Genetic and Agronomic Parameter Estimates of Growth, Yield and Related Traits of Maize (Zea mays L.) under Different Rates of Nitrogen Fertilization

This study evaluated the genetic and agronomic parameter estimates of maize under different nitrogen rates. The trial was established at the Njala Agricultural Research Centre experimental site during 2021 and 2022 in a split block design with three maize varieties (IWCD2, 2009EVDT, and DMR-ESR-Yellow) and seven nitrogen (0, 30, 60, 90, 120, 150 and 180 kg∙N∙ha−1) rates. Findings showed that cob diameter and anthesis silking time (ASI) had intermediate heritability, ASI had high genetic advance, ASI and grain yield had high genotypic coefficient of variation (GCV), while traits with high phenotypic coefficient of variation (PCV) were plant height, ASI, grain yield, number of kernel per cob, number of kernel rows, ear length, and ear height. The PCV values were higher than GCV, indicating the influence of the environment in the studied traits. Nitrogen rates and variety significantly (p < 0.05) influenced grain yield production. Mean grain yields and economic parameter estimates increased with increasing nitrogen rates, with the 30 and 180 kg∙N∙ha−1 plots exhibiting the lowest and highest grain yields of 1238 kg∙ha−1 and 2098 kg∙ha−1, respectively. Variety and nitrogen effects on partial factor productivity (PFPN), agronomic efficiency (AEN), net returns (NR), value cost ratio (VCR) and marginal return (MR) indicated that these parameters were significantly affected (p < 0.05) by these factors. The highest PFPN (41.3 kg grain kg−1∙N) and AEN (29.4 kg grain kg−1∙N) were obtained in the 30 kg∙N∙ha−1 plots, while the highest VCR (2.8) and MR (SLL 1.8 SLL−1 spent on N) were obtained in the 180 kg∙N∙ha−1. The significant influence of variety and nitrogen on traits suggests that increasing yields and maximizing profits require use of appropriate nitrogen fertilization and improved farming practices that could be exploited for increased productivity of maize.

Grasshopper Incidence and Severity of Damage as Influenced by Cyanogenic Potential in Leaf Tissue of Cassava (Manihot esculenta Crantz)

This study assessed the effect of cyanogenic potential (CNP) in leaf tissue on grasshopper incidence and severity of damage in cassava for the identification of parents with desired complementary traits for crossing. The experiment was conducted at the Foya Wulleh, Njala experimental site in Sierra Leone during 2020 and 2021 cropping seasons in a randomized complete block design with three replications. A total of 30 genotypes comprising 26 breeding lines, two improved and two local genotypes were assessed. Results showed a significant (p < 0.05) linear relationship between leaf CNP and grasshopper infestation (incidence and severity of damage) among cassava genotypes. Findings showed that the higher leaf CNP, the lower the grasshopper infestation in cassava genotypes. About two genotypes (Cooksoon and Cocoa) had low leaf CNP;three genotypes (TR0020, TR0037 and TR0013) CNP had moderately low leaf CNP;eight genotypes (SLICASS 6, TR0029, TR0032, TR0011, TR0012, TR0016-1/17, TR0002 and TR0010) had intermediate leaf CNP;seven (TR0009, TR0015-1/17, TR0036, TR0022-1/17, SLICASS 4, TR0007 and TR0026-1/17) had moderately high leaf CNP;eight (TR0008, TR0019-1/17, TR0006, TR0005, TR0021, TR0021-1/17, TR0022 and TR0024-1/17) had high leaf CNP;and two genotypes (TR0001 and TR0018-1/17) had very high leaf CNP. This suggests the indirect dependence of leaf cyanogenic potential on grasshopper infestation (incidence and severity of damage) in cassava that could be exploited for the genetic improvement of cassava for improved resistance to grasshopper infestation, nutrition and utilization of the crop.

Preference and adoption of Farmer Field School (FFS) Prosopis juliflora management practices: Experiences in Baringo District, Kenya

This research was carried out to evaluate the preference and adoption of harvesting, uprooting, stump burning, pruning and thinning practices for controlling the spread ofProsopisjuliflora （prosopis） within Marigat Division of the Baringo District, Kenya. A survey methodology was employed using a random sample of 25 Farmer Field School （FFS） members and 5 non=FFS members from each of the five locations of Marigat Division. In total, 100 FFS members and 25 non-FFS members participated in the study; addi- tional supplementary data were collected from the Kenya Forestry Research Institute （KEFRI）, a major facilitator and trainer of the identified FFS activities and practices in the study area since 2004. More than 80% of the local community never undertook any form of prosopis management practice; however, this changed after FFS training, indicating an acquisition and retention of knowledge which probably diffused to the non-FFS counterparts, through either formal or informal ways. Harvesting was the most preferred （100%） and stump burning the least preferred （46%） practice of managing the spread of prosopis. The success and preference of any prosopis management practice was attributed to wood and non-wood benefits derived from prosopis and growing of animal fodder and food crops on rehabilitated land. More than 80% of respondents attributed ineffectiveness of any prosopis management practice to coppicing and viable seed banks of the tree, while 50% highlighted a lack of consistency and integration in carrying out manage- ment practices. The reported negative attitude towards prosopis changed after training with none of the view to eradicate it. Labor intensity and frequent regeneration of seedlings were identified as the major challenges faced during the implementation of proso- pis management practices. In conclusion, the study shows that harvesting, uprooting, stump burning, pruning and thinning realized through consistent holistic integration contribute to containing the spread of prosopis trees in Baringo, Kenya.

Oviposition Site Preference and Its Effects on Subsequent Development of Variegated Grasshopper (Zonocerus variegatus L.) under Laboratory Conditions

Female grasshoppers can affect the fitness of their offspring through their selection of oviposition site. Knowledge of soil type on oviposition, and its effects on subsequent development can provide guidelines for habitat manipulations that reduce the harmful effects of these pests on farmers fields. The influence of soil types on the oviposition site preference of variegated grasshopper (Zonocerus variegatus L.) reared some cassava (Manihot esculenta Crantz) varieties, was investigated in a cage trial carried out at the Bio factory laboratory, School of Agriculture and Food Sciences, Njala University, Sierra Leone during 2022/2023. The treatments comprised three soil types (Sandy, Loamy and Clay), each with three replications laid out in a randomized complete block design (RCBD) in wooden cages. Data were collected on the following development parameters including, Net reproductive growth ratio (R0), Generation time (Tc), Intrinsic rate of increase (rm), Finite rate of increase (), Doubling time (Dt), and overall survivorship. Findings revealed that, Z. variegatus L. preferred sandy soil in which, on average, most eggs were deposited (338, 6.62 4.40), followed by loamy soil, 286 (5.53 3.96), and then, clayey soil, 200 (3.91 3.85);though, the differences were not significant. This study established that Z. variegatus deposited more eggs in sandy soil > loamy soil > clayey soil, respectively;and subsequent survivorship of the immature unto mature adult insect, revealed a similar order. This indicates that the sandy soil is the most preferred substrate for oviposition and subsequent development into adult insects.

Effect of Lime and Phosphorus on Yield and Yield Components of Groundnut Varieties [Arachis hypogaea L.] on Acidic Soil in Nedjo District, Western Ethiopia

Groundnut (Arachis hypogaea L.) is an important cash crop for smallholder farmers in western Ethiopia. However, the yield of the crop is very low mainly because of strong soil acidity and poor soil fertility management. A study conducted to evaluate the effect of lime and mineral phosphorus fertilizer on yield components and yield of groundnut. The treatments consisted of three phosphorus rates (0, 46 and 92 kg P2O5·ha-1), three lime rates (0, 6, and 11 ton lime·ha-1), and three groundnut varieties (local cultivar, Werer-961, and Werer-963) was laid-out as a randomized complete design in a factorial arrangement with three replications. The corresponding rates of phosphorus applied per pot of soil (7 kg) amounted to 0, 107 and 215 mg kg·soil-1 and those of lime amounted to 0, 14, and 26 g kg·soil-1. The analysis of variance showed that phenological characters, yield, and yield components significantly affected by interaction of variety, phosphorus, and lime. The highest dry pod yield produced by Werer-963 (2 kg dry pod yield·pot-1) in response to the application 11 t·ha-1 lime and 46 kg P2O5·ha-1. However, Werer-961 produced medium (1.5 kg dry pod yield·pot-1) at 11 t·ha-1 lime and 92 kg P2O5·ha-1 and the local cultivar produced minimum (1 kg dry pod yield·pot-1) at the application of 11 t·ha-1 lime and 92 kg P2O5·ha-1. In terms of phosphorus yield efficiency index, Werer-963 was highly efficient (index of 1.71), and Werer-961 was moderately efficient (index of 0.6). However, the local cultivar was inefficient (index of 0.04). It is at, in acidic soil of the study area Werer-963 is the best to be cultivated with application of lime 11 t·ha-1 and 46 kg P2O5·ha-1 fertilizer, followed by Werer-961. The results of this pot experiment have revealed that farmers in the study area need to switch to cultivating the improved varieties of groundnut rather than local variety with the application of high rates of lime and moderate amounts of phosphorus.

Impacts of livestock grazing on a savanna grassland in Kenya

The dynamics of most rangelands in Kenya remain to be poorly understood. This paper provides baseline information on the response of a semiarid rangeland under different livestock grazing regimes on land inhabited by the Massai people in the east side of Amboseli National Park in Kenya. The data were collected from grasslands designated into four types： （1） grassland from previous Massai settlements that had been abandoned for over twenty years; （2） grassland excluded from livestock grazing for eight years; （3） a dry season grazing area; and （4） a continuous grazing area where grazing occurred throughout all seasons. Collected data included grass species composition, grass height, inter-tuft distance, standing grass biomass and soil characteristics. The results indicated that continuous grazing area in semiarid rangelands exhibited loss of vegetation with negative, long-term effects on grass functional qualities and forage production, whereas grassland that used traditional Maasai grazing methods showed efficiency and desirable effects on the rangelands. The results also showed that abandoned homestead sites, though degraded, were important nutrient reservoirs.

Past,present and future of industrial plantation forestry and implication on future timber harvesting technology

Plantation forests are established,and expanding,to satisfy increasing global demand for timber products.Shifting societal values,such as safety,productivity,environmental,quality and social are influencing the plantation forestry sector.This is primarily driven through an ever increasing world population,which in turn influences the way nations view the value systems by which they live.More people require more resources-also forest products.Also,the availability of information is influencing the pace of technological development.These changes could result in a difference in the management of plantations that could affect the forest engineering systems of the future.This review aimed to summarize the current status of plantation forests;summarize future developments and possible scenarios in forest plantation management for the various products;and assess whether these developments in a plantation environment could affect the harvesting systems used.Factors influencing the form of plantations include the type and nature of the plantation owner;the change in demand for different and new forest products;climate change factors,including the use of biomass for energy,carbon sequestration and trading;ecosystem services and other products and services;and sustainability certification of forest management.The impact and influence of these factors were summarised into a series of key drivers that will influence the technology used in harvesting machines,as well as the choice of harvesting machines,systems and methods.These drivers were the effect of variations in tree size,the expansion of plantation areas onto more difficult terrain,diversity in plantation design,increased attention towards site impacts and the increased use of biomass for energy.Specific information is provided regarding how the harvesting systems could be affected.

Ethnobotanical Study towards Conservation of Medicinal and Aromatic Plants in Upper Catchments of Dhauli Ganga in the Central Himalaya

The present study broadly focused on medicinal plant species collected from wild by the villagers for different purposes in the upper catchment of Dhauli Ganga in Nanda Devi Biosphere Reserve(NDBR),in the central Himalaya.A schedule based survey was conducted during the years 2003-2005 in 15 villages of Chamoli district part of the NDBR.Information was collected from collectors, vaidya(medicine man)and those dealing with domestication and marketing of the medicinal plants. The aim of the study was to understand the prioritiesed medicinal plants,their mode of collection and document their ethnobotanical uses by the Bhotiya tribal communities,in this world heritage site. During the survey,50 medicinal plants belonging to 31 families and 44 genera were documented.Out of these,70% were harvested from the wild,22% were cultivated and 8% were cultivated as well as wild harvested.Of the cultivated species,8% were found growing in the kitchen gardens and 14%in the agricultural fields.However,42%of the plants had their roots and rhizomes used followed by leaves (26%),seeds(10%),seed and leaf(8%),bark and whole plant(6%)and flower(1%).Most plants were reported to be used for rheumatism(16),followed by stomach disorder(14),cold and cough(11),and jaundice(9).Thirty three plants species were reported to have more than one therapeutic uses,while 17 species were reported to be used against single ailment.The distance of villages from road head was one of the factors contributing to the decline in the medicinal plant population in their natural habitats. The availability of medicinal plants increased with increase in distance from road head and also the peoples'dependence on them.Documentation of the traditional knowledge will help in conservation of knowledge and also opportunity for using it for future training and use.The result of this study will help in promoting sustainable cultivation and implementation in conservation protocol of those species,which are in the verge of extinction in this region.

Impact of Altitude and Land Use Type on Some Physical and Chemical Properties of Acidic Soils in Tsegede Highlands, Northern Ethiopia

A study was conducted in the Tsegede highlands of Tigray Region, northern Ethiopia to determine the changes in some physical and chemical attributes across three adjacent acidic soil sites with different elevation and three land use types. Analytical results of the collected surface layer soil samples showed significant (P ≤ 0.05) correlation of soil bulk density, OM and total N with elevation. In the lower elevation site (Indaslasie), soil OM content declined by about 43 and 52% compared with that of the two higher elevation sites (Cheguarcudo and Indamariam), respectively. Soil pH, exchangeable acidity, exchangeable Al, OM, total N and available phosphorus also exhibited significant (P ≤ 0.05) disparity across the three land use types of the area. Soils of the forest land were less acidic by 0.43 and 0.68 pH units than the cultivated and grazing lands, respectively. The soil OM content of the cultivated land was significantly lower by about 25 and 35% than the grazing and forest land soils, respectively. Available soil P status was low and showed significant correlations with pH (r = 0.65), exchangeable acidity (r = –0.58) and Al (r = –0.53). In general, the study results revealed altitude did not impose any significant effect in aggravating soil acidity whereas land use type affected significantly not only soil acidity but also the important soil fertility related parameters such as OM, total N and available P contents. Therefore, it can be suggested that besides to the usual acid soil management and/or reclamation practices, introducing proper land use management systems are of paramount importance.

Effect of mixed-cropping and water-stress on macro-nutrients and biochemical constituents of rhizomatous medicinal plants in Central Himalaya,India

Plants in the alpine zone mainly depend on the reserved food materials stored in their rhizomes for the next growing season. We investigated the effect of mixed cropping （Phaseolus vulgaris L. var. Pinto） with four rhizomatous medicinal plants, i.e., Angelica glauca, Arnebia benthamii, Rheum emodi and Pleurospermum angelicoides as well as three levels of water stress treatment under two conditions （shade net and open field） on macronutrients （NPK） and biochemicals （carbohydrates and protein）. The experiment was conducted by completely randomized design （CDR）. The data were analyzed with ANOVA as well as CDR. The experimental results show that in all the species shade conditions with sever water stress （SSWS） increased the level of macronutrients （NPK）. However, （N） concentration was highest under shade with mixed cropping （SMIX）. Under SMIX, carbohydrate content was highest than open field control conditions （CONT）. This investigation results demon- strate that mixed cropping of medicinal plants with Phaseolus vulgaris could be a good livelihood option in the mountainous regions of Indian Central Himalaya. And the water-stress conditions along with mixed cropping could improve the biochemical constituents in the rhizome of these species.

Parkland Agroforestry of Ethiopia;Key to Production, Productivity, Biodiversity Conservation and Climate Change Mitigation: A Review

Compiled information on parkland agroforestry tree species in relation to diversity, tree management options and the challenges of the system is important for production and productivity, and biodiversity conservation through availing the required information which in turn has an implication to the sustainability of the system and climate change mitigation. So, the aim of this review paper is to compile information on parkland agroforestry practices of Ethiopia, particularly: on tree species diversity, their roles, management options available and challenges of the practice. Parkland agroforestry which is a system practiced by many local populations comprises the large part of agricultural landscapes in Ethiopia and is very important in different aspects such as;for food security, microclimate amelioration, economic benefits, environmental protection, household energy, household utensils, cultural values, traditional medicines, and fodder. There are many indigenous multipurpose tree species scattered on farmlands in Ethiopia, and the common one includes: Millettia ferruginea, Cordia africana, Ficus vasta, Ficus sur, Croton macrostachyus and Faidherbia albida. However, nowadays these trees are facing challenges like: expansion of exotic trees in the expense of the native ones, expansion of cash crops through removal of the parkland trees from the farm area, climate change, land shortage and tenure system which require high emphasis for the production and productivity as well as sustainability of the system especially, in this era of climate change;hence this system is one of climate change mitigation options.

Tradeoffs of Small Scale Irrigation and Its Contribution to Land Use and Land Cover Change in Mai-Dimu, Tahtay Koraro <i>Wereda</i>, North-Western Tigray, North Ethiopia

Improving and understanding of land use and land cover change (LULC) can help in projecting future land use dynamics and provide appropriate interventions for achieving better land management. The aim of this study is to evaluate the status of induced small scale irrigation practices that affect the different land use changes over time in mai-dimu Kebele, Tigray, northern Ethiopia. Remote Sensing (RS), Geographic Information System (GIS) were used to determine the LULC dynamics with its land cover changes (1995-2015) by dividing in to three decades. In analyzing the accuracy assessment, the Kappa coefficient was found strong agreement between classified land cover classes and observed land cover/use with greater than 80% values. The coverage of cultivated land has high land use map cover with 28.45%, 31.83% and 27.74% in 1995, 2005 and 2015 respectively. No irrigation practice was observed in 1995 and 2005. However, in 2015 it was covered with 1.65 % of irrigated land. While the overall change difference from the year 1995 to 2015, was also by enlarge attributed to expansion of settlement, dam, cultivated land and irrigated lands increased positively with 700.20 ha, 124.02 ha, 33.48 ha and 181.98 ha respectively which subsequently decrease the land use of grass land (?336.48 ha), bush land (?561.52 ha), bare or rocky land (?68.94 ha) and forest land (?343.03 ha). Hence, inducing the irrigation practices could be additional yield production under dry season which later helps in improving the lively hood of the community.

Effects of Hydrogels on Soil Moisture and Growth of <i>Cajanus cajan</i>in Semi Arid Zone of Kongelai, West Pokot County

Studies on the effects of hydrogels on soil amendments, moisture conservation and growth of Cajanus cajan in arid and semi-arid lands were carried out. Seedlings of C. cajan were established both in the nursery and in the field with and without hydrogels. In the field, three replications were used with three levels of hydrogels concentration (7 g, 11 g, and 15 g). Control seedlings were established in soils without hydrogels. In the nursery, root collar diameters and heights were measured every two weeks up to eight weeks. Seedlings established without hydrogels in the nursery were transplanted into field soils with none, 7 g, 11 g and 15 g of hydrogels. Root collar diameters and heights were again measured every month for three months. In addition, soil was collected randomly once every month from the base of each seedling and analyzed for soil moisture using standard laboratory procedures. All data were subjected to analysis of variance. The results show that growth in both the height and root collar diameter of the species was significantly different at the three levels of hydrogels. This suggests that use of hydrogels retards plant growth in nursery soils but improves growth in the field. Hydrogels increased soil moisture volume from 8.3% to 10% in H15g level of hydrogels under C. cajan after transplanting. It was concluded that hydrogels do not contribute to growth of seedlings in the nursery but they do so after transplanting. Hydrogels increase soil moisture in the soil, so they are recommended for use in semi-arid lands to boost the survival and growth of seedlings.

Socioeconomic Characteristics of Child-Bearing Mothers and Feeding Practices of Under-Five Children in Kori Chiefdom, Sierra Leone

Introduction: The use of proper feeding practices is key for the overall development of children. Generally, breastfeeding and complementary feeding make up the diet and therefore the nutritional status of children. However, the degree to which mothers adhere to the recommendations of the World Health Organization (WHO) and the United Nations Children’s Fund (UNICEF) regarding breastfeeding and complementary feeding is key to the nutritional status of children. Again, the adherence to this dietary recommendation is contingent on the socio-economic conditions of the child-bearing parents, especially the mothers. Here in this study, the socio-economic characteristics were analyzed along with the feeding practices of children not more than five years old in rural Sierra Leone. Method: Data were collected in 2017 on representative mothers with children within 0 - 5 years old. A total of 10 communities and 200 respondents were randomly covered in the Kori Chiefdom of Moyamba District, Sierra Leone. The data collection instruments included structured questionnaire, inter-personal interaction, personal observation and experience. The collected data were analyzed in Microsoft Excel and SPSS and the results presented in simple graphs. Results: A large number of the respondents were married teenage mothers with 1 - 2 children and living under extreme hardship by the United Nations (UN) standard. Also, most of the mothers were illiterate and started breastfeeding their children within the very hour of birth. Because complementary feeding was started all too early, exclusive breastfeeding last for not more than two months for most of the respondent mothers. Also, because rice is by far the most widely eaten the staple food in Sierra Leone, complementary food was mostly powdered rice mixed with salt and oil. Hardly was protein food supplement used as complementary food, probably due to the economic conditions of the poor rural women. Conclusion: The study has thrown sufficient light on the socio-economic characteristics and adopted feeding practices of children in poor rural Sierra Leone. In this sense, the study has laid the basis for sufficient for in-depth correlativity studies on the factors driving feeding practices of children and how it in turn impacts nutritional status of children in poor rural Africa. From here, practically adoptable recommendations can be advanced for the attention of the governments, public institutions, the private sector and the individuals of the society.

Ethnobotanical Studies on the Use of Medicinal Plants among Forest Fringe Communities around the Kasewe Forest in Moyamba District, Southern Sierra Leone

Forests are home to many flora and fauna species. Forest flora have been very important to man and sustainability of forest ecosystem. Forest flora provides provisional, regulatory, protective and cultural services. These services have been the foundation of civilization and development. Local communities depend on these natural resources for livelihood generation and cultural services. Local communities have been using medicinal plants to cure different ailments. In this study, an ethnobotanical survey was conducted to document medicinal plants diversity and use in forest fringe communities. The study adopted a method used by Martin in 1995 on Ethnobotanical reviews of medicinal plants. Ethnobotanical information was gathered through structured questionnaires administered to 57 inhabitants constituting key informants, community leaders, and household heads who are believed to have vast indigenous knowledge of medicinal plants. The snowball technique was used to identify respondents in communities around the Kasewe forest. For the diversity of medicinal plants use and associated indigenous knowledge, a plot of size 25 m × 25 m was demarcated with a linear tape and ranging poles in the different habitat types in the study area. Sampling was stratified based on the size of habitat types. A total of 10 sample plots comprising of 4 plots in the closed forest;3 plots in disturbed areas, 2 plots in farmland, and 1 plot in the grassland were studied. A total of 3377 individual plant stems were documented comprising of 84 individual species belonging to 53 families and 78 genera. Of the 84 individual plant species, 42 were medicinal. The most dominant family was Malvaceae. Tree species were the most dominant life form representing 32.14% followed by shrubs 30.5, herbs 26.8% and climbers 10%. Majority of the plant species are of little conservation concern and few have been categorized as endangered and vulnerable that need special conservation attention. Species with the highest density was Chromolaena odorata 110 m2, while Xylopia quintais 0.1 m2 had the least density per hector. The Shannon-wiener index recorded 1.236 as the highest in plot 3 while plot 10 in the grassland was considered as the lowest with 0.757. The finding revealed that 92.98% of respondents around the Kasewe forest in the Moyamba district used medicinal plants to treat therapeutic ailments. At the same time, a very limited proportion depends on other medication sources to treat therapeutic ailments. 98.25% of the respondents, mostly older people, know medicinal plants to treat therapeutic ailments. All parts of the plant were indicated to be used for treatment of different ailments. However, the root (43.8%), bark (36.8%) and leaves (35%) are the most common plant parts used to treat different therapeutic ailments. 96.49% of the respondents have knowledge on administering prepared herbal medicine.

Ground Water Harvesting through Traditional Water Harvesting Technology: Adopting Himalayan Practices in Ethiopian Highlands

The fresh water system is most critical for sustainability of life. In present days the world is facing a shortage of potable water. Though Ethiopia is known as “The water tower of East Africa” yet it is facing severe water shortage that leads to poor agricultural productivity and imparts serious negative impact on human lives. It is essential to develop water resources in a sustainable way to ensure food security and economic development. The water scarcity is due to the lack of resource management and due to the changes in environmental factors. In Ethiopia ground water is a major source of drinking water to vast rural population. The country’s perennial water budget depends on the ground and spring water system. The ever increasing population, mismanagement and global climatic changes are having an adverse impact on these resources. To harvest the available resources in a sustainable way will help to meet the needs of present era without compromising the future generation. The present study is an approach to compare and utilize the traditional water harvesting practices of Himalaya in Ethiopian highlands. A detailed study of the water sources and mechanism of ground water, geology and social management system of their water resources were studied booth side. Further application of the indigenous technical knowledge for sustainable of the ground water is proposed based on Himalayan practices. The Ethiopian “Minches” could be preserved and better utilized by adopting the merits of time tested indigenous management system of “Naule” of Himalaya.

Carbon Dioxide and Nitrous Oxide Emissions from Naturally Occurring Sulfate-Based Saline Soils at Different Moisture Contents

Soil salinization may negatively affect microbial processes related to carbon dioxide （CO2） and nitrous oxide （N20） emissions. A short-term laboratory incubation experiment was conducted to investigate the effects of soil electrical conductivity （EC） and moisture content on CO2 and N20 emissions from sulfate-based natural saline soils. Three separate 100-m long transects were established along the salinity gradient on a salt-affected agricultural field at Mooreton, North Dakota, USA. Surface soils were collected from four equally spaced sampling positions within each transect, at the depths of 0-15 and 15-30 cm. In the laboratory, artificial soil cores were formed combining soils from both the depths in each transect, and incubated at 60% and 90% water-filled pore space （WFPS） at 25 ~C. The measured depth-weighted EC of the saturated paste extract （ECe） across the sampling positions ranged from 0.43 to 4.65 dS m-1. Potential nitrogen （N） mineralization rate and CO2 emissions decreased with increasing soil ECe, but the relative decline in soil CO2 emissions with increasing ECe was smaller at 60% WFPS than at 90% WFPS. At 60% WFPS, soil N20 emissions decreased from 133 g N20-N kg-1 soil at ECe （ 0.50 dS m-1 to 72 μg N20-N kg-1 soil at ECe = 4.65 dS m-1. In contrast, at 90% WFPS, soil N20 emissions increased from 262 g N20-N kg-1 soil at ECe ： 0.81 dS m-1 to 849 g N20-N kg-1 soil at ECe ： 4.65 dS m-1, suggesting that N20 emissions were linked to both soil ECe and moisture content. Therefore, spatial variability in soil ECe and pattern of rainfall over the season need to be considered when up-scaling N20 and CO2 emissions from field to landscape scales.

Effect of Combined Chilling and GA_3 Treatment on Bud Abortion in Forced ‘Luoyanghong' Tree Peony(Paeonia suffruticosa Andr.)

This research investigated the effect of combined chilling and GA_3 treatment on bud abortion of tree peony under greenhouse conditions to determine the dynamics of exogenous hormones and chilling effects on bud abortion. Research of such nature will increase the understanding of the effects of GA_3 and chilling level on flower development thereby, promoting off-season cultivation techniques in tree peonies to increase production that meets market demand. Hormone and sugar levels in the ‘Luoyanghong' tree peony were respectively determined using High-Performance Liquid Chromatography(HPLC) and spectrophotometer. Non-potted chilling with 200 mg·L^(-1) GA_3 treatment reduced bud abortion rate. Flowering rate in non-potted chilling with 200 mg·L^(-1) GA_3 plants was 58%, as against 21% in potted chilling plants with 200 mg·L^(-1) GA_3 treatment. Sugar accumulation in retained or aborted flower buds was conversely related to ABA level. Low ABA and high sugar levels were noted in retained buds whereas the reverse induced bud abortion. ABA level apparently inhibited sucrose and reducing sugar uptake in aborted buds whereas GA_3 enhanced sucrose uptake in retained buds. GA_3 and IAA levels were higher in retained than in aborted buds, which made plants with retained bud more competitive in nutrient uptake(by root)for growth and development. Overall, combined chilling and GA_3 treatment enhanced plant growth and development, particularly bud sprouting, growth and flowering.

Tissue distribution of perfluoroalkyl acids and health status in wild Mozambique tilapia(Oreochromis mossambicus) from Loskop Dam, Mpumalanga, South Africa

This study examined concentrations of 15 perfluoroalkyl acids（PFAAs） in tissues from male Mozambique tilapia（Oreochromis mossambicus） collected at Loskop Dam, Mpumalanga,South Africa in 2014 and 2016. Nine of the 15 PFAAs were detected frequently and were included in statistical analysis and included two of the most commonly known PFAAs,perfluorooctanesulfonic acid（PFOS）（median, 41.6 ng/g） and perfluorooctanoic acid（PFOA）（median, 0.0825 ng/g）. Of the tissues measured, plasma（2016 and 2014 median, 22.2 ng/g）contained the highest PFAA burden followed by（in descending order）： liver（median,11.6 ng/g）, kidney（median, 9.04 ng/g）, spleen（median, 5.92 ng/g）, adipose（median, 2.54 ng/g）, and muscle（median, 1.11 ng/g）. Loskop Dam tilapia have been affected by an inflammatory disease of the adipose tissue known as pansteatitis, so this study also aimed to investigate relationships between PFAA tissue concentrations and incidence of pansteatitis or fish health status. Results revealed that healthy tilapia exhibited an overall higher（p-value 〈 0.05） PFAA burden than pansteatitis-affected tilapia across all tissues.Further analysis showed that organs previously noted in the literature to contain the highest PFAA concentrations, such as kidney, liver, and plasma, were the organs driving the difference in PFAA burden between the two tilapia groups. Care must be taken in the interpretations we draw from not only the results of our study, but also other PFAA measurements made on populations（human and wildlife alike） under differing health status.

Tree species determine soil seed bank composition and its similarity with understory vegetation in a semi-arid African savanna

Introduction:The presence of larger trees in semi-arid African savannas creates sub-habitats,which influences on herbaceous plant communities grown under their canopies differently from opened areas.Knowledge of seed banks accumulated in the soils over time beneath larger trees could facilitate the recovery of plant communities that might disappear due to sustained heavy grazing,prolonged fire,or other anthropogenic factors in semi-arid African savannas.However,the impact of larger trees on soil seed bank composition and its similarity with plant communities grown under their canopies are less understood in semi-arid African savannas.Therefore,we studied the effect of leguminous and non-leguminous tree species and their canopies on soil seed bank(SSB)composition and its similarity with understory vegetation(USV)in a semi-arid savanna of Ethiopia.Methods:We selected 20 matured trees from 3 dominant tree species,representing one leguminous(Acacia robusta Burch)and 2 non-leguminous tree species(Ziziphus spina-Christi and Balanites aegyptiaca(L.)Del),found in isolation,a total of 60 trees for this study.Under each selected individual tree,the species composition of USV were recorded using 1-m2 quadrat in four directions(north,south,east,and west)under the inside and outside tree canopies during the flowering stage.Similarly,soil samples in a 1-m2 quadrat were also collected under the inside tree canopies and their corresponding outside canopies,in each individual tree,for the determination of SSB composition,using a seed emergence method.Then,the soil was thoroughly mixed after removal of all roots and plant fragments,and spread over sand in plastic pots to a depth of 20 mm.The pots were placed at random in a glasshouse,examined every 3 days,for the first 2 months,and thereafter weekly for 6 months.A total of 960 soil samples were used for the determination of SSB composition during this study.Results:A total of 64 species were emerged from the SSB samples,of which 27 were grasses(19 annual and 8 perennial grasses),35 annual forbs and 2 woody species.Acacia robusta had a higher seedling density in the SSB compared to other tree species,whereas Z.spina-Christi had higher species diversity in the SSB than other tree species.Moreover,seedling density and species diversity were higher under the inside canopies than outside tree canopies.The mean similarity in species composition between the SSB and USV was low.However,it was higher under the leguminous trees than non-leguminous trees,and under the inside tree canopies than outside canopies.Conclusions:We found that mature tree species maintained a higher SSB species diversity and abundance under their canopies than the surrounding opened areas.Therefore,conservation of mature dominant tree species is of paramount importance for ecological stability and possible restoration of degraded semi-arid savannas under the changing climate and global warming.