Browsing by Author "Barron, J."

Now showing 1 - 3 of 3
  • Conservation farming strategies in East and Southern Africa: Yields and rain water productivity from on-farm action research
    Rockström, J.; Kaumbutho, P.; Mwalley, J.; Nzabi, A. W.; Temesgen, M.; Mawenya, L.; Barron, J.; Mutua, J.; Damgaard-Larsen, S. (Elsevier B.V., 2009)
    Conservation farming for smallholders has been primarily applied and researched in humid and sub-humid regions, where it has shown significant improvements in agricultural productivity. In these regions, water generally is not a limiting constraint on plant growth and CF methods emphasize no-till or minimal tillage and mulch cover. However, in semi-arid and arid regions, rainfall variability and scarcity are significant constraints to productivity, the potential for attaining substantial mulch coverage is low, and no-tillage contributes to a soil crust that further decreases water infiltration. This study develops a CF approach focused on non-inversion tillage methods, adapted to the needs of arid and semi-arid agriculture. Using a participatory approach with local farmers and extension agents, trials comparing CF and conventional farming, with and without fertilization, were conducted in Tanzania, Kenya, Ethiopia, and Zambia. Neither CF tillage methods nor fertilization alone showed a significant improvement, but CF methods with fertilization improved both yields and water productivity (amount of water required per unit of crop). The improvements of CF over conventional farming methods were especially pronounced in seasons with the lowest rainfall, suggesting that CF could be a valuable water harvesting method in water-scarce regions.
  • Managing water in rainfed agriculture
    Rockström, J.; Hatibu, N.; Oweis, T. Y.; Wani, S. (London, UK: Earthscan and Colombo: International Water Management Institute, 2007)
    Main ideas (excerpts from chapter overview):
  • Yield and soil system changes from conservation tillage in dryland farming: A case study from North Eastern Tanzania
    Enfors, E.; Barron, J.; Makurira, H.; Rockström, J.; Tumbo, Siza D. (Elsevier, 2011)
    Conservation agriculture (CA) and its related practices of soil cover, cover crops, and reduced-tillage have often been touted as an effective means of in situ water harvesting, which provides stable yields in times of low rainfall. Applications have been especially relevant to semi-arid sub-Saharan Africa, where yields are characteristically low due to decreased water availability during critical crop development periods. In this study, the impact of adopting CA on the soil's capacity for moisture retention (as indicated by productivity) was assessed over six seasons between 2005 and 2008 in Northern Tanzania. Treatments included conventional tillage, conventional tillage with mulch and manure, tillage via ripper, and tillage via ripper with mulch and manure. No changes in physiological properties of the the soil were observed after treatment, but changes in chemical and microbiological components were measured. Additionally, yield increases were seen for ripper plus manure and mulch treatments but not ripper alone compared to control (conventional). However, results question the ability of conservation agriculture practices to stabilize yields in times of abnormally low rainfall, considering yield increases relative to control were primarily observed after times of elevated rainfall. Thus, short-term benefits to farmers would be increased yields during seasons of high rainfall rather than yield stabilization during low rainfall.