Productivity of pigeonpea (Cajanus cajan L. Millsp.) in neem (Azadirachta indica A. Juss.) based agroforestry system on Alfisols in semi arid tropics

An investigation was carried out to assess the directional and spatial influence of bund planted neem trees on pigeonpea grown in association during 2018–19 in semi-arid tropics of Karnataka, India. At short distance from the tree lines, growth attributes of pigeonpea were significantly reduced on western and eastern directions of North–South tree line compared to northern and southern directions of East–West tree line, while significantly higher number of pods per plant, seed yield per plant, seed yield and stalk yield (74.00, 24.80 g plant−1, 780 kg ha−1 and 1970 kg ha−1, respectively) were recorded in control without trees. The magnitude of reduction followed southern–northern > eastern–western directions. However at 12.8–18.2 m from the tree lines, growth attributes were not different from control in any direction. Further, significantly lower number of pods per plant (43.33), seed yield per plant (14.36 g), seed yield (376 kg ha−1), stalk yield (1283 kg ha−1) and harvest index (0.23) were recorded closer to the tree line (D1-2–7.4 m distance), but increased and reached the highest (70.94, 22.30, 761, 1921 kg ha−1 and 0.28, respectively) at 12.8–18.2 m away from tree line and were comparable to control irrespective of directions of planting. Overall, at latitude 160 N it was found that east–west tree planting had lower inhibitory interference on associated pigeonpea.