Soil sample data highlights P & K at inadequate levels in many soils

The second annual report of the Professional Agricultural Analysis Group highlights how many UK soils remain below target indices for phosphate and potash threatening farmers ability to achieve yield potential.

The report contains data from routine soil analyses undertaken by the 14 laboratories that join forces to run a Proficiency Test Scheme and publish an annual summary of soil sample results. The report can be found at www.nutrientmanagement.org.

The new data, reflecting samples analysed in the year ended May 2010, show that less than a third of all samples are at target indices for phosphorus (P) and potassium (K):

– 29% of samples were at target indices of 2 for P and 2 minus for K,

– 26% of samples were below target index for P and 35% below target index for K,

– 16% of samples for P and 19% of samples for K were more than one Index above the target.

The results show the need to address shortfalls in P and K supply on low status soils which reflect more than a quarter of all soils sampled. Crops grown on such soils run the risk of under-utilisation of applied nitrogen fertilisers and failure to achieve yield potential. At the same time on soils that exceed a crops target status, there is a need to run-down P index to avoid potential phosphate loss to water from eroded soil, says AICs Jane Salter who Chairs PAAG for the Industry Professional Nutrient Management Partnership.

The report also addresses the pH status of soil samples. The distribution of soil pH for arable and grassland is similar to last year, a consistency that adds validity to the findings.

This years report identifies, for the first time that on arable land, soils with a high P index tend to have high K status too. Whereas in grassland samples, there was a high proportion that had either high or low indices of both nutrients.

While providing an immediate call to action for farmers and their advisers, the PAAG report will over time play a vital role in helping to establish an evidence base of actual farm practice.

Over time, we hope trends will emerge that show an increasing number of soils are managed to attain nutrient statuses nearer to target indices, said Mrs Salter. If we can demonstrate good practice, the industry will have strong evidence to avoid policy intervention, which can be costly and burdensome to administer.

For farmers wishing to know more about nutrient management, including simple ways to plan crop nutrition and keep records, a wealth of information, approved by the main industry bodies, can be found at www.nutrientmanagement.org.uk.

The Professional Agricultural Analysis Group (PAAG) is comprised of 14 UK soil laboratories participating in a Proficiency Testing Scheme for routine soil analysis and undertaking to collate and publish an annual report of soil analysis data.

www.nutrientmanagement.org.uk has been brought together by an industry-team that includes the NFU, FWAG, LEAF, AIC and CLA). Funding has been provided by England Catchment Sensitive Farming Delivery Initiative (ECSFDI) and support has also been provided by the statutory and voluntary levy boards, as well as Defra and the Environment Agency.