Department of Plant Sciences

No-till can increase soil microbial activity, which can affect phosphorus availability. The use of some crops in rotation can also modify P availability, and it has been evidenced that brachiaria may enhance soil P availability. The activity of acid phosphatases and the changes in soil P as affected by Brachiaria were studied in a pot experiment, in two tropical soils. Brachiaria ruziziensis was grown for 84 days in 8 L pots. At harvest, brachiaria response to P rates and soil P forms were evaluated. Dry matter production and P accumulation by Brachiaria were increased with P doses. Fertilizer addition increased microbial P, but decreased the activity of acid phosphatases in the soil. Brachiaria modified some forms of inorganic and organic P in soil, but the changes were not enough to support the nutrition of the subsequent crop.