Climate Smart Agricultural Intensification With Desmodium Legume Cover Crops in Coffee Farm at Kabete in Times of Climate Change.

Abstract

The conventional coffee production systems has promoted intensive weeding relying heavily on the common broad-spectrum herbicide named glyphosate and manual regular weeding for weed control. These practices have been shown to increase the risks of soil erosion and the associated loss of beneficial ecosystems services, increased rate of soil degradation and related reduction in coffee productivity. The loss of the soils ability to provide the necessary ecosystem services have resulted in the need for compensation using synthetic inputs especially herbicides and fertilizers despite their associated negative environmental impacts. Climate change has been documented to adversely affect coffee and livestock production with declining yields and reduced incomes while perpetual shortages of livestock fodder is pushing farmers to rely heavily on commercial feeds increasing cost of production and reducing earnings. This study at the University of Nairobi Kabete farm evaluated the performance of desmodium legume fodder as a suitable legume cover crop for coffee to benefit from the associated ecosystem services without farmers suffering from yield penalties and provide livestock fodder. A survey on knowledge, attitude and practices of coffee farmers’ in Githunguri on integration of legume cover crops for ecosystem services and serving as livestock fodder was carried out. A medium term experiment was done at the University of Nairobi in 2019, at Kabete coffee plantation comparing soil moisture, nutrient relationship and coffee production among 3 weed control treatments of desmodium legume fodder cover crop, glyphosate herbicide and tillage using hand hoes. A completely Randomized Block Design was utilized where the 3 treatments were replicated 3 times where ANOVA was used to compare moisture differnces, weed control, biomas production and effect of each treatment on coffee production. Soil sampling used montly assessment using 9 cores of 30 cm and then analysed at the University of Nairobi Kabete laboratory. A face to face structured questionnaire using snowball sampling for 97 farmers was also administered in Githunguri area in Kiambu where a xiv farmer’s knowledge, attitude and practices was evaluated being an area characterized by coffee farmers recording appreciable milk production income and data analysed using Arch GIS survey tool and regression analysis. Desmodium was able to sufficiently suppress weed growth serving as a cover crop in the plots while the fresh biomass production was extrapolated showing a yield potential of 17 tons/year per hectare. Analysis of soil moisture content indicated better soil moisture retention at 36% where legume cover crop represented by desmodium. comparative coffee yield results on the experimental plots indicated increased coffee productivity where desmodium was intercropped with 1.8 times higher than herbicide treatment and 1.2 times superior than manual weeding. The savings for farmers on the purchase of commercial feeds was estimated at USD 750, per hectare per year which is a significant earning associated with better land use. The results of the farmer’s survey on knowledge, attitude and practices in relation to adoption of legume cover crops in coffee farms in Githunguri indicated a low adoption of desmodium but other annual crops species are widely used as intercrops despite their lacking of complementarity. The logistic regression model used to evaluate the relationship between commercial feeds and milk production showed a significant correlation at r² being less than 0.699, which on average calculation contributed a cost of KES. 19 (USD 0.2) per litre of milk produced. The findings were significantly important as an indicator of farmers reliance on the expensive commercial feeds for the success in milk production despite farmers having planted napier grass (pennisetum purpuleam) while losing on the potential savings of having the supplementary fodder from the desmodium legume fodder cover crop in coffee. Implications of this study on the climate-smart adaptation strategy of adopting desmodium legume cover crops in coffee production controlling weeds, thereby reducing costs of labour, maintaining soil ecosystem services through provision of habitat for soil microbial community and generating fodder biomass for livestock. xv Policy makers need to appreciate the value of ecosystem services and increase sustainable agricultural intensification practices such as legume fodder cover crops