Farmers' perceptions on mechanical weeders for rice production in sub-Saharan Africa

Competition from weeds is one of the major biophysical constraints to rice (Oryza spp.) production in sub-Saharan Africa. Smallholder rice farmers require efficient, affordable and labour-saving weed management technologies. Mechanical weeders have shown to fit this profile. Several mechanical weeder types exist but little is known about locally specific differences in performance and farmer preference between these types. Three to six different weeder types were evaluated at 10 different sites across seven countries – i.e., Benin, Burkina Faso, Côte d'Ivoire, Ghana, Nigeria, Rwanda and Togo. A total of 310 farmers (173 male, 137 female) tested the weeders, scored them for their preference, and compared them with their own weed management practices. In a follow-up study, 186 farmers from Benin and Nigeria received the ring hoe, which was the most preferred in these two countries, to use it during the entire crop growing season. Farmers were surveyed on their experiences. The probability of the ring hoe having the highest score among the tested weeders was 71%. The probability of farmers’ preference of the ring hoe over their usual practices – i.e., herbicide, traditional hoe and hand weeding – was 52, 95 and 91%, respectively. The preference of this weeder was not related to gender, years of experience with rice cultivation, rice field size, weed infestation level, water status or soil texture. In the follow-up study, 80% of farmers who used the ring hoe indicated that weeding time was reduced by at least 31%. Of the farmers testing the ring hoe in the follow-up study, 35% used it also for other crops such as vegetables, maize, sorghum, cassava and millet. These results suggest that the ring hoe offers a gender-neutral solution for reducing labour for weeding in rice as well as other crops and that it is compatible with a wide range of environments. The implications of our findings and challenges for out-scaling of mechanical weeders are discussed

Progres et perspectives du Centre dInformation et dEchanges sur les Plantes de Couverture en Afrique (CIEPCA)

The Center for Cover Crops Information and Seed Exchange in Africa (CIEPCA) was established to support cover crops systems development for researchers, extension workers, and farmers in West Africa. CIEPCA has been in existence for approximately 3years. In that period, much has been accomplished. Among the highlights, we can cite the production of four newsletters (in English and in French), the dissemination of more than 5 tonnes of cover crops seeds, and the connection of 6 (out of 8) CIEPCA country representatives to the internet. Although an impact study has not been conducted, CIEPCA has certainly stimulated more efficient work on cover crops by stimulating information and seed exchange. In the next phase, CIEPCA will attempt to broaden its influence to the rest of Africa and strengthen global linkage

Participatory evaluation of mechanical weeders in lowland rice production systems in Benin

Weeds are a major constraint to rice (Oryza sativa) production in sub-Saharan Africa. Use of mechanical hand weeders could reduce the labor required for weeding. This paper uses a participatory approach to examine the suitability of six mechanical weeders in Benin. A total of 157 farmers (93 male, 64 female) in 14 villages tested the mechanical weeders, ranked them in order of preference, and compared them with their own weed management practices. The ring hoe had the highest rank, followed by the straight-spike weeder; 97% of the farmers preferred the ring hoe to their own weed management practices, by hand or using traditional hoe, because of its easy operation and high efficiency. The ring hoe tended to be preferred especially in the fields with non-ponded water and relatively higher weed pressure. The straight-spike weeder tended to be preferred to ring hoe in the fields where weed pressure is less, whereas in ponded conditions, farmers liked these two weeders in equal proportion. The preference of weeders was not related to gender, rice field size, or years of experience of rice cultivation. Among 23 farmers who used herbicides, 17 farmers preferred herbicides to the ring hoe and have rice field of >0.5 ha. Mechanical weeders can offer an effective approach for weed management, especially for small-scale rice farmers, and different types of mechanical weeders should be introduced to farmers based on water regimes and weed pressure level

Phosphorus micro-dosing as an entry point to sustainable intensification of rice systems in sub-Saharan Africa

Phosphorus (P) deficiency is a major biophysical limitation to rice grain yields in sub-Saharan Africa, and low-cost P management strategies are needed by smallholder farmers to reverse soil fertility decline. On-station field and pot experiments were combined with on-farm testing to evaluate the effect of P micro-dose placement in dry-seeded, dibbled rice on emergence, early vigour and grain yield. Placing a micro-dose of 3–6 kg P ha−1 in the planting hole consistently increased early vigour and grain yield of both a P-efficient and less P-efficient rice genotype. An agronomic efficiency of P fertilizer (AEP) of 356–817 kg grains kg−1 P was achieved with a micro-dose of 3 kg P ha−1. A negative effect on emergence by placing a P micro-dose in the planting hole observed in one experiment was compensated by a higher grain weight per hill. In other experiments, no negative effect on plant emergence under both well-watered and water-stressed conditions and with different P sources was observed even when fertilizers were mixed with seeds. A micro-dose of 20–30 kg of DAP ha−1 placed in the planting hole resulted in an average net increase in profit of $91 to$136 ha−1 and benefit:cost ratio of 3–12 in on-farm experiments. Farmers' appreciation of the technology was positive but lack of credit, availability of appropriate fertilizers in local agrodealers and increased labour requirements were identified as potential constraints for adoption. P micro-dose placement in the planting hole can be used as an entry point towards sustainable intensification in dry-seeded, dibbled rice systems in SSA, provided it is accompanied by institutional support and mechanization options to increase its adoption potential

Deep learning-based estimation of rice yield using RGB image

Crop productivity is poorly assessed globally. Here, we provide a deep learning-based approach for estimating rice yield using RGB images. During ripening stage and at harvest, over 22,000 digital images were captured vertically downwards over the rice canopy from a distance of 0.8 to 0.9 m, and rice yields were obtained in the corresponding area ranging from 0.1 and 16.1 t ha −1 . A convolutional neural network (CNN) applied to these data at harvest predicted 70% variation in rice yield with a relative root mean square error (rRMSE) of 0.22. Images obtained during the ripening stage can also be used to forecast the final rice yield. Our work suggests that this low-cost, hands-on, and rapid approach can provide a breakthrough solution to assess the impact of productivity-enhancing interventions and identify fields where these are needed to sustainably increase crop productio