Innovative agroecological practices can restore degraded farmlands and revive crop yields

Land degradation is a major obstacle to agricultural development in Africa, where it’s accentuated by poor agricultural practices and climate change effects. Restoration of degraded lands is crucial to prevent incursions into virgin and marginal lands. A field experiment was carried out over a four-year period on two degraded sites, to assess and compare the effect of the common practices of: (i) burning crop residues and weeds by resource-poor farmers (T1) and (ii) burning crop residues and weeds followed with application of manure and/or NPK as external inputs (T2) by resource-endowed farmers with (iii) an innovative agroecological package (T3) on soil physical, chemical and biological attributes, and crop yields. T3 consisted of crop rotation and/ intercropping with Mucuna pruriens cover crop, grasses (Pennisetum purpureum and Setaria sphacelate) and shrubs (Calliandra calothyrsus, and Leucaena diversifolia), and the application of manure and NPK. A randomized complete block design with 8 and 10 blocks, with each package appearing once in each block, was used respectively, at Mulungu and Mushinga. The agroecological package significantly improved soil and plant parameters compared to the common practices at both sites. The average plot- level aboveground biomass was significantly lower (p < 0.001) in T1 (11.3–17.4 t/ha) and T2 (10.1–21.9) than in T3 (39.9–60.4 t/ha). Similar trends were observed for bean and maize grain and banana bunch yields. When T1 is compared to T3, mean yields increased 2.6 times (848 kg/ha against 327 kg/ha), 2.8 times (2,201 kg/ha against 792 kg/ha) and 1.5 times (7.4 t/ha against 5.0 t/ha) for bean grains, maize grain, and banana bunches, respectively. Improvements were also observed for soil physical, biological, and chemical properties. A decrease in soil temperature; and increases in soil porosity, earthworm density/m2 (1,932 against 0), nodules/bean plant (28 against 21) and root length density (65 against 15.5cm) were observed in T3. T3 (compared to T1), had a decrease in acidity and Al3+; an increase in soil organic matter, K+, Ca+, and aboveground carbon stock (26.5 t/ha against 5.6 t/ha). The innovative agroecological package is thus an approach that can be used to effectively restore degraded and abandoned farmlan

Évaluation agronomique des variétés de haricot volubile riches en micronutriments dans un système intégré d’Agroforesterie sur deux sols contrastés à l’Est de la RD Congo

Objectif: L’objectif de cette étude était d’évaluer différentes variétés de haricots riches en fer et zinc dans un système intégré de type «jachère-herbage agro-forestière».Méthodologie et résultats: Le dispositif expérimental était le split plot avec comme parcelles principales le type de jachère-herbage agro-forestière, elles étaient subdivisées en quatre sous parcelles secondaires chacune correspondant à une variété de haricot. Les parcelles étaient au total onze et constituaient les différents traitements : T00 (témoin : 0 herbage-arbres, 0 NPK et 0 Fumier) ; T0 (NPK+Fumier), T1 à T9 issus de la combinaison herbes x arbres+NPK et fumier. Les 11 parcelles principales ont constitué un bloc répété cinq fois par site. Le fumier (20 t MS/ha) et les micros doses d'engrais NPK (50 kg.ha-1) étaient appliqués. Des différences ont été observées entre les traitements et les deux sites. Le traitement NPK+Fumier (T0) a donné les rendements en graines de haricots et les teneurs en zinc et en fer dans les graines de haricots les plus élevés dans les deux sites, dans le site avec sol fertile le rendement était de 1144,2 kg.ha-1 de graines et dans le site avec sol pauvre de 260, 6kg.ha-1 de graines). Les traitements T00 et NPK + Fumier+ jachère-herbage agro-forestière ont donné des rendements les plus bas (12,2 et 4,7 kg.ha-1) respectivement dans les sols pauvre et fertile. Les scores de maladies étaient bas, les variétés ont affiché une réaction intermédiaire.Conclusion et application de résultats: L’application de la microdose d’engrais et la jachère-herbage agroforestière ont augmenté le rendement en graines et la teneur en micronutriments dans les graines de haricots. En plus, cet effet était plus prononcé sur sol pauvre que sur sol fertile. L’application de microdoses d’engrais minéral et organique est l’un d'importantes pratiques pour améliorer le rendement de haricots dans le sol pauvre de Mushinga.Mots clés: Arbustes, fertilité du sol, graminées, légumineuses, haricots biofortifiés, rendementEnglish AbstractEnglish Title: Agronomic evaluation of different climbing beans varieties rich in micronutrient in an integrated Agroforestry systems in two contrasting soils in south Kivu, Eastern DR CongoObjective: The objective of this study was to evaluate different varieties of climbing beans (Phaseolus vulgaris L.) rich in iron and zinc in an integrated agroforestry system.Methodology and Results: The experiments were established in two sites using a split-plot design, with the main plot treatments consisting of agroforestry-fallow types. These plots were 11 in total: T00 (control: 0 grasses, trees, NPK and manure); T0 (NPK+manure), T1 to T9 from the combination grass-trees+NPK and manure and were repeated five times per site. They were subdivided into 4 subplots, each corresponding to one variety of beans. Manure (20 t DM/ha) and micro doses of NPK fertilizer (50 kg ha-1) were applied. Differences were observed between treatment and between sites. The treatment with NPK+manure (T0) gave the highest grains yields and content in zinc and iron in the grain beans in the two sites, 1144.2 kg ha-1 for site with fertile soil and 260.6 kg ha-1 in poor soil.The T00 treatments and NPK+manure+agroforestry fallow grassland gave the lowest bean grain yields (12.2 and 4.7 kg ha-1) respectively in the poor and fertile soils. Disease scores were low, varieties showed intermediate reaction.Conclusion and application of results: Bean grain yield and micronutrient content in the grain beans were enhanced with application of microdose of fertilizers and agroforestry-fallow grassland. In addition, this effect was more pronounced on poor soil than on fertile soil. The application of microdose of mineral and organic fertilizer is one of the important practices for improving bean yield in the poor soil of Mushinga.Keywords: Biofortified beans, grasses, legumes, shrubs, soil fertility, yiel