Construction Of Bunds Research Articles

The role of integrated watershed management in climate change adaptation for small-scale farmers in Southwest Ethiopia

Climate change severely affects smallholder farmers in developing countries such as Ethiopia. To overcome the impacts, the government of Ethiopia has been undertaking a massive adaptation programs including integrated watershed management practices. However, there is a limited understanding of climate change, adaptation strategies, and the effect and acceptance of the implemented techniques. The objective of this study was to assess climate variability, farmers’ climate change adaptation strategies, and the role of watershed management in climate change adaptation. A multi-stage sampling technique was used to select 255 household heads from three rural kebeles (lowest administrative unit of government) in high, mid, and low-elevation areas. The household survey, focus group discussion, and key informant interview record were used to collect data. In addition, long term meteorology record was used. Data were analyzed using descriptive statistics and a multinomial logit model. The results showed that more than 80% of the farmers, in each elevation, perceived climate variability such as increasing temperature and rainfall fluctuations. The perceived variability is more pronounced in the low-elevation areas. The meteorology record also showed fluctuation in rainfall. About 90% of respondents in each elevation area perceived population pressure, cultivation, and deforestation as the major causes of climate variability. About 90% of respondents perceived crop yield decline due to climate variability. In drought years, crop yield and livestock production decline by ∼50% compared to the average year. Adjustment of crop planting time, crop diversification, selling household assets, participating in off-farm activities, and using government aid were practiced as climate change adaptation measures. About 70% of farmers perceived the positive role of watershed management in climate change adaptation. On average, 36–43% of the farmers in the study area participated in watershed management activities such as the construction of bunds and tree planting, which assist in coping with climate variability impacts. Farm size, sex, education, and farming experience positively and significantly affect the adaptation practices of the farmers. Policymakers and practitioners need to consider the issues related to climate variability and watershed management as a strategy for climate change adaptation. Policy intervention by the Federal government on sustainable watershed management and rural livelihood strategies could assist in sustainable environmental management and climate change adaptation.

Biostabilization of soils as sustainable pathway for anti-desertification: Present and future perspectives

Desertification is a growing concern worldwide; mainly in drylands, arid/semi-arid regions, sloping terrains and the coastal areas. It poses significant threat for developing resilient rural, urban and coastal infrastructure, and preserving land/forest/coastal biodiversity and ecosystem. Desertification could result from loss of soil fertility, soil erosion due to heavy and variable rainfall events, salinization, wind erosion, deforestation, overgrazing of vegetation, burning of agricultural residue, natural disasters such as floods, droughts, landslides and forest fires, or changes in land use patterns. Anti-desertification (viz., controlling further desertification and in some cases reversal of desertification process) can be achieved by construction of bunds across water flow (erosion control), underground cutoff walls (control of salinization), afforestation activities, providing grass turfs, coupled with soil stabilization techniques. Anti-desertification on a large scale would require implementation of sustainable and natural strategies to prevent land degradation due to erosion, water logging, or salinization. In this context, the present paper reviews in detail the existing state-of-the-art and discusses the different proven and emerging biostabilization strategies/approaches/methods, that can be combined to serve as sustainable pathways for achieving anti-desertification, an important step towards developing resilient infrastructure.

Monitoring impacts of soil bund on spatial variation of teff and finger millet yield with Sentinel-2 and spectroradiometric data in Ethiopia

Data from remote sensing devices are essential for monitoring environmental protection practices and estimating crop yields. However, yield estimates in Ethiopia are based on time-consuming surveys. We used Sentinel-2, spectroradiometeric, and ground-truthing data to estimate the grain yield (GY) of two major crops, teff, and finger millet, in Ethiopia's Aba Gerima catchment in 2020 and 2021. At the flowering stage, we performed supervised classification on October Sentinel-2 images and spectral reflectance measurement. We used regression models to identify and predict crop yields, as evaluated by the coefficient of determination (adjusted R2) and root mean square error (RMSE). The enhanced vegetation index (EVI) and normalized-difference vegetation index (NDVI) provided the best fit to the data among the vegetation indices used to predict teff and finger millet GY. Soil bund construction increased the majority of vegetation indices and GY of both crops. We discovered a strong correlation between GY and the satellite EVI and NDVI. However, NDVI and EVI had the greatest influence on teff GY (adjusted R2 = 0.83; RMSE = 0.14 ton/ha), while NDVI had the greatest influence on finger millet GY (adjusted R2 = 0.85; RMSE = 0.24 ton/ha). Teff GY ranged from 0.64 to 2.16 ton/ha for bunded plots and 0.60 to 1.85 ton/ha for non-bunded plots using Sentinel-2 data. Besides, finger millet GY ranged from 1.92 to 2.57 ton/ha for bunded plots and 1.81 to 2.38 ton/ha for non-bunded plots using spectroradiometric data. Our findings show that Sentinel-2- and spectroradiometeric-based monitoring can help farmers manage teff and finger millet to achieve higher yields, more sustainable food production, and better environmental quality in the area. The study's findings revealed a link between VIs and soil management practices in soil ecological systems. Model extrapolation to other areas will necessitate local validation.

The importance of farm management training for the African rice Green Revolution: Experimental evidence from rainfed lowland areas in Mozambique

The effectiveness of basic farm management training (e.g., seed selection, nursery bed setup, field leveling, bund construction, and transplanting) for the African rice Green Revolution has not been fully examined. This study evaluated a randomized controlled trial (RCT) of such training in the remote rainfed lowland areas of Mozambique. The training taught these practices without introducing modern varieties or inorganic fertilizers. The intention-to-treat (ITT) effect on paddy yield was 447–546 kg/ha (29 %–36 % of the control group average yield), with statistical significance at 7 %–8%. The results indicate that the adoption of these basic practices alone can improve paddy yield without relying on modern purchased inputs, which are usually not readily available in remote local markets or affordable to cash-constrained farmers. Complementarity among these basic practices is also suggested in that the yield increase had the highest statistical significance when all five practices were adopted.

Changing with the weather: Afghan farmers adapt to drought

Drought is one of the significant impacts of climate change affecting agricultural productivity and subsistence for Afghanistan’s farmers. Producers have applied various adaptation measures making use of their native resources in response to drought. Studying the cases of the Panjab and Waras districts in the south of Bamyan province of Afghanistan, this research aims to analyse Afghan farmers’ drought adaptation strategies. Farmers’ adaptation strategies to drought and the effectiveness of such actions to decrease the effects of this natural hazard were studied. The adaptive strategies were categorised into five groups, including: (i) cropping practices, (ii) soil and water conservation, (iii) animal husbandry management, (iv) wage labour use and (v) financial management. Major adaptive strategies for cropping practices include growing early maturing crops, drought-tolerant crops, inter-cultivation systems, changing cropping patterns, seed treatments, growing non-traditional crops and crop rotation. Soil and water conservation adaptive actions include bund construction, watering at night, levelling land, decreasing irrigated areas, reducing water wastage and small-scale watershed management. Drought responses for livestock included supplementary feed, increased rearing of small animals, fodder cultivation and storage. Non-farm adaptive strategies to augment income include production of handicrafts, additional unpaid family labour, borrowing money, reducing expenditures for non-food and costly food items, migration, selling assets and discontinuing agricultural activities due to drought. Data for this study was collected using a field survey with questionnaires and face-to-face semi-structured interviews with 140 farmers from Panjab and Waras districts in the study area. One of the main issues was the necessity and importance of expanding the Technical and Vocational Education and Training (TVET) support programmes for the adaptation strategies.

EVALUATION OF BUND STABILITY USING GEOSTUDIO SOFTWARE WITH GROUND IMPROVEMENT METHOD USING SAND-KEY AT RECLAMATION WORK ON SOFT SOIL

The use of sand-key reclamation works in soft and very soft soils to increase the stability of the bund construction. Reclamation using the hydraulic fill method requires a stable embankment structure to withstand the potential for landslides from landfills, and in sea areas with very soft subgrade soils, with small undrained cohesion values causes the bund to be unstable and do not exceed the critical limit. The purpose of this study is to evaluate the improvement of soft soil in bund construction so that it is stable using GeoStudio. The Bund stability analysis results show that the value of the sand-key depth depends on the variation in the depth of the seabed. At a seabed depth of -6 m, there is a sand-key depth of 7 m, -5 m the sand-key depth of 10 m, -4 m thesand-key depth of 10 m, -3 m the sand-key depth is 5 m. The final safety number of 1.404,1.438,1,675, and 1.354 respectively.

Impact Of Seawater Intrusion Bund On Soil & Water Conservation Along The Coastal Line Of Poonakary, Sri Lanka

Abstract Saltwater intrusion into coastal aquifers is reported at coastal region of Poonakary, Kilinochchi district. A sea water intrusion bund was constructed by United Nations Development Programme in 2015 to reduce the issues with seawater intrusion. This study aimed to measure the variations of soil salinity and pH before (2015), just after (2016) and three years after (2018) the construction of bund and to identify the impacts of seawater intrusion bund on soil, water quality and crop improvement in the area. The study was conducted in three selected Grama Niladari Divisions of Poonakary, during July to September period in 2018. Soil samples were collected from 30 locations at different sampling depths and the locations were recorded by using GPS and fifteen water samples were collected to measure the water quality parameters and the values compared with WHO standards. A questionnaire survey was conducted to assess the crop improvement in the selected locations. When comparing the soil pH in 2016 and 2018, at all depths except 60cm, changes were highly significant and at 60 cm, it was significant. The Soil EC during 2016 and 2018 revealed that, at 15cm, 30cm and 60cm the changes were significantly different and at 45cm it was not significantly differ due to hardpan formation. A considerable improvement in the water quality and yield improvement of paddy were observed. The study reveals that, the seawater intrusion bund can be considered as a potential permanent solution for seawater intrusion at Poonakary.

Towards Eradication of Phytophthora cinnamomi Using a Fallow Approach in a Mediterranean Climate

While eradication from haul roads was achieved, more work is required to eradicate P. cinnamomi from stockpiles and bunds. We can now implement different management strategies to the construction of bunds and stockpiles to facilitate eradication. Infestation by Phytophthora cinnamomi results in large financial and management constraints to environmental managers. This pathogen was considered impossible to eradicate until recent success with treatments including host removal, herbicide and fungicide application, soil fumigation and physical root barriers. We investigated the most benign of these treatments; keeping the area devoid of living host material. In a Western Australian mine site within a Mediterranean climate, haul roads, stockpiles and roadside bunds had P. cinnamomi colonised Pinus stem plugs buried at multiple depths. Over time, we examined the effects of soil moisture and temperature in different soil conditions and types to compare the recovery of the pathogen. Results: Within 12 months, the pathogen could not be recovered from the haul roads. In the stockpiles, depth produced significantly different results. In 3 of the 4 sites, the pathogen was not recovered at 10 cm after 20 months. By 12 months, at 50 cm, there was an 80% reduction in recovery, but only one stockpile had no recovery from 50 cm, which occurred by 36 months. Bunds were up to 1.75 m high and had variable results for plugs buried at 30 cm, influenced by height, the types of soils and shading. One of the smallest bunds was the only bund where the pathogen was not recoverable (by 22 months). This study provides strong support for using a fallow period to reduce or eliminate P. cinnamomi inoculum.

Adaptation strategies by paddy-growing farmers to mitigate the climate crisis in Hyderabad-Karnataka region of Karnataka state, India

Purpose The purpose of this paper is to consider the climatic variables and evaluate the role of non-climatic factors that delicately influence agriculture. This study has come across various adaptation strategies such as modification in cultivation practices such as shifting planting dates, water-saving techniques and strategic nutrient management. Meanwhile, we are trying to forget the ground reality that a majority of the farmers are not aware of climate-resilient production technologies. However, farmers modify themselves in this climate change scenario for sustainable production. The practise of these adaptation strategies helps to reduce vulnerability to improve their “socio-economic status” and the “quality of life”. Design/methodology/approach The present study was attempted to document all the indigenous practices, which are practised by paddy-growers over time for confronting the climate crisis in the Hyderabad-Karnataka region of Karnataka state, India. A cross-sectional and questionnaire-based survey was conducted to collect primary data. The pre-tested interviewing questionnaire consisted of 7 sections with 51 questions. A total of 90 paddy-growing farmers of the region was selected as respondents for the survey. The descriptive statistics was used to analyse the collected data. Findings In respect of adopted strategies, the vast majority (96.67%) of the farmers had used crops as livestock fodder as they fall back in case of failure, followed by the majority (72.22%) of the selected appropriate varieties. Cent per cent of the farmers adopted the construction of waterways along the slope for safe disposal of rainwater. An overwhelming portion of the farmers adopted levelling of the land in between the bunds (96.67%) and construction of bunds to conserve moisture (95.56%). The majority (76.67%) of the farmers intensified agricultural activities on irrigated land. Nearly half of them (47.78%) paddy growers were practising zero tillage to save time and money. Research limitations/implications The current study was carried out in a few districts of Karnataka. Hence, any policy framed based on the outcomes of this study may not conform to the policy specification needs in general to other parts of the country. The farmers did not maintain record books for updating various records. Therefore, the accuracy of data depends on the memory of the respondents. However, the researcher had made every possible effort to make sure that the data collected are the best of the knowledge of the respondents and bear minimal distortions. Practical implications The major constraints to applying agricultural adaptation strategies in the study area have been a general lack of knowledge, expertise and data on climate change issues; a lack of specific climate change institutions to take on climate change work and the need for a better institutional framework in which to implement adaptation. Actions to address these gaps include, namely, training programmes for local government officials, dedicated research activities and post-graduate courses and the initiation of specific institutional frameworks for climate change. Furthermore, improving and strengthening human capital, through education, outreach and extension services, improves decision-making capacity at every level and increases the collective capacity to adapt. Social implications Hyderabad-Karnataka is already under pressure from climate stresses, which increases vulnerability to further climate change and reduces adaptive capacity. The adverse effects of climate change have a devastating effect particularly on paddy cultivation, which is the mainstay of most Hyderabad-Karnataka Region. This has affected food production with its resultant effect on widespread poverty. Farmers in the study area have developed traditional agricultural adaptation strategies to cope with climate variability and extreme events. Experience with these strategies needs to be shared among communities. Originality/value Though the many literatures were available on the adaptation strategies for climate change this research is one of the few studies to document the farmer led adaptation strategies. This study provides a better understanding of the importance of farmer led adaptation strategies which in turn helps to develop or modify the existing adaptation technologies to cope up with climate change. The authors have come across various adaptation strategies such as modification in cultivation practices such as shifting planting dates, water-saving techniques and strategic nutrient management. Meanwhile, we are trying to forget the ground reality that the majority of the farmers are not aware of climate-resilient production technologies. However, farmers modify themselves in this climate change scenario for sustainable production. The practise of these adaptation strategies helps to reduce vulnerability to improve their “socio-economic status” and the “quality of life”. Therefore, farmer-led adaptation strategies to confront with a change in climate require to be recorded.

Effect of information sources on farmers’ adoption of Sawah eco-technology in Nigeria

This study examined the effect of information sources on farmers’ adoption of Sawah eco-technology in Nigeria. Purposive sampling technique was used to select 166 sawah farmers from Delta, Ebonyi, Kebbi, Kwara, Niger and Ondo states. Interview guide was used to elicit information on the farmers’ personal and production characteristics, sources of information and the sawah eco-technologies. Frequency counts, percentages, means, and chi-square were used to analyse the data. The results of the study revealed that average years of rice production and sawah rice production of the respondents were 34.0 years and 6.9 years respectively. The average farm size and yield of sawah rice of the respondents were 0.46 ha and 3.25 tonnes/ha, respectively. Commonly adopted sawah eco-technologies by the farmers were nursery bed preparations (100.0%), bund construction (92.9%), canal construction (84.9%), flooding (78.3%), puddling (73.4%) and use of power tiller (65.2%). The main sources of information on sawah by the respondents were contact farmers (92.4%), farmers’ association (87.3%), extension agents (87.3%), researchers (79.3%) and friends/relations (77.9%). There was significant (p<0.05) association between respondents’ use of contact farmers (χ2 = 31.28), extension agents (χ2 = 22.19), farmers association (χ2 = 23.06), researchers (χ2 = 19.62) and friends / relations (χ2 = 31.09) and adoption of sawah eco-technology. This study concluded that information sources are important in dissemination of sawah technologies in Nigeria. Therefore, improving the use of information sources that significantly affect adoption of sawah technology should be encouraged among farmers.Keywords: Information sources, Sawah eco-technology, technology adoption

Soil Conservation and Water–Resources Management Techniques used by Small- Scale Rice Farmers in Ebonyi State, Nigeria

he study assessed s soil conservation and water – resources management techniques among small- scale rice farmers in Ebonyi State. A sample of 130 respondents generated via multi- stage, purposive and simple random methods were used. Data were generated through questionnaire and interview schedule and analysed using percentage and mean. Results, showed the indigenous methods for soil and water- resources management used by the rice farmers to include: construction of basin and flow walls ( x= 92.3%), construction of dikes (x = 84.6%), ration- harvesting (x = 73%), and compost- manuring ( x= 69%).Other indigenous methods used include: use of IPM ( = 65.4%), shifting cultivation and planting of trees ( x= 61.5%), crop rotation(x = 57.7%) and Mixed cropping ( = 50.0%). Results on level of use of the Agronomical Best Environmental Management Practices (ABEMPs) through physical measures indicated that construction of bund- lines ( x= 3.23) and farm- drainage ( x= 3.00) were at high level of use, while levelling (x = 2.96), dikes (x = 2.77), stone- lines (x = 2.39), terracing ( x= 2.15) were at moderate level of use and plastic mulching (x = 1.85) was at low level of use. Equally, for biological measures mixed- cropping ( = 3.08) was at high level of use, while crop- rotation (x = 2.80), planting of trees (x = 2.62) and fallowcover (x = 2.23) were at moderate level of use and incorporation of residues (x = 1.92) was at low level of use. On the Best Agronomic Practice measures, results showed conservation tillage and liming (x = 3.00) were respectively at high level of use, while mount- making / ridging (x = 2.92), application of compost manure (x = 2.62), use of IPM (2.62) and application of cow dung and poultry droppings (x = 2.50) were at moderate level of use, while irrigation ( x= 1.77) and zero tillage (x = 1.23) were at low level of use respectively. The indigenous and ABEMPs methods are geared towards stable renewable resource use through sustainable (soil and water- resources) management techniques. There should be enhanced farmer–scientist research collaboration to develop soil and water- resource management techniques for more sustainable for rice production in the study area.Key Words: Indigenous ABEMPs, soil and water- resources, rice farmers.

Adaptive capacity of mountain community to climate change: case study in the Semien Mountains of Ethiopia

Climate vagary has exposed farming communities in Semien Mountains (North West Ethiopia) to repeated droughts and famines in recent years. Most of the farming communities in this area have failed to produce sufficient food and have become dependent on foreign food donations. Yet, the impact, vulnerability and adaptive capacity of the community to climate change in the above-mentioned mountain areas are not well documented. This paper examined the temporal temperature and rainfall trends, and the communities’ vulnerability to climate change as well as their adaptive capacities to the changing climate to fill the existing information gaps regarding issues called forth in the Semien Mountains and other highland environments. Data were gathered using questionnaires, interviews, focus group discussions and field observations. Information from meteorological recordings was also collected for this study. The collected data were analyzed using standardized precipitation index, livelihood vulnerability index, bi-logit model and descriptive statistics. The results confirmed highest climatic variability manifested in rainfall and temperature changes. Rainfall decreased by a total of 573.46 mm (by ≈ 16.38 mm per year on average) from 1979 to 2013. Mean annual temperature increased from 18.54 °C in 1979 to 20 °C in 2013. In this light, majority of the respondents (85%) reported facing climatic hazards. About 70% of them perceive that climate change has decreased land productivity and numerous others (74%) felt its future implications on farmlands. Recurrent crop and animal diseases were indicated by 95.21 and 93.41% of the sampled households, respectively. These climate change-induced incidents were exacerbated by lower adaptive capacities and limited institutional services. Livestock rearing, livelihood diversification, stone bund building, tree planting, organic fertilizer application, selling home articles, soil bund construction, rainwater harvesting, utilizing synthetic fertilizers and preparing hand-dug wells were important adaptive strategies used and ranked 1–10, respectively, by the studied households. Extension services, family size, farm income, access to training and livestock ownership found influential during the use of composting, terracing and tree planting to reduce the negative impact of climate change. Farmer-to-farmer extension appeared to significantly reduce composting, terrace building and tree planting at p < 0.01 level. This calls for further social and cultural related studies to explore the reasons. Climate change adaptation strategies should thus focus on enhancing households’ access to key livelihood assets such as education (training), family size, farm income, extension service, and livestock ownership opportunities.

Construction Technology Used for the Reclamation of Seri Tanjung Pinang (Phase 2)

The second phase of Seri Tanjung Pinang (STP2) aims to be an exemplar water front development that encapsulates the best of island living in Penang, Malaysia. STP2 offers a range of residential, commercial and leisure facilities to both local and international investors. Based on the geographical area, STP2 is divided into three packages, which are Package 2A (foreshore of Gurney Drive and the western region of the sand island), Package 2B (the southeast region of the sand island) and Package 2C (the northeast region of the sand island). It is an extension of the fully developed STP1 (Phase I) consisting of 240 acres of land reclamation works. Reclamation of the 253-acre STP2 Package 2A commenced in 2016 and is still underway, and reclamation of the remaining packages with the reclamation size of 507-acres shall kick off at a later stage. The main intention of this paper is to address the construction technology adopted since the commencement of the STP2 Package 2A reclamation. Prior to introduction to the various construction technologies used, the background of this reclamation project is first described. The overall construction sequence for the reclamation is also provided. The construction technologies applied for this project including turbidity control measures, delivery modes for construction materials, perimeter bund construction, placement of filled materials, soil improvement, sheet pile installation and construction of revetment, are respectively detailed in this paper.

Distribution and nature of sedimentary organic matter in a tropical estuary: An indicator of human intervention on environment

Sediment texture controls the spatial distribution of sedimentary organic matter (SOM) in the Vembanad Lake. Influences of marine derived organic matter (OM) on SOM decreased inner-wards in the northern part of the lake. However, SOM from the southern part of the lake was dominated by terrestrial OM. Marine-derived OM showed the highest affinity for the clay-sized fraction (<2μm) of the sediment in the northern part of the lake. However, aged and humified soil-derived OM was predominant in the clay-sized fractions from the southern part. Alteration of sediment texture led to a change in the distribution pattern of SOM in the lake after bund construction. Human intervention and changes in land-use pattern were also found to influence the SOM content in the southern part of the lake.

The hydrology of the Bois-des-Bel bog peatland restoration: 10 years post-restoration

Restoration measures (ditch blocking, bund construction, etc.) were applied to a cutover part of the Bois-des-Bel (BdB) bog peatland in autumn 1999; since then a near complete cover of Sphagnum rubellum (∼15cm) has developed over the old cutover peat, along with a suite of bog vegetation. This research assesses the restored site's (RES) hydrological condition after 10 growing seasons (May 15th–August 15th, 2010) through comparison with an adjacent unrestored site (UNR) and a natural site (NAT) located elsewhere in the peatland. Evapotranspiration (ET) from RES (242mm) has not noticeably changed since the first 3 years post-restoration (2000–2002) still maintaining lower ET rates than UNR (290mm). The highest ET occurred at NAT (329mm), dissimilar to RES despite similar vegetation cover. UNR generates more runoff (37mm) than RES (7mm), similar to the initial assessments. However, since the initial assessments the average water table has continued to rise, from −35.3 (±6.2)cm (2000–2002) to −27.3 (±14.9)cm (2010) below the cutover peat surface but still fluctuates predominantly within the cutover peat and not the regenerated Sphagnum. The regenerated Sphagnum at RES has increased the surface elevation by ∼15–20cm, and with respect to its surface the average water table was at ∼−42.3 (±20.9)cm. However, its water table was still lower (and more variable) than at NAT (33.2±9.0cm), with respect to the moss surface. Average soil water pressures in 2010 were similar to the early post-restoration condition at depths of 10cm (−43.0±12.2 and −44.1±13.1mb) and 20cm (−41.4±13.0 and −40.6±10.5mb) below the cutover surface at RES and UNR, respectively. Volumetric soil moisture contents (θ) at 2.5, 7.5 and 17.5cm depths were higher in the Sphagnum moss at NAT (0.23, 0.31, and 0.71) compared to RES (0.12, 0.11, and 0.23), where the underlying cutover peat had a relatively high θ of 0.74. The low moisture content in the new moss overlying the relatively moist cutover peat indicates there was restricted connectivity between the two layers. Ten years following the implementation of restoration measures and the development of a near complete 15cm thick Sphagnum moss layer, further time is required for the moss layer to develop (increase in thickness and bulk density, hence water retention capacity) and more consistently host the water table, so that the average water content more closely mimics NAT.

Economic transformation and biological welfare in colonial Burma: Regional differentiation in the evolution of average height

Did economic development result in an improvement in biological welfare in the tropics before the diffusion of modern public health techniques in the 1950s and 1960s? Between the mid-19th and early 20th century, Lower Burma experienced a rapid rise in population and became increasingly commercialized as a major rice exporter. Land reclamation on a massive scale in the Irrawaddy delta required an arduous process of jungle clearance, land drainage and preparation, and canal and bund construction, mostly in malarial swamps. Once paddy lands were created, rice was grown with rudimentary tools in malarial zones. By contrast, in most parts of Upper Burma the economy remained more subsistence-oriented, and less commercialized. In this paper, we investigate changes in physical stature by processing and analyzing data reported in two anthropometric surveys conducted in various regions of Upper and Lower Burma in 1904 and in 1938–1941. An inverted U curve is observed in the evolution of average height in Lower Burma, while stature remained fairly stable in Upper Burma until the 1930s.

Watershed development in India. 1. Biophysical and societal impacts

This paper recommends a revision of watershed development policy in India in relation to the planning of development interventions involving agricultural intensification and rainwater harvesting following biophysical and societal impact studies carried out on two watershed development projects in Karnataka. A need for changes in policy has arisen in response to progressive catchments closure at the basin level and declining volumes of water flowing into village level reservoirs (known locally as tanks). Flow reductions have occurred largely as a result of increased agricultural intensification over the past 10–15 years. Field levelling, field bund construction, soil water conservation measures, farm ponds, the increase in areas under horticulture and forestry and the increased abstraction and use of groundwater for irrigation are all contributing factors to reduced flows. Planning methodologies and approaches, which may have been appropriate 20 years ago for planning water harvesting within watershed development projects, are no longer appropriate today. New planning approaches are required which (1) take account of these changed flow conditions and (2) are also able to take account of externalities, which occur when actions of some affect the livelihoods of others who have no control or influence over such activities and which (3) contribute to the maintenance of agreed minimum downstream flows for environmental and other purposes.

Modeling the effect of three soil and water conservation practices in Tigray, Ethiopia

Severe land degradation affects the livelihood of many farmers in the highlands of Tigray, northern Ethiopia. Various soil and water conservation practices have been proposed to reduce land degradation and to improve the quality of the natural resource base but quantitative information on their agro-ecological effects is often lacking. In this study, effects of three soil and water conservation practices are assessed using a crop growth simulation model (WOFOST), a nutrient monitoring model (NUTMON) and a hydrological erosion model (LISEM), which are applied at field, farm and regional scale, respectively. Evaluated soil and water conservation practices include (i) bunds along field contours to improve water availability for crop production, (ii) mulching of crop residues to improve soil nitrogen stocks and (iii) reforestation to reduce erosion. Data from the watershed Gobo Deguat in northeastern Tigray have been used as a case-study. Bunds slightly increased crop productivity at sowing dates when water-limited yields were low, while productivity decreased at more favorable sowing dates due to the reduction in cropped area required for the construction of bunds. Crop residues used as mulch hardly contributed to lower soil nitrogen depletion at farm level as the total amount of nitrogen in crop residues was limited, while part of the crop residue nitrogen returned to the soil anyway in the form of manure and compost. Reforestation reduced erosion up to 14% but this is insignificant compared to the sacrifice in cultivated land which needs to be reforested. Applied tools allow rapid ex-ante evaluation of soil and water conservation practices and may contribute to improved cost-benefit analysis of proposed measures, and identification of more appropriate means to combat land degradation. The analyses show important trade-offs and the effects of the assessed soil and water conservation practices may partially explain their low rate of adoption in Tigray.

Does prolonged flooding prevent or enhance regeneration and growth of Sphagnum?

Site preparation for restoration of peat-mined bogs in eastern Canada frequently involves the construction of bunds or shallow basins to enhance peat moisture content. As a consequence, Sphagnum reintroduced within restored areas may be subjected to extended periods of flooding, particularly following snow melt or heavy rainfall. This paper examines two aspects of the effect of flooding on growth and development of Sphagnum: (1) the production of innovations (growth buds and shoots) and capitula from plant fragments (six species) under continuous, intermittent or non-flooding conditions, and (2) the growth response of whole plants (10 species) under long-term continuous shallow flooding. The development response of Sphagnum fragments to short-term continuous (8–10 cm), intermittent (−1 to +1 cm) or non-flooding conditions (−3 to 0 cm), was investigated in growth chambers. Environmental parameters were selected to investigate the possible differential effects of early spring flooding (10:7 °C, day:night), or inundation following heavy rainfall events later in the season (20–25:20 °C, day:night). Both temperature regimes yielded similar results. After 1 month of flooding the number of innovations was generally similar to that for non-flooded controls. However, after a further 3 months, fragments that had been flooded for 1 month (either continuously or intermittently) produced more capitula than non-flooded fragments. Although S. fuscum, a hummock-forming species, showed delayed formation of innovations, flooding still increased final capitula production. The growth response of whole Sphagnum plants to long-term continuous flooding in the field (+1 cm), revealed that most species grew well, but that several becoming etiolated. These modifications may result in plants more prone to desiccation during drier events than individual with a regular growth form. It is concluded that limited periods of shallow flooding could enhance Sphagnum development in restored areas. Care must be exercised though, as deep or extensive inundation may result in excessive plant etiolation or cause severe physical disturbances to the restorated areas.

Improved water control and crop management effects on lowland rice productivity in West Africa

Much of the rapidly-growing demand for rice in West Africa will be met from production in inland valley swamps which are abundant and relatively robust with regard to cropping intensification. Rice yields in the traditional, predominating non-bunded systems are low (about 1.5 Mg ha−1). Informal development of traditional rainfed lowlands is currently occurring across the region, mainly with low-cost interventions such as the building of field bunds. Relating lowland rice yield to quantitative information on resource base quality and agronomic practices will improve future research priorities and guide site and system-specific targeting of available technical options. Diagnostic on-farm trials were conducted in 62 traditional and 40 improved (bunded) rainfed lowland fields in three agro-ecological zones of Cote d'Ivoire (Guinea savanna, bimodal forest, and monomodal forest zones) to quantify effects of improved water control on productivity. Weed biomass and rice grain yield were determined in farmers' fields and in super-imposed researcher-managed subplots (clean weeding, zero N control treatment, and mineral fertilizer N application). Grain yield variability was attributed to agronomic practices using multiple regression analysis. Bunding significantly increased rice grain yield across sites by about 40% and controlled weeds, with approximately 25% less weed biomass in bunded than in open plots. Mineral fertilizer N application significantly increased rice yields (18% on average across sites) only in bunded fields, where N use efficiency was 12 compared to 4 kg of rice grain per kg of applied N in open fields. Across environments, about 60% of the observed variability in rice grain yields was explained by water control and the timing of agronomic management interventions (weeding, N application). The increased development of lowland rice areas through the construction of field bunds has the potential to significantly increase rice production in West Africa, while also possibly reducing labor requirements for hand weeding and allowing for a more efficient use of mineral N fertilizers. The benefits from construction of bunds are likely to be largest in the relatively well-drained inland valleys of the savanna and bimodal rainfall forest, compared to the high-rainfall monomodal forest zones.