In comparison,the average silt content was significantly increased by 12.82%.The biopores two-dimensional number with 0-10 mm pore diameter of F20 treatment was higher than that of X20 treatment,and the difference of the non-biopores two-dimensional pore number between the two was not obvious;the bio‐pores roundness in F20 treatment was significantly increased by 10.58%compared with X20 treatment.Among the three-dimensional pore parameters,the connectivity of biopores in F20 treatment was significantly increased by 67.55%com‐pared with X20 treatment,and the rest of the parameters were smaller than X20 treatment;the porosity,tortuosity,con‐nectivity,and specific surface area of non-biopores in F20 treatment were lower than those in X20 treatment,but the dif‐ferences were not significant(P>0.05).In the three-dimensional reconstruction maps,the biopores of the X20 treatment were only mostly distributed in the 0-10 cm soil surface area,while the biopores of the F20 treatment formed more downward-extending continuous tubular structures in the 10-30 cm soil layer;the distribution of the non-biopores in the X20 treatment was more sparse;and more non-biopores existed around the main growing area of the crop root system in the F20 treatment.【Conclusion】The biopores structure formed by Fenlong tillage is superior to that of traditional rotary plowing,especially in the formation of upper and lower connected biopores and denser distribution of non-biopores,which can better promote the formation of water and fertilizer transport channels.In the process of sugarcane cultivation in Guangxi,Fenlong tillage can be used to effectively improve the soil pore structure.