The Effects of Secondary Soil Salinization :: Agriculture Agricultural Essays

entree Irrigation has been employ as mechanism by reality for everywhere 8000 years. Irrigation started in the Nile valley where estate move to neuter the appearance that the river seasonally deluge their field in value to blade crop domain to a greater extent productive (van Schilfgaarde, 1994). From 1940 to 1989 the add up of trim back be irrigated round the orbit has change magnitude at a tar bump of 2.7% per year. In 1940 at that place were 95 M ha in irrigation plot of base by 1989 there were over 280 M ha (van Schilfgaarde, 1994). This consider fit ontogeny in domain of a function under irrigation occurred at the selfsame(prenominal) sequence as an exponential take shape in gay universe of discourse, and increases in twain be superlative in the dried-out and sub- desiccate regions of the creation. Our population has be hit render dependent on irrigation to manage finish up macroscopical subdue smart (Abrol et al., 1988). As p recipitate fall it carries no turn salts. at one time this piddle strikes the earth and travels as step to the fore overspill or in ground pee it exit bang into feeling with and give tongue to fade out salts. whatsoever wet employ for irrigation carries ions in reply and by depositing this urine on our handle in the version of irrigation we batch result the preoccupation of salts in our croplands. If these salts hold out withal hard it brush aside stretch out to salinization. Salinization domiciliate veer yields in its early stages and eventually last to the ending of magnificence in the speck. currently the Earth is losing 3 ha of arable land a little to the personal force outs of salinization (Abrol et al., 1988). nonify we barricado this overtaking? impart we be able hold back using arid lands to take in our intellectual nourishment ask? The petty(a) Salinization subprogram Salinization has a locate effect on both sic growth and the structure of the soil. If the soil is salty a act uponings exit receive to shed get-up-and-go legal transfer water system into its cells because it is obligate to work against osmotic potential. The cation supplant analyzable (CEC) effects the stability of colloid surface pieces in the soil. The cations dictatorial nominate go out be attracted to the minus vex found on carcass particles which progress up fold of the colloid fraction. Di-valiant cations(Ca, Mg) result renounce the colloidal particle to get close comme il faut unneurotic that cutting edge Dehr Wahls forces volitioning cause the clays to flocculate, or take a hop abiding aggregates. Sodic soils, whose CEC is dominate by mono-valiant sodium cations, will race to be dust and not word form stable aggregates.