Soil processes affecting crop production in salt-affected soils

Abstract

Salts can be deposited in the soil from wind and rain, as well as through the weathering of rocks. These processes, combined with the influence of climatic and landscape features and the effects of human activities, determine where salt accumulates in the landscape. When the accumulated salt in soil layers is above a level that adversely affects crop production, choosing salt-tolerant crops and managing soil salinity are important strategies to boost agricultural economy. Worldwide, more than 800 million hectares of soils are salt-affected, with a range of soils defined as saline, acidic-saline, alkaline-saline, acidic saline-sodic, saline-sodic, alkaline saline-sodic, sodic, acidic-sodic and alkaline-sodic. The types of salinity based on soil and groundwater processes are groundwater-associated salinity (dryland salinity), transient salinity (dry saline land) and irrigation salinity. This short review deals with the soil processes in the field that determine the interactions between rootzone environments and plant responses to increased osmotic pressure or specific ion concentrations. Soil water dynamics, soil structural stability, solubility of compounds in relation to pH and pE and nutrient and water movement all play vital roles in the selection and development of plants tolerant to salinity.

NaCl salinity affects germination, growth, physiology, and biochemistry of bambara groundnut

“…In Kenya the potentially saline areas include some regions of Coastal, North Eastern, Rift Valley, and Nyanza provinces (Musyimi, 2005). Saline soils are mainly dominated by Na + and Cl -anions, in which NaCl constitutes from 50 to 80% of the total soluble salts (Rengasamy, 2010). Salt stress affects plant growth in three ways: osmotic stress by reducing soil water potential; induction of ion imbalance in cells, especially lowering concentrations of K + , Ca 2+ , and NO -3 ; and causing ion (Na + and/or Cl -) toxicity.…”

“…Salinization of agricultural lands is widespread and occurs in semiarid, low-lying, irrigated, and poorly drained areas (Musyimi, 2005;De Abreu et al, 2008). Such salinization of the soil hugely contributes to low-crop productivity worldwide (Alam et al, 2004), and a drop of crop yield over large areas due to physicochemical constraints in the subsoil (Rengasamy, 2010). Minimal successes have been achieved when using irrigation and drainage as viable management options to improve productivity of saline-sodic soils (Tavakkoli et al, 2011).…”

Impact of ancestral wheat sodium exclusion genes Nax1 and Nax2 on grain yield of durum wheat on saline soils

“…Seawater intrusion onto land, due to global warming causing rising sea levels and more violent storms, can deposit a large amount of salts in soils of coastal lands. These particular processes contributing to salinisation, combined with the influence of other climatic and landscape features and the effects of human activities, determine where the salt accumulates in the landscape (Rengasamy 2010). The type of vegetation also determines how far below the soil surface salts accumulate (Rengasamy 2002).…”

Soil alkalinity and salt tolerance: adapting to multiple stresses

“…We agree that, given the overlap of salinity and alkalinity on the landscape [1,9], it would be interesting to ask whether there has been co-adaptation to salinity and alkalinity. Although clear differences in tolerance to salinity and alkalinity exist for some species (e.g.…”