Comparative Analysis of the Growth Performance of Three Varieties of Cowpea Under Different Soil Amendment Treatments in Kano State

Cowpea (Vigna unguiculata) is a critical grain legume for food and nutritional security across North West Nigeria, and optimising its growth under amended soil conditions is important for smallholder farmers in Kano State. This study conducted a comparative analysis of the growth performance of three cowpea varieties (IT97K-499-35, Ife Brown, and Dan Ila) under three soil amendment treatments: farmyard manure, NPK fertiliser, and a control. A 3 x 3 factorial experiment was arranged in a randomised complete block design with three replications on sandy loam soils in Kano Municipal. Growth parameters measured included plant height, leaf area, stem girth, number of leaves, and days to first flower. Data were analysed using ANOVA and Duncan's Multiple Range Test at 5% significance level. Results showed that variety IT97K-499-35 significantly outperformed the other varieties in plant height (52.4 cm at 6 weeks after sowing) and leaf area index (3.12) under farmyard manure amendment. Ife Brown showed superior early flowering under all treatments. NPK fertiliser produced the highest mean stem girth across all varieties. No significant interaction between variety and amendment treatment was observed for most parameters at the 5% level. The study concludes that farmyard manure application is the most cost-effective amendment for improving cowpea vegetative growth in Kano State soils, and recommends varietal selection based on the farmer's production objective, whether yield or early maturity.

Keywords: cowpea, growth performance, soil amendment, farmyard manure, Kano State