Response of short-rotation Melia dubia Cav. agroforestry plantation to mineral fertilization in a semiarid Alfisol

Abstract

A field experiment was conducted to optimize the mineral fertilizer application dose to a short-rotation Melia dubia plantation raised in semiarid alfisol. Four fertilizer treatments consisting of absolute control, 100:50:100 kg NPK ha-1, 150:75:150 kg NPK ha-1 and 200:100:200 kg NPK ha-1, applied in 24 monthly equal splits, were studied for their effect on mean annual increments in tree height, GBH, stand volume and total biomass production in 36-month-old stand. Results confirmed the positive role of mineral fertilizers on mean annual growth increments in parameters such as tree girth (p =. 001), stand volume (p =. 012), total biomass production (p =. 034) and carbon sequestration (p =. 049) in short-rotation M. dubia plantations, with the application rate of 200:100:200 kg NPK ha-1 recording the highest values. However, the residual standardized regression analysis showed that application of mineral fertilizers are non-significant in increasing tree height (F = 1.561; p =. 216) and total biomass production (F = 4.774; p =. 34) due to a short-rotation of 3 years, a less fertilizer-responsive duration. In contrast, the mean annual increment in tree GBH (F = 6.433; p =. 015) and stand volume (F = 6.546; p =. 014) was found to be statistically significant. This study recommends application of 200:100:200 kg NPK ha-1 to short-rotation M. dubia plantations for higher wood productivity and to extend the rotational period for a higher fertilizer response, with increased wood and biomass production as well as the farm income.