Response of Cowpea (Vigna unguiculata (L) Walp) Varieties to Varied Phosphate Fertilizers in Acidic Soil of Shira Town, Bauchi State, Nigeria

Abstract

Cowpeas are mainly cultivated in Africa, especially in Nigeria and Niger, which together contribute the largest share of global production. This study investigates the response of cowpea (Vigna unguiculata) variety to varied phosphate fertilizers in acidic soil of Shira, Bauchi State Nigeria. Soil samples were collected from Shira, Nigeria and analyzed for their acidity and some physicochemical parameters which include; pH, electrical conductivity (EC mS/m), exchangeable acidity (EA cmol/kg) and phosphorous content (P mg/kg). Nine (9) selected cowpea varieties were planted in the soil samples treated with lime, phosphate rock (PR) and organo minerals phosphorous fertilizer (OMF) as well as a combination of lime and OMF. The experimental set up was a factorial design with five treatment (including control) and three replicates. Data was collected for growth parameters which included plant height, stem girth and number of leaves, leaf area and number of seeds per plant. The results indicated that soil sample collected from Shira showed a sandy loam texture composed of 60% sand, 16% silt, and 24% clay, indicating dominance of sand (60%). The soil was strongly acidic with average a pH of 4.50, an electrical conductivity (EC) of 5.7mS/m, and exchangeable acidity (EA) of 0.17cmol/kg. Among cowpea varieties, IT97-49-35 recorded the highest plant height (27.7 cm), followed closely by IT98K-205-8 (27.4 cm) and IT09-131-1 (27.0 cm), while IT97K-819-118 had the lowest (15.9 cm). Dansaminu produced the highest stem girth (4.0 mm), whereas IT97K-819-118 had the least (2.0mm). For leaf production, IT97-49-35 recorded the highest number of leaves (19.4), while IT98K-57-1-1 had the lowest (12.2). Leaf area was highest in IT97-49-35 and IT98K-205-8 (24.2), but lowest in IT07K-230-2-9 (18.2). Seed production was highest in Dansaminu (29.1) and lowest in IT97K-819-118 (15.0). More so, OMF plus Lime gave the highest plant height (35.0 cm) and stem girth (3.7), while Lime alone recorded the lowest (11.5 cm). OMF produced the highest number of leaves (23.6), whereas Lime and Control had the lowest (7.6). Leaf area was highest under OMF plus Lime and OMF (36.0), while Lime recorded the least (7.9). Similarly, OMF produced the highest seed number (33.7), while Lime had the lowest (8.3). The study revealed that the application of OMF and OMF plus Lime improved the growth and yield performance of cowpea varieties under the acidic sandy loam soil conditions of Shira. OMF plus Lime produced the highest plant height, stem girth, and leaf area, while OMF alone resulted in the highest number of leaves and seeds. Among the cowpea varieties evaluated, IT97-49-35 and Dansaminu showed superior performance in most growth and yield parameters compared to the other varieties studied.