Root zone salinity management using fractional skimming wells with pressurized irrigation: Inception report

Wells / Aquifers / Pumping / Groundwater irrigation / Water quality / Salinity control / Irrigation programs / Climate / Waterlogging / Drainage / Soils / Land use / Cropping systems / Farm income

Arsenic an emerging issue: experiences from Pakistan

Arsenic contamination has emerged as a serious public health concern in Pakistan. In Punjab over 20% of the population are exposed to arsenic contamination of over 10 ppb in drinking water while nearly 3% of the population are exposed to over 50 ppb. In Sindh, the situation is even worse with 36% and 16% of population exposed to arsenic contaminated water over 10 ppb and 50 ppb respectively. Both shallow and deep sources have arsenic contamination. A recent study on prevalence of arsenicosis confirmed presence of 40 cases in the study population giving a prevalence 140/100,00 for established and borderline cases. The purpose of this paper is to share experiences gained in implementing an arsenic mitigation programme in the country

Waterlogging, salinity and crop yield relationships

Waterlogging / Soil salinity / Irrigated farming / Fertilizers / Water table / Water quality / Soil degradation / Irrigation practices / Economic analysis / Farm income / Production costs / Cost benefit analysis / Sodic soils / Cotton / Wheat / Sugarcane / Rice / Subsurface drainage / Crop production / Crop yield / Pakistan

Effect of water table management and elevated CO 2 on radish productivity and on CH 4 and CO 2 fluxes from peatlands converted to agriculture

Anthropogenic activity is affecting the global climate through the release of greenhouse gases (GHGs) e.g. CO2 and CH4. About a third of anthropogenic GHGs are produced from agriculture, including livestock farming and horticulture. A large proportion of the UK's horticultural farming takes place on drained lowland peatlands, which are a source of significant amounts of CO2 into the atmosphere. This study set out to establish whether raising the water table from the currently used − 50 cm to − 30 cm could reduce GHGs emissions from agricultural peatlands, while simultaneously maintaining the current levels of horticultural productivity. A factorial design experiment used agricultural peat soil collected from the Norfolk Fens (among the largest of the UK's lowland peatlands under intensive cultivation) to assess the effects of water table levels, elevated CO2, and agricultural production on GHG fluxes and crop productivity of radish, one of the most economically important fenland crops. The results of this study show that a water table of − 30 cm can increase the productivity of the radish crop while also reducing soil CO2 emissions but without a resultant loss of CH4 to the atmosphere, under both ambient and elevated CO2 concentrations. Elevated CO2 increased dry shoot biomass, but not bulb biomass nor root biomass, suggesting no immediate advantage of future CO2 levels to horticultural farming on peat soils. Overall, increasing the water table could make an important contribution to global warming mitigation while not having a detrimental impact on crop yield

Soil and aquifer salinization: toward an integrated approach for salinity management of groundwater

Degradation of the quality of groundwater due to salinization processes is one of the key issues limiting the global dependence on groundwater in aquifers. As the salinization of shallow aquifers is closely related to root-zone salinization, the two must be considered together. This chapter initially describes the physical and chemical processes causing salinization of the root-zone and shallow aquifers, highlighting the dynamics of these processes and how they can be influenced by irrigation and drainage practices, thus illustrating the connectivity between soil and groundwater salinization. The processes leading to aquifer salinization in both inland and coastal areas are discussed. The roles of extractive resource industries, such as mining and coal bed methane operations, in causing aquifer salinization are also outlined. Hydrogeochemical changes occurring during salinization of aquifers are examined with the aid of Piper and Mixing Diagrams. The chapter then illustrates the extent of the problem of groundwater salinization as influenced by management and policy using two case studies. The first is representative of a developing country and explores management of salt-affected soils in the Indus Valley, Pakistan, while the second looks at a developed country, and illustrates how through monitoring we can deducecauses of shallow aquifer salinity in the Namoi Catchment of NSW, Australia. Finally, there is a section on integration and conclusions where we illustrate how management to mitigate salinization needs to be integrated with policy to diminish the threat to productivity that occurs with groundwater degradation