School of Agriculture & Food Science

Growth, Yield and Quality of Selected Sweet Potato (Ipomoea Batatas [L.] Lam.), Lines Under Varying Soil Moisture Conditions and Nutrient Management Levels

Mon, 01 Jan 2024 00:00:00 GMT

Growth, Yield and Quality of Selected Sweet Potato (Ipomoea Batatas [L.] Lam.), Lines Under Varying Soil Moisture Conditions and Nutrient Management Levels Ngugi, Penina Sweet Potato (Ipomoea batatas [L.] has increasing potential as a food security crop in Kenya. However, its’ production is comparatively low compared to its potential production, which is attributed to drought conditions and low soil fertility conditions alongside the use of local landrace cultivars that are quite low-yielding. A study was conducted at Meru University of Science and Technology comprising two field experiments (NPK fertilizer levels) and (soil moisture regimes) to assess the performance of selected improved sweet potato lines under the varied conditions. Three sweet potato varieties were used: CIP 106988.1 (Naspot13) and CIP 112286.1(Margarette), and a farmer-preferred variety, Kemb-10. The varieties were subjected to three watering regimes: (i) Severe stress (SS), 30 days WAE (ii) Moderate Stress (MS), 60 days WAE, and (iii) (WW) well-watered to maturity; three NPK levels: 0, 120 and 240 Kg NPK ha-1. A randomized complete block design in a split-plot with 3 replicates was used: water treatment as the main plot and, varieties as a subplot for moisture experiment and varieties on the main plot, and NPK levels as the subplots for the fertilizer experiment. Data collected data was analyzed using SAS 2007, and means were separated using the least significance difference test (P≤0.05). There was no significant interaction between moisture treatments and NPK levels with varieties. Water treatments and NPK levels significantly affected vine length, number of leaves, and tuber yield. Plants under severe stress had significantly lower vine length, branches, and leaves. Under Moderate stress 60 days WAE, plants experienced a significant reduction in vine length, leaves, and branches compared to the well-watered. However, this reduction was less compared to severe stress. The reduced vine length and tuber yield are attributed to impaired photosynthesis, reduced cell division, elongation, and assimilate partitioning. Tuber numbers correlated with leaves (r = 0.63*, 0.74*), and vine length (r = 0.62*, 0.76*).This positive correlation implies that if drought significantly reduces the number of leaves and vine length, it reduces tuber yield, indicating the effect of drought on tuber yield can be estimated by measuring tuber length and number of leaves. Sweet potato growth parameters (vine length, number of branches, number of leaves) and tuber yields (tuber length, tuber circumference, number of tubers, and tuber fresh weight were significantly affected by the different NPK levels applied. Application at 240 Kg NPK ha-1 produced the highest vegetative growth and tuber yields. As the NPK rates were increased from 0 Kg NPK ha-1 through 120 Kg NPK ha-1 to 240 Kg NPK ha-1, the vegetative and tuber yields also increased. Based on findings, ensuring the crop obtains enough moisture during the first nine weeks after planting is recommendable. In contrast, NPK nutrient supply is fundamental to the growth and development of the crop. It is recommended that farmers incorporate inorganic fertilizers in sweet potato farming, rather than just organic manures, for enhanced production.

Effects of Land Preparation Method and Organic Soil amendment on Soil Physical Properties, growth and yield of Maize (Zea Mays L.) and its residual Effects on Collards (Brassica Oleracea Var Acephala) Production.

Mon, 01 Jan 2024 00:00:00 GMT

Effects of Land Preparation Method and Organic Soil amendment on Soil Physical Properties, growth and yield of Maize (Zea Mays L.) and its residual Effects on Collards (Brassica Oleracea Var Acephala) Production. Kemboi, Victor Kiptoo Maize (Zea mays L.) and collard (Brassica oleracea var acephala) are important food crops popular in Kenya and their production has a direct influence to nutrition and economic security. The high demand for these food crops has resulted to innovation of new farming techniques to increase their production. A study was conducted at Meru University of Science and Technology, Kenya demonstration Farm comprising of two experiments maize and collard experiment to assess the effects of land preparation method and organic amendments on soil physical properties, growth and yield of maize and collards. Collards were used to determine the residual effects of land preparation method and organic amendments on maize experiment. Therefore, this experiments were set up in randomized complete block (RCBD) designed in split plot arrangements. Land preparation method being the main plot and organic amendment being the subplots. Two land preparation method were used conservational and conventional land preparation method (CA and CT). The nutrient levels were 2.5 t ha-1 BSF, 5.5 t ha-1 BSF, 8.5 t ha-1 BSF, 2.5 t ha-1 BSF + Biochar, 5.5 t ha-1 BSF + Biochar, 2.5 t ha-1 BSF + Trichoderma spp. 125 g ha-1, 5.5 t ha-1 BSF + Trichoderma spp. 125 g ha-1, 5 t ha-1 FYM, 100 kg N ha-1 DAP and control. Data collected was on soil bulk density, soil moisture, vegetative growth and yields. Data collected data was analyzed using SAS 2007, and means were separated using the least significance difference test (p≤0.05). There was no significance interaction between land preparation method and organic amendments in both experiments. Land preparation method significantly (p<0.05) influenced soil moisture retention with conservational land preparation method recording higher soil moisture than conventional land preparation method. Land preparation method had no significance effect on maize and collard growth. Organic amendments influenced soil bulk density significantly (p<0.05) with 8.5 t ha-1BSF and 5.5 t ha-1 BSF + Biochar recording the lowest soil bulk density while control recorded the highest soil bulk density. Organic amendment also influenced vegetative growth and yields of maize significantly (p<0.05). Land preparation method had a residual effect on soil moisture, vegetative growth and yields of collards per plant. Organic amendments had a significant (p<0.05) residual effects on collard vegetative growth and yields than chemical fertilizer applied treatments and control.

Control of Bacterial Wilt in Tomato Using Warburgia Ugandensis Extracts

Mon, 01 Jan 2024 00:00:00 GMT

Control of Bacterial Wilt in Tomato Using Warburgia Ugandensis Extracts Lideke, Oliver Libese Ralstonia solanacearum is a soil-borne bacterial pathogen that poses significant threat to the Solanaceae family and other crops. Tomato plants are affected by R. solanacearum which causes bacterial wilt, that has no treatment. Bacterial wilt is a devastating disease that affects the plant's water transport system, leading to wilting and death. Numerous chemical agents and treatment methods have been employed in attempts to control R. solanacearum, but were ineffective. Warburgia ugandensis crude extract have exhibited biocontrol properties against pathogenic fungi and bacteria in animals but the information is limited in plants. This study aimed to determine the in vitro and in vivo efficacy of W. ugandensis stem bark and leaf crude extracts against R. solanacearum. W. ugandensis stem bark and leaf crude extracts were obtained using organic solvents viz. methanol, ethanol, dichloromethane and hexane. In vitro, antagonistic activities against R. solanacearum of all organic crude extracts of W. ugandensis were determined by standard agar well diffusion assay on Kelman’s 2, 3, 5- triphenyl tetrazolium chloride medium in triplicates. Two-way analysis of variance (ANOVA) was used in the statistical analysis of the mean diameter inhibition zones. All the organic solvents crude extracts of W. ugandensis were inhibitive against R. solanacearum. However, the stem bark crude extracts exhibited significantly higher efficacy against R. solanacearum compared to the leaf crude extracts. The crude extracts were subjected to a serial dilution to determine the minimum inhibitory concentration (MIC). W. ugandensis stem bark dichloromethane crude extracts had the lowest MIC of 1 mg/ml. W. ugandensis stem bark dichloromethane crude extracts were most effective against R. solanacearum. The crude extracts were tested against R. solanacearum in the greenhouse. The treatments were done in triplicate. Statistical analysis of the data was carried out using analysis of variance. Tomato plants established in soil inoculated with R. solanacearum but treated with W. ugandensis stem bark dichloromethane crude extract showed bacterial wilt disease incidence and severity of 0% which was similar to positive control. Tomato plants established in soil inoculated with R. solanacearum but treated with W. ugandensis leaf ethanol crude extract had the highest average height of 62.50 cm which was similar to positive control. The study proposed that W. ugandensis crude extract has the ability to be used as antibacterial biocontrol against R. solanacearum. Further research is important to determine the bioactive compounds against R. solanacearum present in the extracts that are inhibitory to R. solanacearum.

Influence of Spacing, Nitrogen Supply and Soil Moisture on Growth and Yield of Chia (salvia hispanica l.) in Meru County, Kenya

Sun, 01 Jan 2023 00:00:00 GMT

Influence of Spacing, Nitrogen Supply and Soil Moisture on Growth and Yield of Chia (salvia hispanica l.) in Meru County, Kenya Muriithi, Moses Njoka Production of Chia (Salvia hispanica L.) in Kenya is gaining momentum, and it has attracted a lot of attention due to its nutritious seeds. The high demand for this food crop has resulted in haphazard cultivation and production. There is still scarce agronomic information regarding nitrogen nutrition, spacing and water requirement in Meru County. Two field experiments (nitrogen and spacing) and (soil moisture) were conducted at Meru University of Science and Technology, to develop a suitable crop management system for the cultivation and production of Chia plant. The nitrogen and spacing experiment was setup in a split-plot randomized design with three replications. Chia plants were subjected to four nitrogen levels (0,40, 80,120 kg N ha) and three spacing arrangement (30cmx15cm (S1), 30cm x 30cm (S2) and 50cmx50cm(S3). The soil moisture experiment was set up in a randomized complete block design with three replications. Plants were subjected to four soil moisture regimes; watering to the seedling stage, watering to the vegetative stage, watering to the flowering stage, and continuous watering. Data was collected on growth parameters (number of leaves, stem height, number of branches, stem diameter, total dry weight) and yield parameters. Collected data were analysed using SAS 2007, and means were separated by LSD test (P≤0.05). A higher nitrogen level of 120 KgN/ha significantly increased the number of leaves, stem height, stem diameter, number of branches, total dry weight and seed yield compared to 0 KgN/ha. Wider spacing (S3) significantly increased growth of Chia compared to a closer spacing (S1). The seed yield per plant increased significantly with the increase in spacing from $1 to $3. However, a significant reduction in the seed yield per area was reported in a wider spacing (S3) compared to a closer spacing (S1). Variation of soil moisture significantly influenced (P<0.05) growth and yield of Chia. Watering to the seedling stage significantly decreased the growth of Chia plant. The plant water status in regards to leaf relative water content decreased with a decrease in the soil moisture in the soil from 21% to 8%. Control plants had a higher seed yield per plant than plants watered to the seedling stage. Application of a high nitrogen level of 120kgNha, a closer spacing of 15 cm x 30 cm and watering to the vegetative stage is recommended as the best management practice for farmers.