Comparative Performance of Organic Fertilizers in Maize (Zea mays L.) Growth, Yield, and Economic Results

Maize is a major crop grown and consumed in Uganda and it requires a high fertilizer input. However, the existing inorganic fertilizers in the market are often not affordable especially to small scale farmers, which results in decreased maize yields in the country. On the other hand, there is an abundance of unutilized animal manure, which, when treated, can be used to increase maize yields. This study evaluated the response of maize to products of different cattle manure treatment methods as well as inorganic fertilizer. The treatments such as cattle manure stored under shade (T), cattle manure stored in the open (M), cattle manure slurry digestate (S), vermicompost (V), and an inorganic fertilizer, DAP (D) were all applied in completely randomized block plots at an equal application rate of 50 kg N ha−1 with four replications per treatment. Control plots (C) where no fertilizer was applied were also considered. The experiment was done for two planting seasons in 2018. Number of leaves, plant height, cob, and grain yields were used to evaluate the performance of different fertilizer treatments. Economic assessment of all the six treatments was also carried out to determine the economic viability of applying these fertilizers on maize. Maize growth parameters and yields were all significantly increased (p < 0.05) with an application of both organic and inorganic fertilizers when compared with the control. However, there was no significant difference (p > 0.05) in the maize yields under the different fertilizer treatments. Vermicomposting was the most economically viable manure treatment method due to low operating costs and higher returns on investment that are supplemented with the production of chicken fodder (earthworm biomass) and, thus, can be recommended to farmers for production of a fertilizer that increases maize yields with assurance of economic returns

Assessment of a Cattle Manure Vermicomposting System Using Material Flow Analysis : A Case Study from Uganda

Growth in cattle population is associated with increased manure generation whose current management in low-income countries is associated with health and environmental problems as well as low utilization rates. This trend can be reversed by promoting better manure management technologies. This study assessed vermicomposting as one of the technologies to manage organic wastes, using the case study in Uganda. A vermicomposting system using cattle manure and earthworms (Eudrilus euginea) was monitored for one year with the harvesting of products (compost, earthworm biomass) after every three months. Vermicompost samples from the beginning of the experiment and after every harvest were analyzed for the following parameters: pH, ash content, volatile and total solids, nutrients N, P, K, and C. Emissions of CO2, CH4, NH3, and N2O were also measured. Material flow analysis was used to determine the flows and retention of nutrients within the system. Results showed that total solids, ash, N, P, and K content significantly increased, while contents of volatile solids and C, as well as the pH, significantly decreased over time. Of the materials that entered the vermicomposting system, 46% went to vermicompost, 2% into earthworms, and 52% was lost to the atmosphere. Substance flow analysis showed that 30% of C went to vermicompost, 69% was emitted to the atmosphere, and 2% ended up in earthworms while 75% of N was transferred to vermicompost, 7% went to earthworms, and 18% escaped into the atmosphere. The cumulative emissions were 102 g CO2 kg−1 waste, 7.6 g CH4 kg−1 waste, and 3.943 × 10−5 g N2O kg−1 waste on a dry basis, while NH3 was not detected throughout the measurement time. Compared to other manure management methods, vermicomposting demonstrated good potential in conserving nutrients as well as reducing greenhouse gas emissions. View Full-TextAustrian Development Cooperation (ADC

Species Composition and Occurrence of Thrips on Tomato and Pepper as Influenced by Farmers’ Management Practices in Uganda

A biological monitoring survey was carried out in central Uganda for two consecutive seasons to provide information on species composition and occurrence of thrips on tomato and pepper as influenced by farmers’ management practices. A total of 50 farms for each crop participated in the study. Data was collected on cropping system, crop variety, type of pesticide used, pesticide spray regime, and on thrips populations. Results indicated that a total of six thrips species: Frankliniella occidentalis, Thrips tabaci, F. schultzei, Scirtothrips dorsalis, Ceratothrips ericae and Megalurothrips sjostedti infest tomato in the region. Pepper had the same thrips profile with the exception of F. schultzei. There was a distinct seasonal effect on thrips occurrence in the case of tomato. Higher thrips populations (61%) were recorded in the first season of the study as compared to the second. The majority of the thrips were recorded in the flowering stage of crop development for both crops, and 100% in the case of pepper. Generally, for both crops, plants in intercropped arrangements had higher thrips counts than the monocropped ones. Different tomato/pepper varieties sustained variable thrips populations. All the farmers applied pesticides to manage the complex of pests on the crops, albeit to variable extents. In this region, thrips populations were reduced when an increase in the number of pesticide applications in a given week was used

Influence of Cassava Morphological Traits and Environmental Conditions on Field Populations of Bemisia tabaci

High populations of species in the whitefly complex Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) were reported to cause severe damage to cassava in East and Central Africa. However, reasons for B. tabaci population increases are not well understood. We investigated the effect of cassava morphological traits, temperature, rainfall and relative humidity (RH) on the abundance of B. tabaci. Five cassava genotypes with varying levels of resistance to cassava mosaic disease, cassava brown streak disease, and B. tabaci infestation were planted in three Ugandan agro-ecological zones. The experiment was conducted in 2016 and 2017 in a randomized complete block design. Across all locations, the tallest genotype Alado alado supported the lowest number of B. tabaci adults. In areas with high B. tabaci prevalence, leaf area, leaf lobe width, and leaf lobe number exhibited significant positive effects (p < 0.001) on B. tabaci adult count. Positive effects of relative humidity and negative effects of temperature and rainfall on B. tabaci adult and nymph counts were observed in 2016 and 2017, resulting in low populations in Lira. Evidently, temperatures of 28–30 °C, rainfall of 30–150 mm and RH of 55–70%, and deployment of cassava genotypes of low plant height, large leaf area, and lobe width significantly enhanced B. tabaci population growth

Can local nutrient-circularity and erosion control increase yields of resource-constraint smallholder farmers? A case study in Kenya and Uganda

As many regions in sub-Saharan Africa, the border region of Kenya (KE) and Uganda (UG) has faced a declining soil fertility for decades, resulting from soil erosion, intensely managed agricultural soils due to population pressure and small inputs of mineral and organic fertilizers. With limited financial means, farmers need measures and/or technologies that effectively reduce nutrient losses or increase inputs at a low cost. In this study, four such measures are in focus, namely erosion reduction practices, vermicomposting of animal manure, collection of human urine in jerry cans and, collection of human excreta in urine-diverting dry toilets. Current soil nutrient balances in five districts in the Sio-Malaba-Malakisi River Basin and the potential of these measures to reduce the soil nutrient deficit are studied using the method of material flow analysis and the software STAN. Furthermore, crop-nutrient-response functions are used to determine their potential impact on maize harvests. Overall, results reveal that there exists a non-negligible and exploitable potential of local resources to reduce the soil nutrient deficit, improve harvests and in turn food security of the smallholder farmers in the region. Soil nutrient deficits could be reduced by 20–30%, 23–42% and 9–15% for nitrogen (N), phosphorus (P) and potassium (K), respectively. Subsequently, maize harvests could be increased by 8–40%, depending on the applied technology and area. This research provides useful insights for agricultural extension workers, politicians and researchers alike, highlighting that simple and easily available technologies can harness similar amounts of nutrients as more complex and expensive ones if all specific technology-constraints are adequately incorporated in the analyses.1171