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Landscape Salinity and Water Management for Improving Agricultural Productivity
Closed for proposals
Project Type
Project Code
D12013CRP
1922Approved Date
Status
Start Date
Expected End Date
Completed Date
30 January 2019Description
Addressing soil and water salinity in agricultural landscapes involves either reducing soil and water salinity (mitigation) or making agriculture resilient to salinity (adaptation) by using innovative soil and water management technologies and practices in salt affected soils and saline water. Efficient investment in salinity mitigation requires an understanding of how different landscapes respond to alternative land and water use options at the field and landscape scale. This CRP aims to address salinization problems in agricultural landscapes and protect the soil and water resources needed to sustain food production. Nuclear and isotopic techniques will be used to unravel the relative importance of processes involving soil-plant-water interaction, quantify evaporation from the soil, improve irrigation scheduling and minimize water loss.
Objectives
The overall 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.
Specific objectives
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.
Impact
Several methodologies were developed in this CRP to assess and monitor soil water content and salinity at field and landscape scales:
-The cosmic ray neutron sensor (CRNS) was first tested for monitoring landscape soil water content.
-Two electromagnetic (EM) soil water sensors TDR-315 and TDR-315L demonstrated that they can accurately estimate soil water contents at bulk electrical conductivities up to 2.5 to 3.0 dS/m in soils with a large clay fraction, and in coarser textured soils, these sensors is feasible up to a bulk electrical conductivity of 5 dS/m.
-Oxygen-18 isotopic technique in combination with chemical analysis e.g. concentration of chloride ion in water, can be applied to assess the source of salinity in root zone (seawater intrusion) and in determining salinity flushing efficiency in opened-wet rice fields.
-A 2D model was developed for optimizing soil water and salt movement under drip irrigation to keep maintain total salinity in root zone in a sustainable level.
-An improved method was developed to evaluate plant water status (plant water deficit index, PWDI) in salt impacted field by considering the relative position of soil water and salinity to roots on root-water-uptake and plant transpiration.
From this project, one international project and three national projects in China were supported
1) China-EU SHui project: Soil hydrology research platform underpinning innovation to manage water scarcity in European and Chinese cropping systems (0.5 million Chinese Yuan)
2) A key project supported by National Natural Science Foundation of China: Mechanism and technical modes of water-fertilization-salt integration regulation in the saline land of Yellow River Delta (3 million Chinese Yuan)
3) Two key projects supported by China Ministry of Science and Technology (4 million Chinese Yuan)
4) Two young researchers from Bangladesh were trained in China Agricultural University on isotopic technology
5) Four PhD and one M.Sc. students were trained as part of the CRP in China, and
6) At least 20 other post-graduate students trained in Bangladesh, Iran, Pakistan, Uzbekistan and Vietnam.
Several major guidelines were published as a result of this CRP:
Zaman, M., Shahid, S.A. Heng, L. (2018). Guideline for Salinity Assessment, Mitigation and Adaptation Using Nuclear and Related Techniques, Springer Open. 131 pp.
Wahbi, A., Heng, L., Dercon, G. (2018). Cosmic Ray Neutron Sensing: Estimation of Agricultural Crop Biomass Water Equivalent, Springer Open, Cham. 33 pp.
IAEA (2018). Soil Moisture Mapping with a Portable Cosmic Ray Neutron Sensor, IAEA-TECDOC-1845, 43 pp.
IAEA (2017). Cosmic Ray Neutron Sensing: Use, Calibration, and Validation for Soil Moisture Estimation, IAEA-TECDOC-1809. 48 p.
A protocol on using oxygen-18 for studying seawater intrusion was developed.
A novel and reliable method was also developed to remove salt from the rooting zone (saline field) through hydrophilic porous materials in arid region, with almost no additional fresh water consumption.
To enhance the long-term sustainability of afforestation as a management option for highly saline lands in Uzbekistan, the 13C isotopic signature was found to be useful for examining salt tolerance of candidate species as the indicator of water and salt stress, salt leaching needs, this has implications for regional scale planning.
Relevance
1. The cosmic ray neutron sensor (CRNS) was found to be a suitable and relevant soil moisture sensor for on-farm moisture monitoring for regional crop productivity, water fluxes under both current and future climate scenarios.
2. The salinity data from this CRP is relevant for further testing of FAO's AquaCrop model. This was tested in Bangladesh, China and Pakistan and found to be relevant for estimating water and salt balances.
3. The salt-removal technology through geotextile and the established smart irrigation system can be applied in other arid regions all over the world for other crops besides cotton.
4. An improved method was developed to evaluate plant water status (plant water deficit index, PWDI) in salt impacted field by considering the relative position of soil water and salinity to roots on root-water-uptake and plant transpiration is relevant globally.
5. Several Technical Cooperation projects have been developed as a result of this CRP:
a. RAS5083: Developing Sustainable Agricultural Production and Upscaling of Salt-Degraded Lands through Integrated Soil, Water and Crop Management Approaches - Phase I, II and III
b. RAS5084: Assessing and Improving Soil and Water Quality to Minimize Land Degradation and Enhance Crop Productivity Using Nuclear Techniques
In view of the widespread occurrence of global salt-affected areas 322.9 million of hectares (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), the work and output from this CRP has significance relevance.