Nutrient Uptake of Poplar Plantation at Various Ages of Growth in Isolated and Intercropped Stands under Agro-forestry System

Net primary productivity, concentration of N, P, K(% dry weight) standing state of N, P, K (kg ha^-1), uptake of N, P, K (kg ha^-1 y^-1) in different components of Populus deltoides at different ages as affected by different treatments were studied under agro-forestry systems involving P. deltoides with intercrop of aromatic crops at Central Institute of Medicinal and Aromatic Plants, Regional Centre, Pantnagar, Uttaranchal. NPP was found lowest in pure stands of P. deltoides than the intercropped stands. Among the intercropped stands it is found highest in M. arvensis and lowest in Cymbopogon winterianus. The concentration of N, P, K in different tree parts decreased with the increase in age of plantations. It remained at a lower level in pure stands in comparison to intercropped stands. Standing state of N, P, K (kg ha^-1) in different components of P. deltoides, increased with the increase in age of plantations. But, in uptake of N, P, K (kg ha^-1 yr^-1) in different components of P. deltoides, decreased as the tree goes towards maturity, but in foliage it is just reverse to the above fact.