By: Inti Luna
Aistech’s agricultural development and business strategy has been evolving and one of the strategic crops to focus on based on the 2021 unique Thermal monitoring capabilities is rice.
Rice is one of the most important crops in the world with more than 167 million cultivated ha in 2018, is part of the top 3 crops along with wheat and maize1. But Rice is not only one of the most cultivated crops, but it is also the crop that consumes more fresh water, especially in flooded conditions. It has been estimated that around 2500 liters of water are being used to produce 1 kg of rough rice. These 2500 liters account for all the outflows of evapotranspiration, seepage, and percolation. At global scale, this means that more than 25% of freshwater in the globe is used to produce rice which is the most common staple food for more than 3 billion people, mostly concentrated in Asia, Africa, and Latin America2.
Water is a precious and limiting resource and recently reduced water availability is becoming a major problem in many regions of the world, producing high quality and sustained yields is quite a challenge that many rice farmers are facing with environmental and socio-economic implications.
There have been developed different technical measurements to deal with water scarcity at field level, however, it is an ongoing process and there is still a large margin of improvement. Thermal information can greatly contribute to fill that gap and tune water management practices taking into account plant physiological processes. The reason for this is that thermal information allows to estimate crop evapotranspiration using energy balance models like SEBAL, S-SEBI and METRIC3. Therefore, we can quantify the water being used in the fields, that along with some ground measurements, can produce a very good picture of the situation which is crucial when irrigation decisions are to be made. Besides allowing farmers to make better decisions that will directly affect their yield and income, thermal information provides an objective and cost-effective approach to water use in a large extension with many water users and interest. In addition, accurately estimating regional evapotranspiration is crucial for effectively managing basin water resources and monitoring agricultural drought4.
Therefore, thermal derived information has been and will be used to a greater extent when Aistech satellites are in orbit as a tool for water accounting for water governance and sustainable development , specially in locations with scarce information.
With information regarding water used and yield per field we can easily estimate an important crop performance indicator called water productivity, which is defined as the relation between cubic meters of water used to produce kilos or tons of grain (yield). The value of this type of information is that it allows us to detect which fields, farmers and practices are doing better, and help us build Good Agricultural Practices (GAP) that we can promote in other parts, improving yield, reducing pest impact and saving water.
Given the importance of water and rice for the world population, Aistech team had started a pilot project in a rice farm in Sevilla, next to the natural reserve Doñana, in which we would study how to improve water management and crop conditions.
(1) FAOSTAT http://www.fao.org/faostat/en/#home (accessed Oct 2, 2020).
(2) Bouman, B. A. M.; Humphreys, E.; Tuong, T. P.; Barker, R. Rice and Water. In Advances in Agronomy; Sparks, D. L., Ed.; Academic Press, 2007; Vol. 92, pp 187–237. https://doi.org/10.1016/S0065-2113(04)92004-4.
(3) Liou, Y.-A.; Kar, S. K. Evapotranspiration Estimation with Remote Sensing and Various Surface Energy Balance Algorithms—A Review. Energies 2014, 7 (5), 2821–2849. https://doi.org/10.3390/en7052821.
(4) Jiang, X.-W.; Sun, Z.-C.; Zhao, K.-Y.; Shi, F.-S.; Wan, L.; Wang, X.-S.; Shi, Z.-M. A Method for Simultaneous Estimation of Groundwater Evapotranspiration and Inflow Rates in the Discharge Area Using Seasonal Water Table Fluctuations. J. Hydrol. 2017, 548, 498–507. https://doi.org/10.1016/j.jhydrol.2017.03.026.