Effects of straw and living grass mulching on soil nutrients, soil microbial quantities and soil enzyme activities in a peach orchard
Aims My aims were to (a) study the effects of mulching materials on microbial quantities, enzyme activities and soil nutrient contents and their relationships and (b) explore feasibility of using soil microbial quantities and soil enzyme activities as indicators of soil health.Methods Straw of wheat {Triticum aestivum), stalks of corn (Zea mays) and weeds with 3.25, 1.97 and 3.67 kg·m-2 of covering weight, respectively, and living grass (Trifolium repens, Medicago sativa and Festuca arundinaced) with 50 kg-hm~2 of sowings were used as mulching materials, with no covering as the control. Important findings The contents of alkali-hydrolyzable nitrogen (N), available potassium (K), total N, total K and organic matter of the rhizospheric and non-rhizospheric soils were significantly increased by straw and living grass mulching, except for total phosphorus (P) and available P in the living grass treatment. Quantities of ammoniflcation bacteria, fungi and actinomycetes, as well as soil moisture, Ph value and activities of urease and phosphatase significantly increased in all treatments. Greatest mean increases of alkali-hydrolyzable N (99%), available K (270%), total N (267%), total K (117%), organic matter (272%), quantities of ammonification bacteria (158%) and fungi (141%) and activities of urease (156%) and phosphatase (64%) occurred in the Trifolium repens treatment. Soil alkali-hydrolyzable N, available K, total N, total K and organic matter showed significantly positive correlation with the amount of ammonification bacteria, fungi and actinomycetes and activities of urease and alkaline phosphatase, except for soil available K with actinomycetes and phosphatase. Path analysis indicated that soil urease activity was the most important factor affecting the accumulation of alkali-hydrolyzable N, available K, total N, total K and organic matter in the three types of soil microbes and two kinds of enzymes.
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万方数据
维普
