Journal of Applied Biosciences (J. Appl. Biosci.) [ISSN 1997 - 5902]
Volume 23: 1387 - 1393. Published November 9, 2009.
Effect of phosphorus fertilizer on growth, yield and crude protein content of cowpea (Vigna unguiculata [L.] Walp) in Nigeria
^Magani, I.E.* and Kuchinda, C.**
*Department of Crop and Environmental Protection, University of Agriculture, PMB 2373, Makurdi, Nigeria. **Department of Agronomy, Ahmadu Bello University, Zaria, Nigeria.
^Corresponding author e – mail: m.enochistifanus@yahoo.com
ABSTRACT
Objective: To evaluate the response of two cowpea varieties to phosphorous fertilizer (P) levels so as to determine P-fertilizer recommendations for the Northern Guinea Savanna agroecological zone.
Methodology and results: Treatments of two cowpea varieties SAMPEA 7 and SAMPEA- 6 (Local) and three P-levels (0, 37.5 and 75 kg P/ha) using single super phosphate (18% P2 05) were laid out in a factorial combination in a randomized complete block design with four replications in Samaru. Generally, in the two years, phosphorous application significantly increased growth parameters assessed. Plant height was increased by 63 and 35.9% at 8 weeks after sowing (WAS) in 2001 and 2002, respectively over compared to the control when the highest P level (75kg P/ha) was applied. SAMPEA – 6 (local) produced more leaves and higher dry matter yield than SAMPEA – 7 at all the sampling periods. The results also indicated that grain yields and crude protein content realized with 35.5kg P/ha did not differ significantly from that of 75kg P/ha.
Conclusion and application of findings: Most farmers in Africa do not have access to P-fertilizer, there is therefore need to select cowpea varieties that can still produce good yield under low soil P or those with high P use efficiency as a low input approach to addressing this constraint. Based on these trials, a significant interaction between P-fertilizer and cowpea varieties on grain yield was noted which suggests that P-fertilizer recommendation for cowpea should be location specific. The application of 37.5kg P/was the most economical level for maximum grain yield and crude protein content. Therefore, when P-fertilizer is available, SAMPEA – 7 is recommended, while SAMPEA – 6 (local) will perform better without P-fertilizer and will give a higher return when P is applied.
Key words: Cowpea, fertilizer, phosphorus, yields.
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