基于不同深翻年限土壤团聚体空间分异与稳定性研究

Spatial variation and stability of soil aggregates based on different deep turning years

【目的】探究不同深翻年限下土壤团聚体在不同土层深度的空间变异和稳定性。【方法】以云南祥云蔬菜连作土壤为对象,基于深翻年限(2014—2020年)对0~20、20~40、40~60 cm土层深度土壤团聚体进行连续采样监测。分析不同土层深度在不同深翻年限下的土壤团聚体含量变化、粒径分布格局、稳定性差异情况。【结果】>0.25 mm的水稳性团聚体含量WR_(0.25)较>0.25 mm的机械稳定性团聚体含量DR_(0.25)对深翻作用的响应更为敏感,受深翻作用,WR_(0.25)明显低于DR_(0.25);WR_(0.25)总体呈随深翻年限的增加而增加,随土层深度的增加而降低的趋势;团聚体平均质量直径(MWD)在0~20 cm土层随深翻年限增加总体变化不明显,20~40 cm土层随深翻年限增加呈逐渐增大的趋势,40~60 cm土层MWD在深翻1~5年表现为随深翻年限的增加而增加的趋势,深翻6~7年后MWD逐渐降低;团聚体破坏率(PAD)表现为随土层深度增加而增大,随深翻年限增加而降低的趋势;WR_(0.25)、PAD、MWD三者呈显著相关关系(P<0.05),其中WR_(0.25)与PAD呈显著负相关关系,相关系数R=-0.750;WR_(0.25)与MWD呈显著正相关关系,相关系数R=0.866;PAD与MWD呈显著负相关关系,相关系数R=-0.795。【结论】深翻措施直接作用于土壤团聚体结构,团聚体含量组分重组导致原生耕作土壤层次分异,层次分异表现为表层和底层两级分化,水稳性团聚体组分变异较大,层次发生响应更为敏感。深翻作用使土壤表层与底层实现空间位移、混匀,致使各土层原有层次分异趋于同质化,随深翻年限的增加,土壤团聚体分布格局逐渐趋同,稳定性逐渐增加。

【Objective】The aims of the present paper is to explore the spatial variation and stability of soil aggregates at different soil depths under different years of the deep turning measure.【Method】The soil of the deep turning measure(2014)was used as a control,and the soil aggregates of 0-20,20-40,40-60 cm soil depths were continuously sampled and monitored based on the years of deep turning(2014-2020).The changes of soil aggregates,particle size distribution patterns and stability of soil aggregates with the age of deep turning were analyzed.【Result】WR_(0.25)was more sensitive to the response to deep turning than DR_(0.25),which was significantly lower than DR_(0.25);WR_(0.25)generally increased with the age of deep turning and decreased with the increase of soil depth;Under deep flipping,WR_(0.25)was more sensitive to the response of deep turning than DR_(0.25),and the content of WR_(0.25)decreased with the increase of soil depth and increased with the increase of deep turning age;MWD showed no obvious overall change with the increase of deep turning age in 0-20 cm soil layer,20-40 cm soil layer showed a gradual increase trend with the increase of deep turning age,MWD in 40-60 cm soil layer showed an increasing trend with the increase of deep turning age after 1-5 years of deep turning,and MWD gradually decreased after 6-7 years of deep turning.PAD showed a tendency to increase with the increase of soil depth and decrease with the increase of deep turning age.WR_(0.25),PAD and MWD showed a significant correlation(P<0.05),in which WR_(0.25)showed a significant negative correlation with PAD,the correlation coefficient R was-0.750,WR_(0.25)showed a significant positive correlation with MWD,the correlation coefficient R was 0.866,and the PAD and MWD showed a significant negative correlation relationship,and the correlation coefficient R was-0.795.【Conclusion】The deep turning measure directly acted on the structure of soil aggregates,and the recombination of aggregate content components led to the hierarchical differentiation of the original tillage soil,which was manifested as two-level differentiation of the surface layer and the bottom layer,and the water stability aggregates had greater variation and more sensitive hierarchical response.The deep turning effect makes the soil surface and bottom layer achieve spatial displacement and mixing,resulting in the homogenization of the original layers of each soil layer,and with the increase of the deep turning age,the distribution pattern of soil aggregates tends to gradually converge and the stability gradually increases.