Salinity in the Soil Environment

Abstract

The purpose of this chapter is to provide plant scientists with a background on the nature of soil salinity with a particular emphasis on irrigated agriculture. Since the chemistry of soil solutions plays a major role in soil salinity, considerable details on this topic are offered. Chemical speciation in the soil solution should be of importance to plant scientists. The dynamic nature of soil salinity in the rootzone affects performance of plants. Profile distribution of salts is affected by leaching fraction and changes with changing water content from irrigation and rootwater extraction. Soluble salts in soils are highly mobile and transported by water through mass flow and dispersion. Irrigation water management is one of the keys in maintaining salt balance in the rootzone. Growing regulations on the disposal and management of poor quality drainage waters is now exacerbating the maintenance of salt balance in the rootzone in irrigated lands. IntroductionThe world's surface area occupies about 13.2 billion ha, but no more than 7 billion ha are arable and 1.5 billion ha are cultivated (Massoud, 1981). Of the cultivated lands, about 0.34 billion ha (23%) are saline (salt-affected) and another 0.56 billion ha (37%) are sodic (sodium-affected). Thus, saline and sodic soils cover about 10% of the total arable lands and exist in over 100 countries. Another set of database (FAO, 1989) indicates that the world has about 227 million ha of irrigated lands of which 20% are salt-affected. Since irrigated agriculture provides about one third of the world food supply, secondary salinization of irrigated lands is of major concern. And of the remaining 1,247 million ha of non-irrigated lands, 31.2 million ha are salinized. Ghassemi et al. (1995)

Chinese rose ( Rosa chinensis ) growth and ion accumulation under irrigation with waters of different salt contents

“…There is little information about the effect of saline water irrigation on roses in field condition. Under field conditions, salinity is a dynamic property in the root zone resulting from evaporation of the soil solution, water extraction, selective plant uptake from plant roots and replenishment by irrigation or rainfall (Tanji, 2002). Meanwhile, environmental conditions such as temperature, light intensity, humidity and wind speed can considerably affect plant response to salinity (Niu and Cabrera, 2010;Zollinger et al, 2007).…”

First and second-year assessments of the rapid reconstruction and re-vegetation method for reclaiming two saline–sodic, coastal soils with drip-irrigation

“…Under field conditions, salinity is a dynamic property of root zones resulting from evaporation of the soil solution, water extraction, selective plant uptake from plant roots and replenishment by irrigation or rainfall (Tanji, 2002). Meanwhile, environmental conditions such as temperature, light intensity, humidity, and wind speed can considerably affect plant responses to salinity (Niu and Cabrera, 2010;Zollinger et al, 2007).…”

Relationship between Soil Salinity and Physico-chemical Properties of Paddy Field Soils of Jhilwanja Union, Cox’s Bazar, Bangladesh

“…Soil salinity (electrical conductivity: EC > 4 dS m -1 ) is a major abiotic stress which limits plant growth and development, causing yield loss in crop species (Qadir, Oster, Schubert, Noble, & Sahrawat, 2007). Salt-affected soils are identified by excessive levels of water-soluble salts, especially sodium chloride (NaCl) (Tanji, 2002). Salinity is causing decline in soil productivity and crop yield which results in severe degradation of bio-environment and ecology (Hoque, Saika, Sarder, & Biswas, 2013) as well as responsible for low cropping intensity in coastal area (Rahman & Ahsan, 2001).…”