McHunu C.N., Lorentz S., Jewitt G., Manson A., Chaplot V.
School of Bioresources Engineering and Environmental Hydrology, Rabie Saunders Bldg., Univ. of KwaZulu-Natal, Private Bag X01, Scottsville, 3209, South Africa; Soil Fertility and Analytical Services, KwaZulu-Natal Dep. of Agriculture and Environmental Affairs, Private Bag X9059, Pietermaritzburg, 3200, South Africa; IRD- BIOEMCO, C/o School of Bioresources Engineering and Environmental Hydrology, Univ. of KwaZuluNatal, Scottsville, 3209, South Africa
McHunu, C.N., School of Bioresources Engineering and Environmental Hydrology, Rabie Saunders Bldg., Univ. of KwaZulu-Natal, Private Bag X01, Scottsville, 3209, South Africa; Lorentz, S., School of Bioresources Engineering and Environmental Hydrology, Rabie Saunders Bldg., Univ. of KwaZulu-Natal, Private Bag X01, Scottsville, 3209, South Africa; Jewitt, G., School of Bioresources Engineering and Environmental Hydrology, Rabie Saunders Bldg., Univ. of KwaZulu-Natal, Private Bag X01, Scottsville, 3209, South Africa; Manson, A., Soil Fertility and Analytical Services, KwaZulu-Natal Dep. of Agriculture and Environmental Affairs, Private Bag X9059, Pietermaritzburg, 3200, South Africa; Chaplot, V., IRD- BIOEMCO, C/o School of Bioresources Engineering and Environmental Hydrology, Univ. of KwaZuluNatal, Scottsville, 3209, South Africa
Although no-till (NT) is now practiced in many countries of the world, for most smallholders, the crop residues are of such a value that they cannot be left on the soil surfaces to promote soil protection, thus potentially limiting NT benefits and adoption. In this study our main objective was to evaluate runoff, soil, and soil organic carbon (SOC) losses from traditional small-scale maize (Zea mays) field under conventional tillage (T) and NT, with crop residues cover of less than 10% during the rainy season, in South Africa. Six runoff plots of 22.5 m 2 (2.25. 10 m) under NT and T since 2002 were considered. At each plot, soil bulk density ( ρb) and SOC content of the 0-0.02 m layer were estimated at nine pits. Top-soil SOC stocks were 26% higher under NT than under T (P = 0.001). The NT reduced soil losses by 68% (96.8 vs. 301.5 g m -2 yr -1, P = 0.001) and SOC losses by 52% (7.7 vs. 16.2 g C m -2 yr -1, P = 0.001), and diff erences in runoff were not significant. Dissolved organic carbon accounted for about 10% of total SOC losses and showed significantly higher concentrations under T than NT (1.49 versus 0.86 mg C m -2 yr -1). The less erosion in NT compared to T was explained by a greater occurrence under NT of indurated crusts, less prone to soil losses. These results showed the potential of NT even with low crop residue cover (<10%) to significantly reduce soil and SOC losses by water under small-scale agriculture. © Soil Science Society of America.
Conventional tillage; Crop residue; Dissolved organic carbon; No-till; Rainy seasons; Reduced soils; Soil bulk density; Soil loss; Soil organic carbon; Soil Protection; Soil surfaces; South Africa; Zea mays; Agricultural wastes; Carbon; Crops; Erosion; Grain (agricultural product); Organic carbon; Runoff; Soils; crop residue; maize; runoff; smallholder; soil carbon; soil erosion; soil organic matter; traditional agriculture; zero tillage; South Africa