Impact of climate change and management strategies on water and salt balance of the polders and islands in the Ganges delta

Enhancing crop production, particularly by growing a crop in the typically-fallow dry season is a key strategy for alleviating poverty in the Ganges delta region. We used a polder water and salt balance model to examine the impact of several crop management, salt management and climate change scenarios on salinity and crop evapotranspiration at Dacope and Amtali in Bangladesh and Gosaba in India. A key (and unsurprising) finding is that salt management is very important, particularly at the two drier sites, Dacope and Gosaba. Good salt management lowers salinity in the shallow groundwater, soil and water storage ponds, and leads to more irrigation. Climate change is projected to alter rainfall, and this in turn leads to modelled increases or decreases in runoff from the polders, and thence affect salt concentrations in the soil and ponds and canals. Thus, the main impacts of climate change are through the indirect impacts on salt concentrations, rather than the direct impacts of the amount of water supplied as rainfall. Management practices to remove salt from polders are therefore likely to be effective in combatting the impacts of projected climate change particularly at Dacope and Gosaba.

MODELING OF A WATER-SALT BALANCE OF A RIVER POOL WITH DEVELOPED IRRIGATED AGRICULTURE

The construction of a mathematical model of the water-salt balance for river basins with the predominant development of irrigated agriculture is considered. The structures of the water and salt balance of the irrigated territory and the balance of the main river bed within it are given. It has been established that if the inflow and outflow of water and salts dissolved in it are caused by its horizontal flows, then the evaporation and accumulation of water (salts) in the aeration zone and groundwater are caused by its vertical flows.This leads to the need to consider instead of the general equation of the water (salt) balance of the irrigated territory of its modifications for the distinguished three vertical zones, that is, “the surface of the territory – aeration zone – groundwater zone”. During the operation of the algorithm, the following are successively determined: elements of the water and salt balance of the irrigated territory and the riverbed; groundwater level as a result of the intake of salts with in-person flow of local tributaries; filtration losses from the channels and the lateral residue of the inflow; moisture content in the aeration zone after irrigation water and precipitation enters it; groundwater level after water from the aeration zone; moisture content in the aeration zone after the influx of groundwater into it; the outflow of groundwater into the riverbed and the final mineralization of water in the aeration zone.

The Effect of Prolonged Irrigation on Soil-amelioration State of the Aley River Steppe in Altai Krai

On the basis of many years of research conducted at the Aley River irrigation system and generalization of literary materials, the impact of irrigation on soil fertility, composition and properties of chernozemic, meadow chernozemic and chernozemic meadow soils, their water and salt regime, and crop productivity has been established. A comprehensive assessment of the long-term impact of irrigation on the change in the hydrophysical and chemical properties of soils and the ecological and reclamation state of the irrigated area is given. The influence of long-term irrigation on the nature and direction of the dynamics of groundwater and salt levels in soils is revealed. The water and salt balance of soils has been compiled, depending on the characteristics and duration of irrigation. It is proved that in conditions of insufficient drainage of the territory, non-compliance with scientifically grounded irrigation regimes, rational irrigation techniques, violation of agricultural technology and crop rotation during long-term irrigation leads to the deterioration of some properties of soils, their salinization and alkalination. Regularities and changes in soil-amelioration conditions during prolonged irrigation of land have been established.

Long nocturnal home hemodialysis : An old therapy brought up to date

Home hemodialysis therapy orientation is rising since 2011 in France due to technical progress in dialysis machines, with a simplified use, an ultrapure and sparing dialysate delivery. The most frequent therapy is short daily dialysis sessions with performing results in terms of water and salt balance, depuration and mainly on autonomy and flexibility. In this article, we describe the organization of an alternative therapy with long nocturnal low flow hemodialysis in a dialyzed patient since 2006 after a graft failure. We discuss the benefits of this therapy, first results, eventual barriers to this method specially the occurrence of an adverse event, security and benefit of a telemonitoring and teleassistance that we develop for this occasion.