The nitrogen and carbon cycles are fundamental ecosystem processes influenced by several factors including soil type and other abiotic factors, plant species, grazing and soil organisms. Herbivores profoundly influence the functioning of ecosystems and the recycling of nutrients in interaction with plants in natural ecosystems. This study focuses on the effects of livestock on carbon and nitrogen cycling in a grazed savanna in Burkina Faso. Dominant grass species (aerial and root parts) and soil samples were collected under grasses and bare soil patches in 48 plots (24 protected and 24 unprotected plots), 18 months after setting up herbivores exclosures. Soil and grass ¹³C and ¹⁵N were used as integrative indicators of carbon and nitrogen cycles. The results revealed no significant effect of livestock on soil total carbon and nitrogen and on soil δ¹³C and δ¹⁵N values. Moreover, grazing had no significant effect on grass carbon and δ¹³C, while it significantly increased grass total nitrogen and δ¹⁵N. Therefore, our hypothesis that grazing would increase soil ¹³C and ¹⁵N values and plant biomass was only verified for grass ¹⁵N. Grass δ¹⁵N results suggest that grazing improves the immediate availability of nitrogen but could also increase nitrogen losses.

氮和碳循环是基本的生态系统过程，受多种因素影响，包括土壤类型和其他非生物因素，植物种类，放牧和土壤生物。草食动物通过与自然生态系统中的植物相互作用，深刻影响生态系统的功能以及养分的循环利用。这项研究的重点是在布基纳法索放牧的热带稀树草原中牲畜对碳和氮循环的影响。设置草食动物禁令后的18个月，在48个样地（24个保护样地和24个未保护样地）中，在草和裸露的土壤斑块下收集了主要的草种（空中和根部）和土壤样品。土壤和草¹³ C和¹⁵氮用作碳和氮循环的综合指标。结果表明家畜对土壤总碳和氮的无显著效果和对土壤δ ¹³ C和δ ¹⁵的N值。此外，放牧对草地碳和δ无显著影响¹³ ℃，同时显著上升草总氮和δ ¹⁵ N.因此，我们的假设，放牧会增加土壤¹³ C和¹⁵的N值和植物生物量只证实草^15个N.草δ ^15个N个结果表明，放牧提高氮的即将上市，但也可能增加氮损失。