Soybean is an important crop with nutrition, economic and soil fertility improvement benefits to farmers. However, its production in western Kenya is partly constrained by low soil pH and soil fertility levels. A greenhouse pot study was conducted to evaluate the effects of inorganic fertilizers, farmyard manure and lime application on soil pH, nutrient uptake, growth and nodulation of soybean grown in acidic soils from western Kenya. The experiment was set up in a randomized complete block design with eight treatments: control; NPK; manure; lime; manure+lime; NPK+manure; NPK+lime and manure+lime+NPK. Significant effects of inorganic fertilizers, manure and lime applications were observed on all the variables. Manure, lime and manure+lime treatments increased soil pH by 1.33, 2.19 and 2.28, respectively, above the control treatment. The shoot N was lower under control (1.71-1.81%), NPK (1.85-1.98%) and manure (2.00-2.11%) than under all other treatments. Treatments NPK+lime and manure+lime+NPK recorded higher uptake of P and K nutrients than all other treatments. The control and NPK treatments recorded shorter plants and low leaf area and above-ground biomass compared to other treatments. The NPK+lime and manure+lime+NPK treatments recorded higher plant height and aboveground biomass than other treatments. Lime+manure treatment recorded highest nodule numbers and dry weights per plant. Positive relationships were observed between pH and N, P and K nutrient uptake (R 2 ranged between 0.30 and 0.77) and between biomass and N, P and K nutrient uptake (R 2 ranged between 0.68 and 0.99). From this study, use of manure and lime could result in improved soil pH for better uptake of nutrients, nodule formation and productivity of soybean in Western Kenya.

IntroductionM ango (Mangifera indica L.) is one of the most produced horticultural fruit crops in the Sub-Saharan Africa region (SSA) with both economic and nutritional values. However, the production potential is yet to be fully realized due to constraints such as soil infertility, drought, diseases (e.g. powdery mildew and anthracnose), insect pests (e.g. thrips, fruit fly, termites, thrips, mango seed weevil, white mango scale), and poor agronomic practices (

Maize and dry bean are the most important food crops that feed over 85% of Kenyan households. However, the productivity of these crops is low due to the high costs of land preparation and weed control, soil infertility and limited soil moisture under the current conventional tillage system of production. A study was carried in Embu County and Kirinyaga County to determine the economic returns of a maize-bean rotation system under different tillage systems and fertilizer regimes. Maize was produced during the long rains under no-till with crop residue retention (NT+CR) and conventional tillage with no crop residue retention (CT-CR) and inorganic fertilizer regimes (NK, NP, PK, NPK, and NPK+CaMgZnBS). Dry bean was planted in the short rains in the same plots where maize under different nutrient management regimes and tillage systems had been grown and harvested. The trial was laid out in a split-plot design with the tillage method as the main plot and fertilizer as sub-plot. Economic performance was assessed using partial budget analysis based on labor data and prices of all inputs used during the production period. Grain yields were reduced by 10% to reflect farmers’ yield levels. Maize and dry bean grains were sold at the prevailing farm gate prices. Results showed that maize-bean rotation was KE 22,718 cheaper under no-till with crop residue retention (NT+CR) than under conventional tillage with no crop residue retention (CT-CR). On average, NT+CR recorded KE 29,569 higher net benefit than CT-CR. The NT+CR tillage recorded a benefit to cost ratio of 3.7 compared to 2.7 recorded under CT-CR tillage system. The NT+CR with NK combined was the most profitable treatment with a benefit to cost ratio of 4.92 for maize and 4.33 for maize-bean rotation system. Based on this research, combination of no-till with crop residue retention has the potential to improve economic status and alleviate poverty among resource-constrained farmers.

The trials were set up in Busia, Embu and Kirinyaga Counties to assess the effect of tillage methods and application of different fertilizer combinations on maize productivity in the lower and upper midland agro-ecological zones of Kenya. Tillage methods were no-tillage (NT) with crop residue retention as mulch (+CR) (NT+CR) and conventional tillage (CT) without crop residue retention on farm surface (-CR) (CT-CR) while fertilizer combinations were NK, NP, PK, NPK, and NPK+CaMgZnBS. The N, P, K, Ca, Mg, Zn, B and S nutrients were applied at the rates of 120, 40, 40, 10, 10, 5 and 26.3 kg ha-1, respectively. The trials were laid in a randomized complete block design with a split-plot arrangement and replicated three times. The results showed that maize leaf area index, plant height, aboveground biomass, crop growth rate, and grain yield were significantly higher under CT-CR than under NT+CR in most of the sites. The CT-CR system out-yielded NT+CR system by 0.3 t ha-1 and 0.6 t ha-1 maize grain in Alupe and Kirinyaga, respectively. However, NT+CR system out-yielded CT-CR system by 0.4 t ha -1 maize grain at Embu. Across all the sites, application of PK and NPK+ZnBMgCaS fertilizer combinations resulted, respectively, in lowest and highest maize shoot biomass, leaf area indices, crop growth rates, plant heights, and grain yields. Based on this result alone, the potential of conservation agriculture in improving yields compared to conventional tillage could not be conclusive despite consistently recording higher soil moisture content across all sites and better yields in Embu. Again, application of a wide range of nutrients may be beneficial to maize production in the study areas as evidenced in the study. Therefore, we recommend multi-season and multi-location trials to comprehensively assess the impact of tillage methods and fertilizer management, particularly in relation to micronutrients.

Due to increasing popularity and use of agro-chemicals to control pests and diseases on fields, applicators of these pesticides, consumers of agricultural products and other living organisms are exposed to the dangers of these chemicals if not used properly. To mitigate these dangers and general environmental pollutions, farmers need to be trained on the dos and don’ts that ensure safer usage and increased efficacy. Key protection measures like use of right spraying equipment and wearing personal protective equipment such as waterproof apron, rubber gloves, gumboots, and breathing masks should be adhered to. Farmers should be reminded to read and follow properly the product labels provided before handling any chemical. In the case of using pesticide tank mixes, care must be taken to ensure that individual chemicals are miscible and never react to each other. The information on using tank mixes could be found from the product labels, approved and certified agro-dealers or agricultural extension officers. Remaining and or unused pesticide products must be stored safely under cool temperature and locked out of reach of children. Proper disposal of expired chemicals and their containers must be guaranteed.