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Item Speciation of heavy metals in water from the Uganda side of Lake Victoria(Tailor and Francis, 2010-02) MBABAZI, JOLOCAM; TWINOMUHWEZI, H.; WASSWA, J.; NTALE, M.; MULONGO, G.; KWETEGYEKA, J.; SCHR DER, K.H.Different forms of copper Cu, zinc Zn, lead Pb and cadmium Cd in water from the Uganda side of Lake Victoria (25°C, pH 6.75–7.18), the second largest inland freshwater lake in the world, have been studied using ion-exchange, dialysis and atomic absorption spectrophotometry. The results indicate that heavy metals Cu, Zn, Pb and Cd are present mainly in the cationic form (80–83%). Small quantities of anionic (13–22%), non-ionic, dialyzable (4–8%), and non-ionic, non-dialyzable (< 1.3–4.4%) forms were also detected for all metals except Cd. The corresponding concentrations lay in the ranges: cationic, 0.06–0.99; anionic, < 0.001–0.25; non-ionic, dialyzable, < 0.001–0.08; non-ionic, non-dialyzable, < 0.001–0.06 µg ml−1 . The existence of the metals in non-ionic and nondialyzable forms is attributable to metal associations with high relative molecular mass (RMM) organic matters.Item Stannate (IV) and Antimonate (V) Hexahydroxy-anion complexes with Di- and Polyhydric Phenols(Research Journal of Chemical Sciences, 2011-05-02) Mbabazi, Jolocam; Ntale, M.; Kwetegyeka, J.; Mulongo, G.; Twinomuhwezi, H.; Nnamuyomba, PAn identification has been achieved of only 1:1 and 1:2 chelates of hexahydroxystannate (IV) anions with ortho (i.e., 1,2)-diphenols, using potentiometric and conductimetric techniques. Lack of evidence for organo-richer complexes in aqueous media is in contrast to antimonite (V) hexahydroxy anions and tellurate (VI), which are each able to form a tris (catecholate).Item Heterogeneity in the prevalence and intensity of bovine trypanosomiasis in the districts of Amuru and Nwoya, Northern Uganda(Biomedical Central- Veterinary Research, 2015) Angwech, Harriet; Nyeko, Jack H. P.; Opiyo, Elizabeth A.; Okello-Onen, Joseph; Opiro, Robert; Echodu, Richard; Malinga, Geoffrey M.; Njahira, Moses N.; and Skilton, Robert A.Background: Livestock trypanosomiasis, transmitted mainly by tsetse flies of the genus Glossina is a major constraint to livestock health and productivity in the sub-Saharan Africa. Knowledge of the prevalence and intensity of trypanosomiasis is important in understanding the epidemiology of the disease. The objectives of this study were to (a) assess the prevalence and intensity of trypanosome infections in cattle, and (b) to investigate the reasons for the heterogeneity of the disease in the tsetse infested districts of Amuru and Nwoya, northern Uganda. Methods: A cross-sectional study was conducted from September, 2011 to January, 2012. Blood samples were collected from 816 cattle following jugular vein puncture, and screened for trypanosomes by HCT and ITS-PCR. A Pearson chi-squared test and logistic regression analyses were performed to determine the association between location, age, sex, and prevalence of trypanosome infections. Results: Out of the 816 blood samples examined, 178 (22 %) and 338 (41 %) tested positive for trypanosomiasis by HCT and ITS-PCR, respectively. Trypanosoma vivax infection accounted for 77 % of infections detected by ITS-PCR, T. congolense (16 %), T. brucei s.l (4 %) and mixed (T. vivax/ T. congolense/T.brucei) infections (3 %). The risk of trypanosome infection was significantly associated with cattle age (χ 2 = 220.4, df = 3, P < 0.001). The highest proportions of infected animals were adult males (26.7 %) and the least infected were the less than one year old calves (2.0 %). In addition, the risk of trypanosome infection was significantly associated with sex (χ 2 = 16.64, df = 1, P < 0.001), and males had a significantly higher prevalence of infections (26.8 %) than females (14.6 %). Conclusion: Our results indicate that the prevalence and intensity of trypanosome infections are highly heterogeneous being associated with cattle age, location and sexItem Immunisation-notification adoption model: strategies for implementing mobile electronic notification of mothers in Uganda(Inderscience Enterprises Ltd., 2017) Abandu, J. and; Kivunike, F.N.Mobile e-health systems play a significant role in information delivery by enhancing efficiency, cost effectiveness and mobility. In Uganda, mobile e-health has been predominantly adopted to facilitate information sharing between Ministry of Health and district health offices despite the availability of mobile phones in the community. This study sought to develop an immunisation-notification adoption model to support the use of mobile technology for creating citizen awareness. It focused on the adoption of mobile technology for notifying and reminding mothers of immunisation schedules. The objective was achieved by extending technology acceptance model to predict user satisfaction with the new system. Descriptive survey design was employed using questionnaire for data collection. The study implemented in Northern Uganda targeted 51 health workers and mothers in Gulu referral and Gulu independent hospitals. The model has the dimensions of knowledge, accessibility, support, content, trust, funding, awareness, knowledge sharing, skills and ease of use. Perceived usefulness was considered the key driver for the system adoption.Item Evaluating the role of perceived usefulness in user adoption of mobile immunisation notification system in Uganda(Inderscience Enterprises Ltd., 2017) Abandu, J. and; Kivunike, F.N.The study sought to evaluate the role of perceived usefulness in user adoption of mobile immunisation-notification system in Uganda. Descriptive survey design was employed and structured questionnaires were administered to 51 healthcare professionals and mothers from Gulu referral and Gulu independent hospitals in Northern Uganda using purposive sampling technique. Regression analysis was performed to evaluate the impact of the identified antecedents on the intention to adopt IMUNOT through perceived usefulness based on technology acceptance model. The findings showed e-health knowledge, accessibility, support, content and trust as the antecedents of perceived usefulness with 87.8% of variance. The findings suggest the importance of perceived usefulness in the mobile Immunisation-notification system adoption. The study provides behavioural and infrastructural strategies for stakeholders on how to foster perceived usefulness in the system adoption. However, more variables may be evaluated to improve the analytical capability of the model.Item The impact of septic systems density and nearness to spring water points, on water quality(African Journal of Environmental Science and Technology, 2017-01-18) Arwenyo, B.; Wasswa, J.; Nyeko, M.; Kasozi, G. N.Worldwide, 1.1 billion people do not have access to clean water and as a result, 2 million children die annually due to preventable waterborne diseases. In Uganda, 440 Children die every week of waterborne diseases. High prevalence of this death is reported in the peri urban areas. It is still unclear however the causes of water pollution in the peri-urban areas. The improper use of onsite sanitation facilities such as latrines and septic systems may lead to groundwater contamination. It is true that drain field of septic system located too close to water point, and or over population of the septic systems in a small area can lead to pollution of groundwater. Our study investigated the impact of septic systems density and nearness to water points on spring water quality. Samples from 15 spring wells were analysed for pH, nitrate and faecal coliform contamination. Locations and distances of spring from septic systems were determined using global positioning system (GPS) device and ArcGIS software, respectively. Water samples from all the spring wells had pH value less than 6.5, 66.7% had faecal coliform and 53% had nitrate above 2 mg L-1. While sample from one of the springs had nitrate concentration above the United States Environmental Protection Agency (US EPA) standard of 10 mg L- 1. It was also noted that coliform counts and nitrate concentrations increases with increase in number of septic systems surrounding the spring well. In addition, increase in distance between spring wells and septic systems indicated decrease in both coliform counts and nitrate concentration. It is therefore concluded that improper use of septic systems is one of the causes of groundwater pollution in the peri urban areas. The study recommends treatments of water from groundwater sources, regular monitoring of groundwater sources and proper design and siting of septic systems using more robust methodologies.Item Factors affecting mobile immunisation notification system adoption in Uganda(Inderscience Enterprises Ltd., 2018) Abandu, J. and; Kivunike, F.N.The aim of this study was to assess factors that affect the adoption of mobile immunisation notification system in Uganda. Methods: Descriptive survey design and structured questionnaires were employed for the study that was carried out in Northern part of Uganda. A total of 51 health workers and mothers were purposively sampled from Gulu Referral and Independent hospitals. Statistical package for social sciences was used to evaluate the impact of the identified factors on the adoption of the proposed system. Results: The findings showed that e-health knowledge; trust; ICT skills; accessibility; support; awareness; knowledge sharing and compatibility affect the adoption of the proposed system. Conclusions: The study provides informative directions to adopt the proposed system. Government needs to improve ICT infrastructure and support user training on e-health to promote the adoption of the system.Item Diet acceptance and preference of the edible grasshopper Ruspolia diferens (Orthoptera: Tettigoniidae)(The Japanese Society of Applied Entomology and Zoology, 2018-02-23) Malinga, Geofrey M.; Valtonen, Anu; Lehtovaara, Vilma J.; Rutaro, Karlmax; Opoke, Robert; Nyeko, Philip; Roininen, HeikkiThe edible grasshopper Ruspolia diferens (Orthoptera: Tettigoniidae) gathered seasonally from the wild is a highly valued and an economically important edible insect, particularly in East Africa. To reduce the pressure on wild populations, a sus tainable mass production technique needs to be developed. Unfortunately, however, basic biological know-how on feeding habits of R. diferens is poorly understood, which poses a constraint on the development of mass-rearing technology. Here, we evaluated the acceptance and feeding preference of R. diferens for 16 cultivated or processed foods using no-choice and multiple-choice laboratory bioassays. The results indicated that adult R. diferens can eat a wide variety of foods but does not necessarily accept all the foods equally. Furthermore, our experiments showed that R. diferens has high ability to select diet among those available. The order of decreasing preference was wheat bran > germinated fnger millet > rice seed head > fnger millet seed head > chicken feed egg booster > sorghum seed head. Finally, our study indicated that sex and color morph are not associated with the order of acceptance and preference of diets in R. diferens. These results show potential foods that could be utilized for developing future mass-rearing methods for R. diferens.Item Assessing Users Involvement in Analysis and Design Tasks of Electronic Health Information Systems: Experiences, Challenges, and Suggestions to Optimise Involvement(HELINA and JHIA, 2019) K. Akello, Christine; F. Bbosa, Francis; Nabukenya, JosephineUser requirements play a vital role in the development of usable EHIS. For developers to design better quality, relevant and safer EHIS that meet user needs, they are required to actively engage stakeholders especially in the analysis and design tasks of its development life cycle. This is because they provide context appropriate solutions based on their needs. However, in most cases developers ignore health stakeholders’ input especially during these tasks due to varying perspectives and expectations, complexity, high cost, and variability in time to complete the tasks. This has resulted into various challenges including difficulty in capturing and interpreting user requirements in an effective and efficient manner, poorly designed and unusable systems, unsatisfied user needs, and high maintenance costs. This study thus aimed at assessing users’ involvement in the analysis and design tasks when developing EHIS with a view to understand their experiences, challenges, and suggestions to optimise their involvement. Methods: We employed a cross-sectional survey to investigate and describe the level of user involvement and challenges faced in the analysis and design tasks of the EHIS development process. A total of 36 health practitioners from 13 Key health institutions located in Uganda were selected as respondents. Results: The study revealed that majority of the respondents was involved in EHIS development, with a few involved at analysis and design tasks. Increased costs associated with data collection, followed by lack of consensus in clarifying, articulating and defining user requirements were recorded as the biggest challenges faced by users at requirements gathering, analysis and system design tasks. Regards suggestions to optimising users’ involvement in EHIS development tasks, the study reported that users were very much interested in being involved at all tasks of EHIS development, and consultation of users was paramount in order to incorporate all their needs in EHIS. Conclusions: The results from the study demonstrate the value of user involvement at the analysis and design tasks of EHIS development cycle. User involvement offers benefits in form of reduction in costs, improved productivity due to users easily arriving at a common consensus and positive growth in user attitudes. The researchers intend to incorporate suggestions that emerged from this study to conduct long-term evaluations of existing EHIS and investigate how users’ involvement changes over time.Item Information and Communication Technology usage in post-conflict maternal healthcare: Northern Uganda Referral hospital perspective(Elsevier Ltd., 2019-05-17) Abandu, J.; Kivunike, F.N.; Okot, P. and; Lamunu, J.The main objective of this study was to assess Information and Communication Technology (ICT) usage in post-conflict maternal healthcare. This adds to the knowledge base as well as boosts the need to prioritize, empower and create awareness among ICT benefactors. Methods: A descriptive survey design was applied to quantify and explain the findings that were obtained from Gulu Referral hospital. A set of structured questionnaires were distributed to the participants during the phase of data collection. Regression analysis was performed to assess the relational impact of the identified factors on the use of ICT with the help of Statistical Package for Social Sciences. Results: Although regression has shown usefulness, ease of use, trust and awareness as the key factors that promote ICT usage in the services of maternal healthcare, a number of deterrents were identified. The deterrents include: limitation of strong ICT infrastructure, skills and knowledge. Conclusion: We recommend management and Government improve ICT infrastructure and offer user training to impart knowledge and skills that are needed for handling sensitive or private health data. Adequate funding is also needed to strengthen ICT infrastructure. Due to the complex or dynamic nature of the society and advance in ICT more promoting and deterring factors should be explored in future.Item Efficacy of In Ovo Delivered Prebiotics on Growth Performance, Meat Quality and Gut Health of Kuroiler Chickens in the Face of a Natural Coccidiosis Challenge(MDPI journal of Nutrients, 2019-10-28) Angwech, Harriet; Tavaniello, Siria; Ongwech, Acaye; Kaaya, Archileo N.; and Maiorano, GiuseppeA study was carried out to assess the efficacy of prebiotic delivered in ovo on performance, carcass traits, meat quality and gut health in the face of a natural coccidiosis infection in Kuroiler chickens. On d 12 of incubation, 150 fertile eggs were divided into a prebiotic group injected with trans-galactooligosaccharides (Bi2 tos) and a control group uninjected. Hatched chicks from each group were further divided: One group received antibiotic chick formula while the other was left untreated, giving rise to 4 groups—Control (C), Antibiotic (A), Bi2 tos (B), and Bi2 tos + Antibiotic (AB). Prebiotic improved growth performance at six weeks of age, AB birds were the heaviest at the end of the rearing period. The highest intestinal lesion scores and oocyst counts were recorded in C birds. B group had a slightly higher carcass weight and cuts yields tended to be higher in treated groups compared to C. Meat from B group displayed a higher amount of polyunsaturated fatty acids compared to C and a positively lower n-6/n-3 ratio compared to C and A. In conclusion, prebiotics with or without antibiotics reduced severity of intestinal lesions and oocyst excretion induced by natural infection with Eimeria, with positive effects on Kuroiler chicken productive traits.Item Performance of the African edible bush-cricket, Ruspolia differens, on single and mixed diets containing inflorescences of their host plant species(Entomologia experimentalis et applicata, special issue: insect production, 2020) Malinga, Geoffrey M.; Valtonen, Anu; Hiltunen, Minna; Lehtovaara, Vilma J.; Nyeko, Philip; Roininen, HeikkiThe African edible bush-cricket, Ruspolia differens (Serville) (Orthoptera: Tettigoniidae), is an eco nomically valuable insect in sub-Saharan Africa. For its mass-rearing, suitable diets that can sustain its performance need to be identified. This study aimed at finding inflorescence diets of 10 host plant species and their mixtures that result in the highest R. differens production. We reared newly hatched nymphs to adults on inflorescences of single host species, and also on a gradient of five diversifying dietary mixtures consisting of one and mixtures of two, three, five, and seven host plant species. For the single host-plant diets, the developmental time was shortest on Pennisetum purpureum, Chloris gayana, and Brachiaria ruziziensis (approximately 63 days), whereas the fresh weight was highest on B. ruziziensis and P. purpureum (approximately 0.383 g). Survival was highest (>65%) on C. gayana, P. purpureum, B. ruziziensis, Setaria sphacelata, and Sporobolus pyramidalis, and lowest on Panicum maximum, Hyparrhenia rufa, Cynodon dactylon, and Paspalum scrobiculatum (<40%). With respect to diet mixtures, the developmental time was significantly shorter (on average 16 days shorter), and survival was higher, in the most diversified diets compared to the least diversified diets. The contents of polyunsaturated fatty acids and fatty acid composition did not differ significantly among the diets. However, the content of monounsaturated fatty acids differed significantly among the diets and there was a significant diet*sex interaction. From the applied point of view, based on our results, for maximal weight and survival plus fast development, we recommend rearing on P. purpureum, C. gayana, B. ruziziensis, and S. sphacelata, and on dietary mixtures of inflorescences. These findings are important in designing large-scale rearing programs for this species.Item Recovery of fruit-feeding butterfly communities in Budongo Forest Reserve after anthropogenic disturbance(Forest Ecology and Management, 2021-04-07) Oloya, Joseph; Malinga, Geoffrey M.; Nyafwono, Margaret; Akite, Perpetra; Nakadai, Ryosuke; Holm, Sille; Valtonen, AnuUnderstanding of how biodiversity can recover after anthropogenic disturbances, such as selective logging, is important for planning conservation strategies for tropical forests and for more sustainable timber harvest re gimes. However, the knowledge of insect community compositions in regenerating logged forests is still limited, especially in the Afrotropics. Here, we evaluated the recovery patterns of fruit-feeding butterfly communities in four different-aged secondary forest compartments and one primary forest compartment in the Budongo Central Forest Reserve, Uganda. In each compartment, butterflies were sampled monthly for five consecutive months in 2017 using traps baited with fermented bananas. A total of 3,778 individuals, representing 82 species (78 identified at the species level and four morphogroups) were recorded. The fruit-feeding butterfly community composition differed among forest compartments and study months. Fruit-feeding butterfly communities of the oldest 72-year-old secondary forest compartment were similar to the primary forest compartment. In the younger secondary forest compartments the seasonal variation was large; especially the communities of the “core” rainy season months were distinct from the communities in primary and oldest secondary forest. The majority of individuals captured from both primary and secondary forests represented forest-dependent species. Primary forests are irreplaceable for preserving the diversity of tropical forests in the long-term. Nevertheless, our study demonstrates that selective logging can allow fruit-feeding butterfly community composition to recover if enough time (>70 years) is allowed for recovery.Item Phosphorus availability from magnesium-modified P-enriched Douglas fir biochar as a controlled release fertilizer(Soil Use and Management, 2021-08-04) Arwenyo, Beatrice ; Varco, Jac J.; Dygert, Andrew ; Mlsna, ToddPhosphorus (P) is one of the essential elements required for plant growth and de velopment. However, worldwide, many agricultural soils can be deficient in P. The use of fertilizers and manures as a source of P can be costly, limited in sup ply in some regions of the world and ecologically unfavourable. Nutrient-enriched biochar has been suggested as a relatively cost-effective and eco-friendly P source. This study investigated P availability from Douglas fir biochar modified with mag nesium chloride and potassium hydroxide solutions only (B), and modified P enriched Douglas fir biochar B50, B100 and B150 corresponding to B treated with 50, 100 and 150 mg P L−1 solutions of potassium phosphate monobasic. Triple super phosphate fertilizer (FC) and a control treatment without phosphate added (C) used as a reference treatment. Treatments were added to soil in varied amounts to obtain the same P rate of 30 kg P ha−1. Aboveground biomass dry weight yield (R2 = .7) and plant height (R2 = .86) improved with P contents. After harvest, re sidual soil P for the FC treatment was significantly greater than all other treatments (p-value = 1.7848 E-6, R2 = .8). Plant height and aboveground dry weight biomass were greater with B150 compared to B50 at the same total P loading, suggesting that the greater P concentration of the biochar (B150) resulted in less tightly bound P and was therefore more available for plant uptake. This study showed promise of utilizing P-enriched Douglas fir biochar as a slow-release P fertilizer.Item Kinetics and Thermodynamic Studies: Adsorption of Pb, Cr and Ni Ions from Spent Lubrication Oil (SLO) Using Acid Modified Clay(American Journal of Analytical Chemistry, 2021-12) Sughnen Atsar, Felix; Kukwa, Donald; Ahule Wuana, Raymond; Arwenyo, BeatriceAdsorption of Pb, Cr, and Ni ions from spent lubrication oil (SLO) by sulphuric acid modified clay (SAMC) was investigated considering the effect of contact time and temperature of the adsorption system. The removal percentage of the heavy metals was found to be temperature and contact time-dependent. Adsorption of the heavy metals increases with an increase in temperature and contact time with 95.0% - 100% adsorption recorded at the temperature of 331 K with the equilibration time of 12 hours. The thermodynamic and kinetics investigation of the adsorption process showed that the adsorption of these metals by the modified adsorbent is a spontaneous and endothermic physical adsorption process that followed the pseudo-second-order kinetic model.Item Lead immobilization in simulated polluted soil by Douglas fir biochar-supported phosphate(Elsevier Chemosphere, 2021-12-16) Varco, Jac J.; Dygert, Andrew; Atsar, Felix S.; Solomon, Sabrina; Venkatesh, Rooban; Thirumalai, K.G.; Pittman Jr., Charles U.; Mlsna, ToddThis study compared the lead (Pb2+) immobilization efficacy of biochar-supported phosphate to conventional in situ heavy metal immobilization methods (with lime, neat biochar and phosphate). The biochar-supported phosphate was obtained by treating Douglas fir biochar (BC) with anhydrous calcium chloride and potassium dihydrogen phosphate. The amount of Pb2+ immobilized was determined by comparing the concentration of ammonium nitrate extractable Pb2+ lead from lead-spiked soil (without amendment) to that of a 30 d incubation with (a) lead-spiked soil plus 5% (wt./wt.) biochar supported-phosphate, (b) lead-spiked soil plus 5% (wt./wt.) untreated Douglas fir biochar, (c) lead-spiked soil plus 5% (w/w) lime and (d) lead-spiked soil plus 5% (wt./wt.) potassium dihydrogen phosphate. The control (lead-spiked soil without amendment) produced the largest quantity (96.08 ± 9.22 mg L− 1 ) of NH4NO3-extractable Pb2+, while lead-spiked soil treated with 5% (wt./wt.) biochar-supported phosphate resulted in the lowest quantity of NH4NO3 extractable Pb2+ (0.3 ± 0.2 mg L− 1 ). The mechanism for immobilization of Pb2+ by BP occurs at pH < 7 through dissolution of hydroxyapatite embedded in BP during modification, followed by precipitation of insoluble Pb10(PO4)6(OH)2. The residual lead fraction in the lead-spiked soil increased by 20.9% following amendment with BP. These results indicate that biocharsupported phosphate is a candidate to reduce lead mobility (bioavailability) in polluted soil. This amendment may lower Pb2+ uptake into plants while minimizing the potential for water contamination due to Pb2+mobility.Item Application of biochar for the removal of actinides and lanthanides from aqueous solutions.(Elsevier Inc., 2022) Bursztyn, Amalia L. Fuentesa; Arwenyo, Beatrice; Nanney, Andie L.M.; Ramirez, Arissa; Jamison, Hailey; Venson, Beverly; Mohan, Dinesh; Mlsna, Todd E.; Navarathna, ChanakaActinides and lanthanides are elements with unfilled f orbitals and are collectively labeled as the inner transition elements (ITEs). The actinide series includes 15 radioactive metallic ele ments with atomic numbers 89–103 (Cooper, 2000). The actinide elements are classified as light (Ac, Th, Pa, U, Np, Pu, Am) or heavy (Cm, Bk, Cf, Es, Fm, Md, No, Lr) based on their atomic numbers. The actinides fill their 5f sublevels progressively and exhibit char acteristics of both the d-block and the f-block elements. Elements of the actinide series can have oxidation states from +2 to plus +7. In addition to being radioactive, all actinides are paramagnetic and pyrophoric. Except for actinium with one oxidation state of +3, the other actinides are known to show variable oxidation states and more than one crystalline phase. To date, only the first four elements in the actinide series have been found to occur naturally.Item Sustainable Biochar for Water and Wastewater Treatment(Elsevier Inc. All rights reserved, 2022) Mohan, Dinesh (editor); Pittman Jr., Charles U.(editor); Mlsna, Todd E. (editor)This First Edition was motivated by the recent enormous growth in biochar research. From 2010 to the date this Preface was written, the Web of Science database shows 18,224 publica tions on biochar have appeared. This activity is accelerating. In 2010, 119 publications appeared. This grew to 3975 in 2020. By September 2021, 3588 biochar papers had already been counted for that year. The first use of biochar, as distinct from charcoal or activated carbon, for water remediation appeared in the Jour nal of Colloid and Interface Science in 2007 [JCIS, 310(1)2007, 57–73]. Fast pyrolysis by-product biochar obtained from biooil production in an auger-fed reactor was used to remove heavy metals from water. Following this publication, many reports on slow and fast pyrolysis biochar as a substitute for activated carbon in water purification have appeared. Previously, biochar had been used for soil enrichment and carbon sequestration.Item Uptake of Phosphorus from Modified P-Enriched Douglas Fir Biochar and Its Effects on Crop Growth and P Use Efficiency(Journal of Geoscience and Environment Protection, 2022-09-29) Arwenyo, Beatrice; Varco, Jac J.; Dygert, Andrew; Berry, Jaime; Mills, Julianna; Mohan, Dinesh; Pittman, Charles U.; Mlsna, ToddThe potential use of biochar as a sustainable soil amendment has recently gained global recognition. The use of biochar as a soil additive is attributed to its ability to improve soil chemical, physical and biological properties. Studies have shown that biochar amendments can enhance soil nutrient retention and availability, pH, water holding capacity, microbial activity and sequester car bon. In this study using corn (Zea mays L.) as an experimental crop, the in fluence of P availability from modified P enriched Douglas fir biochar (PEB), triple super phosphate fertilizer (SPF), and modified Douglas fir biochar (MB) on plant growth and P Use Efficiency (PUE) were compared. The rate of P applied (0, 30, 60, 90 and 120 kg·ha−1 ) was calculated based on % P content of each soil additive. Except for MB treatments, P recovery, crop growth and P Use Efficiency increased with application rates. The maximum above ground dry matter yields corresponding to PEB, SPF and MB treatments were esti mated at 3488 kg·ha−1 , 2449 kg·ha−1 and 639 kg·ha−1 , while their respective agronomic P use efficiency (AGE) rates were 32 kg·kg−1 , 17 kg·kg−1 , 0.5 kg·kg−1 . Also, recovery of K, Mg, Ca, Zn, Fe, Cu, B and Mn improved in both PEB (p value < 0.0003, r2 > 0.9) and SPF (p value < 0.0058, r2 > 0.9) treatments. More studies at field scale are needed to demonstrate the practicability of using modified P enriched Douglas fir biochar for soil amendments.Item Contribution of modified P-enriched biochar on pH buffering capacity of acidic soil(Elsevier Journal of Environmental Management, 2022-11-06) Arwenyo, Beatrice; Varco, Jac J.; Dygert, Andrew; Brown, Sydney; Pittman, Charles U.; Mlsna, ToddBiochar can directly hold cations in soil because of the negative charge that exists on its surfaces. Besides, improving soil cation exchange capacity, the negative charges on biochar surfaces can buffer acid soil by pro tonation and deprotonation mechanisms. Moreover, biochar ameliorates soil acidity due to the presence of ox ides, carbonates, and hydroxides of its basic cations (Ca, Na, K, and Mg). Both biochar surface functional group and basic cation concentrations can be altered by modification with chemical agents which can affect its soil pH buffering capacity. However, the impact of modified biochar application on soil pH buffering capacity is still scanty. This study investigated the pH buffering capacity of acidic soil amended with three P-enriched modified Douglas fir biochars and compared this buffering capacity to amendment with untreated Douglas fir biochar. These three P-enriched biochars, were prepared by treating Douglas fir biochar (DFB), respectively, with: 1) anhydrous calcium chloride (CaCl2) and potassium phosphate monobasic (KH2PO4), 2) calcium carbonate (CaCO3) and diammonium phosphate {(NH4)2HPO4} and 3) an aqueous solution of magnesium sulfate (MgSO4), potassium hydroxide (KOH) and potassium phosphate monobasic (KH2PO4). The three P-enriched biochars were designated as CCPP, CAPP and MSPP, respectively. The soil pH buffering abilities were largely dependent on the added biochar’s alkalinity and ash contents. The residual soil CEC was highly correlated (r ≥ 0.9), with the soil buffering capacity. Both alkalinity and pH buffering capacity improved following the order CCAP > CCPP > MSPP > DFB, while residual soil CEC followed the order CAPP > MSPP > CCPP > DFB. The pH buffering ca pacity of the soil after amendments with 10% CAPP, CCPP MSPP and BFB rose by 84.8, 58.3, 3.0 and 2.5%, respectively. Whereas MSPP had higher concentrations of K+ and Mg2+, greater concentrations of Ca2+ were present in CCAP and CCPP than MSPP. So, Ca2+ concentrations in biochar exerts a greater influence on alkalinity and buffering capacity than Mg2+ and K+ because of 1) its smaller effective hydration radius and larger charge density. 2) calcium hydroxide has a greater water solubility than magnesium hydroxide providing more available base. Since pH buffering capacity depends on cation exchange sites, soil additives containing Ca2+ are prone to create greater impacts than Mg2+ and K+ additives.