The role of conservation agriculture in enhancing biodiversity and common beans productivity

Conservation of biodiversity in agricultural landscapes is vital for maintaining ecosystem stability and resilience. Conservation agriculture, a sustainable farming approach that involves minimum tillage and reduced use of synthetic pesticides, herbicides, and growth promoters, has gained attention as a potential strategy to enhance biodiversity and reduce production costs. This study investigated the role of conservation agriculture in enhancing biodiversity and common bean productivity in Tanzania. The study compared plots practicing conservation agriculture (minimum tillage and reduced agrochemical use) with those using conventional farming methods. Biodiversity metrics, that is, earthworm populations, bird species richness, bird nest abundance, bird species diversity, bee visitation rates, and bean yield were assessed. The results showed significant positive effects of conservation agriculture on biodiversity, emphasizing its potential role in promoting sustainable agriculture, biodiversity conservation, and household improvement due to reduced production costs and increased yield per unit area. Earthworms per meter square observed to increase from 12 in the non-conservation plots to 34 in the conservation plots, which is likely to improve nutrient cycling and productivity. Furthermore, conservation plots had a higher number of bird species flying around (36−76) compared with 14–32 in non-conservation plots (4000 m 2 ) at 50 % bean flowering. The number of bird nests observed in the two plots during bean harvesting varied significantly ( P <0.05), where the number of bird nests observed in 4000 m 2 of non-conservation plots ranged from 14 to 36, compared to 12–62 in conservation plots. High bird nest numbers in conservation plots indicated higher bird habitat quality in conservation plots than in non-conservation plots. Bees as chief pollinators, bees visiting conservation plots during 50 % flowering per square meter ranged from 5 to 11, compared to 2–6 in non-conservation plots. Bee visitation to bean flowers has a significant influence on productivity, as it influences pollen transfer and fertilization. Common beans yield among plots ranged 0.9 tons/ha to 1.4 tons/ha in conservation plots compared to 0.35–1.01 tons/ha, in non-conservation plots. Land use conservation contributes considerably to economic growth through increased productivity and reduced production costs, where the production cost is reduced by 50 % in conservation plots compared with non-conservation plots. However, the present study was conducted in a single location with smallholder farmers; hence, further experiments over larger areas and longer time periods are needed for a more robust conclusion.