Resumo

BARROTI, Giovane  e  NAHAS, Ely. Effect of phophorus and liming on phosphatase and production of braquiaria ruziziensis and cajanus cajan. Agronomía Trop. [online]. 2003, vol.53, n.2, pp.209-225. ISSN 0002-192X.

Summary Phosphates act in the mineralization of soil organic P, however enzyme activity can be affected by plants, P inorganic sources or soil liming. This study evaluates the effect of the phosphorus sources and liming on activities of acid and alkaline phosphatases and on production of Braquiaria ruziziensis and Cajanus cajan. Statistical design used was a randomized block in a 3x3x2 (plants x fertilizers x liming) with two replications. Contents of total, organic and available phosphate of the soil were also determined. The acid phosphatase activity of the soil was 3,3 times more than the alkaline phosphatase activity and increased in the soil cultivated with B. ruziziensis in relation to the C. cajan or to the non cultivated soil. The alkaline phosphatase activity also increased in the soil cultivated with B. ruziziensis in relation to other treatments, but not significantiy. The alkaline phosphatase activity was repressed by the superphosphate, but not the acid phosphatase activity. In non lirned plots, the activity of both enzymes was repressed in the not fertilized soil or in the fertilized with superphosphate in relation to the rock phosphate. Superphosphate increased phosphate avaliability of the soil, production and P uptake of B. ruziziensis and C. cajan. Contents of total phosphate were largest in all the treatments that reccived rock phosphate or superphosphate.

Palavras-chave : Acid phosphatase; alkaline phosphatase; rock phosphate; superphosphate;; Braquiaria ruziziensis; Cajanus cajan; liming.