The objective of this work was to evaluate the effects of cover crops and direct and conventional tillage systems on soil biological attributes when cultivated with dry bean in winter under sprinkle irrigation. The experiment was conducted in Santo Antônio de Goiás, GO, Brazil, in a clayey Rhodic Haplustox. Cover crops were cultivated annually in the summer since 2001, using Brachiaria brizantha, Cajanus cajan, Pennisetum glaucum, Panicum maximum, sorghum, Stylosanthes guianensis, brachiaria in association with corn, and native vegetation as reference. In 2005, 60 days after cutting the cover crops, BRS Valente bean cultivar, under irrigation, was cultivated. Sowing was performed on June 16, 2005 and the harvest on September 19, 2005. Soil samples were collected to a depth of 0-10 cm, in November 2004 (before cover crops planting), June 2005 (before dry bean planting) and July 2005 (at dry bean flowering). Evaluations of basal respiration, carbon and nitrogen of microbial biomass, microbial/organic carbon ratio, microbial/total nitrogen ratio and metabolic quotient were performed. Soil biological attributes were influenced by cover crops, soil management and sampling time.
microbial biomass carbon; microbial biomass nitrogen; basal respiration; metabolic quotient; microbial quotient; cover crops
