Phosphate rock and triple superphosphate as phosphorus sources for Centrosema

摘要

A large proportion of cultivated forage in Venezuela are planted in acidic soils low in available phosphorus (P). The use of soluble P fertilizers can solve the problem, but the use of phosphate rock could be less expensive alternative. The objective of this study was to test Riecito phosphate rock and triple superphosphate as P sources for three Centrosema macrocarpum ecotypes in an acidic soil. Response of Centrosema dry matter (DM) P and Ca uptake to phosphate rock was evident after 80 days of phosphate rock incubation in the soil. However, Centrosema response to triple superphosphate was detected faster, after a period of only 30 days. Ecotypes response to P source suggested differences in their capacity to use P from phosphate rock and triple superphosphate. Dry matter production, P and Ca uptake were highly dependent on the root length. Dry matter accumulation depended on P and Ca uptake.