Abstract: To examine the effects of effective microorganisms (EM) application with straw cover and organic fertilizer on soil physicochemical properties and peach photosynthetic characteristics, three treatments including EM-organic fertilizer (EM-O), EM-straw cover (EM-S) and control (CK) were employed in a latematuring peach orchard in Linyi City, Shandong Province. Soil physicochemical properties (soil bulk density, porosity, organic matter content, and available nutrient content) and chlorophyll content were measured. Results showed that EM-O and EM-S treatments significantly increased soil NH₄⁺-N, NO₃^--N, resin-P, available K and soil organic matter contents. Higher soil capillary porosity was found under EM-S treatment. EM-S treatment significantly increased chlorophyll a content in peach leaves. Results of stepwise multiple linear regression analysis between peach photosynthetic characteristics and soil properties showed that soil available K content was positively related with chlorophyll a content and total chlorophyll content. In conclusion, application of organic materials with EM substantially enhanced the contents of soil available nutrients, especially in 10-20 cm layer. Soil available K content had greater effects on chlorophyll content than soil organic matter, available N and available P contents.

Key words: thinning, active organic carbon, Larix principis-rupprechtii plantation, enzyme activity