SOIL sampling could be a wasted exercise unless results are correctly interpreted, potato growers have been warned.
Sampling is an essential tool in revealing the nutrient availability of soils and Simon Francis, Technical and Services Manager for agronomy firm ProCam says it is not only required for farm assurance compliance purposes and to meet the statutory requirements of an increasing number of SFI schemes, but it is also time well invested in ensuring potato crops can perform to their full potential.
However, unless soils are sampled and tested in a timely and accurate manner, and the results interpreted appropriately by an experienced agronomist, it is unlikely the investment in soil sampling will generate a viable return, he added.
“Sampling prior to sowing any crop is key, as it provides an essential opportunity for growers to assess the nutrient status of soils and to make plans to redress any identified imbalances or deficiencies,” Simon said.
Simon recommends each field should be tested at least every four to five years. “In extreme cases, for example where continuous high rainfall or an extended period of waterlogging has caused nutrient stores to be depleted due to leaching, increasing the frequency of testing could prove useful. Another example could be where a lack of organic matter prevents nutrients from being retained, thus causing leaching losses to be exacerbated.”
In addition, water logging also compromises root development, affecting a crop’s ability to access nutrients, so understanding what is available to the crop during the early stages of development is vital to maximise potential, Simon said.
“Irrespective of the soil type, the very least growers should be doing is to test each field to build a basic picture of the farm’s P, K and Mg indices as well as pH and organic matter. Testing organic matter content can provide a good indicator of general soil health, from which it is possible to begin to understand the soils capacity to retain both moisture and nutrients,” he said.
“Beyond this, the next step is to build a more comprehensive understanding of the macro- and micronutrients available to plants, so that a tailored nutrient programme can be drawn up proactively rather than reactively during the season.”
