Potassium Nutrient Status and Management in Kenyan Soils for Increased Productivity

Abstract

Nitrogen, phosphorus and potassium are regarded as the main basic nutrients necessary for plant growth and production and their functions are interrelated. Potassium is necessary for regulation of plant cells, for the production of proteins and enzymes. It improves crop's disease and pests' resistance, and it increases crop yield and plays a significant role in enhancing crop quality. Potassium deficiency inhibits protein production even when nitrogen is abundant. The objective of the study was to determine status of potassium in selected Kenyan soils and responses to applied potassium fertilizers. Studies were carried out in Kenya through laboratory soil analysis, meta-data analysis and fertilizer response studies. Soils were collected in the trial sites and analyzed using wet chemistry method. For meta-analysis, published materials were collected, collated, digitized and harmonized. Benefit cost ratios were calculated for each technology to ascertain its profitability. The soil analysis results showed that potassium, nitrogen, organic carbon and zinc were deficient. The meta-analysis results showed that, limited research studies had been conducted on potassium in Eastern, Coast and Rift Valley regions of Kenya. The most economical potassium responses were recorded under application of 60 kg K/ha, although the yields were not profitable. However, the fertilizer response studies showed increased crop yields on addition of potassium fertilizer up to 40 kg K/ha. Hence lower rates of potassium (less than or equal to 40 kg K/ha) are recommended to offset and maintain adequate potassium levels in the soil for optimal crop production and income. Nevertheless, soil analysis is key before any fertilizers are added to soils.