R. S. Yadav

Growth and pruned production of multipurpose tree species in silvo-pastoral systems on degraded lands in semi-arid region of Uttar Pradesh, India.

ABSTRACT Silvo-pastoral systems involve integration of trees with natural or established pasture. This system conserves soil and has the potential to provide a wide range of products on a sustainable basis. In addition, they can also provide many other environmental benefits, such as recharge of ground water and conservation of bio-diversity. Silvo-pastoral systems can improve the existing land productivity of 1 tonne dry matter ha−1 year−1 by an average of 8 to 10 times, depending on site conditions. Initially, multi-purpose trees (MPTs) in silvo-pastoral systems lower the total annual biomass production but, in the longer run, the pruned biomass of MPTs make up for the drop in the yield of the understorey pasture. Pruning the trees, especially fast growing and vigorous species, in silvo-pastoral systems allows pasture production in addition to fuel wood and fodder products. Silvo-pastoral systems will help to improve degraded lands in semi arid region of U.P., India. The results of a five and half year old (July 1992-Dec. 1997) field trial conducted at the National Research Centre for Agroforestry, Jhansi, India revealed that: • growing of pasture and pruning of trees significantly affected the growth and ‘pruned biomass1’ production of the three multi-purpose tree species Dalbergia sissoo Roxb, Acacia nilotica Willd var. cupressiformis and Hardwickia binata Roxb. • of the three, Dalbergia sissoo grew the best and yielded most ‘pruned biomass1’. • Established pasture significantly decreased the growth of MPTs. • The total combined biomass (pruned+pasture) production of the silvo-pastoral systems (excluding standing tree biomass) and pasture alone for the first five years was in the order: pasture alone (39.42 t ha−1) > Dalbergia sissoo (35.01 t ha−1) > Hardwickia binata (34.56 t ha−1) Acacia nilotica var. cupressiformis (32.20 t ha−1), although the differences were not significant. • Pruning up to 50% of the trees height had no significant effect on the MPTs height and collar diameter but significantly increased the pasture production of Dalbergia in 1997. • The 0–15 cm soil layer under the trees and fertilized pasture had a content of to 6.4–7.1 g Kg−1 organic carbon and 0.59–0.67 g Kg−1 total nitrogen, compared to the initial content of 3.9 g Kg−1 and 0.43 g Kg−1 respectively, and 4.7 g Kg−1 and 0.57g Kg−1 for the treatments without trees.