Abstract/Summary

Sustainable soil management underpins many of the UN Sustainable Development Goals (SDGs). Knowledge exchange between farmers and soil scientists or extension officers is essential to create hybrid knowledge for sustainable soil fertility management under climate change. However, miscommunication between them and the unequal distribution of information reduce both the absorption of information and its implementation for soil management. Studies that provide thorough examinations of farmers’ knowledge systems about soil fertility, the effect of the difference of content and sources of information, and the effects of external and internal factors, including determinants of intentions for farmers’ soil knowledge construction and its implementation, are still rare. Therefore, this study’s aim was to explain how the construction of farmers’ knowledge of soil fertility compares to soil scientific knowledge of fertility and how the farmers’ knowledge system is used for land management. The aim is divided into three main objectives: to examine the similarities and differences between farmers’ qualitative evaluation and soil science quantitative analysis for soil fertility classification; to explore farmers’ and scientists’ mental models of soil fertility and the relationship between soil properties and processes for communicating soil knowledge; and to explore how cropping and land management responses to climate variability and soil type are shaped by perception of risk, individual motivation and perceived capacity. Empirical fieldwork was carried out in two villages in Kitui County, Kenya, in 2016 to compare the effect of location on the construction and implementation of soil knowledge. Structured questionnaire interviews, participatory methods and focus group discussion involving 60 farmers, two extension officers and eight soil scientists (in Wageningen) were used for social and soil knowledge data collection. 116 soil samples were taken from the places with the most and worst fertile soils from farmers’ fields, according to the farmers’ perceptions, and their physiochemical parameters were analysed. This study revealed the importance of soil texture and colour in both soil scientific and local soil classification: although the farmers did not use scientific methods or terminology, they were aware of a significant relationship between the amount of nutrients and water holding capacity (WHC). The location of soils and previous soil degradation affected the farmers’ knowledge construction. The mental models clearly showed that farmers’ perception of soil fertility was focused on WHC, manure and fertilizer application, and location. Different perceptions of soil processes also appeared, both among farmers and between farmers and soil scientists. Farmers’ crop selection and timing of seeding differed according to livelihood strategy, soil type, water availability and the occurrence of drought events. Communication with extension officers increased their adoption of innovations. Based on the results, this study recommended the development of a hybrid communication approach in order to co-learn with farmers and accelerate communication among stakeholders, with the goal of creating hybrid knowledge for site-specific sustainable soil management.