Effects of weed management practices on orchard soil biological and fertility properties in southeastern China

Weed management practices on soil biological and fertility properties were studied in a subtropical citrus orchard situated at Changshan County (28°54′N, 118°30′E) in Zhejiang Province, China. Three weed management practices were chemical control plus tillage (herbicide), tillage alone (plowed) and mowing plus tillage (mowed). No significant differences in microbial biomass carbon (MBC), soil organic matter (SOM) or total nitrogen (TN) were observed among the three practices in the first year of the experiment. In the second and third year of the experiment, soil MBC, SOM and TN were significantly higher with mowed and plowed than with herbicide. Soil MBC, SOM and TN were higher with mowed than with plowed treatment only in the third year. Mycorrhizal fungal spore and phosphorus-solubilizing microbial (PSM) activity tended to increase during the experiment in all treatments. Highest mycorrhizal fungal spore and PSM activity were found with mowing throughout the experiment. No difference in the growth of citrus plants was found among herbicide, plowed and mowed treatments. Alternative weed management by mowing during the growing season and tillage in winter could offer both improved weed control and soil quality maintenance.