Labour burden not crop productivity increased under no-till planting basins on smallholder farms in Murehwa, Zimbabwe

Rusinamhodzi Leonard, Corbeels Marc, Nyamangara Justice, Giller Ken E.. 2012. Labour burden not crop productivity increased under no-till planting basins on smallholder farms in Murehwa, Zimbabwe. In : Integrated Soil Fertility Management in Africa: from Microbes to Markets, Nairobi, Kenya, 22-26 october 2012. CIAT. s.l. : s.n., Résumé, 102. Integrated Soil Fertility Management Africa, Nairobi, Kenya, 22 Octobre 2012/26 Octobre 2012.

Résumé : No-till planting basins are promoted using seed and fertiliser inputs as incentives for their widespread uptake in Zimbabwe. Notill planting basins are planting holes measuring 15 cm width x 15 cm length x 18-20 depth, spaced 60 cm within the row and 75- 90 cm between rows leaving up to 90% of the soil surface undisturbed. They are intended to conserve moisture and improve the targeting of nutrient application. We evaluated the effect of planting basins on crop yield and labour requirement in an on-farm experiment over two seasons in Murehwa district, Zimbabwe. The experiment was established in clay and sandy soils, in two fields types; degraded and better managed fields in 2009/2010 and 2010/2011 seasons. Two tillage treatments i.e mouldboard ploughing and no-till planting basins were tested. Tillage plots measured 1080 m2 (18 m x 60 m) and labour hours were derived by direct measurement in these plots. Due to grazing in the dry season, soil surface cover by crop residues in the experimental fields was less than 10% in both seasons. Previous field management, nutrient management in the experiment and season had a significant effect on crop yields (p <0.001); there was no significant effect of tillage. The largest maize grain yield of 5.6 t ha-1 was obtained with a combination of 3 t of manure and 60 kg N ha-1 under conventional tillage the equivalent treatment under planting basins yielded 4.6 t ha-1 in the 2009-2010 season. Rainfall was poorly distributed in 2010-2011 season and the same treatment gave the largest grain yield of 1.6 t ha-1 under conventional tillage and 1.2 t ha-1 under no-till planting basins. Land preparation under conventional tillage required 6 man days ha-1 while making planting basins required 27 man days' ha-1 for the clay soils and 15 man days ha-1 for the sand soils. Weeding in planting basins required 40% more labour compared with conventional tillage (12 man days ha-1) due to greater weed densities associated with no-tillage. Planting basins did not enhance moisture conservation in a the 2010-2011 season when rainfall was poorly distributed. The increased labour requirement suggests it is unlikely that farmers will abandon the plough in favour of the hand hoe especially if they own cattle. Planting basins are easier to make in sandy soils and require less labour than in clay soils. Conversely, they are easier to maintain in clay soils than in sandy soils. Although planting basins were practiced by about 98% of farmers, the maximum land size allocated to planting basins was only 0.2 ha per farm, 10% of the landholding at most. Given that planting basins increase the labour burden but not crop yield, widespread adoption by smallholder farmers seems unlikely. (Texte integral)

Classification Agris : F07 - Façons culturales
F08 - Systèmes et modes de culture
E80 - Économie familiale et artisanale

Auteurs et affiliations

• Rusinamhodzi Leonard, TSBF (ZWE)
• Corbeels Marc, CIRAD-PERSYST-UPR SCA (BRA)
• Nyamangara Justice, ICRISAT (ZWE)
• Giller Ken E., Wageningen University (NLD)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/570626/)

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