Rainfall risk and the potential of reduced tillage systems to conserve soil water in semi-arid cropping systems of southern Africa

Mupangwa, W and Walker, S and Masvaya, E and Magombeyi, M and Munguambe, P (2016) Rainfall risk and the potential of reduced tillage systems to conserve soil water in semi-arid cropping systems of southern Africa. AIMS Agriculture and Food, 01 (01). pp. 85-101.

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Abstract

Improvement of household food security in the Limpopo Basin has been elusive due to a combination of factors related to information and market constraints, but also farmers’ risk aversion induced by the high variability of rainfall during the growing season. The purpose of this study was to (1) characterize the rainfall and growing season patterns experienced by smallholder farmers, and (2) measure soil water dynamics in ripper and basin tillage systems being promoted in the semi-arid Limpopo Basin of southern Africa. The results show that the second half of the growing season receives more rainfall than the first half in the Limpopo Basin. However, rainfall is more variable during the January-March than the October-December period. Growing seasons start earlier and end later in the Mozambique part of the basin which is closer to the Indian Ocean. The Limpopo Basin is prone to two and three week dry spells with chances of 14 day spells higher (34–42%) than the 21 day spells (8–12%). The chances of 14 and 21 day dry spells increase substantially during the second half of the growing season. The 1980–1990 was one of the driest decades in the Limpopo Basin. Planting basin system conserved more soil water on sandy loam (18–24%) and clay loam (4–12%) soils than the conventional practice during flowering and grain filling maize growth stages. Ripper had 17–29% more soil water than conventional practice during flowering and grain filling maize growth stages. There is a high risk of dry spells and soil water deficits in smallholder cropping systems of the Limpopo basin. There is therefore scope in promoting rain and soil water management technologies, and good land husbandry in order to reduce risk of crop failure in the smallholder cropping systems.

Item Type: Article
Divisions: Research Program : East & Southern Africa
CRP: CGIAR Research Program on Dryland Systems
Uncontrolled Keywords: Drought; Dry spell; Limpopo Basin; Rainfed agriculture; Risk
Subjects: Others > Soil Science
Others > Climate Change
Depositing User: Mr Ramesh K
Date Deposited: 14 Mar 2016 08:28
Last Modified: 14 Feb 2017 07:54
URI: http://oar.icrisat.org/id/eprint/9382
Official URL: http://dx.doi.org/10.3934/agrfood.2016.1.85
Projects: UNSPECIFIED
Funders: UNSPECIFIED
Acknowledgement: This paper is a contribution to the WaterNet Challenge Program Project 17 “Integrated Water Resource Management for Improved Rural Livelihoods: Managing risk, mitigating drought and improving water productivity in the water scarce Limpopo Basin”. The authors acknowledge the meteorological offices of Mozambique, South Africa and Zimbabwe for providing daily rainfall data.
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