PRODUCTIVE RESPONSE OF GRASSES AND LEGUMES TO DIFFERENT LEVELS OF PHOSPHORUS FERTILIZATION

Phosphorus deficiency in tropical soils restricts forage production, requiring appropriate fertilisation to improve the yield of grasses and legumes. The objective of the study was to evaluate the productive response of two forage grasses (Brachiaria decumbens and Brachiaria dictyoneura) and three legumes (Desmodium ovalifolium, Stylosanthes guianensis cv. "Pucallpa", and Pueraria phaseoloides - "Kudzu") to different levels of phosphorus fertilisation and its combination with calcium, sulphur, and potassium. A randomised complete block design with three replications was used at the "La Esperanza" Experimental Station, Puerto Bermúdez, Peru. Ten fertilisation treatments were established, ranging from no fertilisation to combined applications of 60 kg ha-1 of P₂O₅, 750 kg ha-1 of Ca, 20 kg ha-1 of S, and 40 kg ha-1 of K₂O. The results showed significant differences in dry matter production between species and treatments (p < 0.05). Among grasses, Brachiaria decumbens achieved its highest yield with treatment 10 (2953 kg ha-1), while among legumes, Stylosanthes guianensis excelled with 2682 kg ha-1 under treatment 8. These findings highlight the importance of balanced fertilisation in forage productivity, providing key information for optimising agronomic management in low-fertility tropical soils. Keywords: forage grasses; forage legumes; forage productivity; tropical soils.