Abstract: One- year field experiments were conducted to evaluate the effect of fertilization on growth & yield of rainfed blackgram in custard apple based agri-horti-system with alley cropping pattern on Vindhyan soil. The factors under study comprised of Control plot (T1), 2% urea spray (twice fifteen days intervals)(T2), 100% RDF (T3), 50%RDF + 25kg Zinc sulphate(T4), 50% RDF + 2% urea spray + 25 kg zinc sulphate (T5), 100%RDF + 25kg Zinc sulphate(T6) and 2% urea spray + 25kg Zinc sulphate(T7) were laid out in randomized block design. The treatments were replicated three times. However, a significant increase in grain yield was observed under 100% RDF + 25kg Zinc sulphate (T6). It was recorded maximum net return Rs.18143/ha in case of 100% RDF + 25 kg zinc sulphate under the alley cropping.