Seeds of Life: How wastelands become fertile fields (original) (raw)

Published as part of a theme on Salt-Prone Land Resources

Salinization of soils is a major impediment to their optimal utilization in many arid and semi-arid regions throughout the world. In several large irrigation schemes, salinity-induced land degradation has increased steadily over the last few decades with concurrent reductions in agricultural pro- ductivity and sustainability. Currently, saline soils occur within at least 100 countries. These soils need explicit approaches in their amelioration since soil salinization cannot be reduced by routine irrigation and crop management practices. The approaches used to ameliorate saline soils can be broadly divided into four major categories: (1) leaching of bare saline soils to move excess soluble salts from upper to lower soil depths or out of soil profile in the presence of a natural or artificial drainage system; (2) leaching of cropped saline soils with certain plant species, which can withstand ambient salinity levels; (3) surface flushing or mechanical removal of salts from soils that ...

Irrigated Agriculture on Saline Soils: A Perspective

Agronomy, 2020

Approximately 6.5% of the world’s arable and marginal soils are either saline or sodic. The situation will worsen due to climate change. Regardless of the cause that generated the salinity, i.e., whether primary or secondary, the effect of soil salinization on plant growth and on living organisms will be severe. To mitigate such impacts, several studies have been carried out over the years with the aim of providing technical or management solutions to deal with the multiple consequences of soil salinity. A review by Cuevas et al. proposes a new approach looking for solutions through soil-improving cropping systems (SICSs). The SICSs have to prevent, mitigate or remediate the negative impacts of soil salinization. The efforts of Cuevas et al. were to organize the analyses by focusing on SICSs that would: (1) prevent or halt secondary salinization; (2) cope with salinization; (3) reverse salinization. The study is concluded by an effort to assess the impacts of each SICS and of the co...

Agroforestry Practices for Salt Affected Lands (Biosaline Agroforestry)

Agroforestry: Theory and Practices, 2014

Soils which contain excess soluble salts, adversely affect the plant growth are called the salt affected soils. They occur where potential evapotranspiration greatly exceeds precipitation, which is in arid and semi-arid regions. They are grouped under Aridisols order as well as Intrazonal order or Halomorphic sub-order. In irrigated areas, drainage, leaching and soil amendments are used to reclaim these soils. This traditional approach to ameliorate salt affected soils is difficult and expensive. The alternative way is the biological approach, which involves selection and planting of salt tolerant plants and trees in plantation or agroforestry practices for fodder, fuelwood and/or timber production. Salt tolerant plants and trees have the potential to ameliorate salt lands and can be grown using poor quality water. Planting trees in salt affected soils requires a specialized approach with reference to site development, choice of species and level of management. Though many tree species are astonishingly tolerant to adverse conditions, yet to raise viable plant cover on naturally inhospitable sites requires special attention. The stress faced by the trees depends upon the nature and extent of the problem in soil, which itself is governed by the soil reaction, nature and amount of soluble salts, physical barriers like hard pan, quality of underground water and depth of water table, etc. So understanding the soil problem is a pre-requisite for successful plantation/ agroforestry practices on salt affected soils. Finding ways to make marginal land and saline wasteland productive will permit better quality land to be farmed in more rational ways and lessen the risk of degradation. The standard approach is to increase the salt tolerance of trees and plants with concerted research, but the gains come slowly. The alternative approach is to make use of those plants and trees (halophytes) that have high tolerance for salinity. Substantial progress has been made in evaluating halophytes for their potential to rehabilitate salt affected lands. In recent years, it has been demonstrated that revegetation of saline habitats with halophytic species is profitable and provides many additional benefits. There are about 6,000 species of terrestrial and tidal halophytes in the world which offer promising options for reclaiming salt affected lands.