Your search found 5 records
1 Qadir, Manzoor; Noble, Andrew; Qureshi, Asad Sarwar; Gupta, R. K.; Yuldashev, T.; Karimov, Akmal. 2009. Salt-induced land and water degradation in the Aral Sea basin: a challenge to sustainable agriculture in Central Asia. Natural Resources Forum, 33:134-149.
Water resources ; River basins ; Groundwater ; Soil salinity ; Soil degradation ; Soil improvement ; Soil reclamation ; Fertilizer application ; Waterlogging ; Water quality ; Saline water ; Irrigation water ; Subsurface drainage ; Trees ; Evapotranspiration ; Pumps ; Land degradation ; Farming systems ; Rice / Central Asia / Kyrgyzstan / Tajikistan / Kazakhstan / Turkmenistan / Uzbekistan / Aral Sea / Amu-Darya Basin / Syr-Darya Basin
(Location: IWMI HQ Call no: e-copy only Record No: H042212)
(0.49 MB)
Expansion of irrigated agriculture in the Aral Sea Basin in the second half of the twentieth century led to the conversion of vast tracks of virgin land into productive agricultural systems resulting in significant increases in employment opportunities and income generation. The positive effects of the development of irrigated agriculture were replete with serious environmental implications. Excessive use of irrigation water coupled with inadequate drainage systems has caused largescale land degradation and water quality deterioration in downstream parts of the basin, which is fed by two main rivers, the Amu-Darya and Syr-Darya. Recent estimates suggest that more than 50% of irrigated soils are salt-affected and/or waterlogged in Central Asia. Considering the availability of natural and human resources in the Aral Sea Basin as well as the recent research addressing soil and water management, there is cause for cautious optimism. Research-based interventions that have shown significant promise in addressing this impasse include: (1) rehabilitation of abandoned salt-affected lands through halophytic plant species; (2) introduction of 35-day-old early maturing rice varieties to withstand ambient soil and irrigation water salinity; (3) productivity enhancement of high-magnesium soils and water resources through calcium-based soil amendments; (4) use of certain tree species as biological pumps to lower elevated groundwater levels in waterlogged areas; (5) optimal use of fertilizers, particularly those supplying nitrogen, to mitigate the adverse effects of soil and irrigation water salinity; (6) mulching of furrows under saline conditions to reduce evaporation and salinity buildup in the root zone; and (7) establishment of multipurpose tree and shrub species for biomass and renewable energy production. Because of water withdrawals for agriculture from two main transboundary rivers in the Aral Sea Basin, there would be a need for policy level interventions conducive for enhancing interstate cooperation to transform salt-affected soil and saline water resources from an environmental and productivity constraint into an economic asset.
2 Saleth, Rathinasamy Maria; Inocencio, Arlene; Noble, Andrew D.; Ruaysoongnern, S. 2009. Economic gains of improving soil fertility and water holding capacity with clay application: the impact of soil remediation research in northeast Thailand. Colombo, Sri Lanka: International Water Management Institute (IWMI). 30p. (IWMI Research Report 130) [doi: https://doi.org/10.3910/2009.130]
Soil improvement ; Impact assessment ; Research projects ; Soil fertility ; Sandy soils ; Water holding capacity ; Clay soils ; Soil water relations ; Soil management ; Farming systems ; Crop yield ; Vegetable crops ; Rice ; Sorghum ; Models ; Statistical methods ; Cost benefit analysis ; Economic analysis ; Economic aspects / Thailand
(Location: IWMI HQ Call no: IWMI 631.422 G750 SAL Record No: H042267)
(427 KB)
Declining productivity of agricultural soils in Northeast Thailand is a challenge facing land managers and farmers. A program was initiated in 2002 to investigate the potential role of incorporating clay-based materials into degraded soils as a means of enhancing productivity. This research report attempts to provide an ex-post assessment of the field level impact and economic viability of this approach, using the empirically derived estimates of the average income impacts that the application of bentonite or clay technology has generated among farm communities in Northeast Thailand. From an exclusive IWMI perspective, the impact evaluation suggests that the program has a net present value (NPV) of US$0.41 million with a benefit-cost ratio (BCR) of 2.44 for the sample, and a NPV of US$21 million with a BCR of 75 for the region.
3 Jouquet, Pascal; Plumere, Thierry; Doan Thu, T.; Rumpel, C. 2010. The rehabilitation of tropical soils using compost and vermicompost is affected by the presence of endogeic earthworms. Applied Soil Ecology, 46:125-133. [doi: https://doi.org/10.1016/j.apsoil.2010.07.002]
(Location: IWMI HQ Call no: e-copy only Record No: H043190)
(0.34 MB)
As soil engineers, earthworms play a key role in soil organic matter turnover and ecosystem functioning. Numerous studies have shown their positive influence on plant growth and soil quality. At the same time, organic matter inputs in compost or vermicompost, produced in the presence of earthworms, are valuable soil amendments that may increase plant growth. However, whether the combination of earthworm activity and organic matter amendments can be a successful approach for soil rehabilitation remains insufficiently studied. The aim of the present study was to determine the interactions between Dichogaster bolaui , an endogeic earthworm species, and compost or vermicompost produced by Eisenia andrei , an epigeic earthworm species, in a degraded tropical soil. We assessed nutrient availability and natural vegetation recovery. Treatments with and without D. bolaui earthworms were compared. The incorporation of both types of organic matter improved soil quality (i.e., higher pH, more C and nutrients) and led to the recovery of vegetation growth (i.e., development of seedlings and higher above- and belowground biomass). Mineral nutrients, on the other hand, had no effect on vegetation development and led to more pollution of groundwater (i.e., higher concentrations of N-NH 4 +, N-NO 3 - , K and P). Although we could not draw definite conclusions about whether vermicompost had a more positive effect on plant growth than compost, this substrate improved soil chemical properties compared with compost. Dichogaster bolaui enhanced leaching of N-NH 4 + , N-NO 3 - and K when mineral nutrients were used. However overall, D. bolaui had a neutral impact on plant growth when combined with compost, but a negative effect when in combination with vermicompost inputs. In conclusion, this experiment demonstrated that organic matter amendment is an interesting alternative for the rehabilitation of tropical soils. However, negative interactions can occur between local endogeic earthworms and vermicompost.
4 International Water Management Institute (IWMI). 2010. Improving soils and boosting yields in Thailand. Colombo, Sri Lanka: International Water Management Institute (IWMI). 2p. (IWMI Success Stories 002) [doi: https://doi.org/10.5337/2011.0031]
(Location: IWMI HQ Call no: e-copy only Record No: H043316)
(310.20 KB)
5 Mekuria, Wolde; Sengtaheuanghoung, O.; Hoanh, Chu Thai; Noble, A. 2012. Economic contribution and the potential use of wood charcoal for soil restoration: a case study of village-based charcoal production in Central Laos. International Journal of Sustainable Development and World Ecology, 19(5):415-425. [doi: https://doi.org/10.1080/13504509.2012.686070]
Wood ; Trees ; Charcoal ; Fuelwood ; Case studies ; Production possibilities ; Chemicophysical properties ; Economic aspects ; Profitability ; Biomass ; Energy consumption ; Soil improvement ; Water availability ; Forestry ; Developing countries ; Rural areas ; Income / Laos
(Location: IWMI HQ Call no: e-copy only Record No: H044884)
(0.65 MB)
Wood charcoal production provides affordable energy in many developing countries and has substantially contributed to the economy through the provision of rural incomes. In several countries, charcoal production leads to overexploitation of forests due to inefficiencies in processing. This study was undertaken in central Laos to (1) examine and document traditional charcoal production systems; (2) investigate the production capacity, recovery efficiencies and economic gains of existing traditional charcoal production methods; (3) characterize the chemical properties of wood charcoal and investigate the potential for soil restoration and (4) investigate local charcoal producers’ perception on forest degradation and their species preferences. Through a socio-economic survey, a cost-based method for economic valuation was undertaken on a range of charcoal production methods currently being used. Laboratory chemical analyses were performed on wood charcoal samples. Results indicated that the traditional mud charcoal mound was used by the majority (82%) of charcoal producers. Total charcoal production per production cycle varied between 400 (produced from 2.7 m3 of wood) and 1600 kg (produced from 18 m3 of wood), with a mean of 938 kg (±120) for traditional mud charcoal mounds. The volume of the traditional mud charcoal mounds correlated positively and significantly with total charcoal production (R2 = 0.45, p = 0.03), whereas correlated negatively and significantly with the recovery efficiency (R2 = 0.58, p = 0.01). On average, the local producers receive a total net benefit of 457,272 Lao kip (USD 57.2) in 17 days. We also identified a rice husk mound method of charcoal production, which may not encourage further deforestation while producing rice husk biochar that can be used for soil restoration. Furthermore, we found that there are significant differences (p < 0.05) between the sampled wood charcoals in chemical properties, indicating that the potential of using wood charcoal for the restoration of degraded soils varies from charcoal to charcoal.
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