Responses of sweet sorghum to sources and rates of phosphorus under greenhouse conditions: III. Red yellow latosol - medium texture

Abstract

The efficiency of Catalão rock phosphate (FG) was studied in comparison to that of triple superphosphate (ST) . Four rates of P2O5 were used either in the presence or in the absence of liming. The residual effect was evaluated in two successive crops. The main conclusions were the following: ST was shown to be a better source of P than FG, its eficiency being icreased by liming which also increased P up take from both sources, especially in the second and third crop; method of application of FG had no effect on dry matter yield; there was a positive correlation between residual P (Olsen) and yield; in the third crop, however, a higher correlation coefficient was found to occur with soil Ca.