Effect of Supplementary Irrigation on the Yield of Sorghum (Sorghum bicolor L. Moench) in the Context of Climate Change in the Dry Savannahs of Togo

Under the current context of climate change, supplementary irrigation may be needed for crop production resilience. We determined the effects of supplementary irrigation on sorghum grain yield in the dry Savannah region of Togo. A two-year trial was conducted in a controlled environment at AREJ, an agro-ecological center in Cinkassé. The plant material was sorghum variety Sorvato 28. The experimental design was a Completely Randomized Block with three replications and three treatments as follows: T0 control plot (rainfed conditions);T1 (supplementary irrigation from flowering to grain filling stage) and T2 (supplementary irrigation from planting to grain filling stage). Two irrigation techniques (furrow and Californian system) were used under each watering treatment. The results showed that irrigation technique significantly affected panicle length with no effect on 1000 grains mass. Panicle length and grain yields varied from 15.59 to 25.71 cm and 0.0 to 2.06 t∙h−1, respectively, with the highest values (25.66 cm and 2.06 t∙h−1, respectively) under the T2 treatment with the California system-based supplementary irrigation. The comparison of results obtained on treatment T0 and T2, shows that supplementary irrigation increased the yields by at least 68.62%. Supplementary irrigation during sowing and growing season (T2) improved sorghum yields in the dry savannahs of Togo, with a better performance of the California irrigation system.

Anthropogenic Threats to Degraded Forest Land in the Savannahs’ Region of Togo from 1984 to 2020, West Africa

This study focuses on the landscape dynamics of the savannahs’ region in the far north of Togo. Based on a literature review and satellite images analysis using GIS and remote sensing, the study aims to ascertain the effects of anthropogenic threats on the forest coverage of the Savannahs’ Region between 1984 to 2020. The objective is to clarify the dynamics of land use in the region from 1984 to 2000 and from 2000 to 2020. The findings indicate a significant decline in forest coverage within the region from 1984 to 2020, a trend attributed to land use patterns. Dry forests in the Savannah region are largely converted to farmlands, housing, dry savannahs or agroforestry parks, leading to a steady reduction in forest areas.

Response of Rice Varieties to Water Stress in Sokoto, Sudan Savannah, Nigeria

Pot experiment was conducted at the Botanical Garden of the Department of Biological Science, Usmanu Danfodiyo University, Sokoto Nigeria, during the 2013 dry season. The main objective of this research was to determine the effect of water stress and variety on productivity of rice (Oryza sativa) at Sokoto. The treatment consisted of water stress at three growth stages (Tillering, flowering, Grain filling) and unstress (control) and three rice varieties (FARO 44, NERICA 2 and FARO 15) laid out in a Completely Randomised Design (CRD) replicated three times. The result indicated that water stress significantly (P < 0.05) resulted to decreased in plant height, number of leaves per plant, total biomass, harvest index and grain yield. The results indicated significant (P < 0.05) differences among genotypes. Faro 44 differed significant from in plant height, number of leaves per plant, total biomass, harvest index and grain yield. FARO 44 differed significantly from NERICA 2 and FARO 15 at all the parameters under study. Water is very vital as far as rice production is concern should be applied at every stage of rice production. FARO 44 is recommended for the area for higher yield.

Interactive influence of rainfall manipulation and livestock grazing on species diversity of the herbaceous layer community in a humid savannah in Kenya

Changes in rainfall regime and grazing pressure affect vegetation composition and diversity with ecological implications for savannahs. The savannah in East Africa has experienced increased livestock grazing and rainfall variability but the impacts associated with those changes on the herbaceous layer have rarely been documented. We investigated the effect of livestock grazing, rainfall manipulation and their interaction on the composition and diversity of the herbaceous community in the savannah for two years in Lambwe, Kenya. Rainfall manipulation plots were set up for vegetation sampling;these plots received either 50% more or 50% less rainfall than control plots. Simpson’s diversity and Bergere Parker indices were used to determine diversity changes and dominance respectively. The frequency of species was used to compute their abundance and their life forms as determined from the literature. Grazing significantly increased species diversity through suppression of dominant species. Rainfall manipulation had no significant impact on plant diversity in fenced plots, but rainfall reduction significantly reduced diversity in grazed plots. In contrast, rainfall manipulation had no impact on dominance in either fenced or grazed plots. The interaction of grazing and rainfall manipulation is complex and will require additional survey campaigns to create a complete picture of the implications for savannah structure and composition.

Impact of Climate Change on Cotton Production: Case of Savannah Region, Northern Togo

Among the numerous problems that are facing cotton farmers, climate change is one of the most important still out of their control. Adaptation appears to be one of the best alternatives. The objective of this research is to assess the impact of climate change on cotton production in the Savannah region of Togo. The study was conducted with 172 cotton farmers sampled randomly in many stages in order to determine the impact of climate change on cotton production. The impact assessment of climate change on cotton production was carried out using ATE (Average Treatment Effect) and ATET (Average Treatment Effect on the Treated) models introduced by Rubin in 1974. The results show that climate change has a significant negative impact at 1% level on cotton production observed with an average decrease per farmer of 2330 kg, on the yield efficiency with an average decrease of 515 kg/ha and on the income level with an average decrease of US $745 per farmer. Climate change reduces the level of soil fertility, favours pest resistance and leads to an increase in consumption of cotton production inputs per unit of area. The study also reveals a low level of adaptation of cotton farmers to climate change. The expansion of cultivated areas remains the main reaction of cotton farmers to climate’s negative effects. Raising producers’ awareness on the reality of climate change and adopting adaptation techniques and strategies would greatly improve cotton farmers’ adaptive capacity and positively affect cotton production in Savannah region, and Togo in general.

Effect of Intercropping Pattern on Stem Borer Infestation in Pearl Millet (<em>Pennisetum glaucum</em>L.) Grown in the Nigerian Sudan Savannah

Fields experiments were conducted at the Department of Crop Protection, Faculty of Agriculture, University of Maiduguri Teaching and Research Farm, Maiduguri during 2010 and 2011 cropping seasons to investigate the effects of intercropping pattern on stem borer pest infestation in pearl millet (Pennisetum glaucum L.) intercropped with ground nut (Arachis hypogea L.). A split-plot design was used to test the intercrop pattern of 1:0 ratio (sole millet), 1:1 ratio (1 millet row to 1 ground nut row), 2:1 ratio (2 millet rows to 1 ground nut row) and 1:2 ratio (1 millet row to 2 ground nut rows). The results obtained showed that the intercrop pattern of 1:2 ratio and 1:1 ratio yielded less stem borer infestation and abundance in pearl millet, and as well supported high panicle weight and grain yield. In addition to recommending either of these two intercropping patterns to pearl millet farmers for more effective stem borer pest management, results further show the need for identification of effective intercropping patterns in other cropping systems.

美国小城萨凡纳(Savannah)的城市历史景观建筑保护

对于国内为数众多的历史名城,无论是从经济发展还是文化传承上来说,历史景观建筑的保护在当下和未来的城市规划建设中都扮演着越来越重要的角色。萨凡纳作为美国南方一个重要的历史名城,虽然只有短短200多年的历史,但其醇厚绵长的历史景观建筑风貌却给人们留下了极为深刻的感受。萨凡纳长久以来对于城市历史建筑的保护和重视已经深深的融入了整个城市的经济发展,这种交融的发展保护方式以及其所取得的良好人文和社会效益是值得我国同类城市借鉴学习的。

Nematode distribution in cultivated and undisturbed soils of Guinea Savannah and Semi-deciduous Forest zones of Ghana

Climate change affects air temperature, sea levels as well as the soil and its ecosystem. The Guinea Savannah and Semi-deciduous Forest zones of Ghana are characterized by different climatic conditions and vegetative cover. Annual average temperature has been steadily increasing whilst annual total rainfall has been decreasing in both zones, and this has been causing a southward shift of the Savannah into the Forest zone. Soil organisms provide crucial ecosystem services which are required for sustainable agriculture and food production yet crop cultivation disturbs the soil ecosystem. The harsh conditions associated with the Savannah further expose the soil ecosystem to disturbance and loss of biodiversity which threatens food production and security. Soil nematodes are the most abundant animals in the soil and play a central and critical role in the soil food web complex. Studying the nematode community structure gives a reflection of the status of the entire soil ecosystem. Soil samples were taken from cultivated and natural landscapes in the Guinea Savannah and Semi-deciduous Forest agroecological zones to analyse the nematode community. Results from the study showed the Guinea Savannah zone recording warmer soil temperatures, lower organic matter percentage and lower nematode diversity(Genus Richness) as compared to the Semi-deciduous Forest zone. If the Savannah continues to shift southward, the Forest zone soil ecosystem risks disturbance and loss of biodiversity due to the harsh Savannah conditions. Our findings indicate that prevailing crop cultivation practices also disturb soil ecosystem in the two ecological zones which span across West Africa. A disturbed soil ecosystem endangers the future of food production and food security.

Complementing Water Supply through Rainwater Harvesting in Some Selected Villages of Sahel Savannah Ecological Zone in Borno State Northeastern Nigeria

One of the greatest environmental challenges that confront rural communities in Nigeria especially in Borno state is scarcity of water supply. Rainwater harvesting can reduce over dependence on centralized piped water supply and checkmate climate change. This study in two rural communities determined the water per capita use, examined water sources and then estimated the amount of rainwater that can be harvested by households in these villages. The villages are Kukurpu and Yelwa Bam in Hawul local government area of Borno state Nigeria. The choice of the villages is justified on the basis of their location in the semi-arid region of the Sahel ecological zone with lesser rainfall compared to other parts in the region. Lack of adequate access to water supply is precursor to water related diseases and challenge to sustainable development. This study used scheduled interview with households and 100 household were surveyed using simple random sampling. In each of the village, 50 observations were made Results revealed that 87% of the households rely water from hand dug wells, ephemeral streams and boreholes equipped with manual hand pumps that are susceptible to drought and frequent breakdown. Borno state where the villages are located had a mean annual rainfall of 860 mm from 1980 to 2009;however, the annual rainwater harvesting potential was put at 51.21 m3. Although over 80% are aware of rainwater harvesting practices only 2% of households harvest rainwater due to the seasonality of rain-fall coupled with inadequate water storage facilities. There is therefore the need to embark on massive rainwater harvesting with corresponding water reservoir as a way to reduce the effects of the five months dry spell experienced in the region.

Modeling Vegetation Lifeforms Abundance based on <i>Epigeal Termitaria</i>Physiography and Altitude in Tropical Savannah of Katolo Sub-Location, Kisumu County

Termite mounds are major sites of functional heterogeneity in the tropical ecosystems globally;through their prodigious influence on vegetation and soil perturbation. They aid soil aeration, water infiltration and catabolism of vegetative matter into nutrient rich humus. There is no documentation of a model for prediction of vegetation lifeforms with respect to mound basal radii, heights and altitude. Objective of this study was therefore to develop a model for rapid prediction of vegetation lifeforms (trees, shrubs, lianas and grass) abundance based on physiography (basal radii and heights) and altitude of the termite mounds. Study population of the mounds was unknown. Cross sectional research design was used. Saturated sampling was done where sixty accessible termite mounds were studied. Both basal radii and heights of termite mounds were measured using 50 m tape measure or hand-held inclinometer. Altitude data were captured by hand-held Global Positioning System (GPS). Trees, shrubs and lianas were identified visually and counted on the mounds while grass abundance was estimated using 0.3 m by 0.3 m quadrat on every termitarium. Multiple Linear Regressions were done to model vegetation lifeforms abundance based on termite mound basal radius, height and altitude. Results indicated that predicted MLR significantly (p ≤ 0.05) predicted trees, shrubs and lianas but not grass abundance. Predicted trees abundance = -89.2587 + 10.46157 (radius (m)) - 4.96989 (height (m)) + 0.074074 (altitude (m)), predicted shrubs abundance = 19.26065 + 6.780626 (radius (m)) - 6.09157 (height (m)) - 0.00822 (altitude (m)) and predicted lianas abundance = -24.9345 + 5.881659 (radius (m)) - 0.68423 (height (m)) + 0.020729 (altitude (m)). This study demonstrated significant effect of termite mound physiography on vegetation lifeforms abundance as well as developed a model for rapid prediction of their abundance on termite mounds.

A Single-Season Irrigated Rice Soil Presents Higher Iron Toxicity Risk in Tropical Savannah Valley Bottoms

With the aim of finding the geochemical differences and helping to build alleviating strategies against iron toxicity, two hematite dominant valley bottoms irrigating rice soils were investigated in the Tropical Savannah region of Burkina Faso. The first site was Tiefora, a 15-ha modern double-season irrigated rice system and moderately affected by iron toxicity (10% of the area with a toxicity score of 4). The second site was Moussodougou, a 35-ha traditional singleseason irrigated rice valley-bottom, with 50% facing more severe iron toxicity (score 7). Nine soil extracts were taken from three depths—30, 50 and 100 cm—i.e. 27 at Tiefora and 27 at Moussodogou. Five techniques were used to measure the data: 1) the ferrous iron concentration was determined using a reflectometer, 2) a pH-meter yielded the pH, 3) clay-proportions were obtained by United States Department of Agriculture (USDA) grain size analysis and densitometry, 4) the organic matter was determined by oven drying (900℃) and v) the dry bulk density was determined by using undisturbed soil samples. Statistical hypothesis testing of One-way ANOVA and Welch t-test was applied to the data to isolate the similarities and the differences between the two sites. A geochemical analysis followed to find the causes of these differences. The results showed that while oxidation of pyrite leads to a simultaneous increase in Fe2+ concentrations and acidity in the soils of coastal floodplains and mangroves, the oxidation of hematite in Tropical savannah valley bottoms decreases Fe2+ but also increases acidity during the dry season. As a consequence, it was found that the single-season irrigation scheme Moussodougou is significantly (p-value 0.4%) more acidic (pH 5.7) than the double-season system of Tiefora (6.4) with also 750 - 1800 mg/l higher ferrous Fe2+. The ferrous iron reached 3000 mg/l in some layers in Moussodougou. This result is a justification to modernize a traditional single-season spate irrigation schemes into a double-season irrigated rice scheme.

Changes in Epipelic Diatom Diversity from the Savannah River Estuary

Littoral zones can be characterized with temporal exposure of algae to diurnal desiccation at low tides. Combinations of diverse freshwater, marine, and brackish diatoms dominate exposed mud samples. With enlargement of the delta of the Savannah River, Georgia and other anthropogenic influences, changes in the rich epipelic community will not be estimated accurately without baseline data. In the current study, mud samples were taken from the Savannah River estuary along with physicochemical characteristics every two months throughout 2011. Live algal communities were assessed in every sample and live to dead diatom proportions in the communities were calculated. Cleaned diatoms were analyzed following standard protocols. Community indices were compared between sampling events and with literature reports from similar habitats in the Southeastern USA diverse diatom community of 241 species was documented and 39 of those species should be described as new to science. Decrease in species richness and diversity was due to dominance of representatives of the genera Cymatosira and Minidiscus during the summer months.

Understanding the Local Carbon Fluxes Variations and Their Relationship to Climate Conditions in a Sub-Humid Savannah-Ecosystem during 2008-2015: Case of Lamto in Cote d’Ivoire

The temporal variations of the Gross Primary Productivity (GPP), the Total Ecosystem Respiration (TER) and the Net Ecosystem Exchange (NEE), and their responses to meteorological conditions (e.g. temperature, radiative flux and precipitation) at Lamto, in wet savannah region across C?te d’Ivoire are analyzed using GFED-CASA and daily meteorological data recorded over the 2008-2015 period. The study shows the links between these carbon fluxes and climate variability at Lamto that is subject to high anthropogenic pressures and seasonal bushfires. The correlative statistics from multiple regression methods were used to assess the different relationships and show how they change in time. The results show important seasonal variability in the Gross Primary Productivity and the Total Ecosystem Respiration mainly associated with the changes in temperature and radiative flux. In addition, the statistical analysis suggests a high correlation between meteorological conditions and the GPP and TER. These climatic conditions may explain 83% and 79% of the variances of GPP and TER respectively. Moreover, the interannual variability of the Net Ecosystem Exchange indicates that around Lamto, in the subhumid savannah, the ecosystem behaves as a carbon sink similar to other West African ecosystems. On the other hand, there is no clear link between the NEE and temperature, radiative flux and precipitation. This lack of connection may suggest a limited response of the NEE interannual dynamics related to the changes in climatic features.

Local Climate Forcing and Eco-Climatic Complexes in the Wooded Savannah of Western Nigeria

Many climate impact applications are sensitive to local differentials in the climate system. This study investigates how eco-geographic factors influence the local climate and propagate eco-climatic complexes that vary spatio-temporally. Local geography data including elevation, slope, aspect, rainfall, temperature, vegetation, population density, and soil potential for agriculture were integrated and analyzed using geographic information system and principal component analysis. The result was profiled for local climate drivers and associated spatial structures in present and future climate (2046-2065) scenarios. The results suggest a local climate system driven by the coupling between terrain, rainfall and temperature in all seasons. In the present climate, this coupling creates eco-climatic complexes that extend from the southeast to northwest corridor in all seasons except June-July-August (JJA) when it is shifted to the northeast axis. This pattern is projected to continue in the future climate scenario, but its spatial influence and intensity would weaken around the northwest axis and rainfall will become less significant in the system in JJA. The clustering of rural settlements these complexes suggests the climate-positives produced by the system significantly support rural livelihoods. Thus, these eco-climatic complexes represent climate sensitive natural resource systems that should be targeted as a fulcrum for climate change mitigation and adaptation in the wooded savannah.

Mapping and Floristic Diversity of the Nakpadjouak Community Forest, Tami Canton, Togo (West Africa)

Since 2015, community forests have been promoted in Togo as an alternative to protect areas from degradation and as a means of contributing to forest landscape restoration. The study focuses on the Nakpadjouak Community Forest (NCF) in Tami (Togo, West Africa) which contributes to community forests sustainable management. It aims in (i) mapping forest ecosystems and analysing their dynamic and (ii) characterizing the floristic diversity of the NCF. The ecosystems were mapped and their dynamic was evaluated based on Google Earth images of 2014 and 2020. Floristic and forestry inventories were carried out using the transect technique in a sample of 20 plots of 50 m × 20 m. The NCF was made up mainly by wooded/shrub savannahs (95.37%) and croplands/fallow (4.63%) in 2014. These two land use types undergone changes over the 6 years prior to 2020. By 2020, the NCF had 3 land use types: wooded/shrub savannahs (77.59%), open forest/wooded savannahs (22.23%), and croplands/fallows (0.18%). A total of 89 plant species belonging to 70 genera and 28 families were recorded within the NCF. The dominant species are: Heteropogon contortus (L.) P.Beauv. and Combretum collinum Fresen. followed by Pteleopsissuberosa Engl. & Diels, Annona senegalensis Pers. The most common species are: Lannea acida A.Rich. s.l., A. senegalensis, Vitellaria paradoxa C.F.Gaertner subsp. paradoxa, C. collinum and Acacia dudgeonii Craib ex Holland. Due to its small area of just 40 hectares and its diverse plant life, this community forest of Savannahs Region is a significant biodiversity hotspot and warrants conservation efforts.

Distribution patterns of fire regime in the Pendjari Biosphere Reserve, West Africa

Pendjari Biosphere Reserve(PBR),a primary component of the W-Arly-Pendjari transboundary biosphere reserve,represents the largest intact wild ecosystem and pristine biodiversity spot in West Africa.This savannah ecosystem has long been affected by fire,which is the main ecological driver for the annual rhythm of life in the reserve.Understanding the fire distribution patterns will help to improve its management plan in the region.This study explores the fire regime in the PRB during 2001–2021 in terms of burned area,seasonality,fire frequency,and mean fire return interval(MFRI)by analysing moderate resolution imaging spectroradiometer(MODIS)burned area product.Results indicated that the fire season in the PBR extends from October to May with a peak in early dry season(November–December).The last two fire seasons(2019–2020 and 2020–2021)recorded the highest areas burned in the PBR out of the twenty fire seasons studied.During the twenty years period,8.2%of the reserve burned every 10–11 months and 11.5%burned annually.The largest part of the reserve burned every one to two years(63.1%),while 8.3%burned every two to four years,5.8%burned every four to ten years,and 1.9%burned every ten to twenty years.Only 1.3%of the entire area did not fire during the whole study period.Fire returned to a particular site every 1.39 a and the annual percentage of area burned in the PBR was 71.9%.The MFRI(MFRI<2.00 a)was low in grasslands,shrub savannah,tree savannah,woodland savannah,and rock vegetation.Fire regime must be maintained to preserve the integrity of the PBR.In this context,we suggest applying early fire in tree and woodland savannahs to lower grass height,and late dry season fires every two to three years in shrub savannah to limit the expansion of shrubs and bushes.We propose a laissez-faire system in areas in woodland savannah where the fire frequency is sufficient to allow tree growth.Our findings highlight the utility of remote sensing in defining the geographical and temporal patterns of fire in the PBR and could help to manage this important fire prone area.

Land Use and Environmental Gradients Influence on Riparian Woody Plant Diversity and Structure in Lake Manyara Watershed Ecosystem, Tanzania

Riparian vegetations are important in supporting ecological connectivity between aquatic and terrestrial ecosystems. The structure and species composition of riparian woody plants have been subjected to multiple forces with varying degree of influences. This study examined the influence of land use and environmental gradient to the structure and composition of the riparian woody plants in northern Tanzania. A total of 270 plots were surveyed for woody plant species in the riparian ecosystems and later analysed to determine the influence of land use categories (homegarden, crop field, woodlot, open canopy forest, and closed canopy forest) and environmental variables (temperature, precipitation, elevation and slope) to the species richness, abundance, and stand parameters. Basal area was higher in woodlots, homegardens and crop fields than in the open and closed canopy forests;and as expected the reverse was true for the number of stocking density. Correlation among stand parameters with environmental variables varied significantly. Species richness and species abundance were negatively correlated to precipitation, temperature and elevation, while stocking density and basal area were positively correlated to precipitation. The study recommends continual retentions of trees on farm, further promoting of agroforestry interventions and sustainable utilization of woody plants in open and close canopy forests.

美国萨凡纳河生态流量管理实践案例研究

河湖生态流量管理是加强生态文明建设、保障河湖健康的重要内容之一。欧美发达国家较早开展了生态流量研究和管理实践,本文从流域基本概况、保护目标确定、方案制定过程、推荐方案、监测与评价等多个方面,系统介绍了美国东南部受水库调节的萨凡纳河生态流量的研究与管理实践经验,结合我国实际情况,提出尽快完善生态流量保障相关法律规章制度,制定科学合理的生态流量保障方案,尽早开展生态流量适应性管理,持续开展监测积累数据资料等对策建议。

中国东亚飞蝗新蝗区──海南热带稀树草原蝗区的研究

本文通过东亚飞蝗在海南岛近６年来的田间发生动态，参考本岛近５００年来该种害虫的发生为害资料，结合本岛飞蝗发生地近百年来的生态地理的演变特征分析，提出了海南东亚飞但蝗区是“热带稀树草原蝗区”。该蝗区系由于本岛多年来不合理的伐林造田，使大面积的原始森林破坏，生态环境恶化，气候干旱，而演变为次生的热带稀树草原生境而成。这与由大沙河三角洲而成的大陆温带蝗区，在形成原因、结构特征与控制对策等方面完全不同，因此是中国东亚飞蝗新蝗区。文中通过数埋统计分析，不仅明确了影响该蝗区的主动因素（即森林破坏面积、干旱指数）与关键因素（即灌溉面积、撩荒地面积）。而且提出了控制该蝗区的生态对策。

中国东亚飞蝗新类型蝗区──海南热带稀树草原蝗区的生态地理特征及其与大沙河蝗区比较

本文系统地对海南热带稀树草原螟区的生态地理结构特征进行了分析，说明本蝗区是Ｕｖａｒｏｖ（１９３６）提出的飞蝗两类蝗区理论中．由于森林破坏而形成的一类蝗区，作者将它定名为＂热带稀树草原蝗区＂。这类蝗区在我国过去尚缺乏研究。文中进而根据本蝗区的成因、生态特征以及对蝗区的生态控制对策，分别与我国大陆的东亚飞蝗大沙河类型蝗区进行了比较。