ADAS soil scientists have been working to understand how soil mapping technologies can be used to support farmers. Soil variability is one of the main factors that determines differences in crop yields. Variation in soil texture, organic matter content, nutrient content, drainage, compaction and soil depth will all be reflected in crop performance.
Where the soil variability is large, and can be managed at practical scales, variable management within the field, e.g. for fertiliser or lime application or cultivations may be worthwhile. Soil ‘mapping’ can be used to identify boundaries between soil types and characterise field areas according to their soil pH or nutrient indices. An increasing numbers of farmers are mapping soil variability as the first step towards understanding and managing soil and crop variability.
Technologies such as soil electrical conductivity (EC) scanning and satellite soil brightness maps can be used to identify soil variability and help define different soil management zones within a field. Precision soil sampling and analysis can be used to map variation in soil pH and soil nutrient content.
The value of precision soil sampling was highlighted in a recent ADAS case study at F.B. Parrish & Son (Bedfordshire); a single composite soil sample taken from the case study field in a ‘W’ pattern showed a soil pH of 6.1; P Index 3; and K Index 2-. However more intensive grid sampling showed within-field variation in soil pH of 5.3-7.1; soil P Index 2-4; and soil K Index 1-4. This type of more detailed soil sampling has the potential to improve yields by increasing fertiliser rates on areas of low soil index and save costs by reducing fertiliser applications on soils at or above target index.
ADAS will also be attending this year’s Crop Tec show at the East of England Showground in Peterborough.