Synthesis of remote sensing and novel ground truth sensors to develop high resolution soil moisture forecasts in China and the UK

The availability of water is a key driver of agricultural productivity. It directly impacts plant growth, and in many countries and locations it is in short or over supply. The impact of water availability on global food production is seen as a key global risk and challenge. Water availability is a hugely contentious international issue, and global climate change, potentially driving increased droughts and flooding, is considered a compounding factor. This projects seeks to develop agri-tech solutions to help alleviate the issue of water in agriculture, and for producers to ultimately drive water use efficiency. Soil moisture directly impacts crop growth, it drives irrigation systems and once a soil has reached its holding capacity excess water rapidly runs into the drainage system, potentially impacting flood risk and system drainage capacity. One of the most significant challenges within the water debate is that there are few simple and reliable systems to measure soil moisture. It is difficult to accurately measure. Techniques developed include spot THD capacitance sensors, the use of neutron probes and more recently the use of remote sensing techniques. Currently, there is no system to measure soil moisture distribution accurately across a field, and the resolution of remote sensing has not been sufficient for agricultural application, or local water management to reduce flood risk. In this project we will bring together a suite of new technologies which increase the resolution of soil moisture measurement to render it applicable for agricultural application on a field, as well as, landscape scale.

The project will deploy two new sensors (one static, one mobile) within China that measures soil moisture content as a function of the albedo of cosmically generated fast neutrons (Cosmos sensor, designed by Hydroinova, US). The static sensor measures soil moisture within a field up to a 200m radius from the measurement point. A mesh of static sensors will be deployed within Henan and Hebei province (which produces 40% wheat of China), China. The mobile sensor will be deployed on a bespoke autonomous vehicle or rover to measure soil moisture variation within a field. The vehicle will be developed within the project and will be the first autonomous deployment of this sensor technology. Data from the soil moisture sensors will be used to calibrate the InSARS sensor on the Sentinel-1 satellite to monitor soil moisture within China to within a 500m x 500m resolution. This is a 5-fold improvement on current resolution from SARS. Ultimately, the technology will enable near real time forecasts of soil moisture at a field scale. This information will be invaluable to agricultural producers and for flood risk forecasting, including key insights to improve water use efficiency, irrigation practices, land drainage and the implementation of precision agricultural techniques.

This is an ambitious multi disciplinary project. The project coordinates the expertise of four key groups, the University of Lincoln (robotics, mapping and deployment of autonomous vehicles), the Institute of Ecology and Agrometeorology (IEAM) of Chinese Academy of Meteorological Sciences, University of Information Science &Technology, the Centre for Ecology and Hydrology (Wallingford) and the School of Geography and Earth Sciences, The University of Aberystwth. Considerable focus is placed on knowledge exchange, not just with the agricultural and hydrological communities, but also between international partners within the project. We anticipate that the UK will benefit from understanding the challenges of developing sensor networks in China, with significant differences in scale and environment. The Chinese team will spend considerable periods embedded with the UK academics to learn new skills in remote sensing, sensor deployment and autonomous vehicles.

This project will have significant economic, environmental and societal impact. The issue of "water" is considered to one of the most significant global risks. A lack of water leads to drought and food shortages, excess water can lead to flooding and soil erosion. Furthermore, the impact of water on global food production is likely to increase, there is mounting evidence that climate change is driving more extreme climatic events, including droughts and floods. The world's global population is likely to increase to 9+bn from 2035 onwards. In the context of these issues any technology which can help understand water availability, to measure it and provide insight to farmers which drives water use efficiency will have a significant and internationally important impact.

The economic impacts will derive from having a more resilient and well understood water management system for farmers. Accurate soil moisture measurement will enable improved irrigation scheduling, improved drainage systems, higher agronomic yields by optimising water use, improved farming systems by being able to monitor the long term impacts of farming practices (for example impacts or organic matter on water holding capacity, tillage systems). Accurate soil moisture measurement will enable a suite of down stream precision agriculture applications. Given that no existing integrated system is available internationally, the technology per se could also be marketed internationally. There would be opportunities to market or provide the outputs of the system to the farming community (for example to provide near real time estimate of soil moisture via apps). The project may also produce a number of more bespoke agri tech opportunities, for example the autonomous vehicle developed in this project may be suitable to mount an array of further sensors (e.g, for monitoring of crop health, soil fertility, nutritional status etc). The UK Satellite Catapult have acknowledged that the project may generate wider scale applications for ESA science assets such as the Sentinel-1 satellite. Valuing these benefits is extremely difficult but they are likely to be very significant.

The environmental benefits are that soil moisture has a significant impact on ecosystems, drought and flood risk. Flood risk amelioration and reduction is a global issue and is a key policy function of UK and Chinese government. An improved higher resolution system to monitor soil moisture will help our ability to forecast drought and floods. It will also help farmers and environmentalists develop new systems (such as rural SUDS) to reduce water flow from fields into water courses. We see application of the higher resolution network to improve hydrological modelling and risk assessment. Improve risk assessment will enable a more focussed deployment of government flood defence funding. .

The societal benefits are highly significant. Drought severely reduces crop yield. The availability of water is politically sensitive and there is an urgent need to find ways to underpin global food security. A key pillar will be the use of accurate soil moisture measurements. This drives water use efficiency and agricultural water resilience.