Horizontal and vertical variations in soil properties under different pruning regimes in Albizia procera and Hardwickia binata based agroforestry systems under semi-arid conditions

Abstract Trees’ canopy pruning is one of the most important management practices in agroforestry that allows understory crops to receive adequate sunlight. The effect of pruning on the productivity of intercrops is well known; however, information on its effect on soil properties is scanty. Hence, studies were conducted to determine 1) whether canopy pruning has any effect on soil properties and 2) what level of pruning should be adopted in selected agroforestry systems. Two separate agroforestry models, based on Albizia procera (10-year-old) and Hardwickia binata (20-year-old), were selected for the study, which included three factors: pruning level (0, 50 and 75%), sampling location (under and outside canopy) and soil depth (0–15 and 16–30 cm), each of which was replicated three times in a completely randomized block design. Canopy pruning yielded varying effects on the studied soil parameters without any definite relationship with pruning levels. Sampling location and soil depth had a significant effect on the studied parameters. Their values were found to be higher and favorable in the upper soil and under the tree canopy. The findings revealed that unpruned trees of A. procera caused the maximum improvement in soil, followed by trees subjected to 50 and 75% crown pruning, while in the case of H. binata , improvement in soil health in 50% pruning over no pruning was noticeable, but similar improvement in 75% pruning over 50% was not so prominent, implying that heavy pruning (75%) should be avoided to keep evapotranspiration under control. Thus, the study concludes that a moderate level of pruning (50%) is desirable in A. procera and H. binata based agroforestry under semi-arid conditions for efficient use of above- and below-ground resources and improved soil health.