Towards a cropping system sustainability tool (CROSST) - Pilot results from evaluating green manure cover crops in Benin and Kenya

Farming practices in sub-Saharan Africa have resulted in declining soil fertility. Hence, Green Manure Cover Crops (GMCC) are promoted for soil improvement and protection. Adoption of GMCCs by farmers, including integration in their cropping systems, requires a good understanding of the multi-dimensional impacts of these crops. We, therefore, developed the Cropping Systems Assessment Sustainability Tool (CROSST), which can compare the performance of different cropping systems with and without the integration of GMCCs. CROSST is an Excel-based tool that assesses both agro-environmental and socio-economic impacts of GMCC technologies. The tool quantifies gross economic margin, productivity (yield), soil health (N and P balances, soil structure, and soil organic carbon), required labour hours, and the trade-offs between these indicators. The tool was pilot-tested in Benin and Kenya under the BMZ-GIZ program on ‘Soil Protection and Rehabilitation for Food Security.’ Data was collected through literature reviews, focus group discussions and key expert interviews. The compared cropping systems were selected and designed by experts with in-depth knowledge on local contexts of Benin and Western Kenya. The first results indicate that GMCCs improve soil structure/soil organic matter as well as soil N balances in both countries. However, investing in soil improvement can result in loss of profitability, especially when a crop that produces grain for consumption or sale is swapped for a GMCC that produces biomass for soil amendment only. CROSST still needs further data refinement with recent official census as well as independent field measurements. Once validated, it can serve as a decision-support tool for development agencies, implementing partners, and local stakeholders when designing sustainable cropping systems that integrate GMCCs

Improving forage productivity for increased livestock production using biochar and green manure amendments

The rapid population growth in West African cities resulted in rising demand for animal source foods. However, this high demand for animal source food is rarely met by domestic production in Benin due to several factors, including low feed availability and poor animal nutrition, especially during the dry months, and degraded soils. To overcome this situation, the effects of maize (Zea mays) cob biochar and green manure from Gliricidia sepium and Mucuna pruriens (2 t/ha each) and their combination (1 t/ha each) were tested on Brachiaria brizantha cv. Xaraés agronomic performance over three months. The combination of biochar and green manure performed best with plant height increased by 57% (103.8 ± 17.12 cm) when compared to the un-amended control plots and each treatment alone two-month after planting. In addition, the number of leaves (22.9 ± 5.82) and the biomass determined (20.3 ± 5.64 t dry matter/ha) were highest with the combined treatment than the un-amended control plots three-months after planting. B. brizantha cv. Xaraés, fertilized with locally available biochar and green manure, could contribute significantly to increasing feed availability at farm level and boost meat and milk production

Towards a Cropping System Sustainability Tool (CROSST) –Evaluating Performance of Green Manure Cover Crops in Benin and Kenya: A Pilot Study

Soil degradation poses a serious threat to food production and rural livelihoods in sub-Saharan Africa1. Nutrient mining ,as a result of unsustainable farming practices, have left the soils unfertile (Fig.1). Green Manure Cover Crops (GMCC’s) are a promising intervention to improve soil health2.Benefits from GMCC’s are well known; however, there has been low uptake. Information on how GMCC technologies impact on profits, soil health ,and ecosystem services had not been thoroughly assessed3. Therefore, a Cropping System Sustainability Tool (CROSST) was developed to better understand agro-environmental and socio-economic impacts and trade-offs of GMCC integration in cropping systems. The tool was pilot tested in Benin and Kenya under the German Federal Ministry for Economic Cooperation and Development (BMZ)/Deutsche GesellschaftfürInternationaleZusammenarbeit(GIZ) program on ‘Soil Protection and Rehabilitation for Food Security.

Increasing nutrient use efficiency through improved feeding and manure manegement in urban and peri-urban livestock units of a West African city: A scenario analysis

In many African cities urban and peri-urban agriculture (UPA) plays a major role in creating jobs and contributing to food security. However, many small-scale UPA systems are characterised by excessive nutrient inputs to the livestock unit and poor handling of manure. To assess the impact of improved feeding and manure management on nutrient use efficiency within the cattle unit, simulation modelling was used to compare three typical UPA farm types in Niamey, Niger, that comprised: animal husbandry alone (AH), animal husbandry plus gardening (AH+G), and animal husbandry plus gardening plus millet cultivation (AH+G+M). Improved feeding increased annual body weight gain and milk offtake from cattle and reduced the amount of nitrogen (N) excreted in urine, thereby lowering the risk of N emissions. With improved manure management, dry matter (DM) and nutrients recycled per animal and year, and potentially available for cropping, ranged from 321–690 kg DM, 8–22 kg N, 1.2–2.5 kg phosphorus (P), and 3.0–5.6 kg potassium (K) in AH as well as AH+G+M farms compared to 221–479 kg DM, 5.0–14.0 kg N, 0.7–1.6 kg P, and 2.0–4.0 kg K in AH+G farms. These amounts were up to 2.2-, 2.5-, 1.9- and 1-fold higher than the quantities of DM, N, P and K recycled under current practices. Feeding dairy cattle according to their requirements will enhance milk and meat production; if coupled with regular manure collection and low-cost covering of manure heaps, substantial amounts of nutrients are recycled to cropland and vegetable gardens and environmental pollution is reduced

Feeding and spatial behaviours of transhumant cattle in southern Benin: implications for the sustainable management of rangelands

Feed intake on pastures plays a vital role in cattle rearing in West Africa. However, the scarcity of pastures during the dry season may result in changing grazing behaviour by cattle. Therefore, we studied the management practices of transhumant herders on communal rangelands through monitoring of cattle herds’ behaviour in southern Benin. We expected changes in grazing behaviours of cattle and shifts in diet composition and diet overlaps between herds. Therefore, feeding and spatial behaviours of cattle were studied on six transhumant herds monitored daily, each during three consecutive days on communal rangelands of Djidja. In each herd, three adult cows of four to five years old were equipped with two GPS data loggers (GT-730FL-S) to monitor animals’ movements. The data loggers were set to record the positions of the animals every 10 s and direct observations of the animal activities were made. The results indicated that the activities of cattle varied greatly according to site (p < 0.05). Moreover, feed ingested varied with site. The ration was dominated by woody species with 70% Fabaceae, whereas shrubs and grasses were less represented, indicating a shift in diet. This analysis is required for better monitoring of grazing cattle. Keywords: cattle tracking, communal pasture use, grazing activities, resource conservation, West Afric

Effet de la litière de biochar à base de rafles de maïs sur les performances zootechniques du poulet de chair au Nord Bénin

This study aims to evaluate the effect of biochar from corn cobs on the zootechnical performance of chickens. For this study, 201 broiler chicks from the Cobb 500 strain were divided into three batches of 67 chicks laid each on litter consisted of (i) 100% corn cobs (Rafle); (ii) 100% corn cobs biochar (Biochar) and (iii) 50% corn cobs plus 50% Biochar designated (Mixte). The zootechnical parameters including live weight, feed consumption, feed consumption index, morbidity and mortality were monitored and the weight of some organs was measured. The result indicated a significant improvement in feed intake and average daily gain in the Biochar treatment compared to the ‘Rafle’ batch only during the growth phase. Chickens from the Biochar and ‘Rafle’ treatment had heavier legs and gizzards than those from the ‘Mixte’ litter. The use of biochar litter therefore gave the best zootechnical performances. Economic and environmental analyzes are necessary to promote the use of these biomass as bedding in poultry farming. Keywords: bedding materials, biochar, corncobs, Cobb 500, production, BeninCette étude a pour objectif d’évaluer l’effet de l’utilisation du biochar à base de rafles de maïs sur les performances zootechniques des poulets de chair. A cet effet, 201 poussins de chair de souche Cobb 500 ont été répartis en trois lots de 67 poussins: un premier lot sur la litière constituée de 100% de rafles de maïs (Rafle); un deuxième lot constitué de100% de litière de biochar (Biochar) et un troisième à litière constituée de 50% de rafles de maïs et 50% de biochar (Mixte). Les paramètres zootechniques tels que le GMQ, l’ingestion alimentaire, l’indice de consommation, la morbidité et la mortalité ont été relevés et les poids de certains organes déterminés après abattage. Les résultats indiquent une amélioration significative de l’ingestion alimentaire et du GMQ pour le lot Biochar comparé au lot Rafle en phase de croissance. Les poulets des lots Biochar et Rafles ont eu des pattes et des gésiers plus lourds que ceux du lot Mixte. L’usage de la litière au biochar a donc donné les meilleures performances zootechniques. Des analyses d’ordre économique et environnementale seront nécessaires pour promouvoir l’utilisation de cette biomasse comme litière en aviculture. Mots clés: litière, biochar, rafles de maïs, Cobb 500, Béni

CROSST - Version 1.0.1

CROSST is an Excel-based tool that assesses both agro-environmental and socio-economic impacts of Green Manure Cover Crop (GMCC) technologies. The tool quantifies gross economic margin, productivity (yield), soil health (N and P balances, soil structure, and soil organic carbon), required labor hours, and the trade-offs between these indicators. The tool was pilot-tested in Benin and Kenya under the BMZ-GIZ program on ‘Soil Protection and Rehabilitation for Food Security.