Biomass production of Moringa oleifera as affected by N, P, and K fertilization

Abstract

Moringa (Moringa oleifera Lam.) is a high value, multiuse tree species in tropical and subtropical regions. The objective of this study was to evaluate the effect of different levels of N, P, and K fertilizations on the biomass yield of moringa. Five levels of N (0 to 2200 kg ha−1) were tested either with a fixed N:P:K ratio of 2:1:1, or tested in factorial combination with two levels of P (0 and 290 kg ha−1) and three levels of K (0, 290, and 580 kg ha−1). The biomass yield showed a quadruple increase with the N fertilization levels (R2 = 0.96 and 0.62 for fixed and factorial combination of N, P and K, respectively; P < 0.001). In the factorial experiment, N, P, and K fertilizations each had significant effects on the biomass yield with an interaction effect between N and P. The highest biomass occurred at 290 kg P and K ha−1. The maximum biomass yield was achieved from applying N at 1425 kg ha−1. The actual timing of the N application requires further study based on uptake and soil conditions. At the high N rates, available P at 25 ppm appeared to be sufficient in this study. The critical level of tissue N content was 2.75%. Marginal increase in biomass could be achieved with extra inputs of N, P, and K above the sufficient levels. However, the feasibility of maximizing N, P, and K is questionable based on the economic and environmental assessments.