Response of pangola grass to NPK fertilization in a native field of Paraná

Abstract

Field experiment conduced at the Municipal Agricultural Center of Guarapuava, in the State of Paraná. The response of Pangola grass (Digitaria decumbens Stent.) to three levels of NPK was studied. Treatments were factorially arranged (3³) with three replications. The treatments were as follows: 0, 30 and 60 kg/N/ha/cut (as ammonium sulphate); 60, 120 and 180 kg/P2O5/ha/year (as ordinary superphosphate) and 0, 60 and 120 kg/K₂O/ha/year (as potassium chloride). The regression analysis showed that dry matter yield was linearly related to the N and K application rates. Response to phosphorus levels was observed only in the first year. Maximum dry matter yield was obtained with 120 kg/P₂O₅ ha/year, although, this had not been significantly different from the yield obtained with 60 kg/P₂O₅ ha/year rate. Visual observations indicated that high levels of N without K lead to an increase in infestation of the plots by native grasses. Also, in these plots the plants of Pangola grass showed increasing necrosis from the bottom to the upper leaves.