Irrigation of the future: sources of information for property and regional management
Robust conceptual frameworks to estimate the water consumption of crops, together with information sources based on modern technologies, allow efficient management of irrigation at a parcel and regional scale.
Context of the story
The competition for the use of water between economic sectors, the increase in the demand for food and the evident effects of climate change, foresee limitations in the availability of water for agriculture. In contrast, the efficiency of water use in agriculture is only 50%. Today, the wide range of technology allows the use of robust conceptual frameworks to accurately establish the water consumption of crops and the contribution of irrigation. In this sense, the availability of satellite-based vegetation index is a great advance as a source of information on the development of crops at a parcel and/or regional scale. Having this information openly to make decisions on irrigation management represents a quantitative advance to improve water efficiency.
Crop water consumption can be estimated at two work scales: plot and region.
The implemented initiative
The objective is to improve the water use efficiency in agriculture of LAC countries. For this, robust conceptual frameworks and modern technologies are used that generate useful information in the irrigation management. The project is developed in pilots in Chile, Argentina, Colombia and Uruguay, where the conceptual-technological framework is implemented in two work scales: plot and region. The technological tools used are satellite imagery (Platform Map Web Server - PLAS) and sensors of environmental demand and water availability in the soil. In this way, information with high spatial and temporal resolution is available, transforming traditional irrigation management into informed systems, which allow the implementation of methodologies to improve the efficiency of water use.
Satellite images allow the monitoring of crop development in a frequent and economical manner and make efficient irrigation management operational.
The technological solution
Scientific works on satellite remote sensing has demonstrated the ability of vegetation indices (VI) to assess the development of crops and estimate their evapotranspiration (ETc). The rationale is based on the ability of VIs to estimate the fraction of crop cover, the absorption of photosynthetically active radiation (fPAR) and the leaf area index, all parameters of the transpiration rate and biomass production of the crops. From sequences of satellite images it is possible to estimate the amount of vegetation displayed by the crop and the ability to transpire against the demand of the environment. The PLAS FONTAGRO platform is routinely updated with NDVI vegetation index images from the Sentinel 2A and 2B satellites. The transformation of the NDVI to a strategic irrigation parameter such as the crop coefficient (Kc) and which, together with the environmental demand, allows estimating the water consumption of crops and therefore the irrigation rate.
THE EXPERIENCES GATHERED DURING THE PAST 30 YEARS SUPPORT THE OPERATIONAL USE OF IRRIGATION SCHEDULING BASED ON FREQUENT MULTI-SPECTRAL IMAGE DATA.
The PLAS FONTAGRO online platform allowed users quick and easy access to the NDVI vegetation index time series, as well as the basal crop coefficient. In this way, and together with the information from the forecast of the environmental demand ETo (meteorological models), it is possible to estimate the water consumption of the crops within the pilot zones. From the information vegetation index, climate, soil and crop type, the regional water balance was estimated at a pixel scale (10 m x 10 m) for the analysis area in Chile and Spain and then grouped into analysis territories of water management. The modeled values of the water consumption of the crops were adjusted to the allocations reported by the water administration. On a farm scale, satellite irrigation was advised on potatoes, lettuce, beans (Chile pilot) and irrigation analysis was established for industrial tomatoes (San Juan) and vineyard (Mendoza).