Browsing by Author "Mugwe, Jayne"
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Item Adapting African Agriculture to Climate Change(Springer, 2015) Kisaka, Oscar M.; Mucheru-Muna, M.; Ngetich, F.K.; Mugwe, Jayne; Mugendi, Daniel N.; Mairura, F.Drier parts of Embu County, Eastern Kenya, endure persistent crop failure and declining agricultural productivity which have been attributed, in part, to prolonged dry-spells and erratic rainfall. Nonetheless, understanding spatialtemporal variability of rainfall especially at seasonal level, is an imperative facet to rain-fed agricultural productivity and natural resource management (NRM). This study evaluated the extent of seasonal rainfall variability and the drought characteristics as the first step of combating declining agricultural productivity in the region. Cumulative Departure Index (CDI), Rainfall Anomaly Index (RAI) and Coefficients-of-Variance (CV) and probabilistic statistics were utilized in the analyses of rainfall variability. Analyses showed 90 % chance of below croppingthreshold rainfall (500 mm) exceeding 213.5 mm (Machanga) and 258.1 mm (Embu) during SRs for one year return-period. Rainfall variability was found to be high in seasonal amounts (CV = 0.56 and 0.38) and in number of rainy-days (CV = 0.88 and 0.27) at Machang’a and Embu, respectively. Monthly rainfall variability was found to be equally high even during April (peak) and November (CV = 0.42 and 0.48 and 0.76 and 0.43) with high probabilities (0.40 and 0.67) of droughts exceeding 15 days in Embu and Machang’a, respectively. Dry-spell probabilities within growing months were high (81 %) and (60 %) in Machang’a and Embu respectively. To optimize yield in the area, use of soil-water conservation and supplementary irrigation, crop selection and timely accurate rainfall forecasting should be prioritizedItem Alley cropping of maize with calliandra and leucaena in the subhumid highlands of Kenya Part 1. Soil-fertility changes and maize yield(Kluwer Academic Publishers, 1999-06) Mugwe, Jayne; Mugendi, Daniel N.; Nair, P.K.; O’neill, M.K.; Woomer, P.L.Although N-rich leaf biomass of multipurpose trees is known to be a good source of N to crops, integrating such trees into crop production systems is a major challenge in the development of viable agroforestry systems. An approach to integrating calliandra (Calliandra calothyrsus Meissner) and leucaena (Leucaena leucocephala (Lam.) de Wit), two promising agroforestry tree species, into maize (Zea mays L.) production system was investigated in the subhumid highlands of central Kenya during four maize-growing seasons from 1994 to 1996. The experiment consisted of maize plots to which tree prunings obtained from hedgerows grown either in situ (alley cropping) or ex situ (biomass transfer from outside) were applied. When alley-cropped with leucaena, maize produced significantly higher yields compared to maize monoculture (both non-fertilized and fertilized) treatments, but when alley-cropped with calliandra, the yield of maize was less than that of the monocropped unfertilized control. Application of ex situ grown calliandra and leucaena prunings with or without fertilizer resulted in higher maize grain yield than in the nonfertilized and fertilized treatments. Yields of calliandra alleycropped maize were 11% to 51% lower than those of nonalley-cropped treatments receiving calliandra prunings from ex situ grown trees; the decrease was 2% to 17% with leucaena, indicating that calliandra hedges were more competitive than leucaena hedges. The alley-cropped prunings-removed treatments produced the lowest maize yields. The study showed that, in the subhumid tropical highlands of Kenya, inclusion of calliandra hedges on cropland adversely affected maize yields. On the other hand, alley cropping with leucaena was advantageousItem Alley cropping of maize with calliandra and leucaena in the subhumid highlands of Kenya Part 2. Biomass decomposition, N mineralization, and N uptake by maize(Kluwer Academic Publishers, 1999-06) Mugendi, Daniel N.; Nair, P.K.; Mugwe, Jayne; O'Neill, M.K.; Swift, M.J.; Woomer, P.A major challenge in developing agroforestry approaches that utilize tree-leaf biomass for provision of N to crops is to ensure synchrony between the N released from decomposing prunings and N demand by crops. A study was conducted in the subhumid highlands of Kenya to assess the rate of decomposition and mineralization of soil-incorporated Calliandra calothyrsus Meissner (calliandra) and Leucaena leucocephala (Lam.) de Wit (leucaena) tree biomass and maize roots (Zea mays L.) both in an alley cropping and a sole cropping system. The amount of mineralized N peaked four weeks after planting (WAP) maize in all the treatments during both seasons of 1995. Cumulative mineralized N at week 20 ranged from 114 to 364 kg N ha−1 season−1, the absolute control treatment giving the lowest and the prunings-incorporated treatments giving the highest amounts in the two seasons. Total N uptake by maize, ranging from 42 to 157 kg ha−1 season−1, was lowest in the 'alley-cropped, prunings-removed' treatments, and highest in the 'non alley-cropped-prunings-incorporated' treatments. The apparent N recovery rate by maize was highest in the fertilizer applied treatments in the two seasons. Decomposition rate constants (kD) ranged from 0.07 to 0.21 week−1, and the rates among the different plant residues were as follows: leucaena < calliandra < maize roots. Nitrogen release rate constants (kN), ranging from 0.04 to 0.25 week−1, followed a similar pattern as the rate of decomposition with leucaena releasing the highest amount of N followed by calliandra and lastly by maize rootsItem Applicability of conservation agriculture for climate change adaptation in Rwanda’s situation(Academic Journals, 2015-09) Kabirigi, M.; Musana, B.; Ngetich, F.K.; Mugwe, Jayne; Mukuralinda, A.; Nabahungu, N. L.Improving food security and environmental conservation should be the main targets of innovative farming systems. Conservation agriculture (CA), based on minimum tillage, crop residue retention and crop rotations has been proposed against poor agricultural productivity and soil degradation. This paper discusses the applicability and potential benefits of CA in Rwanda under the unfolding climate change scenario. The potential and benefits from CA may vary with rainfall regime. In high rainfall areas (For example North and West of Rwanda), the soils are susceptible to soil erosion and face fertility decline while in low rainfall areas (For example East of Rwanda) crops fail due to sub-optimal water use efficiency. Furthermore, low organic carbon content lower fertilisers response and government targets of increasing production through Crop Intensification Program, is limited. It has been shown that CA can: Reduce soil loss from 35.5 to 14.5 t/ha/year, have 50-70% greater infiltration and increase 42% of organic carbon. Long term analysis using Agricultural Production System Simulator showed that CA can increase yield from 3.6 to 4.4t/ha in areas having >770 mm. Based on the evidence from regional research, CA has a good potential for climate change adaptation in both high and low rainfall areas of Rwanda. However, decreased yield observed in high rainfall areas, increased labour requirements when herbicides are not used and lack of mulch due to priority given to feeding of livestock constrained CA adoption. We conclude that there is a need for critical assessment under which ecological and socio economic conditions CA is suited for smallholder farming in Rwanda.Item Determinants of smallholders farmers' participation in collective marketing of maize in the central highlands of Kenya(African Journal of Rural Development, 2019-06-30) Mogaka, Hezron; Mugwe, Jayne; Ayieko, David, M; Bett, Eric, kCollective marketing has been proposed as a solution to the problem of poor access to markets in developing nations. However, smallholders’ market participation is still limited. This study assessed farmers’ perception of the benefits and challenges in collective marketing, and identified the determinants of smallholder farmers’ participation in collective marketing of maize from 126 households in the central highlands of Kenya. Logistic regression model was used to analyze factors explaining farmers’ participation in collective marketing. The key benefits of collective marketing were better prices and low cost of inputs, while the main challenges were poor infrastructure, disagreement among members and lack of credit. Gender of household head, years of farming experience, training on market information search, keeping records, ability to search market information, marketing group size, extension contact frequency and group meeting frequency were significantly associated with farmers participation in collective marketing. Participation in collective marketing could be improved by targeting women already organized in groups, offering training to households on record keeping, enhanced extension contacts, improving marketing group operations and searching for markets.Item Dissemination of Integrated Soil Fertility Management Technologies Using Participatory Approaches in the Central Highlands of Kenya(Springer Netherlands, 2011-06) Mugendi, Daniel N.; Mugwe, Jayne; Mucheru-Muna, Monicah; Karega, R.; Muriuki, J.; Vanlauwe, B.; Merckx, R.Declining soil fertility and productivity is a critical problem facing smallholder farmers in the central highlands of Kenya. A study to improve soil fertility and farm productivity within the smallholder farming systems in the area was carried out from 2003 to 2006. The specific objectives were to identify farming system constraints, evaluate and disseminate potential integrated soil fertility management (ISFM) interventions using participatory approaches, assess achievements and impacts, and document learning experiences emanating from the methodologies used. The participatory approaches used were Participatory Rural Appraisal (PRA), mother–baby approach (with emphasis on demonstration), farmer groups, stakeholders planning meetings, village training workshops, cross-site visits and participatory monitoring and evaluation. The core problems identified were low crop and fodder yields that were caused by erratic rainfall, soil erosion, low soil fertility and small land sizes. There was high participation of farmers in all the partnership activities, and this possibly contributed to the high uptake of the technologies for testing by farmers whereby after only 2 years a total of 970 households were testing the new technologies. Maize yields at the farm level increased by more than 150% following use of the new ISFM interventions and about half of the farmers within the groups planted close to 500 trees propagated in the group nurseries. We recommend that pathways to reach more farmers should concentrate on demonstrations, farmer training grounds, field days and farmer groups and that a policy framework should be put in place to impart appropriate skills in ISFM to the extension workers.Item Economic evaluation of local inputs in Meru South District, Kenya(Springer, 2007) Mucheru-Muna, Monicah; Mugendi, Daniel N.; Mugwe, Jayne; Kung’u, JamesDeclining land productivity is a major problem facing smallholder farmers in Kenya today. This decline is as a result of reduced soil fertility caused by continuous cultivation without adequate addition of manures and fertilizers. Low soil fertility is one of the greatest challenges facing farmers in the central highlands of Kenya. A farmers’ participatory trial was established in Meru South District, Kenya in 2000 to investigate feasible soil nutrient replenishment technologies for poor resource smallholder farmers. Results across seven seasons indicate that sole tithonia gave the highest grain yield followed closely by tithonia with half recommended rate of inorganic fertilizer with 6.4 and 6.3 Mg ha-1respectively. The control treatment gave the lowest yield of 2.2 Mg ha-1 across the seasons. The integration of organic and inorganic nutrient sources of N gave higher maize grain yield as compared to the sole organic materials in all seven seasons. Economic analyses indicate that on average tithonia with half the recommended rate of inorganic fertilizer recorded the highest net benefit (US$ 787.2) whereas the control treatment gave the lowest benefit (US$ 271.7). On the other hand the recommended rate of inorganic fertilizer gave the highest (US$ 12.5) return to labour while sole tithonia gave the lowest (US$ 4.0). On average in the farmers’ fields, manure alone gave the highest return to labour of US$ 3.6, while the control treatment gave the lowest return to labour US$ –0.2.Item Effect of plant biomass, manure and inorganic fertilizer on maize yield in the central Highlands of Kenya(2007) Mugwe, Jayne; Mugendi, Daniel N.; Kungu, James; Mucheru-Muna, MonicahSoil fertility degradation remains the major biophysical cause of declining per capita crop production on smallholder farms in sub-Saharan Africa. Appropriate soil fertility regimes, are therefore, critical for improved crop productivity. This study investigated the feasibility of using sole organics or their combinations with inorganic fertilisers to improve maize (Zea mays) production in the highlands central Kenya. Sole application of Calliandra calotyrsus, Leucaena trichandra trichandra, Mucuna pruriens, Crotalaria ochroleuca, Tithonia diversifolia and cattle manure at 60 kg N ha-1 or combined application of the organic materials (30 kg N ha-1) plus inorganic fertiliser (30 kg N ha-1) gave significantly (P < 0.05) higher maize grain yields than the recommended rate of inorganic fertiliser (60 kg N ha-1). These treatments maintained maize yields at 4 to 6 t ha-1. Farmers had their own innovations where they combined organic resources and generally appreciable yields (3.0 to 5.6 t ha-1) were obtained from these innovations. However, there was a maize yield gap between on station and on farm trials with on station yields having on average 65% more yields than the on-farm yields. This was mainly attributed to differences in management practices arising from partial adoption of recommended rates. There is need therefore to develop and implement mechanisms tailored to ensure that farmers’ modications recommended soil amendment regimes and other agronomic practices are appropriate for enhanced crop productivity. Further studies are needed to establish the optimum mixture of different organic materials.Item Effects of organic and mineral fertilizer inputs on maize yield and soil chemical properties in a maize cropping system in Meru South District, Kenya(Springer, 2007-01) Mucheru-Muna, Monicah; Mugendi, Daniel N.; Kung’u, James; Mugwe, Jayne; Bationo, A.Soil nutrient depletion as a result of continuous cultivation of soils without adequate addition of external inputs is a major challenge in the highlands of Kenya. An experiment was set up in Meru South District, Kenya in 2000 to investigate the effects of different soil-incorporated organic (manure, Tithonia diversifolia, Calliandra calothyrsus, Leucaena leucocephala) and mineral fertilizer inputs on maize yield, and soil chemical properties over seven seasons. On average, tithonia treatments (with or without half recommended rate of mineral fertilizer) gave the highest grain yield (5.5 and 5.4 Mg ha–1 respectively) while the control treatment gave the lowest yield (1.5 Mg ha–1). After 2 years of trial implementation, total soil carbon and nitrogen contents were improved with the application of organic residues, and manure in particular improved soil calcium content. Results of the economic analysis indicated that on average across the seven seasons, tithonia with half recommended rate of mineral fertilizer treatment recorded the highest net benefit (USD 787 ha–1) while the control recorded the lowest (USD 272 ha–1). However, returns to labor or benefitcost ratios were in most cases not significantly improved when organic materials were used.Item Effects of selected soil and water conservation techniques on runoff, sediment yield and maize productivity under sub-humid and semi-arid conditions in Kenya(Elsevier, 2014-05) Ngetich, F.K.; Diels, J.; Shisanya, C.A.; Mugwe, Jayne; Mucheru-muna, M.; Mugendi, Daniel N.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 (TR) was the most efficient technique in reducing runoff and sediment yield and at the same time boosting crop yields in the semi-arid region. It significantly (p b 0.05) reduced sediment yields by 94% compared to the conventional tillage (CT) during the study period. The effects were particularly strong in periods of belowaverage rainfall (dry seasons). During the drier season of short rains 2010 (SR10), grain yield under TR was 7 times higher compared to CT (p b 0.01). In the sub-humid region, minimum tillage (MT) generated high runoff but relatively low sediment yield compared to CT. During periods of enough rainfall (over 450mmper season) in the drier site, intercropping suppressed maize yields significantly (p b 0.01) by 42% compared to conventional tillage in the drier site. The results on the magnitude of runoff and sediment under the different soil and farm management practices are crucial in selection and promotion of valid farm management practices and tillage alternatives that not only abate soil erosion but also boost agricultural productivity in both sub-humid and semi-arid agro-ecological zones.Item Effects of selected soil and water conservation technologies onnutrient losses and maize yields in the central highlands of Kenya(Elsevier, 2014-02) Okeyo, A.I.; Mucheru-Muna, M.; Mugwe, Jayne; Ngetich, F.K.; Mugendi, Daniel N.; Diels, J.; Shisanyaaa, C.A.tMitigating nutrient loss is a prerequisite of sustainable agriculture in the tropics. We evaluated threesoil and water conservation technologies (mulching, minimum tillage and tied ridging) for two croppingseasons (long rains 2011, short rains 2011) at two sites in the central highlands of Kenya. The objectiveswere: 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. Experimental design was a randomizedcomplete block with 3 treatments replicated thrice. At the beginning of experiment, soil was sampledat 0–15 cm depth and analyzed for pH, N, P, K, C, Ca and Mg. Mulch was applied at a rate of 5 t ha−1.Runoff was sampled, sediments extracted by drying in oven at 105◦C, and analyzed for NPK and C loads.Data were subjected to analysis of variance using SAS 9.1.3 and means separated using Fishers’ LSD at5% level of significance. Results showed reduced nutrient losses with the technologies. In Meru South,sediment yield was reduced by 41 and 7% during long rains 2011 (p = 0.03), and by 71 and 68% duringshort rains 2011 (p = 0.01) under mulching and minimum tillage, respectively. Runoff and maize yieldswere positively influenced by mulching. In Mbeere South, sediment yield was lower under soil and waterconservation technologies. Runoff was reduced by 52 and 49% during long rains 2011 and by 51 and30% during short rains 2011 under tied ridging and mulching respectively, compared with control. Totalcrop failure occurred during long rains 2011 due to erratic rains. During short rains 2011 tied ridging andmulching increased maize yield by 94 and 75%, respectively, compared with control. This study highlightsthe importance of analyzing soil and water conservation technologies within rain-fed farming systemsperspective in response to declining food production and supports a focus on tied ridging and mulchingItem Evaluation of the Potential of Using Nitrogen Fixing Legumes in Smallholder Farms of Meru South District, Kenya(Springer, 2007) Mugwe, Jayne; Mugendi, Daniel N.; Odee, D.W.Soil fertility depletion in sub-Saharan Africa is a big constraint to increased food production to feed the ever-growing human population. Use of legumes to improve soil fertility is an option in the central highlands of Kenya and this study evaluated soil characteristics on farms and screened effectiveness of five rhizobia strains on four legumes. Soilssampled from 31 farms showed that the soils were generally acidic with more than 50% of the farms having pH inthe range of extremely acidic and strongly acidic (pH < 5.0). Organic carbon was low «2%) on most farms and total nitrogen was deficient with more than 80% having <0.2% N while P ranged from 1.3 to 15.8 ppm with more than70% of the farms being critically deficient in P. Nodulation on Mucuna pruriens and Crotalaria ochroleuca was observed to be variable within farms with individual farms having fewer nodules per plant than on-farm researcher managed trial. Consequently trials to evaluate effectiveness of rhizobia strains were conducted under glass house conditions. Results showed that KWN35 and TAL 1145 were highly effective on C. calothyrsus and L. trichandra and not on C. ochroleuca. Crotalaria ochroleuca nodulated effectively only with CP354 and NGR457. The NGR 457was highly effective on all the legume plants while NGR185 was only effective on L. trichandra. These studies showed that performance of legumes among the smallholder farms was likely to vary due to varying soil characteristics and that them could be potential for improving legume performance within the smallholder farms through inoculationItem Household's socio-economic factors influencing the level of adaptation to climate variability in the dry zones of Eastern Kenya(Elsevier, 2015-11) Mugendi, Daniel N.; Mugi-Ngenga, E.W.; Mucheru-Muna, M.W.; Mugwe, Jayne; Ngetich, F.K.; Mairura, F.S.Climate variability has a negative impact on crop productivity and has had an effect on many small-holder farmers in the arid and semi-arid lands (ASALs). Small-holder farmers in Eastern Kenya are faced with the constraint associated with climate variability and have consequently made effort at local level to utilize adaptation techniques in their quest to adapt to climate variability. However, documentation of the factors that influence the level of adaptation to climate variability in the study area is quite limited. Hence, this study aimed at assessing how the household's socio-economic factors influence the level of adaptation to climate variability. The study sites were Tharaka and Kitui-Central sub-Counties in Tharaka-Nithi and Kitui Counties of Eastern Kenya respectively. The data collected included the household demographic and socio-economic characteristics and farmers' adaptation techniques to cope with climate variability. Triangulation approach research design was used to simultaneously collect both quantitative and qualitative data. Primary data was gathered through a household survey. Both random and purposive sampling strategies were employed. Data analysis was done using descriptive and inferential statistics. Multinomial and Binary logistic regression models were used to predict the influence of socioeconomic characteristics on the level of adaptation to climate variability. This was done using variables derived through a data reduction process that employed Principal Component Analysis (PCA). The study considered five strategies as measures of the level of adaptation to climate variability; crop adjustment; crop management; soil fertility management; water harvesting and crop types; boreholes and crop variety. Several factors were found significant in predicting the level of adaptation to climate variability as being either low or medium relative to high. These were average size of land under maize; farming experience; household size; household members involved in farming; education level; age; main occupation and gender of the household head. Household socio economic factors found significant in explaining the level of adaptation should be considered in any efforts that aim to promote adaptation to climate variability in the agricultural sector amongst smallholder farmers.Item Improving food production using ‘best bet’ soil fertility technologies in the Central highlands of Kenya(Springer, 2007) Mugendi, Daniel N.; Mucheru-Muna, Monicah; Mugwe, Jayne; Kung’u, James; Bationo, A.Declining crop productivity is a major challenge facing smallholder farmers in central highlands of Kenya. This decline is caused by continuous cultivation of soils without adequate addition of external inputs in form of manures and fertilizers. With this background, an on-station trial was initiated at Embu in 1992 to evaluate the feasibility of using two leguminous shrubs; Calliandra calothyrsus and Leucaena leucocephala for improving food production. In 2000, an off-station farmers’ participatory trial aimed at offering farmers soil enhancing technologies for replenishing soil fertility was established in Meru South District. The results from the Embu on-station trial indicate that, over the 11 years of study, calliandra and leucaena biomass transfer with half recommended rate of inorganic fertilizer treatments gave the best average maize grain yields of 3.3 Mg ha-1. Treatment where calliandra was alley cropped with maize but the prunings removed recorded the lowest maize yield of 1.2 Mg ha-1. Treatments with calliandra and leucana biomass transfer had similar yields but treatments that were alley cropped with leucaena did better than those that were alley cropped with calliandra. On the other hand, results from the off-station trial in Meru South indicate that, on average, across the seven seasons, sole tithonia gave the highest maize grain yield followed closely by tithonia with half recommended rate of inorganic fertilizer with 6.4 and 6.3 Mg ha-1 respectively. Control gave the lowest yield of 2.2 Mg ha-1 across the seasons. On average, integration of organic an inorganic sources of nutrients gave higher yields compared to all the other treatments.Item Integrating Farmers and Scientific Methods for Evaluating Climate Change Adaptation Options in Embu County(Springer International Publishing, 2014-11) Njeru, P.N.; Mugwe, Jayne; Maina, I.; Mucheru-Muna, Monicah; Mugendi, Daniel N.; Lekasi, J.K.; Kimani, S.; Miriti, J.; Oeba, V.O.; Esilaba, A.O.; Mutuma, E.; Rao, K.P.; Muriithi, F.Potential for promoting sorghum crop as a climate change adaptation strategy for rain-fed agriculture in Embu County, Kenya was evaluated using farmer perceptions and scientific methods. Three hundred and sixty six smallholder farmers participated in the evaluation. The treatments which were overall rated as ‘good’ are tied ridges with a mean score of 2.9 and mean rank (2,873.87). Under this treatment sorghum grain yield of 3.7 t ha−1 was recorded with application of 40 kg P ha−1 + 20 kg N ha−1 + Manure 2.5 t ha−1. This was closely followed by tied ridges and contour furrows overall rated ‘good’ best three under the same soil fertility management options with a mean score ranging from 2.65 to 2.8 and yielding 2.7–3.7 t ha−1. However, the treatments which were rated as ‘poor’ were experiment controls with a mean score below (1.43), mean rank (1,101.24) and yielding as low as (0.7 t ha−1). Therefore, integration of organic and inorganic inputs under various water harvesting technologies could be considered as an alternative option towards food security under climate change for semi-arid areas of Embu County.Item Length of growing season, rainfall temporal distribution, onset and cessation dates in the Kenyan highlands(Elsevier, 2013-12) Ngetich, F.K.; Mugendi, Daniel N.; Mucheru-Muna, M.; Mugwe, Jayne; Shisanya, C.A.; Diels, J.Dependence on uncertain rainfall and exposure to unmitigated climate risk are major obstacles in efforts to sustainably intensify agricultural production and enhance rural livelihoods. There is generally enough seasonal total rainfall; the challenge is its poor distribution over time and across the season. The amount of water available to plants strongly depends on the rainy season’s onset, length, temporal distribution and cessation and can indirectly indicate the climatic suitability of the crop and its chances of success or failure in a season. Thus, the objective was to determine rainfall pattern; temporal distribution, onset, cessation and length of growing seasons in the tropical sub-humid and a semi-arid regions with contrasting rainfall patterns and agricultural potential in central highlands of Kenya. The study was carried out in Maara and Meru South Sub-Counties in Tharaka Nithi County and Mbeere North and South Sub-Counties in Embu County of the central highlands of Kenya (CHK). Central highlands of Kenya cover both areas with high potential for crop production and low potential, attributed to rainfall differences. Meteorological data were sourced from Kenya Metrological Department (KMD) headquarters and research stations within the study areas. Length of growing season, onset and cessation dates for both Long (LR) and short (SR) rains seasons were determined based on historical rainfall data using RAIN software and derived using various spatial analysis tools in ArcGIS software and presented spatially. Generally there was high frequency of dry spells of at least 5 days length in all the sites with Kiamaogo site having the highest (84 occurrences during LR season) and Kiambere having the least (44 occurrences during LR season) in 10 years. The occurrence of dry spells longer than 15 days in a season was more rampant in the lower altitude parts (semi-arid regions) of the study area as reflected by the Kiambere, Kiritiri, Machang’a and Kamburu sites in both seasons. For the higher altitude regions, average LR onset, representative of the normal/conventional growing period, ranged from 22nd to 26th March to end of April in the region. For the lower altitude region, it ranged from 16th to 30th March. For SR, onset was generally earlier in the high altitude areas with Kiamaogo having the earliest on 13th October. In the low altitude region, onset was comparatively late compared to the higher potential region, but unlike the LR season, spatial and temporal variation was narrower. The high frequency of dry spells more than 15 days long, coupled with the generally low total amount of rainfall receive per season makes agriculture a risk venture. Homogeneity test revealed that the generated onset and cessation dates for the two rain seasons were homogeneous over the 10 years for each of the seven stations. This indicates that, there has been no shift in onset and cessation within the period under consideration. Dynamic derivation of the spatial onset and cessation data at a local scale can be useful in monitoring shifts in onset dates and hence advice small scale farmers and other stakeholders in agriculture sector accordingly in the quest for enhanced agricultural productivity.Item Potential of deterministic and geostatistical rainfall interpolation under high rainfall variability and dry spells: case of Kenya’s Central Highlands(Springer Vienna, 2015-03) Kisaka, Oscar M.; Mucheru-Muna, Monicah; Ngetich, F.K.; Mugwe, JayneDrier parts of Kenya’s Central Highlands endure persistent crop failure and declining agricultural productivity. These have, in part, attributed to high temperatures, prolonged dry spells and erratic rainfall. Understanding spatial-temporal variability of climatic indices such as rainfall at seasonal level is critical for optimal rain-fed agricultural productivity and natural resource management in the study area. However, the predominant setbacks in analysing hydro-meteorological events are occasioned by either lack, inadequate, or inconsistent meteorological data. Like in most other places, the sole sources of climatic data in the study region are scarce and only limited to single stations, yet with persistent missing/unrecorded data making their utilization a challenge. This study examined seasonal anomalies and variability in rainfall, drought occurrence and the efficacy of interpolation techniques in the drier regions of eastern Kenyan. Rainfall data from five stations (Machang’a, Kiritiri, Kiambere and Kindaruma and Embu) were sourced from both the Kenya Meteorology Department and on-site primary recording. Owing to some experimental work ongoing, automated recording for primary dailies in Machang’a have been ongoing since the year 2000 to date; thus, Machang’a was treated as reference (for period of record) station for selection of other stations in the region. The other stations had data sets of over 15 years with missing data of less than 10 % as required by the world meteorological organization whose quality check is subject to the Centre for Climate Systems Modeling (C2SM) through MeteoSwiss and EMPA bodies. The dailies were also subjected to homogeneity testing to evaluate whether they came from the same population. Rainfall anomaly index, coefficients of variance and probability were utilized in the analyses of rainfall variability. Spline, kriging and inverse distance weighting interpolation techniques were assessed using daily rainfall data and digital elevation model in ArcGIS environment. Validation of the selected interpolation methods were based on goodness of fit between gauged (observed) and generated rainfall derived from residual errors statistics, coefficient of determination (R 2), mean absolute errors (MAE) and root mean square error (RMSE) statistics. Analyses showed 90 % chance of below cropping-threshold rainfall (500 mm) exceeding 258.1 mm during short rains in Embu for 1 year return period. Rainfall variability was found to be high in seasonal amounts (e.g. coefficient of variation (CV) = 0.56, 0.47, 0.59) and in number of rainy days (e.g. CV = 0.88, 0.53) in Machang’a and Kiritiri, respectively. Monthly rainfall variability was found to be equally high during April and November (e.g. CV = 0.48, 0.49 and 0.76) with high probabilities (0.67) of droughts exceeding 15 days in Machang’a. Dry spell probabilities within growing months were high, e.g. 81 and 60 % in Machang’a and Embu, respectively. Kriging interpolation method emerged as the most appropriate geostatistical interpolation technique suitable for spatial rainfall maps generation for the study region. Theoretical and Applied Climatology Theoretical and Applied Climatology Look InsideItem Potential of deterministic and geostatistical rainfall interpolation under high rainfall variability and dry spells: case of Kenya’s Central Highlands(Springer, 2015-03) Kisaka, Oscar M.; Mucheru-Muna, M.; Ngetich, F.K.; Mugwe, Jayne; Mugendi, Daniel N.; Mairura, F.; Shisanya, C.A.; Makokha, G. L.Drier parts of Kenya’s Central Highlands endure persistent crop failure and declining agricultural productivity. These have, in part, attributed to high temperatures, prolonged dry spells and erratic rainfall. Understanding spatial-temporal variability of climatic indices such as rainfall at seasonal level is critical for optimal rain-fed agricultural productivity and natural resource management in the study area. However, the predominant setbacks in analysing hydro-meteorological events are occasioned by either lack, inadequate, or inconsistent meteorological data. Like in most other places, the sole sources of climatic data in the study region are scarce and only limited to single stations, yet with persistent missing/unrecorded data making their utilization a challenge. This study examined seasonal anomalies and variability in rainfall, drought occurrence and the efficacy of interpolation techniques in the drier regions of eastern Kenyan. Rainfall data from five stations (Machang’a, Kiritiri, Kiambere and Kindaruma and Embu) were sourced from both the Kenya Meteorology Department and on-site primary recording. Owing to some experimental work ongoing, automated recording for primary dailies in Machang’a have been ongoing since the year 2000 to date; thus, Machang’a was treated as reference (for period of record) station for selection of other stations in the region. The other stations had data sets of over 15 years with missing data of less than 10 % as required by the world meteorological organization whose quality check is subject to the Centre for Climate Systems Modeling (C2SM) through MeteoSwiss and EMPA bodies. The dailies were also subjected to homogeneity testing to evaluate whether they came from the same population. Rainfall anomaly index, coefficients of variance and probability were utilized in the analyses of rainfall variability. Spline, kriging and inverse distance weighting interpolation techniques were assessed using daily rainfall data and digital elevation model in ArcGIS environment. Validation of the selected interpolation methods were based on goodness of fit between gauged (observed) and generated rainfall derived from residual errors statistics, coefficient of determination (R 2), mean absolute errors (MAE) and root mean square error (RMSE) statistics. Analyses showed 90 % chance of below cropping-threshold rainfall (500 mm) exceeding 258.1 mm during short rains in Embu for 1 year return period. Rainfall variability was found to be high in seasonal amounts (e.g. coefficient of variation (CV) = 0.56, 0.47, 0.59) and in number of rainy days (e.g. CV = 0.88, 0.53) in Machang’a and Kiritiri, respectively. Monthly rainfall variability was found to be equally high during April and November (e.g. CV = 0.48, 0.49 and 0.76) with high probabilities (0.67) of droughts exceeding 15 days in Machang’a. Dry spell probabilities within growing months were high, e.g. 81 and 60 % in Machang’a and Embu, respectively. Kriging interpolation method emerged as the most appropriate geostatistical interpolation technique suitable for spatial rainfall maps generation for the study region.Item The Potential of Organic and Inorganic Nutrient Sources in Sub-Saharan African Crop Farming Systems(2012-02) Ngetich, F.K.; Shisanya, C.A.; Mugwe, Jayne; Mucheru-Muna, Monicah; Mugendi, Daniel N.he Potential of Organic and Inorganic Nutrient Sources in Sub-Saharan African Crop Farming SystemItem The Potential of Organic and Inorganic Nutrient Sources in Sub-Saharan African Crop Farming Systems(2012-02) Ngetich, F.K.; Shisanya, C.A.; Mugwe, Jayne; Mucheru-Muna, M.; Mugendi, Daniel N.