Nutrient Cycling of Poplar Plantation in Relation to stand age in agroforestry System

The trees intercropped with Mentha produced higher quantity of litter than pure or the trees intercropped with Cymbopogon spp. The litter produced by the intercropped stands had higher N,P,K contents than their pure stands. The concentration of nutrients in the litter decreased with increasing age of the stands. Similarly, the total addition of nutrients (N,P,K) through litterfall to the soil was higher in intercropped than that of pure stands. The available N,P,K contents of soil under the pure stands was highest than the soil of the intercropped stands. Maximum amount of N and K was found in the superficial layer of the soil which decreased with increasing depth. Most of the Phosphorus was accumulated in the soil at the depth of 15-30 cm in all the stands. The available N, P and K in the soil increased with increasing age of the stands.