GROWERS were advised to check their soil phosphate and potash levels at a Mole Valley event at Croft Grange Farm, Croft, County Durham, on Friday, June 20.

Mole Valley’s Richard Martin pointed to the decline in the use of phosphate and potash, which he estimated had fallen by about 40 per cent, as a direct result of rising prices in 2008.

While they have eased back slightly since that date, they remained high, with a deficit of these two nutrients limiting yield potential on many farms.

“High input costs and poor returns meant growers got into the habit of taking P and K holidays,” said Mr Martin. “They felt they could afford to miss a year or two, but I believe this practice is inadvisable.”

Where soil phosphate is at index 0-1, growers will see a significant response in yield, if levels are topped up to target quantities. The response will not be so great when applied at index 1-2, but it should outweigh the cost of the fertiliser.

A phosphate index of below two will have a detrimental effect on all crop yields; oilseed rape is particularly responsive to phosphate and the same applied to potash, he added.

“It is fairly easy to identify a crop, which is low in nitrogen, but phosphate and potash deficiencies are not so easy to spot. These two nutrients have a vital role to play, as they help with the development of a healthy root system. They also provide a buffer in any situation where the plants are under stress, such as drought or a disease challenge.

“I would strongly recommend the testing of soils every four years, as well as annually replacing the phosphate and potash taken off the field by removing the crop at harvest, said Mr Martin.

Julie Goult, of plant breeding company, KWS told delegates that rapid progress had been made on the breeding of winter feed barley varieties. This was partly due to the introduction of genomics, which is also being used in dairy cattle. Genomics is the identification and characterisation of the genes involved in the expression of a specific trait, so that varieties which exhibit favourable traits can be selected, she explained.

“Some of our winter feed barley varieties are performing so well that it may be worth using them to replace a second wheat. In seven out of eight of our trial plots, winter barley out yielded wheat and gave a higher gross margin,” said Ms Goult.