Your search found 6 records
1 Berthelsen, S.; Noble, Andrew D.; Ruaysoongnerm, S.; Webb, M.; Hengfu, H.; Jiexiang, Y. 2005. Addition of clay based soil ameliorants to light textured soils to reduce nutrient loss and increase crop productivity. In International Union of Soil Sciences (IUSS); Institut de Recherche pour le Developpement (IRD); Thailand. Land Development Department (LDD); International Water Management Institute (IWMI); FAO. Regional Office for Asia and the Pacific (FAO RAP); Khon Kaen University. Faculty of Agriculture. Management of tropical sandy soils for sustainable agriculture: a holistic approach for sustainable development of problem soils in the tropics. Proceedings of the First Symposium on Management of Tropical Sandy Soils for Sustainable Ariculture, Khon Kaen, Thailand, 27 November – 2 December 2005. Bangkok, Thailand: FAO Regional Office for Asia and the Pacific (FAO RAP). pp.373-382.
Soil texture ; Soil fertility ; Soil chemicophysical properties ; Soil organic matter ; Clay soils ; Sandy soils ; Cation exchange capacity ; Bentonite ; Plant water relations ; Agricultural production ; Productivity ; Rice ; Yields ; Farmers ; Biomass / Northern Australia / Northeast Thailand / China / Hainan
(Location: IWMI HQ Call no: 630 G000 INT Record No: H047329)
(0.46 MB) (16.9 MB)
Productivity decline occurs in many agronomic systems due to loss of soil organic matter and a consequent decline in soil fertility. This is pronounced in light textured soils, which even in their pristine state can have low levels of fertility. High temperatures and leaching conditions in tropical environments further exacerbates this poor fertility. In order to facilitate agronomic production on these soils, significant amounts of organic or inorganic fertilizers are required to maintain economic yields. However, the inherent low cation exchange capacity (CEC) of these soils limits their ability to retain nutrients such as Ca2+, Mg2+ and K+. The addition of inorganic fertilizer is often beyond the means of resource poor farmers and has the potential negative impact on the environment due significant leaching losses associated with the high hydraulic conductivity of light textured sandy soils. This paper reviews results from field experiments designed to assess the efficacy of bentonite (high-activity clay with a high CEC) additions on improving crop productivity and reducing nutrient loss. A number of field trials were established on light-textured soils in Northern Australia, Northeast Thailand and Hainan Province in China. Treatments and crop species (including sugarcane and various forage crops) differed at each of the study locations and included a range of rates (from 10 to 60 t ha-1), different application methods (broadcast, banded and slotted), and in some trials a comparison with other commonly used field amendments (e.g. various organic materials and termite mound material). These field trials demonstrated significant increases in crop biomass and yields associated with clay additions. Additional glasshouse studies support the observed increases in biomass observed in the field trials, and suggest that the yield increases were due to a combination of increased water-holding capacity, nutrient availability and reduced nutrient loss. These results support the notion that degraded light textured soils can be highly productive if intrinsic properties are addressed through clay additions.
2 Kim, J.-H.; Kim, K.-H; Thao, N. T.; Batsaikhan, B.; Yun, S.-T. 2017. Hydrochemical assessment of freshening saline groundwater using multiple end-members mixing modeling: a study of Red River delta aquifer, Vietnam. Journal of Hydrology, 549:703-714. [doi: https://doi.org/10.1016/j.jhydrol.2017.04.040]
Groundwater ; Salinity ; Aquifers ; Hydrology ; Chemical composition ; Geochemistry ; Cation exchange capacity ; Sulphates ; Models ; Principal component analysis ; Rivers ; Sea water ; Deltas / Vietnam / Red River Delta
(Location: IWMI HQ Call no: e-copy only Record No: H048159)
(2.80 MB)
In this study, we evaluated the water quality status (especially, salinity problems) and hydrogeochemical processes of an alluvial aquifer in a floodplain of the Red River delta, Vietnam, based on the hydrochemical and isotopic data of groundwater samples (n = 23) from the Kien Xuong district of the Thai Binh province. Following the historical inundation by paleo-seawater during coastal progradation, the aquifer has been undergone progressive freshening and land reclamation to enable settlements and farming. The hydrochemical data of water samples showed a broad hydrochemical change, from Na-Cl through NaHCO3 to Ca-HCO3 types, suggesting that groundwater was overall evolved through the freshening process accompanying cation exchange. The principal component analysis (PCA) of the hydrochemical data indicates the occurrence of three major hydrogeochemical processes occurring in an aquifer, namely: 1) progressive freshening of remaining paleo-seawater, 2) water-rock interaction (i.e., dissolution of silicates), and 3) redox process including sulfate reduction, as indicated by heavy sulfur and oxygen isotope compositions of sulfate. To quantitatively assess the hydrogeochemical processes, the end-member mixing analysis (EMMA) and the forward mixing modeling using PHREEQC code were conducted. The EMMA results show that the hydrochemical model with the two-dimensional mixing space composed of PC 1 and PC 2 best explains the mixing in the study area; therefore, we consider that the groundwater chemistry mainly evolved by mixing among three end-members (i.e., paleo-seawater, infiltrating rain, and the K-rich groundwater). The distinct depletion of sulfate in groundwater, likely due to bacterial sulfate reduction, can also be explained by EMMA. The evaluation of mass balances using geochemical modeling supports the explanation that the freshening process accompanying direct cation exchange occurs through mixing among three end-members involving the K-rich groundwater. This study shows that the multiple end-members mixing model is useful to more successfully assess complex hydrogeochemical processes occurring in a salinized aquifer under freshening, as compared to the conventional interpretation using the theoretical mixing line based on only two end-members (i.e., seawater and rainwater).
3 Kadyampakeni, Davie M.; Mul, Marloes L.; Obuobie, E.; Appoh, Richard; Owusu, Afua; Ghansah, Benjamin; Boakye-Acheampong, Enoch; Barron, Jennie. 2017. Agro-climatic and hydrological characterization of selected watersheds in northern Ghana. Colombo, Sri Lanka: International Water Management Institute (IWMI). 40p. (IWMI Working Paper 173) [doi: https://doi.org/10.5337/2017.209]
Watersheds ; Agricultural production ; Intensification ; Agroclimatology ; Hydrology ; Analytical method ; Agronomic practices ; Water balance ; Water quality ; Water management ; Water deficit ; Climatic factors ; pH ; Electrical conductivity ; Soil texture ; Soil quality ; Soil sampling ; Soil fertility ; Land cover mapping ; Land use ; Rain ; Temperature ; Evapotranspiration ; Farmers ; Wet season ; Dry season ; Reservoir storage ; Wells ; Rivers ; Irrigation schemes ; Catchment areas ; Cropping systems ; Crop production ; Meteorological stations ; Cation exchange capacity / Ghana
(Location: IWMI HQ Call no: IWMI Record No: H048209)
(1 MB)
This paper provides the climatic and biophysical context of three watersheds in northern Ghana. The objective of the study is to describe the agro-climatic and hydrological features of the watersheds from a landscape perspective. The analyses show that water surplus occurs about 3 months in a year, with only one month providing a significant surplus. Small-scale irrigation is, therefore, carried out in the dry months between November and June. The quality of water used for irrigation from wells, reservoirs and rivers is good for irrigation and domestic purposes. The soil chemical parameters across the study sites show that the soils are suitable for irrigation and crop system intensification, although it requires substantial fertilizer inputs. The paper concludes that there are opportunities from both a soil quality and water availability perspective to enhance sustainable intensification through small- and medium-scale irrigation in the selected watersheds.
4 Hishe, S.; Lyimo, J.; Bewket, W. 2017. Soil and water conservation effects on soil properties in the Middle Silluh Valley, northern Ethiopia. International Soil and Water Conservation Research, 5(3):231-240. [doi: https://doi.org/10.1016/j.iswcr.2017.06.005]
Soil conservation ; Water conservation ; Land degradation ; Soil chemicophysical properties ; Soil density ; Soil texture ; Soil organic matter ; Nitrogen ; Phosphorus ; Cation exchange capacity ; Valleys / Ethiopia / Middle Silluh Valley
(Location: IWMI HQ Call no: e-copy only Record No: H048336)
http://www.sciencedirect.com/science/article/pii/S2095633917300679/pdfft?md5=555c872c6770f549b14171beeee2810d&pid=1-s2.0-S2095633917300679-main.pdf
https://vlibrary.iwmi.org/pdf/H048336.pdf
https://vlibrary.iwmi.org/pdf/H048336.pdf
(1.94 MB) (1.94 MB)
Community-based Soil and Water Conservation (SWC) practices have been adopted in the Tigray region since 1991 for restoration of the degraded landscape. The effects of those conservation measures on physico-chemical properties of soil were limitedly studied. Thus, this study evaluated the effects of SWC on selected soil properties in the Middle Silluh Valley, Tigray region, Northern Ethiopia. The study considered conserved landscapes (terraced hillside, terraced farmland and exclosure area) and non-conserved landscapes (non-terraced hillside, non-terraced farmland and open grazing land) for comparison using a one-way analysis of variance (ANOVA). A total of 24 samples were collected from each landscape at a depth of 10–30 cm. The results indicated that mean bulk density (BD) was low on terraced hillside, non-terraced hillside and exclosure area. Sand and clay content were significantly different at P <0.05 for the six landscape categories. Higher mean organic matter was observed in the conserved landscape, as compared with the corresponding non-conserved landscape. Pearson's correlation between Soil Organic Matter (SOM) and clay content, SOM and Total Nitrogen (TN) showed strong positive relationships. Overall, the results show that SWC had significantly positive effects on soil's physical and chemical properties in the study area.
5 Berazneva, J.; McBride, L.; Sheahan, M.; Guerena, D. 2018. Empirical assessment of subjective and objective soil fertility metrics in East Africa: implications for researchers and policy makers. World Development, 105:367-382. [doi: https://doi.org/10.1016/j.worlddev.2017.12.009]
Soil fertility ; Agricultural productivity ; Soil analysis ; Soil pH ; Soil types ; Soil quality ; Cation exchange capacity ; Natural resources management ; Researchers ; Policy making ; Farmers attitudes ; Crop yield ; Maize / East Africa / Kenya / Tanzania
(Location: IWMI HQ Call no: e-copy only Record No: H048769)
(1.09 MB)
Bringing together emerging lessons from biophysical and social sciences as well as newly available data, we take stock of what can be learned about the relationship among subjective (reported) and objective (measured) soil fertility and farmer input use in east Africa. We identify the correlates of Kenyan and Tanzanian maize farmers’ reported perceptions of soil fertility and assess the extent to which these subjective assessments reflect measured soil chemistry. Our results offer evidence that farmers base their perceptions of soil quality and soil type on crop yields. We also find that, in Kenya, farmers’ reported soil type is a reasonable predictor of several objective soil fertility indicators while farmer-reported soil quality is not. In addition, in exploring the extent to which publicly available soil data are adequate to capture local soil chemistry realities, we find that the time-consuming exercise of collecting detailed objective measures of soil content is justified when biophysical analysis is warranted, because farmers’ perceptions are not sufficiently strong proxies of these measures to be a reliable substitute and because currently available high-resolution geo-spatial data do not sufficiently capture local variation. In the estimation of agricultural production or profit functions, where the focus is on averages and in areas with low variability in soil properties, the addition of soil information does not considerably change the estimation results. However, having objective (measured) plot-level soil information improves the overall fit of the model and the estimation of marginal physical products of inputs. Our findings are of interest to researchers who design, field, or use data from agricultural surveys, as well as policy makers who design and implement agricultural interventions and policies.
6 Yakob, G.; Habte, M.; Smith, J. U.; Hallett, P. D.; Phimister, E.; Rivington, M.; Black, H.; Mekuria, Wolde. 2023. Changes in soil properties with long-term organic inputs due to distance from homestead and farm characteristics in southern Ethiopian farmlands. Geoderma Regional, 35:e00710. [doi: https://doi.org/10.1016/j.geodrs.2023.e00710]
Soil properties ; Soil fertility ; Soil organic carbon ; Farmland ; Agricultural practices ; Canopy ; Cation exchange capacity ; Agricultural productivity ; Households ; Income ; Gender ; Women / Ethiopia / Halaba / Andegna Choroko / Lay Arisho / Asore
(Location: IWMI HQ Call no: e-copy only Record No: H052330)
https://www.sciencedirect.com/science/article/pii/S2352009423001062/pdfft?md5=d7dc9a6b182797b14078593359e2edaa&pid=1-s2.0-S2352009423001062-main.pdf
https://vlibrary.iwmi.org/pdf/H052330.pdf
https://vlibrary.iwmi.org/pdf/H052330.pdf
(4.95 MB) (4.95 MB)
Traditional farming systems across much of Sub-Saharan Africa have greater organic inputs near to the homestead than in fields further away. This is likely to produce a fertility gradient that impacts production capacity, and so provides an opportunity to explore impacts of organic amendments on soils. Across 198 farm plots in 69 households in Halaba, Southern Ethiopia, we investigated the influence of different organic input systems on soil properties. The study also examined the influence of household and farm characteristics on the adoption of land management practices and its impact on soil properties. Samples were taken from farm plots located close (300 m) from the homestead, representing different levels of organic amendments. Soils located close to homesteads had significantly greater soil organic carbon, cation exchange capacity and soil nutrient content compared to soil located near and far from the homestead areas. Soil organic carbon concentrations close to the home were 15%, 27% and 45% greater than farm plots located at far from the home in Andegna Choroko, Asore and Lay Arisho kebeles, respectively. Across all sites, the mean soil organic carbon stock ranged from 20.6 t ha- 1 to 84.6 t ha- 1 , depending on the location of the plots with respect to the homestead. Household and farm characteristics also influenced land management practices and soil properties. In some catchments, farm plots managed by female headed households and relatively rich farmers displayed significantly greater soil organic carbon than farm plots managed by male headed and relatively poor households. This was likely due to greater organic inputs in female headed households in areas where men were otherwise engaged in off-farm activities and in wealthier households with greater access to organic manures. Tree cover in farmlands influenced accumulation of soil organic carbon. The results suggest that out-scaling farm management practices that are common around homesteads, such as adding animal manure or household wastes and maintaining tree cover, would help to improve key soil properties and agricultural productivity.
Powered by DB/Text WebPublisher, from
