Formação de pastagem de capim mulato II (Urochloa spp. cv. Mulato II) sob diferentes doses de fósforo e nitrogênio com fertilização foliar complementar

Abstract

The low availability of phosphorus in Cerrado soils compromises pasture establishment, making it necessary to adopt efficient fertilization strategies. This study aimed to evaluate the effects of the interaction between rates of monoammonium phosphate (MAP) and the foliar fertilizer KP Plus on the initial development of Urochloa spp. cv. Mulato II. The experiment was carried out at the Capim Branco Experimental Farm (UFU), in a randomized block design, in a 3 × 3 factorial scheme, with three rates of monoammonium phosphate (MAP) (0, 50, and 100 kg/ha⁻¹) and three rates of foliar fertilizer containing phosphorus and potassium in its composition (KP Plus) (0, 0.5, and 1 kg/ha⁻¹), with four replications per treatment. The evaluated variables included forage yield per area, dry matter, and morphological composition. Statistical analyses were performed using ANOVA, with Tukey’s test at a 10% significance level. The highest dry matter yield in the first cut (57,565 kg/ha⁻¹) was observed with 1 kg/ha⁻¹ of KP Plus in the absence of MAP, indicating a positive effect of the foliar fertilizer, even without basal phosphorus fertilization. The 0.5 kg/ha⁻¹ dose of KP Plus, also without MAP, provided the best leaf:stem ratio (3.14) and the highest leaf percentage (75.66%), suggesting a morphological balance favorable to forage quality. In the third cut, approximately six months after establishment, the combination of 0.5 kg/ha⁻¹ of KP Plus and 0 kg/ha⁻¹ of MAP maintained the highest leaf:stem ratio (2.775), indicating a residual effect of the foliar fertilizer. Overall, higher MAP doses did not result in significant increases in productivity and, in some combinations, led to lower leaf proportions, possibly due to nutrient excess or negative interactions. Environmental conditions, such as drought and low temperatures, also influenced the results, especially in the evaluations carried out after the dry season. It is concluded that the foliar fertilizer KP Plus, particularly at the 0.5 kg/ha⁻¹ dose, showed potential to promote higher productivity and morphological quality of pasture and may be used as a complementary or alternative strategy to conventional phosphorus fertilization in the establishment of Urochloa spp. cv. Mulato II.