Effect of Tillage Practice on Growth and Yield of Three Selected Cowpea Varieties

Aim: To evaluate the influence of tillage practice on growth and yield performance of three cowpea varieties.

Study Design: The treatments were laid out in a randomized complete block design with a factorial arrangement and replicated three times.

Place and Duration of Study: Study was carried out at St. Theresa demo farm and Nakamane irrigation scheme in Turkana county between November 2014 and January 2015.

Methodology: Treatments comprised three tillage practices: conventional tillage (control), conventional tillage + mulch and zero tillage and three cowpea varieties: M66, K80 and Kenkunde. Data collected included: Plant height, nodule count, total leaf vegetable yield, pod length, number of pods per plant, number of seeds per pod, grain yield,100 seed weight, total biomass and harvest index.

Results: Tillage practice and variety had no effect on plant height. Conventional tillage+ mulch increased the number of nodules per plant by 42.98%, while zero tillage reduced it by 27%. Conventional tillage + mulch increased fresh leaf weight, total grain yield, total biomass and harvest index. Tillage practice and variety had no significant influence on 100 seed weight at St Theresa demo farm. However, at Nakamane irrigation scheme, tillage+mulch increased 100 seed weight by 12.6% while zero tillage reduced it by 7.2%. Nodule count and pod length were different among varieties; however, the effect of variety on the number of pods per plant, total biomass and harvest index were not significant. Variety had significant effect on total grain weight at St Theresa demo farm Kenkunde out yielded K80 and M66 by 10.1% and 16.9% respectfully.

Conclusion: Conventional tillage + mulch significantly outperformed conventional tillage and zero tillage in growth, nodule number, total biomass, grain yield and yield components. Zero tillage produced higher grain yield and harvest index than conventional tillage. Based on these results generally, Kenkunde variety was superior to the other two varieties in nodulation, fresh leaf weight and grain yield. The effects of variety on biomass and harvest indices were not significant implying little genetic variability among varieties on these yield attributes.

Further work is required on the effect of tillage practice on soil moisture retention in Turkana County.