Landscape Salinity and Water Management for Improving Agricultural Water Productivity - D1.20.13


Background:

Soluble minerals, commonly termed as salts are a natural component in soils and water. They occur especially in dry areas where evaporation exceeds the rainfall and the soil and groundwater became relatively enriched in salts leached from rocks during their weathering. If salt concentration reaches threshold value it became a severe obstacle for plant growth and especially for agriculture. Moreover, natural salinization can be enhanced by irrigation. Recently, according to FAO/UNESCO Soil Map approximately 322,9 million of hectares of salt affected land occur (69.5 mil. in Africa, 53.1 mil. in Near and Middle East, 19.5 mil. in Asia and Far East, 20.7 mil. in Europe, 16 mil. in North America, 59.4 mil. in Latin America and 84.7 mil. in Australia).

Landscape Salinity and Water Management for Improving Agricultural Water Productivity The salinization prevention and the management and mitigation of saline soils require an interdisciplinary approach. Understanding of soil and water processes is an essential condition for these tasks. Among a wide range of disciplines contributing to investigation of these problems the isotope techniques used in soil, water and crop management can play an important role. Unfortunately, the potential of these techniques is not yet explored. It needs an intensive research coordinated at international level. The environmental stable isotopes can provide information related to water and nutrient circulation in agroecosystems and can be used as complementary approach in combination with crop growth modelling using conventional models simulating the crop growth and yields in response to salinity stress (such as AquaCrop and HYDRUS-1D models).

Objective:

The objective of this CRP is to identify ways to improve crop productivity and sustainability through water and salinity management and to define approaches and technologies to assess and monitor soil water content and salinity at field and area-wide scales, to reduce the impacts of climate change and variability on the widespread increase in landscape water and soil salinity on food production. The specific objectives are: (1) to optimize crop productivity through soil and water management under saline conditions at the field scale; (2) to improve soil quality (physical-chemical- biological) and to export salt from the root-zone by water (rain and irrigation) and agronomic management; (3) to assess the impact of on-farm practices on regional crop productivity, water and salt stores and fluxes under current and future climate.

Participants:

Seven research contract holders from Bangladesh, China (two participants), Iran, Pakistan and Vietnam (2 participants), two agreement holders from Spain and USA and two technical contract holders from USA and Czech Republic participate in this CRP.

Activities:

This CRP was formulated on the basis of recommendation of a Consultants' Meeting held at IAEA Headquarters, Vienna, 1-4 October 2012. The first Research Coordination Meetings (RCM) was held on 15 – 19 July 2013 in Vienna, Austria. This meeting was attended also by representatives of Technical University of Vienna and private sector. The second RCM was held in Beijing, China in 8-12 September 2014 where results from the first year’s findings were presented. The activities covered a wide range of topics such as 1) isotopic applications dealing with seawater inclusions in the Red River and Mekong Delta in Vietnam endangering the rice production, 2) the use of soil moisture neutron probe for monitoring the use of saline irrigation water for salt-tolerant barley, rice and wheat, 3) soil water measurements by cosmic ray probe and 4) the deep profile soil water content and bulk electrical conductivity measurements. Research and analytical protocols were fine-tuned.

Nuclear and isotopic techniques will be used to unravel the relative importance of processes involving soil-plant-water interactions, quantify soil evaporation, improve irrigation scheduling, minimize water loss and reduce soil-water salinization. The following techniques are used:

  • Soil moisture neutron probe (SMNP) to measure point scale changes in soil water in combination with cosmic ray probes (COSMOS) to measure larger scale changes in the soil water in the upper soil layer.
  • The use of δ18O and δ2H to quantify the proportion of soil evaporation at field scale, as part of the field and regional water balances.
  • The use of C-13 in plant tissues as indicator of drought and salinity tolerance.

The CRP Mid-Term Review was successfully defended at the IAEA CCRA meeting in 2016 and the third RCM was held in Ho Chi Ming City, Viet Nam, from 12-16 December 2016. The final RCM was held 9-12 July 2018 in Vienna.

Project Officer:

Lee Heng