Rainwater harvesting to enhance water productivity of rainfed agriculture in the semi-arid Zimbabwe

Kahinda, J M and Rockstroma, J and Taigbenu, A E and Dimes, J (2007) Rainwater harvesting to enhance water productivity of rainfed agriculture in the semi-arid Zimbabwe. Physics and Chemistry of the Earth, Parts A/B/C, 32 (15-18). pp. 1068-1073. ISSN 1474-7065

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Zimbabwe’s poor are predominantly located in the semi-arid regions and rely on rainfed agriculture for their subsistence. Decline in productivity, scarcity of arable land, irrigation expansion limitations, erratic rainfall and frequent dry spells, among others cause food scarcity. The challenge faced by small-scale farmers is to enhance water productivity of rainfed agriculture by mitigating intra-seasonal dry spells (ISDS) through the adoption of new technologies such as rainwater harvesting (RWH). The paper analyses the agro-hydrological functions of RWH and assesses its impacts (at field scale) on the crop yield gap as well as the Transpirational Water Productivity (WPT). The survey in six districts of the semi-arid Zimbabwe suggests that three parameters (water source, primary use and storage capacity) can help differentiate storage-type-RWH systems from “conventional dams”. The Agricultural Production Simulator Model (APSIM) was used to simulate seven different treatments (Control, RWH, Manure, Manure + RWH, Inorganic Nitrogen and Inorganic Nitrogen + RWH) for 30 years on alfisol deep sand, assuming no fertiliser carry over effect from season to season. The combined use of inorganic fertiliser and RWH is the only treatment that closes the yield gap. Supplemental irrigation alone not only reduces the risks of complete crop failure (from 20% down to 7% on average) for all the treatments but also enhances WPT (from 1.75 kg m−3 up to 2.3 kg m−3 on average) by mitigating ISDS

Item Type: Article
Uncontrolled Keywords: Rainfed agriculture; Rainwater harvesting system; Water productivity; Yield gap
Subjects: Others
Depositing User: Ms K Syamalamba
Date Deposited: 15 Nov 2011 09:12
Last Modified: 03 Jan 2012 05:28
URI: http://oar.icrisat.org/id/eprint/3932
Official URL: http://www.sciencedirect.com/science/article/pii/S...
Funders: WaterNet Challenge Program
Acknowledgement: The authors appreciate and acknowledge financial assistance from the WaterNet Challenge Program, Project Number 17 and Mr Phiri Maseko for his cooperation on the field study
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