Intelligent soil sampling saves time and money

Soil is a complex and irreplaceable natural resource which varies hugely locally and nationally. While farmers sample their soil to learn about its nutrient levels to help manage their land, soil quality must also be monitored at national or regional scale. With growing populations and stricter legislation, such environmental surveys are becoming increasingly important to ensure sustainable land management, but current sampling methods can be time consuming, costly and produce insufficient results.

However, the new ‘intelligent computer program’ looks set to change this by enabling soil sampling to be tailored to local conditions, allowing land managers to obtain high quality information without over or under sampling.

The program has been designed by researchers at Rothamsted Research, with funding from a Biotechnology and Biological Sciences Research Council (BBSRC) Industrial Partnership Award with the Home-Grown Cereals Authority.

Dr Murray Lark, head of the Environmetics group which developed the software, explained: “Our program learns about the variation of the soil as it samples, and is therefore able to generate a sampling scheme that is tailored to local conditions and ensures that the sampling effort is used to greatest effect. Our program rapidly identifies where variation in the soil is complex and many samples are needed or where less sampling is needed because there are large patches of contrasting soil, so samples can be further apart.”

The underlying concept behind the program is the variogram – a mathematical model of how soil varies across an area. As sampling begins, the computer program is ignorant of the variogram and uses data from the sampling to reduce the level of uncertainty and to direct where subsequent samples should be taken. As data accumulate, this uncertainty is reduced.

Once the program has a sufficiently robust model of the spatial variation within the area, a final phase of sampling points is identified to ensure that the resulting map of the soil will be sufficiently precise.

Both computer simulations and practical trials have shown that this adaptive sampling scheme can converge from no initial knowledge to a reliable map of how soil varies. When tested on real landscapes, the scheme has reduced the number of sampling sites needed without any loss of accuracy.

Professor Julia Goodfellow, BBSRC Chief Executive, said: “This new program is a real breakthrough in modern land management and highlights the important role of a multidisciplinary systems approach to bioscience. By combining theory, computer modelling and experiments, scientists are producing useful and easier to apply outputs, such as this soil sampling program, which will ultimately benefit the wider public.”