Soybean [Glycine max (L) Merrill] yields in Kenya range from 445-1200 kg ha-1 against potential yields of 3500 kg ha-1. The low yields are attributed to soil moisture stress and use of poor agronomic practices. The objectives of the study were to determine effect of soil moisture regimes on CO2 assimilation, growth and yield of selected soybean cultivars; to determine effect of planting density on yield and yield components of soybean and to determine effect of soybean and maize intercropping...
Abstract To attain agricultural sustainability, use of soil resources and tillage requires equal consideration for chemical and physical components of soil fertility. We assessed responses of selected soil physical and chemical properties to tillage and soil fertility amending resources. The study was carried out in Meru South and Kandara sub-counties located in the Central Highlands of Kenya for four cropping seasons. The experimental design was split-plot with tillage as the main factor - ...
Abstract Soil acidity and phosphorus deficiency are some of the constraints hampering agricultural production in tropical regions. The prevalence of soil acidity is associated with phosphorus (P) insufficiency and aluminum saturation. We conducted a two-seasons experiment to evaluate soil phosphorus availability and exchangeable aluminum in response to phosphate rock and organic inputs in acidic humic nitisols. The field experiment was installed in Tharaka Nithi County in the Central Highlan...
Abstract Planting pits are rain water harvesting structures that trap water and nutrients in surface runoff and rain water falling directly into the pits. Planting pits have been promoted for improving crop yields without considering the nutrient dynamics. To contribute to this knowledge, a study was conducted to determine the soil nutrient content after four seasons of growing sorghum and pigeon pea in rotation in “Chololo” and “Five by Nine” pits. Two planting pits; “Five by Nine...
Abstract Soil Collembola communities were sampled along a gradient of land use intensification in Taita-Taveta, Wundanyi division, Coast Province during the wet season (October-November 2007) and dry season (February- March 2008). This gradient ranged from Natural undisturbed land use to intensively cultivated (disturbed) horticulture fields. The eight land use types (LUTs) were stands of (1) Pinus patula, (2) Cypress lusitanica, (3) Indigenous forest, (4) Fallow, (5) Pennisetum purpureum, (...
Abstract Populations of soil-dwelling Collembola were monitored on a land use gradient ranging from Natural forests to intensively cultivated land during the wet season October-November, 2007 and dry season February-March, 2008. Eight land use types (LUTs) which included stands of; Eucalyptus saligna, Vitex keniensis, Pennisetum purpureum, indigenous forest, fallow fields, Cammelia sinensis, Coffea africana and Zea mays intercropped with Phaseolus vulgaris were sampled for Collembola in Embu...
Abstract Continuous land cultivation without adequate soil nutrients replenishment causes soil fertility decline leading to reduced crop productivity. Significant research on external fertility inputs application rates and type have been carried out under researcher designed and managed conditions in Kenya. But little research on the same has been carried out to evaluate their performances under on-farm smallholder farmers’ conditions. Hence, the study evaluated the decomposition rates (go...
Abstract The study aimed at identifying soil fertility management practices that promote the Collembola population, diversity and survival in the soil. Soil samples were randomly collected from on farm plots amended with: 1-Mavuno ((Ma)-is a compound fertilizer containing 26% Potassium, 10% Nitrogen, 10% Calcium, 4% Sulphur, 4% Magnesium and trace elements like Zinc, Copper, Boron, Molybdenum and Manganese)), 2-Manure (Mn), 3-Trichoderna (Tr) inoculant (is a soil and compost-borne antagonist...
Abstract tillage practices on runoff amounts, sediment yield and maize yields under semi-arid and sub-humid environments. Field trials were set in Kigogo primary school in Meru South Sub-County, Tharaka Nithi County, representing the sub-humid conditions, and Machang'a secondary in Mbeere South Sub-County, Embu County (semi-arid) in the central highlands of Kenya. The experiment layout was a randomized complete block design and the treatments were implemented in runoff plots. Tied ridging (T...
Abstract Mitigating nutrient loss is a prerequisite of sustainable agriculture in the tropics. We evaluated three soil and water conservation technologies (mulching, minimum tillage and tied ridging) for two cropping seasons (long rains 2011, short rains 2011) at two sites in the central highlands of Kenya. The objectives were: to determine effects of the technologies on runoff, sediment yield and nutrient loads in sediment, and to assess influence of the technologies on maize yields. Experi...
Abstract An experiment in the Blue Mountains of Jamaica investigated the consequences of three land-use treatments applied following forest clearance on soil fertility and resulting crop growth over a five year period. The treatments were: maintained weed-free without cultivation (bare); cultivated with herbaceous crops (agriculture); and cultivated with herbaceous crops and intercropped with Calliandra calothyrsus contour hedges (agroforestry) and compared with an uncleared secondary forest...
Abstract/Overview ABSTRACT: Soil has influenced progression of civilization in many regions because it supports food production. Growth in world population has been met by intensification of soil utilization which in turn has caused diverse changes in physical, biological and chemical properties of soil resource. In Nyakach Sub-county in western Kenya intensified agricultural production and soil degradation have proceeded hand-in-hand. This area portrays a mismatch between agricultural pr...
Abstract Integrated soil fertility management and soil water conservation practices are possible solutions to persistent soil quality decline and low availability of soil moisture which are affecting agricultural productivity in the dry lands of Tharaka-Nithi County. Nonetheless, the rate of uptake of these technologies and practices by smallholder farmers has stagnated over the years despite recommendations for their use. Lack of effective communication between the extension agents and rese...
Abstract Degraded landscapes and soil water stress are long-standing problems to smallholder agriculture in the drylands. Despite the important roles of soil and water conservation in restoring degraded landscapes and improving agricultural productivity, the technologies are yet to be adopted to their fullest extent. This can be attributed to gender-linked disparities in agricultural technology utilization. This study, therefore, sought to evaluate gender-specific choice and use-intensity de...
Abstract Four proximal soil sensors were tested at four smallholder farms in Embu County, Kenya: a portable X-ray fluorescence sensor (PXRF), a mobile phone application for soil color determination by photography, a dual-depth electromagnetic induction (EMI) sensor, and a LED-based soil optical reflectance sensor. Measurements were made at 32–43 locations at each site. Topsoil samples were analyzed for plant-available nutrients (N, P, K, Mg, Ca, S, B, Mn, Zn, Cu, and Fe), pH, total nitroge...