D.G. Tanner

Participatory conservation tillage research: an experience with minimum tillage on an Ethiopian highland Vertisol

Farmer participatory tillage trials were conducted in a highland Vertisol area of Ethiopia during the 1999 and 2000 cropping seasons. This participatory initiative clearly demonstrated that incorporating farmers’ knowledge, ideas and preferences could improve the wheat production package. A traditional practice of Chefe Donsa farmers—applying ash from their homesteads to their fields to enable early-sown crops to withstand frost—led to the verification of the yield-enhancing effect of inorganic potassium fertilizer on wheat. Farmer adoption of a minimum tillage production system increased the gross margin of wheat production by US

Fertiliser effects on sustainability in the wheat-based small-holder farming systems of southeastern Ethiopia

132 per hectare—based on 1999 prices—relative to the traditional flat seedbed system. The minimum tillage system was characterized by a much lower level of soil manipulation relative to the traditional flat seedbed system, and, as a consequence, markedly reduced the total human labor and draft oxen requirements for wheat production. Thus, the minimum tillage system could be an effective intervention for soil conservation due to early-season vegetative cover of the soil surface. Also, the early crop harvest associated with the minimum tillage system was highly beneficial for small-holder farmers—since the early harvest coincided with the cyclical period of severe household food deficits and high grain prices in local markets.

Effects of stubble management, tillage and cropping sequence on wheat production in the south-eastern highlands of Ethiopia

Abstract On-farm trials were conducted over three seasons throughout the highlands of Ethiopia to examine the sustainability of increased nitrogen and phosphorus fertilizer application on bread wheat in the peasant farming sector. Nitrogen fertiliser decreased soil pH by 0.2 to 0.3 units over one crop season. Nitrogen rates as low as 20.5 kg ha −1 significantly increased the density of wild oats in the wheat crop; the response to N was quadratic, attaining a maximum of 246 wild oat panicles m −2 at 41 kg ha −1 relative to 191 panicles m −2 for the 0 N treatment. Broadleaf weed densities and the labour requirement for hand weeding the wheat crop were also significantly increased by fertiliser N. The incidence of stripe rust on wheat foliage was increased by 18% on a susceptible bread wheat cultivar with the application of 82 kg N ha −1 . Phosphorus fertiliser jincreased the incidence of stripe rust by 14% with the application of 40 kg P ha −1 . In contrast, P significantly decreased the density of wild oats and broadleaf weeds, presumably affecting both characters through an enhancement of crop biomass production. To have a sustainable impact on wheat grain yields in Ethiopia, increased fertiliser usage should be accompanied by the provision of othe essential farm-level imputs such as herbicide and seed of rust-resistance cultivars.