Effect of Live Mulch Conservation Practices on Crop Yields: A Study of Sweet Potato in Southwest Nigeria

Live mulch can reduce land degradation by protecting the surface soil from direct impacts of rain drops and consequently increasing crop yields. To compare the potential biomass production of sweet potato for soil conservation, two farmlands with different degradation potentials were selected to plant ten commonly grown cultivars of sweet potato of Africa. Soil degradation rate (SDR) and vulnerability potential (Vp) of the two farms were also compared using selected soil properties as assessment tools. Results indicated that Farm A with higher total biomass slightly degraded with low vulnerability potential (SDR/Vp ≈ 2/4) while the Farm B with lower biomass severely degraded with high vulnerability potential (SDR/Vp ≈ 4/2). Correlation between biomass and yields was not significant for both the farms, indicating that biomass alone cannot determine the yields of sweet potato. On a slightly degraded soil, Benue, Akinima, TIS 87/0087 and Arrow tip cultivars had the highest tuber production (100 - 70)%, followed by Ex-Igbaraiam, Eruwa, Shaba, Ishiayi and TIS 8441 (69 - 50)% and least by Akwide (<50%). While on a severely degraded soil, Ex-Igbaraiam cultivar had the highest yield production (100 - 70) %, followed by Shaba, TIS 87/0087, Benue and TIS 8441 (69 - 50)% and least by Akwide, Eruwa, Ishiayi, Akinima and Arrow tip (<50%). The trend of the result reflects the ability of potato cultivars to cope with degraded soils. In terms of biomass production, TIS 87/0087, Ex-Igbaraiam, TIS 8441 and Benue were highest followed by Shaba and Akwide and least by Arrow-tip and Ishiayi. The results indicates that TIS 87/0087 cultivar can perform well under severely degraded soil while Ex-Igbaraiam and TIS 8441 with high biomass potential are better used as folders especially on a degraded soil.