Influence of bund planted neem (Azadirachta indica A. Juss.) on soil biochemical properties in semi-arid tropics

Abstract

A study was carried out during 2018-19, to know the influence of bund planted neem with pigeonpea on soil biochemical properties in semi-arid tropics of Karnataka, India. The results revealed significant positive improvement in soil biochemical properties in neem-based bund planting as compared to control (without trees). Significantly higher soil organic carbon content, available N, P and K (0.46%, 239, 18 and 225 kg ha^-1, respectively) were recorded on Western direction of North-South planting as compared to other direction, and significantly higher organic carbon, available N, P and K (0.54% 265, 19.4 and 242 kg ha^-1, respectively) were recorded near tree line which decreased with increase in distance from the tree line. Similarly, significantly higher organic carbon, available N, P and K (0.56% 273, 20.1 and 251 kg ha^-1, respectively) were recorded on Western direction near tree line. The analysis of microbial population and dehydrogenase activity revealed similar trend and significantly higher population of bacteria, fungi and actinomycetes and dehydrogenase activity (85.3 ×10⁶, 56.7 ×10³, 36.5 ×10² cfu g^-1 and 30.2 μg TPF g^-1, respectively) were recorded on Western direction near tree line and were decreased with increase in distance from the tree line. Bund planting improved soil bio-chemical properties when compared with control. Further, positive influence of trees up to an extant of 16 m was noticed. Hence, it is suggested to have bund planting of neem at intervals of 20 m distance in the field.