Soil salinity under climate change: Challenges for sustainable agriculture and food security.

Poor water resource management is an important factor in soil salinization in arid areas. In this study, the status of soil salinization and its controlling factors are summarized for the Yinchuan ...

https://www.tandfonline.com/doi/pdf/10.1080/07900627.2018.1443059

Conjunctive use of groundwater and surface water to reduce soil salinization in the Yinchuan Plain, North-West China

Responses of soil microbial communities and their network interactions to saline-alkaline stress in Cd-contaminated soils.

Approximately 1 billion ha of the global land surface is currently salt-affected, representing about 7% of the earth's land surface. Whereas most of it results from natural geochemical processes, an estimated 30% of irrigated lands globally are salt-affected through secondary human-induced salinization. Application of lower quality, alternative irrigation water is further threatening expansion of the areal extent of soil salinity, in addition to climate change causing increases of salt-water intrusion in coastal areas and increasing crop water requirements. The reduced availability of freshwater resources for irrigation, the continued reduction of the world's cultivated agricultural area by land degradation and urbanization, in conjunction with a growing world population further complicates the problem seeking sustainable solutions. This scoping review prioritizes critical knowledge gaps and makes recommendations for 10 priorities in soil salinity research toward a sustainable and productive agricultural system for a food-secure future world. We also include basin-specific case studies that illustrate progress of the world's major irrigated areas in addressing impacts of soil salinization. By identifying research priorities, we seek to accelerate enhanced research funding to bring new knowledge and innovative solutions toward mitigation of soil salinity impacts. We further want to inspire the science community to develop new directions in salinity research.

Critical knowledge gaps and research priorities in global soil salinity

Alterations to groundwater chemistry due to modern water transfer for irrigation over decades.

Soil salinity and its associated effects on soil microorganisms, greenhouse gas emissions, crop yield, biodiversity and desertification: A review.

In arid oases, soil salinity and a rise in shallow groundwater are serious threats to long-term sustainability of irrigated agriculture. Understanding the impacts of irrigation practices on soil salinity and shallow groundwater dynamics is critical for improving soil conditions and water efficiency. In this study, the impacts of excessive irrigation of date palms with low-quality water on soil salinization and shallow groundwater properties (depth and electrical conductivity) were evaluated for a 10-year period (2005–2015) in a Saharan Tunisian oasis. The study included three phases: (1) assessment of the suitability of groundwater for irrigating date palms; (2) quantification of the long-term water use of date palm plantations; and (3) quantification of dynamic patterns of soil electrical conductivity and shallow saline groundwater in the studied oasis for a 10-year period (2005–2015). Results of this study indicated that under high evapotranspiration conditions, the identified low-quality water resources (leading to high soil salinization risk) coupled with rapidly rising shallow groundwater at critical depths (<1.5 m) (resulting from the high water use) were key factors of the rapid increase in soil salinization within the oasis. The soil electrical conductivity built up to levels that exceeded the salt tolerance of date palms, estimated at 4 dS m−1. Although the excessive use of irrigation water dilutes the groundwater, and its salinity decreases, the risk of increasing soil salinity is greater because of rising water table.

Effects of excessive irrigation of date palm on soil salinization, shallow groundwater properties, and water use in a Saharan oasis.

Impacts of climate change on irrigation water requirement of date palms under future salinity trend in coastal aquifer of Tunisian oasis

The continuance of agricultural production in regions of the world with chronic water shortages depends upon understanding how soil salinity is impacted by irrigation practises such as water salinity, irrigation frequency and amount of irrigation. A two-year field study was conducted in a Saharan oasis of Tunisia (Lazala Oasis) to determine how the soil electrical conductivity was affected by irrigation of date palms with high saline water. The study area lacked a saline shallow water table. Field results indicate that, under current irrigation practises, soil electrical conductivity can build up to levels which exceed the salt tolerance of date palm trees. The effects of irrigation practises on the soil electrical conductivity were also evaluated using model simulations (HYDRUS-1D) of various irrigation regimes with different frequencies, different amounts of added water and different water salinities. The comparison between the simulated and observed results demonstrated that the model gave an acceptable estimation of water and salt dynamics in the soil profile, as indicated by the small values of root mean square error (RMSE) and the high values of the Nash-Sutcliffe model efficiency coefficient (NSE). The simulations demonstrated that, under field conditions without saline shallow groundwater, saline irrigation water can be used to maintain soil electrical conductivity and soil water content at safe levels (soil electrical conductivity 0.04 cm(3) cm(-3)) if frequent irrigations with small amounts of water (90 % of the evapotranspiration requirements) were applied throughout the year.

Soil salinisation and irrigation management of date palms in a Saharan environment.

In the arid irrigated lands, understanding the impact of shallow groundwater fluctuation on soil salinization has become crucial. Thus, investigation of the possible options for maintaining the groundwater depth for improving land productivity is of great importance. In this study, under saline irrigation condition, the effects of shallow groundwater depth on water and salt dynamics in the root-zone of date palms were analyzed through a particular field and modeling (SWAP) investigation in a Tunisian Saharan oasis (Dergine Oasis). The model was calibrated and validated against the measured soil water content through the date palm root-zone. The good agreement between measured and estimated soil water content demonstrated that the SWAP model is an effective tool to accurately simulate the water and salt dynamics in the root-zone of date palm. Multiple groundwater depth scenarios were performed, using the calibrated SWAP model, to achieve the optimal groundwater depth. The simulation results revealed that the shallow groundwater with a depth of ~80 cm coupled with frequent irrigation (20 days interval) during the summer season is the best practice to maintain the adequate soil water content (>0.035 (cm3 cm−3) and safe salinity level (<4 dS m−1) in the root-zone layer. The results of field investigation and numerical simulation in the present study can lead to a better management of lands with shallow water table in the Saharan irrigated areas.

Zied Haj-Amor

Papers

Soil salinity and its associated effects on soil microorganisms, greenhouse gas emissions, crop yield, biodiversity and desertification: A review.

Effects of excessive irrigation of date palm on soil salinization, shallow groundwater properties, and water use in a Saharan oasis.

Impacts of climate change on irrigation water requirement of date palms under future salinity trend in coastal aquifer of Tunisian oasis

Soil salinisation and irrigation management of date palms in a Saharan environment.

Soil salinization and critical shallow groundwater depth under saline irrigation condition in a Saharan irrigated land