Abstract
Cowpea (Vigna unguiculata) is an essential legume crop widely cultivated in arid and semi-arid regions due to its adaptability to low soil fertility. However, phosphorus deficiency remains a major constraint to its optimal growth. This study investigates the impact of rock phosphate (RP) application levels, placement methods, and cowpea variety selection on growth parameters in Sokoto during the 2024 cropping season. A randomized complete block design (RCBD) was used with two cowpea varieties (Sampea-7 and Baadare), three RP levels (25, 50, and 75 kg ha?), and three placement methods (plough-sole, broadcast, and side-band). Results showed that increasing RP levels improved canopy height, leaf number, and canopy spread, with 75 kg RP ha? yielding the highest vegetative growth. The plough-sole placement method enhanced nutrient uptake, resulting in superior growth parameters compared to broadcast and side-band methods. Additionally, Baadare exhibited better canopy height, while Sampea-7 displayed wider canopy spread and earlier maturity. These findings highlight the importance of optimizing phosphorus application strategies to improve cowpea productivity in phosphorus-deficient soils.
References
Bationo, A., Fening, J. O., & Kwaw, A. (2018). Assessment of soil fertility status and integrated soil fertility management in Ghana. Improving the Profitability, Sustainability and Efficiency of Nutrients Through Site Specific Fertilizer Recommendations in West Africa Agro-Ecosystems: Volume 1, 93-138. Chien, S. H., & Menon, R. G. (1995). Factors affecting the agronomic effectiveness of phosphate rock for direct application. Fertilizer research, 41, 227-234. Chien, S. H., Prochnow, L. I., Tu, S., & Snyder, C. S. (2011). Agronomic and environmental aspects of phosphate fertilizers varying in source and solubility: an update review. Nutrient Cycling in Agroecosystems, 89(2), 229-255. Freiling, M., von Tucher, S., & Schmidhalter, U. (2022). Factors influencing phosphorus placement and effects on yield and yield parameters: A meta-analysis. Soil and Tillage Research, 216, 105257. Ehlers, J. D., & Hall, A. E. (1997). Cowpea (Vigna unguiculata L. walp.). Field crops research, 53(1-3), 187-204. Holford, I. C. R. (1997). Soil phosphorus: its measurement, and its uptake by plants. Soil Research, 35(2), 227-240. Marschner, H. (2012). Mineral nutrition of higher plants. Academic press. Masuda, T., & Goldsmith, P. D. (2009). World soybean markets: Structure, performance and policy. World Soybean Research Conference. Rao, J. K., Dart, P. J., & Sastry, P. V. S. S. (1983). Residual effect of pigeonpea (Cajanus cajan) on yield and nitrogen response of maize. Experimental Agriculture, 19(2), 131-141. Singh, S. K., Pathak, R., & Pancholy, A. (2017). Role of root nodule bacteria in improving soil fertility and growth attributes of leguminous plants under arid and semiarid environments. Rhizobium Biology and Biotechnology, 39-60. Taiz, L., Zeiger, E., Møller, I. M., & Murphy, A. (2015). Plant physiology and development. Sinauer Associates. Zapata, F., & Roy, R. N. (2004). Use of phosphate rocks for sustainable agriculture. Food and Agriculture Organization of the United Nations.
