Yield and soil system changes from conservation tillage in dryland farming: A case study from North Eastern Tanzania
Yield levels in smallholder farming systems in semi-arid sub-Saharan Africa are generally low. Water shortage in the root zone during critical crop development stages is a fundamental constraining factor. While there is ample evidence to show that conservation tillage can promote soil health, it has recently been suggested that the main benefit in semi-arid farming systems may in fact be an in situ water harvesting effect. In this paper we present the result from an on-farm conservation tillage experiment (combining ripping with mulch and manure application) that was carried out in North Eastern Tanzania from 2005 to 2008. Special attention was given to the effects of the tested treatment on the capacity of the soil to retain moisture. The tested conservation treatment only had a clear yield increasing effect during one of the six experimental seasons (maize grain yields increased by 41%, and biomass by 65%), and this was a season that received exceptional amounts of rainfall (549Â mm). While the other seasons provided mixed results, there seemed to be an increasing yield gap between the conservation tillage treatment and the control towards the end of the experiment, and cumulatively the yield increased with 17%. Regarding soil system changes, small but significant effects on chemical and microbiological properties, but not on physical properties, were observed. This raises questions about the suggested water harvesting effect and its potential to contribute to stabilized yield levels under semi-arid conditions. We conclude that, at least in a shorter time perspective, the tested type of conservation tillage seems to boost productivity during already good seasons, rather than stabilize harvests during poor rainfall seasons. Highlighting the challenges involved in upgrading these farming systems, we discuss the potential contribution of conservation tillage towards improved water availability in the crop root zone in a longer term perspective.
If you experience problems downloading a file, check if you have the proper application to view it first. In case of further problems read the IDEAS help page. Note that these files are not on the IDEAS site. Please be patient as the files may be large.
As the access to this document is restricted, you may want to look for a different version under "Related research" (further below) or search for a different version of it.
References listed on IDEAS
Please report citation or reference errors to , or , if you are the registered author of the cited work, log in to your RePEc Author Service profile, click on "citations" and make appropriate adjustments.:
- Diao, Xinshen & Hazell, P.B.R. & Resnick, Danielle & Thurlow, James, 2007.
"The role of agriculture in development: Implications for Sub-Saharan Africa,"
153, International Food Policy Research Institute (IFPRI).
- Diao, Xinshen & Hazell, Peter & Resnick, Danielle & Thurlow, James, 2006. "The role of agriculture in development: implications for Sub-Saharan Africa," DSGD discussion papers 29, International Food Policy Research Institute (IFPRI).
- Rockstrom, J. & Hatibu, N. & Oweis, T. Y. & Wani, S. & Barron, J. & Bruggeman, A. & Farahani, J. & Karlberg, L. & Qiang, Z., 2007. "Managing water in rainfed agriculture," IWMI Books, Reports H040201, International Water Management Institute.
- Haggblade, Steven & Tembo, Gelson, 2003. "Conservation farming in Zambia:," EPTD discussion papers 108, International Food Policy Research Institute (IFPRI).
- Knowler, Duncan & Bradshaw, Ben, 2007. "Farmers' adoption of conservation agriculture: A review and synthesis of recent research," Food Policy, Elsevier, vol. 32(1), pages 25-48, February.
When requesting a correction, please mention this item's handle: RePEc:eee:agiwat:v:98:y:2011:i:11:p:1687-1695. See general information about how to correct material in RePEc.
For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: (Dana Niculescu)
If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.
If references are entirely missing, you can add them using this form.
If the full references list an item that is present in RePEc, but the system did not link to it, you can help with this form.
If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your profile, as there may be some citations waiting for confirmation.
Please note that corrections may take a couple of weeks to filter through the various RePEc services.