Harun Mbatha MbuviEric MasikaMutahi, Wachira Samuel2022-08-192022-08-192022http://ir-library.ku.ac.ke/handle/123456789/23997Thesis Submitted in Partial Fulfillment of the Requirements for the Award of the Degree of Master of Science (Applied Analytical Chemistry) in the School of Pure and Applied Sciences of Kenyatta University, March, 2022In Kenya, Maize is a very vital cereal crop and a major staple food to many Kenyan families. Majority of farmers apply Nitrogenous and Phosphorous fertilizers to boost maize productivity in the country and Nyeri County in particular. Despite all this, acreage yield has been declining. Potassium (K) and micro nutrients fertilizers application in this region is limited yet potassium is required by maize in large quantities. There is also limited report on foliar feed application in this region. This study aimed at determining the nutrients levels in various farm soils of more intensive agricultural areas of Nyeri County in Kenya and formulates a customized potassium foliar feed. Grid sampling technique was used in soil sampling. Four farms under intensive cultivation were selected for the study. Customized Potassium Foliar feed was formulated and analyzed. Maize was grown in 12 plots of 5m by 5m with spacing of 50cm between the adjacent plots at each of the 4 selected farm sites. The 12 plots received the same N and P basal fertilizer dosage of 70kg/ha. In addition, 3 plots in each farm received commercial foliar feed (20mg/l), 3 plots received half dosage (10mg/l) of customized K foliar feed while the other 3 plots received a full dosage (20mg/l) of customized K foliar feed while the other 3 plots were used as control. Plant height, stem girth, length of leaf and grains yields were compared with the treatment applied. Soil analysis found that the total nitrogen ranged between 0.06- 0.06% as opposed to the recommended level of 0.25%, phosphorous levels ranged between 1.6-1.9mg/L below the recommended value of 10mg/L. The available Potassium had a mean of 7.76±1.10 mg/L; Calcium and Magnesium had a mean value of 6.28±0.16mg/L and 10.164±0.19 mg/L respectively. However, these levels are below the recommended values of 160 mg/L, 15mg/L and 25mg/L respectively. The study also indicated micro nutrients were. Micro nutrients such as Zn(0.14±0.06mg/L),Cu(0.15±0.01mg/L),Fe(0.11±0.03mg/L) and Mn (0.10±0.03mg/L), as opposed to the recommended critical values of 5mg/L, 5mg/L, 6mg/L and 2mg/L respectively. Customized K foliar feed contained nutrients such as Potassium, Phosphorous, Nitrogen, Magnesium and Calcium with concentration level of 13±0.13mg/L, 6.64±1.02mg/L, 0.75±0.001%, 6.19±0.18 mg/L, and 23.94±1.10 mg/L respectively. In addition, levels of zinc, copper, iron and manganese were determined. These nutrients registered 0.15±0.05mg/L, 0.66±0.008 mg/L, 0.34±0.18 mg/L and 0.46±0.003 mg/L respectively. The data obtained from the study found that farms treated with full dose customized K foliar feed fertilizer had increased plant height (45.5±42.23 %), ear length (76.7±21.05 %), stem girth (44.4±15.63 %) and maize yields (132.4±23.92%). Thus, the study established that customized foliar feed significantly improved the maize yield in the region. There is need to supplement nutrients to the soil for optimum yield of maize. Farmers and policy makers should put a lot of efforts to correct the soil nutrients deficiency by applying 20mg/l of customized K foliar feed for optimum yield of maize in this region.enCustomizedPotassium Foliar FeedOptimum YieldMaize (Zea Mays L)Nyeri CountyKenyaThesis