Abstract: The results show that mulches creat good ecological environment for citrus growth and development. The soil temperature of mulching orchard is higher in winter and early spring, lower in summer and early autumn. The drought is resisted effectively duing growth of fruit because the higher water content is kept in dry season. Due to the improved nutrient status in soil with mulches the content of nutrient in citrus tree increase significantly . The net economic benefit of citrus orchard with mulching especially mulch with film and rice-straw treatment is 2.229 times the control.

Key words: index of biological integrity (IBI), aquatic ecosystem health, microbe-index of biological integrity (M_IBI).