Soil microbial biomass under mulch types in an integrated apple orchard from Southern Brazil

the use of mulching is an alternative to control weeds but there are few studies on its effect on soil quality. in this sense, this study aimed to evaluate the effect of types of mulching on the attributes of microbial carbon, nitrogen and phosphorus in a typic hapludox with production of integrated apples in southern brazil. the experiment was conducted in randomized blocks in the vacaria, state of rio grande do sul, southern brazil. the soil mulch types studied were: pine needle, sawdust, black plastic and a control. the soil samples were collected in february (summer) and august (winter) of 2006, and the attributes related to total organic and microbial carbon, nitrogen and phosphorus were determined. organic mulchings (pine needle and sawdust) promoted lower soil temperature, and greater moisture, microbial carbon (cmic), microbial nitrogen (nmic), and the ratios cmic:corg, nmic:norg and microbial c:n than black plastic. microbial phosphorus was greater in winter. sawdust mulching promoted the best conditions to microbial biomass in winter. the mulch types increased the microbial compartment in winter as compared to the nonweeded control .