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Agricultural intensification - Saving space for wildlife?

Baudron F.. 2011. Wageningen : Wageningen University, 253 p.. Thesis Ph. D..

Increasing agricultural production and preventing further losses in biodiversity are both legitimate objectives, but they compete strongly in the developing world. In this study, current tensions between agricultural production and environmental conservation were described and analysed in Mbire District, an agricultural frontier shared with wildlife that lies in the Mid-Zambezi Valley, in the northern fringe of Zimbabwe. The potential of conservation agriculture (CA) to intensify agricultural production with minimum negative environmental effects was then explored. The population of Mbire District almost doubled between 1992 and 2002, while the livestock densities increased at rates above 15% in the early 1990s and the late 2000s. From 1980 to 2007, the expansion of farmland over the years was described by an exponential relationship. It was suggested that these changes affected elephant and buffalo numbers negatively. Increase in human population, increase in cattle population, and expansion of cotton farming were all drivers on the observed land use change. However, cotton farming was demonstrated to be paramount, enabling cattle accumulation and expansion of plough-based agriculture. The "environmental footprint" per farm was increasing significantly with the area under cotton and with the number of draught animals owned. A kilogram of seed cotton required 50% more land, removed twice as much N, 50% more K and 20% more P than a kilogram of cereal. However, except for pesticide, one man-day invested in cotton production had a smaller environmental footprint than a man-day invested in cereal production. As farming in Mbire District is limited by labour more than by land, specialising in cereal production would increase the total area occupied by crops and fallows, whilst specializing in cotton production would reduce this area. Therefore, maintaining or increasing the relative profitability of cotton vs. cereal may "spare land" for nature. Compared with current far

Mots-clés : agriculture; intensification; zone semi-aride; faune et flore sauvages; agriculture alternative; gossypium; sorghum; impact sur l'environnement; petite exploitation agricole; biodiversité; système de culture; agroécosystème; zimbabwe; front pionnier; agriculture de conservation; service environnemental

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