Phosphorus use efficiency of soybean cultivars in Cerrado conditions of Tocantins, Brazil / Eficiência do uso de fósforo de cultivares de soja em condições de cerrado tocantinense

In order to determine the efficiency and response regarding the use of phosphorus of soybean cultivars, experiments were conducted in the 2013/2014 season, to evaluate 15 soybean genotypes under two phosphorus using a randomized complete block, with three replications. To simulate environments with low and high levels of phosphorus, doses of 40 and 120 kg.ha -1 of P 2 O 5 were applied. Characteristics were evaluated for number of pods per plant, grain yield and using the methodology proposed by Fageria & Kluthcouski (1980), determined efficiency in the use of phosphorus. The environment high phosphorus positively affected the average grain yield in all genotypes, with an increase of 48.9% over the average grain yield in low-phosphorus environment. Cultivars JULIANA RR, M9056 RR, P99R01 and M9144 RR were classified as efficient and responsive as the use of phosphorus.