Use of Calliandra calothyrsus and leucaena tricandra tree species for soil nutrient enhancement in Chuka division, central highlands of Kenya

The central highlands of Kenya are characterized by high soil and nutrient losses through soil erosion and leaching. Research has reported Positive results from the use of appropriate vegetative contour hedges since they are able to hold topsoil while simultaneously capturing and pumping up leached nutrients. It has also been shown that farmers' adoption of new technologies is dependent on their perception of those technologies. Against this background, an on farm trial involving use of Calliandra, Leucaena and napier contour hedges was started in farmers fields of Chuka Division to evaluate the feasibility of these technologies in the control of soil and nutrient losses. The trial farmers were recruited on the basis of gender and slope after a Participatory Rural Appraisal (PRA). The slopes were categorized as 5-10, 10-20, 20-30 and > 30% slope. Treatments were laid down on these slope categories along the contours in a zig-zag manner with an inter-row spacing of 0.25 m, intea-row spacing of 0.5 m and a variable inter-hedge spacing depending on the slope. Soils were sampled at the start and 20 months after establishment of the trials at 0-30, 30-90 and 90-150 cm depths. Soils from 0-30 cm depth were analysed for PH, Ca, Mg, K, C, N, P, and inorganic N, while soils from 30-90 and 90-150 cm depth were analysed for inorganic N only. Farmers' perceptions of these technologies were determined by use of questionnaires. Treatments that had trees either as sole or combination hedges registered a significant (P

---

• View source