Integrated Soil Fertility Management: Use of NUTMON to Quantify Nutrient Flows in Farming Systems in Central Kenya

A study based on Participatory Learning and Action Research (PLAR) to categorize soil fertility management was carried out in three districts of Central Kenya: Kirinyaga, Maragua and Kiambu. The PLAR classified farms according to their economic and soil fertility management status. In each district 20-30 farmers were selected who represented three hundred farmers. The selected farmers had discussions with the facilitators who grouped them into three categories according to their soil fertility management level: Good (Class I), Average (Class II) and poor (Class III). Three farmers in Classes I and II and four in Class III were selected to represent the groups. Out of the selected representatives in each group, two were selected for Nutrient Monitoring (NUTMON) questionnaire assessment and this was done during the short rains cropping season. The farmers were visited at their homes and researchers had free discussions with them related to their farming systems and soil fertility management. Farm plans were drawn, fertilizer and manure inputs recorded and cash in and out flows monitored. Results were analyzed using NUTMON software model. Results showed a general trend of negative nutrient balances particularly in food crop fields. Mineral nutrient inputs (IN1) was high in classes II and I but low in class III, low negative nutrient balances were recorded in Kiambu district while Maragua district had higher nutrient balances. In fields where both organic and inorganic nutrient sources were used had positive nutrient balances.