DSpace Repository :: Browsing by Author "Korir, Nicholas K."

Browsing by Author "Korir, Nicholas K."

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Agromorphological Performance and Character Association of Finger Millet under Varying Phosphorus Regimes
(Macrothink Institute, 2017) Wekha, Wafula Nelson; Korir, Nicholas K.; Siambi, Moses; Ojulong, Henry F.; Gweyi-Onyango, Joseph P.
Biochar and gypsum amendment of agro- industrial waste for enhanced black soldier fly larval biomass and quality frass fertilizer
(PloseOne, 2020) Beesigamukama, Dennis; Mochoge, Benson; Korir, Nicholas K.; Komi, K; Fiaboe, M.; Nakimbugwe, Dorothy; Khamis, Fathiya M.; Dubois, Thomas; Subramanian, Sevgan; Wangu, Musyoka M.; Ekesi, Sunday; Tanga, Chrysantus M.
Black soldier fly (BSF) (Hermetia illucens L.) is one of the most efficient bio-waste recyclers. Although, waste substrate amendments with biochar or gypsum during composting process are known to enhance nutrient retention, their impact on agro-industrial waste have not been documented. Hence, this study focuses on a comparative effect of agro-industrial waste amended with biochar and gypsum on BSF larval performance, waste degradation, and nitrogen (N) and potassium retention in frass fertilizer. Brewery spent grain was amended with biochar or gypsum at 0, 5, 10, 15 and 20% to determine the most effective rates of inclusion. Amending feedstock with 20% biochar significantly increased wet (89%) and dried (86%) larval yields than the control (unamended feedstock). However, amendment with 15% gypsum caused decrease in wet (34%) and dried (30%) larval yields but conserved the highest amount of N in frass. Furthermore, the inclusion of 20% biochar recorded the highest frass fertilizer yield and gave a 21% increase in N retention in frass fertilizer, while biomass conversion rate was increased by 195% compared to the control. Feedstock amendment with 5% biochar had the highest waste degradation efficiency. Potassium content in frass fertilizer was also significantly enhanced with biochar amendment. At maturity, frass compost with more than 10% inclusion rate of biochar had the highest cabbage seed germination indices (>100%). The findings of this study revealed that initial composting of biochar amended feedstocks using BSF larvae can significantly shorten compost maturity time to 5 weeks with enhanced nutrient recycling compared to the conventional composting methods.
Differential Biomass Accumulation among African Leafy Vegetables as Affected by Wastewater Irrigation in Kitui County, Kenya
(International Journal of Plant & Soil Science, 2019) Wambua, Judy Mwende; Ngene, Shadrack; Korir, Nicholas K.; Ntinyari, Winnie; Gweyi-Onyango, Joseph P.
Water scarcity of fresh water in Sub-Saharan has led to utilization of the wastewater in home gardening and also in commercial production of vegetables. Wastewater is associated with various substances including nutrients and heavy metals hence it is pertinent to evaluate its effects on growth and yield of vegetables. An experiment was conducted to evaluate the effect of waste water released from the municipal council on the biomass accumulation in African leafy vegetables. Field experiments were carried out in two seasons and one greenhouse experiment. The field trial was laid out in a Randomized Complete Block Design (RCBD) and in the greenhouse the treatments were arranged in Complete Randomized Design (RCD) replicated three times. Four leafy vegetables were the treatments replicated three times. The vegetables were irrigated with waste water. Plant samples were collected at 6 WAP and 12 WAP, partitioned and dried in an oven and later weighed using electronic weighing balance. The findings revealed differences in biomass accumulation into various organs. Black nightshade depicted the highest leaf dry matter in the greenhouse at both 6 weeks after plant (WAP) and 12 WAP (24.62 g and 81.12 g respectively). Cowpea showed the highest increment (7 folds) in leaf weight between 6 to 12 WAP as compared to was paltry 3.6 folds. The highest stem dry weight was obtained in the amaranth species at 6 WAP and 12 WAP both in the greenhouse; recording 32.59 g and 90.12 g respectively. A similar trend was noted in root dry weight and root: shoot ratio. Cowpea had the least biomass accumulation potential across all the parameters in both seasons and in the greenhouse. The increased biomass growth is an indication sufficient availability of nutrient that promoted vibrant plant growth and also less toxicity from the heavy metals. Therefore, waste water can be put into use to enhance improved productivity of African leafy vegetables.
Effect of Phosphate Levels on Soil Rhizosphere Nutrient Balances and Finger Millet Yield
(SCIENCEDOMAIN International, 2016) Wafula, Wekha N.; Korir, Nicholas K.; Ojulong, Henry F.; Gweyi-Onyango, Joseph P.
Flowering and maturation periods of Finger Millet as influenced by phosphorus and variety in different agro-ecologies in Kenya
(Elixir Publishers, 2016) Wafula, Wekha N.; Korir, Nicholas K.; Ojulong, Henry F.; Gweyi-Onyango, Joseph P.
Phosphorus is important for finger millet production in many tropical African soils with low phosphorus fertility. Knowledge of redirection of this limited resource for reproduction is fundamental in realization of potential yields. The effect of four phosphorus levels (0, 12.5, 25.0 and 37.5 kg ha-1 P2O5) and three varieties (U-15, P-224 and a local check) on the days to flowering and maturity of finger millet were evaluated in three agro-ecologies in Kenya during the raining seasons of 2014-2015. Phosphorus application significantly (P<0.05) increased early flowering and physiological maturity in Kakamega and Busia. The varieties elicited significantly different days to 50% flowering and maturation periods in all the study sites. The days to flowering and maturity were found to be lowly but negatively correlated with the grain yield of finger millet in all the sites.
Green Pepper Growth and Yield Response to the Integration of Mulching Materials and Row Plant Spacing
(Academic Research Publishing Group (ARPG), 2017) Ocharo, Edgar N.; Korir, Nicholas K.; Gweyi-Onyango, Joseph
An experiment was conducted at the Crops Research Station of the Kenya Agricultural and Livestock Research Organization Alupe, Busia County. The experiment was performed to find out the most suitable mulching material and an ideal spacing for green pepper cultivation under Busia County Conditions. The experiment was laid out in a Factorial Randomized Block Design with three replications. The treatments comprised of four mulching materials viz. black plastic mulch, transparent plastic mulch, straw mulch and bare soil which was the control with three row spacings viz. 30 x 50 cm, 40 x 40 cm and 50 x 40 cm. Data collected was subjected to SAS statistical software for analysis and means separated using LSD at P≤0.05. Significant responses on plant height and number of branches per plant were observed for both seasons due to spacing and mulching treatments. The highest branches (6.97) per plant were recorded in the 40 by 40 cm spacing under the transparent mulch with the lowest (2.83) shown under the same spacing in the straw mulch of California Wonder variety. The widest spacing elicited the highest number of fruits per plant (7.37) in the black plastic mulch while only a mean of 1 fruit per plant was recorded in the mulch control during the short rain season. The highest fruit mean yield per plant of 1556 g and 1533 g was recorded in the widest spacing (50 by 40cm) during the long and short rain seasons respectively. Therefore this study recommends the use of plastic mulches at wider spacing.
Influence of Mulching Materials on the Growth and Yield Components of Green Pepper at Busia County in Kenya
(SCIENCEDOMAIN International, 2016) Edgar, Ocharo N.; Gweyi-Onyango, Joseph P.; Korir, Nicholas K.
Aims: Green pepper (Capsicum annuum) also named the bell pepper or sweet pepper is one of the most important and remunerative vegetable crops in the world. Due to the increased pressure on land, climate change and increased demand for the crop, there is need for better agronomical practices that will ensure enough food production. Place and Duration of Study: In Kenya, little attention has been given to the use of organic and inorganic mulch materials to increase productivity of horticultural crops and therefore this study was conducted in Alupe, Busia-Kenya, during the long and short rains season of 2015 to assess the efficacy of black plastic, transparent plastic and straw mulch on growth and yield of green pepper. Methodology: The treatments were black polythene mulch, transparent polythene mulch, straw mulch and bare soil as the control. Results: The straw mulch elicited significantly vigorous growth of seedlings compared to the other treatments but had the lowest number of leaves unlike transparent mulch which had the most with 58. The widest stem circumference was observed on mulched plots as well as the plant height where the control recorded the lowest height. The black polythene mulch gave significantly (P=.05) heavier fruits of 924.5 g/plant during the long rain and 681.1 g/plant in the short rain season. Unmulched plots of either variety had the lowest mass recorded for fruit in both seasons. The transparent mulch showed significantly (P=.05) more seeds per fruit (196), longest fruit length (8.5 cm) and greatest fruit diameter (9.2 cm). Based on the experimental results the black polythene mulches had greatest effects on the growth, and yield of sweet pepper and showed superior performance among the plastic mulches in the study area and therefore is recommended.
Influence of Sri Fertilizer Practice on Yield Components and Grain Yield of Hybrid Rice Varieties in Kenya
(Asian Plant Research Journal, 2019) Mbatha, Wathome N.; Korir, Nicholas K.; Onyango, Joseph P. Gweyi
Rice is one of the staple food crops in Kenya and its demand is generally increasing annually especially when maize production has declined due to various factors. The national rice consumption is estimated at 300,000 metric tonnes compared to annual production of 45,000-80,000 where the deficit is met through importation. The low production can be increased through adoption of system of rice intensification methods that can lead to higher yields and sustainable production. Several studies have been conducted on SRI water requirements, plant systems and soil but very little has been done on fertilizer regime on hybrid rice in Kenya. To address this challenge, yield performance of two rice hybrid varieties; Arize Tej Gold and Arize 6444 Gold against a locally inbred variety (BW 196) under SRI fertilizer regime were evaluated at two sites; Mwea irrigation scheme in Kirinyaga County and Ahero irrigation scheme in Kisumu County. The experiment was laid out in a split-plot design where the SRI fertilizer practices were the main plots (2.5 t ha-1Evergrow, 200 Kg ha-1SA, 2.5 t/ha Evergrow + 100 Kg ha-1SA, 2.5 t ha-1Evergrow +200 Kg ha-1SA, and a control-without fertilizer) and the rice varietieswere the sub-plots anreplicated three times. Data was collected on number of grains per panicle, filled grains per panicle and grain yield then subjected to analysis of variance (ANOVA) using SAS 9.2 and means separated using Fischer’s Protected LSD. Significant differences were observed on the number of grains per plant with the Evergrow+100 Kg ha-1SA and Evergrow+200 Kg ha-1SA SRI fertilizer treatments showing the highest at 293 and 275 grains per plant respectively under variety Arize Tej Gold at Mwea and 256 grains per plant at Ahero. The high number of grains per plant consequently led to the highest grain yield under the SRI treatments where the Evergrow+100 Kg ha-1SA treatment had the highest grain yield per plot in Ahero (1202 g) and Mwea (4002 g). The application of 100 Kg ha-1of SA and organic fertilizer is recommended in rice production.
Integration of mulching and row spacing on weed management in Green Pepper varieties
(Society for Tropical Plant Research, 2017) Ocharo, Edgar N.; Korir, Nicholas K.; Gweyi-Onyango, Joseph P.
A field experiment was conducted at the Kenya Agricultural and Livestock Research Organization, Alupe Research Farm, Busia County for two cropping seasons during the year 2015 to determine the impact of row spacing and mulching materials on weed management of two green pepper varieties. The two varieties California Wonder and Yolo Wonder were sown in a randomized complete block design in factorial arrangements, comprising three-row spacing treatments and four mulching materials then replicated thrice. The row spacing were; 30, 40 and 50 cm whereas the mulching materials were; black plastic mulch, transparent plastic mulch, straw mulch and bare soil which was the control. Data collected was subjected to SAS statistical software for analysis and means separated using LSD at P≤0.05. Significant differences (p≤0.05) were observed between the treatment combination of mulch and row spacing in the fresh and dry weed biomass, weed species density per m2 and the weed growth vigor. The highest fresh weed biomass (5008 g.m-2) was elicited by the control mulch treatment at the widest row spacing during the long rains season while the lowest (188 g.m-2) was observed in the black plastic mulch at the narrow row spacing of 30 cm. The weed species density was highest (7) in the control at 40 cm row spacing with the lowest elicited in the black plastic mulch at the 40 cm row spacing (1.7) during the short rain seasons. The weed growth vigor was highest in all the control mulch treatments at 30 cm row spacing while the lowest vigor was in the black plastic mulch which was closely followed by the transparent mulch at the various row spacings. The competitiveness of sweet pepper with weeds can be significantly enhanced by using black plastic as mulch under narrow row spacing with an optimum of 30 cm.
Interaction Effect of Growth Regulators and Irrigation Schedules on Growth and Yield of French Beans in Kiambu County, Kenya
(SCIENCEDOMAIN International, 2018) Kalawa, Ikiba L.; Wafula, Wekha N.; Korir, Nicholas K.; Gweyi-Onyango, Joseph
Inadequate and unreliable rainfall distribution in Kenya has affected negatively agricultural yields and family incomes. Integration of growth regulators can stimulate favorable crop growth under limited moisture, but there has been scarce research and documentation on them. Therefore the gibberellic acid and cytokine in effect on French beans growth and yield was assessed under different irrigation schedules at Kenyatta University Field Station in two seasons of 2014/2015. The experiment was set in Randomized Complete Block Design (RCBD) in split-plot arrangement with three levels of each hormone as sub-plots and three watering regimes as main plots and replicated three times. The results showed that optimum rates of growth regulators positively improved the growth and yield components of French beans. Significant differences between the treatments at P<0.05 were observed on the leaf area where the 0.50ml level of cytokine in had the greatest at week nine after sowing with 1335.3 cm2 during the first season and 1343.1 cm2 during the second season at a daily watering regime. Consequently, this led to significantly the highest pod fresh yield of the French beans with 58.97 g/plant and 84.99 g/plant for the first and second seasons respectively at week nine in the same treatment combination. The highest level of gibberellic acid (0.675 ml) led to the lowest fresh pod yields at week six, seven and eight, while the highest rate of cytokine in (0.750 ml) had the least fresh pod yield at week nine showing the negative effect of excessive application of growth regulators on French beans, yield components. The study, therefore, recommends an application of cytokinin at a rate of 0.50ml to achieve maximum yields in French beans.
Phosphorus Influence on Plant Tissue Nitrogen Contents and Yield Attributes of Finger Millet Varieties in Semi-arid Region of Kenya
(SCIENCEDOMAIN International, 2016) Wafula, Wekha N.; Korir, Nicholas K.; Ojulong, Henry F.; Siambi, Moses; Gweyi-Onyango, Joseph P.
Plant Row Spacing Effect on Growth and Yield of Green Pepper (Capsicum annuum L.) in Western Kenya
(SCIENCEDOMAIN International, 2017) Edgar, Ocharo N.; Gweyi-Onyango, Joseph P.; Korir, Nicholas K.
Green pepper production based on the package of recommendations developed has not given the desired growth and yield performances in the world and specifically Kenya. Information is required with which to evolve the agronomic practices that will be adopted to maximize yield in green pepper production. Great attention should be paid when selecting the most appropriate spacing where there are very few reports and limited information regarding plant spacing in cultivation of the crop under the agro-climatic conditions of Kenya. Therefore, a field study was carried out at the Alupe Research Station, Busia County, to evaluate the growth and yield responses of green pepper under three row plant spacings namely: 50x40 cm, 40x40 cm and 30x40 cm during the long and short rainy seasons of 2015. The experiment was set up in a randomized complete block design with three replicates. The treatment effects were measured on plant growth for 12 weeks and ripe fruit yield parameters which were later cleaned statistically analyzed. The plant spacing had significant variation in almost all the growth and yield components except the fruit length. In both seasons, the number of branches per plant, stem girth and number of fruits per plant were found to be significantly increased with the increasing of plant spacing but the plant height, number of leaves per plant, fruit breadth and yield per plant were found to be significantly increased with the decreasing plant spacing. The highest yield per plant of 555.1 g and 551.8 g were realized during the short and long rainy seasons respectively in the 40 by 40 cm spacing treatment. Considering the yield of fruits per plant, the 40 by 40 cm plant spacing appeared to be the most recommendable for the cultivation of green pepper.
Unpacking the benefits of black soldier fly frass fertilizer towards nematode suppression and potato production
(frontiers, 2025) Anedo,Emmanuel O.; Beesigamukama,Dennis; Mochoge,Benson; Korir, Nicholas K.; Solveig Haukeland; Xavier Cheseto; Nyongesa,Moses; Pwaipwai,Patrick; Sevgan Subramanian; Abdou Tenkouano; Betty Kibaara; Tanga,Chrysantus M.
Potato production is hindered by soil degradation and nematode infestation. Mineral fertilizers and synthetic nematicides are costly and cause negative impacts on humans and the environment, while organic fertilizers are less effective for soil health and nematode management. This study demonstrates the contribution of black soldier fly frass fertilizer (BSFFF) in nematode suppression and potato productivity when compared to commercial mineral fertilizer, organic fertilizer (SAFI), and nematicide. The on-farm experiments consisted of eight treatments: BSFFF, SAFI, BSFFF+5%chitin, NPK+nematicide, 50%BSFFF+50%NPK, 50%SAFI+50%NPK, 50%BSFFF+5% chitin+50%NPK, and control (unfertilized soil). Results revealed that all fertilizer treatments significantly increased potato growth, number of tubers (34 – 61%), and tuber yield (20 – 72%) relative to the control. Application of BSFFF+5% chitin produced 9 – 28% higher tubers per plant compared to other treatments. Over 26% higher tuber yield was achieved using BSFFF+5% chitin compared to NPK+nematicide treatment. Soil amendment with BSFFF+5% chitin caused 5–35% higher reduction in the number of cysts per 200 g soil-1 compared to NPK +nematicide and SAFI treatments. The same treatment reduced the PCN reproduction rate by 20% and 75% compared to NPK + nematicide and SAFI, respectively. Both BSFFF and NPK+nematicide treatments achieved comparable suppression of the number of eggs and infective juveniles (J2) per cyst-1 and eggs g-1 of soil. However, BSFFF+5% chitin reduced the number of eggs and J2 per cyst-1 and eggs g-1 of soil by 55–92% compared to SAFI. Our findings demonstrate that chitin-fortified BSFFF can significantly contribute to potato cyst nematode suppression and boost potato yields in smallholder farming...

Browsing by Author "Korir, Nicholas K."

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