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CRP Success Story: Landscape Salinity and Water Management for Improving Agricultural Water Productivity (D12013)

Success story

Salt-affected soil is a widespread phenomenon in many countries, affecting crop production. (Photo: M. Zaman/IAEA)

Soil salinity is a major global challenge impacting plant growth and yield and hindering agricultural sustainability. Salinity problems can occur naturally but can also be induced through human action such as irrigation. A recent FAO/UNESCO Soil Map estimates that there are about 400 million hectares of salt affected land globally and that area is increasing every day.

To prevent, manage and mitigate saline soils, an accurate understanding of soil and its water content and the interactions between the two is essential. Using a range of nuclear-related techniques including stable isotopes, it is possible to provide information related to the movement and cycling of water and nutrients in agroecosystems. These methods can be used to complement conventional techniques and models to simulate crop growth in response to water and salinity stress.

A recently completed coordinated research project (CRP) by the IAEA, in partnership with FAO, explored ways to improve crop productivity through water and salinity management with the help of nuclear and related techniques. It also sought to define approaches and technologies to assess and monitor soil water content and salinity at field and area-wide scales.

The project had three specific research objectives: To optimize crop productivity through soil and water management under saline conditions at the field scale; to improve soil quality and to export salt from the root-zone by water (rain and irrigation) and agronomic management; and to assess the impact of on-farm practices on regional crop productivity, water and salt stores and fluxes under current and future climate scenarios.

To assess and monitor soil water content at field and area-wide scales, CRP participants tested the cosmic ray neutron sensor (CRNS), which provides soil water estimates over a larger area (approx. 20 ha, to a depth of 40 cm). This research was carried out in Xinjiang, China, Texas, USA and Petzenkirchen, Austria. With proper calibration, the CRNS was found to be relevant and suitable for area-wide soil water monitoring under saline conditions.

A collaboration was established between the IAEA and the Technical University, Vienna to validate the university’s remote sensing soil moisture data. In addition, a new analysis is being carried out to generate rainfall information from CRNS data, which can be useful for irrigation management.

Tracking the source of salinity

In terms of improving water and soil quality in the crop root zone, the oxygen-18 (18O) isotopic technique was used in Viet Nam to identify salinity due to sea water intrusion relative to poor irrigation management. These results have led to a protocol on the approach. In addition, two Springer and two IAEA Guidelines were developed and published from the CRP:

Guideline for Salinity Assessment, Mitigation and Adaptation Using Nuclear and Related Techniques

Cosmic Ray Neutron Sensing: Estimation of Agricultural Crop Biomass Water Equivalent,

Soil Moisture Mapping with a Portable Cosmic Ray Neutron Sensor,

Cosmic Ray Neutron Sensing: Use, Calibration, and Validation for Soil Moisture Estimation.

The CRP demonstrated that irrigation scheduling using a soil moisture neutron probe and improved salt management combined with the use of salt-tolerant crops such as varieties of barley, rice and wheat were important for improving crop production under saline conditions.

To assess the impact of on-farm practices on regional crop productivity, water and salt stores and fluxes under current and future climatic conditions, the FAO’s AquaCrop model was tested in four countries (Bangladesh, China, Iran and Pakistan) for simulating soil salinity and crop grain yield. The results were then extrapolated to other locations and for various climate scenarios.

An additional output of the CRP was that at least 20 MSc and PhD students were trained under this project. A number of scientists from Bangladesh were invited by Chinese institutions as part of exchange and training between China and Bangladesh.

A total of eleven scientists participated in the CRP, with eight research contract holders (Bangladesh, China (2), Iran, Korea, Uzbekistan, Pakistan, Viet Nam (2)), two technical contracts (Czech Republic, USA) and one agreement holder (Spain).

For further information related to this CRP, please see the CRP page.

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