Soil and Water Management

CEH is heavily involved with the science of land and water management, which considers catchment to global scales.

CEH is responsible for the Countryside Survey which is a unique study or ‘audit’ of the natural resources of the UK’s countryside including soils. The Survey has been carried out at regular intervals since 1978. The countryside is sampled and studied using rigorous scientific methods, allowing us to compare this year’s results with those from previous surveys. In this way we can detect the gradual and subtle changes that occur in the UK’s countryside over time.

Soil is an important component of the survey: soil properties such as soil carbon concentration, total nitrogen, nitrate, pH, phosphorus, heavy metals and soil fauna are all measured.

JULES is the Joint Land Environment Simulator. It is a community model that has been developed from MOSES to improve the land phase representation of the land surface energy and water budget. JULES has been applied at a 1km square scale for the United Kingdom, but its main focus is not soil moisture estimation, and further development of the model is being undertaken to investigate and improve the reliability of the soil moisture estimates. Nevertheless, in the longer term it is likely that models like JULES will provide progressively improving model estimates of soil moisture and thermal behaviour where direct measurements are not available.

In addition, JULES is being linked with other models to understand carbon and nitrogen dynamics.

Numerical and theoretical studies have shown that mesoscale gradients in land surface properties can induce circulations in the atmosphere. Studies conducted at CEH provide the first well-resolved observations of such flows induced by soil moisture from recent rainfall, and are based on aircraft data in the Sahel. In addition, satellite imagery has been used to identify fine scale soil moisture features within a wet zone spanning 160km. Results from this research suggest that mesoscale convergence lines forced by soil moisture may play a significant role in the meteorology of the Sahel.

Many countries in the EU and in other parts of the world are finding that water resources are limited. For agriculture the cost of non-saline water becomes prohibitive so we are looking at ways of using more readily available brackish or grey water for crop production. Irrigation water can be a mixture of saline with non-saline water (blending). Saline water can also be applied in cycles with non-saline water.

The use of saline drainage water for irrigation has an environmental advantage. It reduces the non-saline water requirement for salt tolerant crops and it decreases the volume of drainage water requiring disposal or treatment.

This research programme has lead to the development of the SALTMED model that can predict the impacts of irrigation water quality and crop growth on soil salinity.