餐厨垃圾调理剂对果园土壤团聚体组成及分布的影响

针对我国贫瘠果园土壤结构和功能退化的问题，以餐厨垃圾制备的土壤调理剂为研究对象，从时间和空间两个层面，采用DR_0.25（团粒结构体占比）、MWD（平均质量直径）、GMD（几何平均直径）和分形维数评价长期施用餐厨垃圾土壤调理剂对贫瘠果园土壤团聚体结构特征及其有机质赋存转化的影响.结果表明:施用餐厨垃圾土壤调理剂可增加0~20 cm土壤层中粒径 < 0.25 mm微团聚体的W_wi（水稳性团聚体占比），施用3 a后其W_wi最大值为23.04%，有利于提升土壤抗侵蚀性；随着施用餐厨垃圾土壤调理剂时间的延长，30~40 cm土壤层的DR_0.25逐渐增加，施用5 a后各土壤层MWD和GMD均大于对照组；随着施用时间的延长，相同深度土壤层的分形维数逐渐减小，施用5 a后0~20 cm土壤层分形维数最小值为2.13，表明施用餐厨垃圾土壤调理剂有利于改善土壤团聚体粒径分布和土壤分维特征；施用餐厨垃圾土壤调理剂可提升0.5~5 mm粒级团聚体中的有机质含量.研究显示，长期施用餐厨垃圾土壤调理剂可改善土壤团聚体粒径和有机质的分布，有助于土壤团聚体中有机质的赋存转化，提高团聚体稳定性和土壤抗侵蚀力. 

Effects of Soil Aggregates Composition and Distribution Using Food Waste Soil Conditioner in the Orchard Soil

The increase in population and food demand poses challenges to agriculture and the excessive use of chemical fertilizer has led to the deterioration of soil functions in China. The green and sustainable development of agriculture is seriously affected due to the impoverished organic-matter and structural damages of the orchard soil. In this study, the effects of long-term application of food waste soil conditioner on the characteristics of soil aggregates and the generation and transformation of organic matter in barren orchards were carried out from the perspective of time and space. The proportion of soil granular structure (DR_0.25), mean weight diameter (MWD), geometric mean diameter (GMD) and fractal dimensions of soil aggregates were investigated using food waste soil conditioner in the orchard soil. The results showed that under the application of food waste soil conditioner, microaggregates (<0.25 mm) in the surface soil of 0-20 cm increased, and the maximum value of proportion of water-stable aggregates (W_wi) reached 23.04% after 3 years of the food waste soil conditioner application. Therefore, food waste soil conditioner application had the potential to improve the soil erosion resistance. With the long-term application of food waste soil conditioner, the DR_0.25 in 30-40 cm deep soil increased with time. The MWD and GMD were better than the blank group after 5 years of application the food waste soil conditioner. With the long-term application of food waste soil conditioner, the fractal dimensions decreased in 0-20 cm surface soil. Then, the minimum value of fractal dimensions was 2.13 after 5 years of treatment. These changes indicated that food waste soil conditioner application was conducive to improving the soil aggregate particle size distribution and the fractal features. Under the food waste soil conditioner application, the content of organic matter in 0.5-5 mm aggregates increased. Overall, the results showed that long-term application of food waste soil conditioner improved the particle size and organic matter distribution in aggregates, helped the generation and transformation of organic matter in aggregates, enhanced the stability of the aggregates and soil erosion resistance.