Spatial planting arrangements of multipurpose gum-yielding trees affect growth and yield of understory crops in a rainfed agri-silviculture model

Abstract

Acacia senegal and Acacia nilotica are important plant species that produce edible gums. Besides, they are a good source of nutritious green fodder and best suited in arid and semi-arid tropics. Large-scale plantations for producing gum and fodder can be established in the Bundelkhand region of central India, which has typical semi-arid climatic conditions. Both plant species can be grown in agroforestry, either on field boundaries or in farmlands. However, before planting these species in Bundelkhand, optimization of spatial planting spacing for these species for securing good growth of trees and yield of intercrops is essentially required. Hence, a study was conducted to determine the best agroforestry spacing for A. senegal and A. nilotica in order to maximize their growth, and their effects on growth and yield of understory crops in rainfed agroforestry system. A model consisting of A. senegal and A. nilotica was established at the research farm of ICAR-CAFRI, Jhansi, wherein they were planted in three different spacing: 5 × 5 (400 trees ha^-1), 10 × 5 (200 trees ha^-1) and 10 × 10 m (100 trees ha^-1). Crop sequence of Vigna radiata-Eruca sativa for rainy-winter seasons was followed. Study revealed that planting A. senegal and A. nilotica in 10 × 5 and 5 × 5 m influenced the growth and yield of understory crops (Vigna radiata, Eruca sativa and Sesamum indicum). Under 5 × 5 and 10 × 5 m spacing, the reduction in yield of different crops ranged from -35.8 to -25.0 and -26.6 to -8.7%, respectively. Further, growth and yield of understory crops were relatively better in association with A. nilotica than with A. senegal and planting both species at 10 × 5 m spacing in the Bundelkhand region appears to be feasible with little impact on understory crop yield in rainfed conditions.