Restoring degraded Kenyan grassland soils

土壤是非洲粮食生产的基础，它们承受着极大的压力，虽然对非洲土壤的作物生产管理进行了大量研究，但对草原管理的研究却少得多。不良的放牧方式以及养分和有机物的持续流失对植物营养产生负面影响；土壤侵蚀降低了土壤深度，降低了储水量，使地表的底土变得更贫瘠，在极端情况下导致完全放弃放牧牲畜。据估计，非洲40%至60%的土壤已经退化，因此显然需要恢复土壤生产力以维持生计。我们在肯尼亚资助的GCRF-ODA资助的非洲退化景观恢复（ReDeal）工作已开始探索恢复方案。我们在不同的土壤环境下建立了三个因子实验，研究了施肥、播种和耕作对土壤生物地球化学过程的影响。这些实验的长期维护由我们的CASE合作伙伴ILRI保证。此外，我们将在2023年建立一个由ILRI和UKRI资助的大规模实验来研究牲畜放牧的影响。这些实验将为热带非洲草原土壤恢复策略的研究提供无与伦比的资源。该项目旨在利用ReDeal实验和新的操作实验来评估恢复策略对草地土壤多功能的影响，以测试干预措施对未来极端气候（包括干旱和洪水）的弹性。这个项目将增加对正在进行的项目的机械理解，为这些未被充分研究的热带草原提供新的知识。量化恢复策略对土壤物理（团聚体稳定性、持水量、入渗）、生化（碳、氮、磷储量）和生物（养分循环和微生物群落）特性的影响。考察土壤反应的差异是否受到土壤矿物学特征和放牧的影响。确定恢复干预后土壤的气候敏感性和恢复力。

Soils underpin food production in Africa, and they are under extreme pressure and while there has been considerable research into the management of African soils for crop production, far less research has been conducted into grasslands management. Poor grazing practices and the continuous removal of nutrients and organic matter negatively impacts on plant nutrition; soil erosion reduces soil depth lowering water storage and brings poorer subsoil to the surface and in extreme cases leads to the abandonment of livestock grazing altogether. Estimates suggest 40 to 60% of soils in Africa are degraded, therefore there is clearly need to restore the soil productivity to sustain livelihoods.Our GCRF-ODA funded Restoring Degraded African Landscapes (ReDeal) work in Kenya has begun to explore options for restoration. We have established three factorial experiments in contrasting pedological settings investigating the role of manures, seeding and tillage on soil biogeochemical processes. The long-term maintenance of these experiments has been guaranteed by our CASE partner ILRI. In addition, we will establish in 2023 a large-scale experiment to study the influence of livestock grazing funded by ILRI and UKRI. These experiments will provide an unparalled resource for work into soil restoration strategies in tropical African grasslands.This project aims to evaluate the impact of restoration strategies on grassland soil multifunctionality utilising the ReDeal experiments and new manipulation experiments to test how resilient the interventions are to future climate extremes including drought and flooding. This project will add mechanistic understanding to the ongoing programme delivering new knowledge on these understudied tropical grasslands.Objectives:1. Quantify the impact of restoration strategies on soil physical (aggregate stability, water holding capacity, water infiltration), biochemical (C, N and P stocks) and biological (nutrient cycling and microbial community) properties.2. Examine whether differences in the soil response are influenced by the soil mineralogical characteristics and by grazing.3. Determine the climate sensitivity and resilience of the soils following restoration interventions.