Mineral Acquisition and Utilization Strategy of Three Tropical Forages at Different Phosphorus and Nitrogen Supply

Mineral Acquisition and Utilization Strategy of Three Tropical Forages at Different Phosphorus and Nitrogen Supply

A glasshouse experiment was conducted to examine mineral acquisition and utilization strategies of Brachiaria decumbens (BD), Brachiaria brizantha (BB) and Panicum maximum (PM). The plants were grown under nine treatments resulted from the combination of three levels of phosphorus (0, 25 and 50 kgP/ha) and three levels of nitrogen (25, 150 and 300 kgN/ha). BD showed the lowest value of root weight and root length per pot, but the highest efficiency of P and N uptake (P and N uptake mg / unit root weight g). On the other hand, PM showed lower mineral uptake efficiency, but the highest mineral use efficiency (dry matter production g / absorbed P and N mg). Moreover, total P and N uptake in BB was the highest, and this seems to be achieved by the multiplicative effect of moderate mineral uptake efficiency and the moderate size of the root system.