LEGUME INTEGRATION AND APPLICATION OF ORGANIC FERTILIZERS ON CROP YIELD

Introduction Maize, tomatoes and kales are important food security crops grown by majority of small holder farmers in Kenya. However, their production is constrained by declining soil fertility, pests, diseases and adverse effects of climate. Strategies to boost soil fertility and manage pests and diseases are mainly chemical based with adverse negative environmental impacts. Similarly continuous mono-cropping without application of organic amendments results in mining of same plant nutrients and depletion of soil organic matter.

Introduction cont’d; Thus the need to generate information on contribution of legumes and soil amendments on crop performance. A study was carried out to determine the effect of cropping systems and organic inputs on soil nutrient dynamics, maize, tomato and kale performance in parts of central Kenya.

APPROACH Field studies (on field in Kajiado County and on-station at Kabete Campus field station) to examine the effect of cropping systems and organic inputs on; productivity and quality of maize, tomatoes and kales intercropped with chickpea/white lupin. The cropping systems were; sole crops and maize/tomato/kale intercropped and in rotation with chickpea/white lupin plus farm yard manure (FYM) and Minjingu rock phosphate (MRP) as organic inputs. 

BENEFITS There was a 50% increase in crop yield under FYM(Fig 1). This leads to increased supply to meet the market demand. Plant Phosphorus and Nitrogen recorded 58% & 40% increase where MRP and FYM were applied respectively (Fig 2). The improved quality of the organic produce enhances demand.

Fig 1a and 1 b. Effect of legume integration and application of organic fertilizers on crop yield

Fig 2. Effect of legume integration and application of organic fertilizers on Nitrogen and Phosphorus concentration in crops tissues

Fig 2. Effect of legume integration and application of organic fertilizers on P concentration in crops tissues

CONCLUSION/RECOMMENDATIONS Application of FYM and MRP and integration of chickpea or lupin over growing seasons doubles maize, tomato and kale yields and increases their nutritive value. Chickpea and white lupin have the potential to solubilize MRP releasing P for crop uptake. The government should come up with concrete policies on organic agriculture.