Np. Stamford et al., Effect of phosphorus, potassium and magnesium fertilization on yam bean inoculated with Bradyrhizobium and growing in an alic latosol soil, PESQ AGROP, 34(10), 1999, pp. 1831-1838
In order to evaluate the effects of phosphorus, potassium and magnesium app
lication on the nutrient absorption and yield of yam bean (Pachyrhizus eros
us (L.) Urban), in a Yellow Latosol of the Zona da Mata of Pernambuco State
, Brazil, an experiment was carried out using the strain of Bradyrhizobium
sp. NFB 450, isolated from yam bean and selected for efficient N-2 fixation
in previous experiments. Potassium and magnesium were applied in the propo
rtion of 2:1 (K2O:MgO) in increasing levels (0:0, 40:20, 60:30 and 80:40 kg
ha(-1) of K2O and MgO, respectively), and crescent levels of phosphorus (0
, 20, 40, 60 and 80 kg ha(-1) of P2O5) were added in the form of triple sup
erphosphate. Maximum dry matter production, total N and total P accumulated
were obtained when applying 64 kg ha(-1) of P2O5. A significant effect of
K2O:MgO levels was observed in relation to the treatment without K and Mg a
pplication; nevertheless, higher levels of K2O:MgO decreased dry matter and
total N, and increased total P accumulation. Yam bean responded to low lev
els of P, K and Mg fertilizer, and showed ability in N-2 fixation, with gre
at potential for biomass production.