Sustainability of the current crop production system on the Chisumbanje Vertisols in south-east Zimbabwe
2002
Mugabe, F.T. | Nyamangara, J. | Mushiri, S.M. | Nyamudeza, P. | Kamba, E.
Soil and plant samples were taken from 29 fields that had been under cultivation for periods varying from 0 to 50 years in order to assess the relationship between period of dryland crop production and soil pH, organic carbon and soil nutrients of the Chisumbanje Vertisols, Zimbabwe. There was a steady decline in soil organic carbon, KCl-extractable N, and foliar concentrations of total K and Ca. The content of P and Mg in the soil associated with increasing cropping periods and the total content of N, P and Zn in the plants increased slightly. Though not significant (P < 0.05), the observed decline in organic C and some nutrients may become a serious limiting factor to sustainable crop production on the Chisumbanje Vertisols in the long-term. There is a need to encourage the smallholder farmers who cultivate the Chisumbanje Vertisols, and similar soils in Zimbabwe, to use fertilizers, but the program has to be coupled with measures to increase available soil moisture, as the latter is the most limiting factor in the area.
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