The role of tree leaf mulch and nitrogen fertilizer on turfgrass soil quality

The influence of tree leaf amendment and N fertilization on soil quality in turfgrass environments was evaluated. Our objective was to assess changes in soil quality after additions of leaf materials and N fertilization by mo nitoring soil chemical and physical parameters, microbial biomass and soil enzymes. Established perennial ryegrass (Lolium perenne) plots were amended annually with maple (Acer spp.) leaves at three different rates (0, 2240, and 4480 kg ha(-1) year(-1)) and treated with three nitrogen rates (0, 63, and 126 kg N ha(-1) year(-1)). Tree leaf mulching did not significantly aff ect water infiltration or bulk density.:However, trends in the data suggest increased infiltration with increasing leaf application rate. Tree leaf mu lching increased total soil C and N at 0-1.3 cm depth but not at 1.3-9.0 cm . Extracted microbial phospholipid, an indicator of microbial biomass size, ranged from 28 to 68 nmol phospholipid g(-1) soil at the 1.3-9.0 cm depth. The activity of beta-glucosidase estimated on samples from 0-1.3 cm and 1. 3-9.0 cm depths, and dehydrogenase activity estimated on samples from 1.3-9 .0 cm were significantly increased by leaf mulching and N fertilizer applic ation. Changes in microbial community composition, as indicated by phosphol ipid fatty acid methyl ester analysis, appear to be due to seasonal variati ons and did not reflect changes due to N or leaf amendment treatments. Ther e were no negative effects of tree leaf mulching into turfgrass and early d ata suggest this practice will improve soil chemical, physical, and biologi cal structure.