Within ten months of shifting from long-term maize monoculture to more diversified cropping systems, several soil health indicators showed measurable improvements at experimental sites in Kenya. Published in Geoderma in 2026, the study examines four long-term trials in Embu, Machanga, Sidada and Aludeka, representing contrasting tropical agroecological conditions. Researchers assessed maize–legume rotations, maize–fodder relay systems, legume intercropping, farmyard manure and mineral nitrogen, measuring indicators related to soil carbon, nutrient availability and microbial activity.

Results show that responses depended strongly on soil type, climate, cropping system and previous degradation. Legume integration had a stronger influence on microbial respiration than manure, with legume-based rotations increasing basal respiration and producing more specialized patterns of substrate use. Manure generally increased available phosphorus and, in some locations, particulate organic matter and potentially mineralizable nitrogen. Sandy soils showed stronger early responses than clay-rich soils. Mineral nitrogen fertilizer had limited effects on most soil health indicators and was associated with soil acidification, reducing pH by 0.3–0.6 units despite recent liming.

The findings demonstrate that diversified cropping and organic amendments can initiate soil regeneration relatively quickly, but no single management practice performs uniformly across environments. The authors therefore emphasize adapting soil restoration strategies to local agroecological conditions and using sensitive biological and biochemical indicators to track change in smallholder farming systems.