Pasture Management and Mineral Fertilization on Soil Properties, Plant Nutrition, and Biomass Production of Urochloa decumbens in Tropical Lixisols

Pasture management and mineral fertilization are key factors influencing soil fertility and pasture yield. However, their effects on the soil properties of Lixisols in the Brazilian semi-arid region, and their subsequent impact on Urochloa decumbens biomass production, remain unclear. We compared soil properties between short- and long-term pastures and evaluated how fertilization affects the growth of U. decumbens. The grass was cultivated in pots with soil subjected to four treatments: nitrogen (N), phosphorus (P), combined NP fertilization, and an unfertilized control. We assessed shoot dry biomass, plant responsiveness to fertilization, plant N and P concentrations, and the fertilization effect on nutrient uptake. Long-term managed pasture exhibited higher levels of K+, soil pH, available P, and total organic carbon, whereas short-term degraded pasture had higher total nitrogen, Mg2+, H+, Al3+, and cation exchange capacity. NP fertilization significantly enhanced U. decumbens growth in both pasture conditions, resulting in greater shoot dry biomass, higher responsiveness to fertilization, and improved N and P uptake compared with the control. In addition, N and P fertilization applied individually promoted the accumulation of their respective nutrients in plant tissues, with N fertilization resulting in the highest plant N content and P fertilization resulting in the highest plant P content. Our findings suggest that (i) short-term degraded pasture management altered soil nutrient status, which may be associated with changes in nutrient cycling and soil chemical properties, and (ii) adequate fertilization in short-term degraded pastures can enhance U. decumbens biomass production.