RP-Department of Agricultural Resources Management (ARM)

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Are the Water Trips in the Dryland Kenya for Sustainable Development, Journeys in Vain or Trips to Oblivion
(2013) Danga, B. O.; Afullo, A. O.
Kenya’s households’ (HH) water access status is appalling. As a gender based task, women and children make billions of trips to satisfy HH water needs, taking a heavy toll on societal growth and development. Kenya’s 4872 randomly sampled HHs from six Arid and semi-Arid land (ASALs) counties were studied using interviews and focused group discussions. The aim was to determine the burden of water fetching in Kenya-ASALs. On a daily basis, HHs make 3.06 water trips of 49.42+0.36 minutes, largely shouldered by females (2.69 trips); males (0.22); women (2.51); men (0.12) and children (0.43 trips). The 2.5 million Kenyan-ASAL households make 7,658,500 trips daily (2,795,352,500 annually). Of these, children make 395,477,500; women (2,287,637,500); and men (112,237,500 trips). With this kind of burden, the children and women are denied opportunity for self-development. Water supply mainstreaming is an urgent priority in Kenya-ASALs. Key words: Water Supply, Sustainability, Gender, Development, Kenya ASALS
Chickpea Residue Properties Controlling Decomposition Dynamics and nitrogen Availability in Some Tropical Acid Soils
(Taylor & Francis; NISC (Pty) Ltd, 2013) Danga, B. O.; Hadas, A.; Wakindiki, I.; Ouma, J. P.; Bar-Tal, A.
Chickpea (Cicer arietinum) grown in a rotation can contribute significant nitrogen (N) if its decomposition and nutrient-release dynamics are known and synchronised with the maximum demand by the succeeding crop. The aims of the study were to investigate the decomposition rates of two chickpea residues, mature (CHR) and green manure (GM), and use their properties to predict N dynamics in acid soils. The N dynamics were predicted by the NCSOIL model using neutral and acidic detergent fibres (NDF and ADF, respectively) measured by near-infrared reflectance spectroscopy (NIRS) for defining residue pools. The GM released 50–60% of total N in 84 d, whereas CHR immobilised N. Simulations based on the two residue pools indicated that NIRS predicted the carbon (C) and N dynamics reasonably well for both residues. The decay rate constants of the NDF − soluble pool varied between 0.5 and 0.2 d−1. Adding an intermediate pool NDF  ADF improved the prediction of C and N dynamics for CHR but not for GM. Therefore, successful prediction of N dynamics required the search of N partitioning among pools by NCSOIL, as long as no chemical analysis of N was suitable for this purpose.
Effect of lime and goat manure on soil acidity and maize (Zea mays) growth parameters at Kavutiri, Embu County- Central Kenya
(Academic Journals, 2015) Gitari, Harun I.; Mochoge, B. E.; Danga, B. O.
A greenhouse pot experiment was conducted to determine the effect of agricultural lime and goat manureon soil acidity and maize growth parameters using soils from Kavutiri-Embu County. Nitrogen and phosphorus fertilizers at the rates of 50 and 70 kg ha-1, respectively, and goat manure at three rates (0, 5 and 10 mg ha-1) and agricultural lime (CaCO3) at six rates (0, 2.5, 5, 7.5, 10, and 12.5 mg ha-1) were used for the study. The pot experiment was arranged in a complete randomised design and replicated three times. Maize, variety H513as test crop, was grown for a period of 8 weeks. The results were measured on maize crop parameters (plant heights, root lengths and dry matter biomass) and soil parameters (soil pH and exchangeable acidity). All the biophysical data generated were subjected to analysis of variance (ANOVA) and the difference between the treatments means separated using the Fischer’s least significant difference at 5% probability level. Linear correlation analyses were done using the Microsoft Excel 2010. Results generally showed that soil acidity decreased with increasing levels of manure and lime. The treatment with 12.5 Mg ha-1 of lime and 10 Mg ha-1 of manure had the best reducing effect on soil acidity and better maize yield performances reflected in the highest pH (6.3), highest root length (41.3 cm), plant height (150.3 cm) and dry biomass weight (755.4 kg ha-1) obtained.
Effect of placement of straw mulch on soil conservation, nutrient accumulation, and wheat yield in a humid Kenyan highland
(Kerala Agricultural University, 2009) Danga, B. O.; Wakindiki, I. I. C.
Mulching affects soil nutrient dynamics and crop yields. The effects of quantity and method of application of wheat straw mulch on soil loss, nutrient accumulation, nutrient loss, and wheat yield were evaluated in a field experiment in the acidic, d ark red, Rhodic Ferralsols of Kenya. The experiment involved three levels of wheat straw mulch (0, 3, and 5 Mg · ha –1 ) either incorporated in the soil (0 to 0.2 m) or surface applied. Surface application at 5 Mg · ha –1 decreased annual soil loss to 1.82 Mg · ha –1 from 14 Mg · ha –1 in the control. Deep placement of 5 Mg · ha –1 of straw, however, increased soil organic matter content by 23%. Annual losses of NH 4 –N, NO 3 –N, PO 4 –P, and available K in the sediments were 0.02, 0.04, 0.06, and 0.44 kg · ha –1 , respectively in the 5 Mg · ha –1 surface treatment. Straw mulch treatments also enriched NO 3 –N concentration in the 0 to 0.4 m soil layer. Surface application of 3 Mg · ha –1 straw gave the highest grain yield of wheat and the highest net returns (US$ 747), which was 30% more than that of the control.
Effect of straw mulch application on nutrient concentration in runoff and sediment in a humid region in Kenya
(African Journal of Agricultural Research, 2011-02) Danga, B. O.; Wakindiki, I. I. C.
Straw mulch use has been studied extensively especially for soil erosion and runoff control in arid and semi-arid regions but few studies have been done with regard to nutrient loss and accumulation in humid climate regions in Africa. The objective of the present study was to investigate the effects of straw mulch application using different methods on nutrient loss and accumulation in a humid region in Kenya. Straw mulch was applied to runoff plots at 0, 3 and 5 Mg ha-1, either incorporated into the 0 to 0.2 m soil layer or placed on the soil surface. The concentration of NH4–N, NO3–N, and PO4–P in the runoff decreased exponentially and significantly with advancing time. The K concentration in the runoff followed a hyperbolic pattern with a minimum value between 33 and 55 days after planting. In all the treatments, the concentrations of the NH4–Nassociated with the sediments decreased, in general, with advancing time. However, no corresponding progressive increases of the NO3–N concentration in the sediments were observed. The concentrations of the sediments-associated NH4–N, NO3–N, PO4–P and K in the mulch treatments were higher than those in the control, although these differences were not significant in all the rainstorms. Under this humid climate, either surface placement or incorporation of straw mulch at 3 or 5 Mg ha-1 enriched the soil with NO3–N, PO4–P and K. The soil was enriched with NH4–N after incorporating straw mulch at 3 Mg ha-1 and or surface application at 3 and 5 Mg ha-1. Key words: Erosion, nutrient accumulation, nutrient loss, sediment enrichment, water quality.
Effects of Manure, Lime and Mineral P Fertilizer on Soybean Yields and Soil Fertility in a Humic Nitisol in the Central Highlands of Kenya
(Academe Research Journals, 2013-09) Danga, B. O.; Mugwe, J. N.; Verde, B.S.
Soybean ( Glycine max (L.) Merrill) is one of the most important legume crops being introduced into the smallholder farming systems of the Central Highlands of Kenya (CHK) to improve income and household nutrition of farmers. However, phosphorus fixation, depletion of soil nutrients and soil acidity are major causes of low yields. The objective of this study is to evaluate effects of manure application, liming and phosphorus application on soil properties and soybean performance. The study consisted of 8 treatments: manure (0, 5 and 10 t ha -1 ), lime (0 and 2 tha -1 ) and P fertilizer (0, 30 and 60 kg P ha -1 ). The experiment was laid out in a randomized complete block design (RCBD) with 4 replicates in plots of 4 m × 4.5 m. Manure and lime significantly reduced exchangeable acidity and increased soil pH. Application of manure alone or combined with lime or P fertilizer also increased Mg and K. Treatments that had sole lime, lime combined with manure and manure combined with P applied gave a significant increase in exchangeable Ca. Soybean responded well and significantly to application of manure either alone or combined with lime, P or both. These results showed the potential role of lime, manure and P fertilizer in improving soil fertility and soybean yields.
Indigenous soil and water conservation techniques in smallholder farms in Africa.
(Springer, 2007) Danga, B. O.; Ben-Hur, M.; Wakindiki, I.I.C.
Runoff and soil erosion are responsible for about 83% of the land degradation worldwide. Many smallholder farmers in arid and semi-arid areas of Africa often use inexpensive indigenous soil and water conservation (ISWC) techniques to control runoff and erosion. This paper is a review of the ISWC methods and categorizes them into three: those suitable for semi-arid areas, those suitable for wet areas and those suitable for both semi-arid and wet areas. The usefulness of ISWC is generally appreciated but literature on the subject is scarce. A case study that investigated effects of 2-m spaced trash lines on runoff, erosion and crop yield in a cowpea – maize rotation is presented. Trash lines reduced runoff and soil loss and increased crop biomass yield three-fold. We conclude that ISWC like close-spaced trash lines are beneficial soil and water conservation methods and should be incorporated in future land resource conservation programmes
Wheat Rotation for Higher Production in a Humid Tropical Region
(Association of Official Seed Analysts, 2010-03) Danga, B. O.; Ouma, J. P.; Wakindiki, I. I. C.; Bar-Tal, A.
Stagnation in grain production in the developing world has contributed to the current worldwide food crisis. The principle objective of this study was to evaluate the possibility of improving grain production in the tropical humid region by chickpea (Cicer arietinum L.) in rotation with wheat (Triticum aestivum L). A 3-yr field experiment in Kenya included four short-rain-season (SRS) management practices (chickpea green manure [GM], mature chickpea grain crop [CG], tilled fallow [TF], and weedy fallow [WF]), and inorganic N fertilizer at three rates (0, 30, and 60 kg N ha−1). The chickpea treatments decreased SRS water storage at wheat planting by 14 to 16% compared with TF, but this did not affect yield of subsequent wheat. The GM accumulated 77 kg N ha−1 yr−1, compared with 42 kg N ha−1 yr−1 for the CG. The chickpea treatments increased soil available N by 19% and N uptake by wheat by 39% compared with the fallow methods. Inorganic N applications of 60 kg N ha−1 increased soil-available N at 30 d after sowing by 21.4% and N uptake by wheat by 47%. The CG and GM increased the average annual wheat grain yield by 14 and 31% compared with the WF and TF. Inorganic N applications of 30 and 60 kg N ha−1 increased wheat grain yield by 20 and 7%, respectively. The combination of GM with 30 kg N ha−1 gave the highest wheat grain yield, but CG with 30 kg N ha−1 fertilizer was the most profitable practice.

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