Influence of Organic and Inorganic Phosphorus Sources on Common Bean (Phaseolus vulgaris L.) in Tropical Soil

Objective: The low phosphorus content and fixation by oxides in acidic soils is an important yield-limiting factor to common bean production in Brazil. The study was conducted to evaluate the common bean yield rate, leaf area development, level of phosphorus in the leaf, variations in the level of available soil phosphorus, submitted to different doses of organic phosphorus compared with chemical fertilization.
Materials and Methods: The experiment was carried out from June to August in a greenhouse condition at Faculty of Agronomy Dr. Francisco Maeda (FAFRAM), in city of Ituverava, SP, Brazil. The culture studied was the common bean (Phaseolus vulgaris L.), Pérola cultivar. Sowing and fertilization were carried out manually on June 2nd 2010, when five seeds were sown per pot and after emergence the plants were thinned to one plant per pot. Completely randomized design (CRD) was performed, with 5 treatments and 4 replications, in a total of 20 plots. Treatment 1 (Control) had no phosphorus application, treatment 2 (50 kg de P2O5ha-1 chemical source), treatment 3 (50 kg de P2O5ha-1 organic source), treatment 4 (25 kg de P2O5ha-1 organic source) and treatment 5 (100 kg de P2O5ha-1 organic source).
Results: The treatment with 50 kg of P2O5ha-1, with chemical source, did not present a significant difference compared with the ones with 50 and 100 kg of P2O5ha-1 using organic source, however, it was different from the Control and the treatment with lower level organic application of 25 kg of P2O5ha-1. The control also presented an alteration in the levels of P in the course of the experiment, indicating that soil correction influenced in the availability of this nutrient in all treatments. However, the availability was increased when the sources were applied.
Conclusion: When used in higher doses, the organic source of phosphorus was as efficient as the chemical source regarding number of pods per plant and also allowed greater P availability in the soil. The chemical source of phosphorus was more absorbed by the plants than the organic sources applied, although higher doses of organic sources have also responded satisfactorily to productivity.