John Tenywa - Academia.edu (original) (raw)

Papers by John Tenywa

Journal of Agriculture and Ecology Research International, 2016

International Journal of Plant & Soil Science, 2015

Sustainable Land Management (SLM) is one of the transformative pillars for agricultural developme... more Sustainable Land Management (SLM) is one of the transformative pillars for agricultural development and environment conservation for food, forage, fuel and fiber security. It aims at the tripartite benefits of high yields, environment protection and income security. The success of SLM is a function of adopting appropriate nutrient and water management practices. Several land management practices have been practiced by smallholder farms in the Great Lakes Region of Africa. However, there is still limited understanding of the level of acceptability of the various technologies in mitigating soil water shortage and nutrient depletion. This paper evaluates the SLM concept with focus on assessing sustainability in the use of various soil water and nutrient management technologies and practices. Nutrient management technologies assessed included a range of common inputs and practices in tropical farming systems. Soil water conservation technologies assessed included the physical, biologica...

African Journal of Food, Agriculture, Nutrition and Development, 2010

The highlands of southwestern Uganda account for the bulk of field pea (Pisum sativum L.) produce... more The highlands of southwestern Uganda account for the bulk of field pea (Pisum sativum L.) produced and consumed in the country. The crop fetches a stable price, which is as high as that of beef, but it has remained outside the mainstream of the research process. Low soil fertility, unfortunately, is poised to eliminate the crop. Nitrogen, phosphorus and potassium have variously been reported as deficient on the bench terraces where crop production is primarily done. Strategic nutrient management requires that the most limiting nutrient is known in order to provide a foundation for designing effective and sustainable soil fertility management interventions. A study was conducted on upper and lower parts of the bench terraces on the highlands in southwestern Uganda to identify the most required macronutrient(s) in field pea production. Treatments included: 0 and 25 kg N ha-1 , 0 and 60 kg P ha-1 , and 0 and 60 kg K ha-1 , all applied factorially in a randomized complete block design. Parameters assessed included nodulation, nodule effectiveness for BNF and dry weight, shoot dry weight, and grain yield. Nutrient applications that resulted in the highest crop responses were considered as most required, and hence, most limiting to plant growth and yield. Phosphorus based nutrient combinations gave the highest increments in total and effective nodule numbers, as well as dry weight, irrespective of terrace position. On the other hand, N based combinations led to the highest shoot dry matter at flowering (39 % higher over the control). The superiority of N was carried over up to final harvesting, with stover and grain yields edging out the other treatment regimes on either terrace positions. Phosphorus was most limiting nutrient, though the effect manifested in terms of the intensity of BNF indicators, followed by nitrogen, that manifested at later stages of crop growth influencing stover and grain yield.

Real solutions representation for the cubic equation with real coefficients in a parametric form ... more Real solutions representation for the cubic equation with real coefficients in a parametric form is given. The dependence of the solutions on the equation coefficients and the bifurcation conditions for these solutions are studied. In the parametric space regions with one and three real solutions are considered. Using parametric representations of the cubic equation solutions, the stability and bifurcation conditions of the equilibrium states for the thermodynamic systems described by the Landau-type kinetic potential are analyzed.

African Journal of Environmental Science and Technology, 2018

Bacterial communities are actively involved in composting process but the environment within the ... more Bacterial communities are actively involved in composting process but the environment within the compost influences their diversity, abundance and succession. In this study, the authors investigated the bacterial communities in tropical crop waste compost using pyrosequencing. Municipal crop wastes from the tropics (Uganda) were composted under four different low-technology methods. Samples were collected from the early thermophilic, late thermophilic, and mesophilic phases, and from mature compost. Pyrosequencing of the amplified variable V4 region of the 16s rDNA generated over 110 000 sequences. Chao1 and cluster analysis at 3% dissimilarity showed that bacterial community richness declined during the composting process. The community was dominated by a few bacterial taxa during the thermophilic phases. Species evenness increased as compost progressed to maturity despite a decline in the number of taxa over the successional progression. Bacterial community diversity, abundance a...

International Journal of Advanced Remote Sensing and GIS, 2013

The modeling capability of the Revised Universal Soil Loss Equation (RUSLE) on a heterogeneous la... more The modeling capability of the Revised Universal Soil Loss Equation (RUSLE) on a heterogeneous landscape is usually limited due to computational challenges of slope length and slope steepness ( LS ) factor. RUSLE can be adapted to Arc-Macro (C++) executable programs to obtain LS values even for highly variable landscapes based on Digital Elevation Models (DEMs); and then predict erosion risk. The objective of this study was to compute LS factor from DEM using C++; and predict soil erosion risk in a banana-coffee watershed of the Lake Victoria Basin (LVB) of Uganda. DEM data of Nabajuzi watershed were used as an input file for running the (C++) executable program to obtain LS factor. The predicted LS values were calibrated against tabulated LS values; and a strong linear relationship (R = 0.998) was observed between them. The LS factor increased with slope length and slope gradient. Erosion risk across landuse were predicted as follows: small scale farmland (38 t ha -1 yr -1 ), built...

Organic waste materials as soil amendments are one of the topical approaches applauded for achiev... more Organic waste materials as soil amendments are one of the topical approaches applauded for achieving sustainable agriculture world-over. The objective of this study was to investigate the effect of urban-based biosolid waste (UBBW) application on heavy metals (Cr, Cu, Zn and Pb) bioaccumulation by maize (Zea mays L.) plants. A pot experiment was conducted three times, using an acid Ferralsol from Makerere University Agricultural Research Institute, Kabanyolo (MUARIK) in Uganda. Treatments included the application of three types of UBBW, namely sewage, brewery and abattoir, each applied independently at the rates of 0, 50 and 100 g per pot filled with 4 kg soil. This was equivalent to 0, 2.5 and 5.0 metric tonnes of dry materials per hectare. Phosphorus fertiliser was also applied at 0, 0.795 and 1.591 g P per pot, equivalent to rates of 0, 25 and 50 kg P ha-1. The brewery waste applied at rates ≥ 2.5 t·ha-1 and phosphorus at 25 kg P ha-1 resulted in shoot Cu concentrations below the...

This study was carried out to determine the optimum nitrogen and phosphorus rates for achieving o... more This study was carried out to determine the optimum nitrogen and phosphorus rates for achieving optimum yields and nutrient use efficiency for wheat in highlands of Eastern Uganda. An on station randomized complete block design experiment was conducted at Buginyanya Zonal Agricultural Research and Development Institute. Two varieties Fahari and Pasa were treated with four levels of nitrogen (0, 30, 60, & 90 kg ha) and three levels of phosphorus (0, 7.5 &15 kg ha). The fertilizer treatments were each replicated three times. The highest grain yield of Pasa and Fahari was 3211kg ha, 2726 kg ha 1 respectively obtained at a nutrient combination of 60 kg N ha and 15 P kg ha The same nutrient combination resulted into highest number of tillers: (Pasa 4 and Fahari 5), kernel per spike of 40 for Pasa and 32 for Fahari. Maximum total kernel weight, spike length and plant height were obtained at 90 kg N ha and 7.5 kg P ha nutrient combinations. Pasa produced a significantly higher Agronomic Ni...

Journal of Agricultural Chemistry and Environment, 2021

Background: The objective of this study was to determine the short-term effect of urea fertiliser... more Background: The objective of this study was to determine the short-term effect of urea fertiliser application on soil reactions in a Ferralsol, with particular thrust on P sorption. Methods: Two experiments were conducted for this purpose: 1) a screenhouse pot experiment; and 2) a laboratory P sorption component. The pot (10 litre capacity plastic pots) experiment was conducted at the Makerere University Agricultural Research, Kabanyolo in Uganda, using a Ferralsol. The study comprised of four urea N (46% N) fertiliser treatments, namely, 0, 40, 80 and 120 kg N·ha-1, equivalent to 0, 200, 400 and 600 mg N per pot. A completely randomised design was adopted with three replicates. Urea rates were applied in 50% split doses, one at planting and the other at 19 days after seedling emergence (to simulate farmer practice). This was followed by watering to field capacity using distilled water. Soil samples were taken at three daily intervals until day fourteen; thereafter, soil sampling wa...

This study was conducted on-farm in central Uganda to evaluate the agronomic effectiveness of urb... more This study was conducted on-farm in central Uganda to evaluate the agronomic effectiveness of urban market garbage compost. The treatments included included sole and combined application of the nutrient inputs (i) compost at 5 t ha-1, (ii) TSP at 9 kg P ha-1 and (iii) urea at 40 kg N ha-1. The set up included a control (no test inputs applied) and a blanket application of muriate of potash at 40 kg K ha-1. The treatments were replicated at 5 small-scale farms with maize (Zea mays L.), var Longe 4 as the test crop. Maize plants treated with N + P were the tallest, while those in the control were the shortest. However, compost + N gave the highest stover and grain yields, representing increases of 89 and 177%, respectively, over the control. This is a phenomenal productivity improvement despite the unfavourably scanty rains received during the study period. Further studies are needed over several cropping seasons to obviate the effects of unfavourable weather. Equally imperative is th...

Urban peasants in Uganda frequently cultivate soils with low intrinsic fertility status (low pH, ... more Urban peasants in Uganda frequently cultivate soils with low intrinsic fertility status (low pH, low organic matter and nutrient contents), which restricts high crop production. A greenhouse study was conducted at Kabanyolo Research Station, Makerere University to evaluate how compost (CO) compares with commercial fertilizers as a soil fertility amendment. The aims included improvement of crop productivity, while reducing environmental pollution with the wastes. The treatments, each of which had two replicates, comprised a control, 5 and 10 t CO ha-1 applied singly or in combination with 40 and 80 kg urea-N ha-1 and 9 and 18 kg triple superphosphate-P (TSP) ha -1. The test crop maize (Zea mays L.) plants were harvested, 39 days after sowing, and dry matter (DM) yields were recorded and analyzed for plant tissue contents of nitrogen (N), phosphorus (P), potassium (K) and sulphur (S). In the single applications, effectiveness measured in terms of average DM yields increased in the ord...

Common bean (Phaseolus vulgaris L.) is a staple food and income crop in eastern Africa, especiall... more Common bean (Phaseolus vulgaris L.) is a staple food and income crop in eastern Africa, especially within the Uganda-Rwanda boarder region where it constitutes a major component of food security. Unfortunately, bush beans are severely affected by frequent water-logging which persists over a considerable period of the year. In spite of this, farmers have continued to cultivate bush bean though with miserable yields. The study aimed to identify farmers’ indigenous coping mechanisms to the climatic predicament, as a foundation for nurturing and subsequently designing appropriate management strategies for improved bean production in the region. A household survey was conducted in Kisoro district, in a location representative of the ecological conditions of Uganda-Rwanda region. 96 respondents were selected randomly at village level from a list of 500 households provided by the extension workers. Data were collected using semi-structured interviews. Findings showed that farmers possess v...

OALib

Soil fertility management is one of the major strategies for improving potato productivity in the... more Soil fertility management is one of the major strategies for improving potato productivity in the highlands of southwestern Uganda. Land belonging to potato farmers is highly fragmented hindering sustainable potato production under smallholder farming systems. Land fragmentation brings a major challenge to small-scale farmers in soil fertility management, increasing costs of production. However, identifying major soil nutrients limiting potato production in the highlands of southwestern Uganda is an avenue of applying appropriate soil nutrients to improve potato productivity without degrading the soils. It also assists farmers in investing in the necessary soil nutrients and, hence reducing the costs of production while improving potato productivity. The study indicated that soil potassium was the most single significant soil nutrient limiting potato productivity especially in the fields located on hilltops and far from homesteads. Hence, it was imperative that farmers apply potassium containing fertilizers to minimize potassium depletion but also increase potato productivity. It was also important for farmers to always integrate disease management with soil nutrient management for improved potato productivity.

Journal of Agriculture and Ecology Research International, 2016

International Journal of Plant & Soil Science, 2015

Sustainable Land Management (SLM) is one of the transformative pillars for agricultural developme... more Sustainable Land Management (SLM) is one of the transformative pillars for agricultural development and environment conservation for food, forage, fuel and fiber security. It aims at the tripartite benefits of high yields, environment protection and income security. The success of SLM is a function of adopting appropriate nutrient and water management practices. Several land management practices have been practiced by smallholder farms in the Great Lakes Region of Africa. However, there is still limited understanding of the level of acceptability of the various technologies in mitigating soil water shortage and nutrient depletion. This paper evaluates the SLM concept with focus on assessing sustainability in the use of various soil water and nutrient management technologies and practices. Nutrient management technologies assessed included a range of common inputs and practices in tropical farming systems. Soil water conservation technologies assessed included the physical, biologica...

African Journal of Food, Agriculture, Nutrition and Development, 2010

The highlands of southwestern Uganda account for the bulk of field pea (Pisum sativum L.) produce... more The highlands of southwestern Uganda account for the bulk of field pea (Pisum sativum L.) produced and consumed in the country. The crop fetches a stable price, which is as high as that of beef, but it has remained outside the mainstream of the research process. Low soil fertility, unfortunately, is poised to eliminate the crop. Nitrogen, phosphorus and potassium have variously been reported as deficient on the bench terraces where crop production is primarily done. Strategic nutrient management requires that the most limiting nutrient is known in order to provide a foundation for designing effective and sustainable soil fertility management interventions. A study was conducted on upper and lower parts of the bench terraces on the highlands in southwestern Uganda to identify the most required macronutrient(s) in field pea production. Treatments included: 0 and 25 kg N ha-1 , 0 and 60 kg P ha-1 , and 0 and 60 kg K ha-1 , all applied factorially in a randomized complete block design. Parameters assessed included nodulation, nodule effectiveness for BNF and dry weight, shoot dry weight, and grain yield. Nutrient applications that resulted in the highest crop responses were considered as most required, and hence, most limiting to plant growth and yield. Phosphorus based nutrient combinations gave the highest increments in total and effective nodule numbers, as well as dry weight, irrespective of terrace position. On the other hand, N based combinations led to the highest shoot dry matter at flowering (39 % higher over the control). The superiority of N was carried over up to final harvesting, with stover and grain yields edging out the other treatment regimes on either terrace positions. Phosphorus was most limiting nutrient, though the effect manifested in terms of the intensity of BNF indicators, followed by nitrogen, that manifested at later stages of crop growth influencing stover and grain yield.

Real solutions representation for the cubic equation with real coefficients in a parametric form ... more Real solutions representation for the cubic equation with real coefficients in a parametric form is given. The dependence of the solutions on the equation coefficients and the bifurcation conditions for these solutions are studied. In the parametric space regions with one and three real solutions are considered. Using parametric representations of the cubic equation solutions, the stability and bifurcation conditions of the equilibrium states for the thermodynamic systems described by the Landau-type kinetic potential are analyzed.

African Journal of Environmental Science and Technology, 2018

Bacterial communities are actively involved in composting process but the environment within the ... more Bacterial communities are actively involved in composting process but the environment within the compost influences their diversity, abundance and succession. In this study, the authors investigated the bacterial communities in tropical crop waste compost using pyrosequencing. Municipal crop wastes from the tropics (Uganda) were composted under four different low-technology methods. Samples were collected from the early thermophilic, late thermophilic, and mesophilic phases, and from mature compost. Pyrosequencing of the amplified variable V4 region of the 16s rDNA generated over 110 000 sequences. Chao1 and cluster analysis at 3% dissimilarity showed that bacterial community richness declined during the composting process. The community was dominated by a few bacterial taxa during the thermophilic phases. Species evenness increased as compost progressed to maturity despite a decline in the number of taxa over the successional progression. Bacterial community diversity, abundance a...

International Journal of Advanced Remote Sensing and GIS, 2013

The modeling capability of the Revised Universal Soil Loss Equation (RUSLE) on a heterogeneous la... more The modeling capability of the Revised Universal Soil Loss Equation (RUSLE) on a heterogeneous landscape is usually limited due to computational challenges of slope length and slope steepness ( LS ) factor. RUSLE can be adapted to Arc-Macro (C++) executable programs to obtain LS values even for highly variable landscapes based on Digital Elevation Models (DEMs); and then predict erosion risk. The objective of this study was to compute LS factor from DEM using C++; and predict soil erosion risk in a banana-coffee watershed of the Lake Victoria Basin (LVB) of Uganda. DEM data of Nabajuzi watershed were used as an input file for running the (C++) executable program to obtain LS factor. The predicted LS values were calibrated against tabulated LS values; and a strong linear relationship (R = 0.998) was observed between them. The LS factor increased with slope length and slope gradient. Erosion risk across landuse were predicted as follows: small scale farmland (38 t ha -1 yr -1 ), built...

Organic waste materials as soil amendments are one of the topical approaches applauded for achiev... more Organic waste materials as soil amendments are one of the topical approaches applauded for achieving sustainable agriculture world-over. The objective of this study was to investigate the effect of urban-based biosolid waste (UBBW) application on heavy metals (Cr, Cu, Zn and Pb) bioaccumulation by maize (Zea mays L.) plants. A pot experiment was conducted three times, using an acid Ferralsol from Makerere University Agricultural Research Institute, Kabanyolo (MUARIK) in Uganda. Treatments included the application of three types of UBBW, namely sewage, brewery and abattoir, each applied independently at the rates of 0, 50 and 100 g per pot filled with 4 kg soil. This was equivalent to 0, 2.5 and 5.0 metric tonnes of dry materials per hectare. Phosphorus fertiliser was also applied at 0, 0.795 and 1.591 g P per pot, equivalent to rates of 0, 25 and 50 kg P ha-1. The brewery waste applied at rates ≥ 2.5 t·ha-1 and phosphorus at 25 kg P ha-1 resulted in shoot Cu concentrations below the...

This study was carried out to determine the optimum nitrogen and phosphorus rates for achieving o... more This study was carried out to determine the optimum nitrogen and phosphorus rates for achieving optimum yields and nutrient use efficiency for wheat in highlands of Eastern Uganda. An on station randomized complete block design experiment was conducted at Buginyanya Zonal Agricultural Research and Development Institute. Two varieties Fahari and Pasa were treated with four levels of nitrogen (0, 30, 60, & 90 kg ha) and three levels of phosphorus (0, 7.5 &15 kg ha). The fertilizer treatments were each replicated three times. The highest grain yield of Pasa and Fahari was 3211kg ha, 2726 kg ha 1 respectively obtained at a nutrient combination of 60 kg N ha and 15 P kg ha The same nutrient combination resulted into highest number of tillers: (Pasa 4 and Fahari 5), kernel per spike of 40 for Pasa and 32 for Fahari. Maximum total kernel weight, spike length and plant height were obtained at 90 kg N ha and 7.5 kg P ha nutrient combinations. Pasa produced a significantly higher Agronomic Ni...

Journal of Agricultural Chemistry and Environment, 2021

Background: The objective of this study was to determine the short-term effect of urea fertiliser... more Background: The objective of this study was to determine the short-term effect of urea fertiliser application on soil reactions in a Ferralsol, with particular thrust on P sorption. Methods: Two experiments were conducted for this purpose: 1) a screenhouse pot experiment; and 2) a laboratory P sorption component. The pot (10 litre capacity plastic pots) experiment was conducted at the Makerere University Agricultural Research, Kabanyolo in Uganda, using a Ferralsol. The study comprised of four urea N (46% N) fertiliser treatments, namely, 0, 40, 80 and 120 kg N·ha-1, equivalent to 0, 200, 400 and 600 mg N per pot. A completely randomised design was adopted with three replicates. Urea rates were applied in 50% split doses, one at planting and the other at 19 days after seedling emergence (to simulate farmer practice). This was followed by watering to field capacity using distilled water. Soil samples were taken at three daily intervals until day fourteen; thereafter, soil sampling wa...

This study was conducted on-farm in central Uganda to evaluate the agronomic effectiveness of urb... more This study was conducted on-farm in central Uganda to evaluate the agronomic effectiveness of urban market garbage compost. The treatments included included sole and combined application of the nutrient inputs (i) compost at 5 t ha-1, (ii) TSP at 9 kg P ha-1 and (iii) urea at 40 kg N ha-1. The set up included a control (no test inputs applied) and a blanket application of muriate of potash at 40 kg K ha-1. The treatments were replicated at 5 small-scale farms with maize (Zea mays L.), var Longe 4 as the test crop. Maize plants treated with N + P were the tallest, while those in the control were the shortest. However, compost + N gave the highest stover and grain yields, representing increases of 89 and 177%, respectively, over the control. This is a phenomenal productivity improvement despite the unfavourably scanty rains received during the study period. Further studies are needed over several cropping seasons to obviate the effects of unfavourable weather. Equally imperative is th...

Urban peasants in Uganda frequently cultivate soils with low intrinsic fertility status (low pH, ... more Urban peasants in Uganda frequently cultivate soils with low intrinsic fertility status (low pH, low organic matter and nutrient contents), which restricts high crop production. A greenhouse study was conducted at Kabanyolo Research Station, Makerere University to evaluate how compost (CO) compares with commercial fertilizers as a soil fertility amendment. The aims included improvement of crop productivity, while reducing environmental pollution with the wastes. The treatments, each of which had two replicates, comprised a control, 5 and 10 t CO ha-1 applied singly or in combination with 40 and 80 kg urea-N ha-1 and 9 and 18 kg triple superphosphate-P (TSP) ha -1. The test crop maize (Zea mays L.) plants were harvested, 39 days after sowing, and dry matter (DM) yields were recorded and analyzed for plant tissue contents of nitrogen (N), phosphorus (P), potassium (K) and sulphur (S). In the single applications, effectiveness measured in terms of average DM yields increased in the ord...

Common bean (Phaseolus vulgaris L.) is a staple food and income crop in eastern Africa, especiall... more Common bean (Phaseolus vulgaris L.) is a staple food and income crop in eastern Africa, especially within the Uganda-Rwanda boarder region where it constitutes a major component of food security. Unfortunately, bush beans are severely affected by frequent water-logging which persists over a considerable period of the year. In spite of this, farmers have continued to cultivate bush bean though with miserable yields. The study aimed to identify farmers’ indigenous coping mechanisms to the climatic predicament, as a foundation for nurturing and subsequently designing appropriate management strategies for improved bean production in the region. A household survey was conducted in Kisoro district, in a location representative of the ecological conditions of Uganda-Rwanda region. 96 respondents were selected randomly at village level from a list of 500 households provided by the extension workers. Data were collected using semi-structured interviews. Findings showed that farmers possess v...

OALib

Soil fertility management is one of the major strategies for improving potato productivity in the... more Soil fertility management is one of the major strategies for improving potato productivity in the highlands of southwestern Uganda. Land belonging to potato farmers is highly fragmented hindering sustainable potato production under smallholder farming systems. Land fragmentation brings a major challenge to small-scale farmers in soil fertility management, increasing costs of production. However, identifying major soil nutrients limiting potato production in the highlands of southwestern Uganda is an avenue of applying appropriate soil nutrients to improve potato productivity without degrading the soils. It also assists farmers in investing in the necessary soil nutrients and, hence reducing the costs of production while improving potato productivity. The study indicated that soil potassium was the most single significant soil nutrient limiting potato productivity especially in the fields located on hilltops and far from homesteads. Hence, it was imperative that farmers apply potassium containing fertilizers to minimize potassium depletion but also increase potato productivity. It was also important for farmers to always integrate disease management with soil nutrient management for improved potato productivity.