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The British Survey of Fertiliser Practice (Defra) shows that since the 1980s rates of Phosphate & Potash fertiliser applications have declined by 1/3 in arable crops, and 2/3 in grassland. With the increase in yields achieved in that time, there is a serious deficit in the P & K being applied from fertilisers, which is […]
With the huge increase in growing forage maize to feed anaerobic digesters, especially in the arable areas of Eastern England, it seems appropriate to consider the harvested offtakes of phosphate and, especially, the high amounts of potash removed.
Soil sampling for the routine measurement of P, K, Mg indices and pH is familiar to most advisers and farmers, with the same well-proven method used for many years. But how are things different where minimum cultivation is practised?
This year we sponsored the Crop Nutrition essay at Newcastle University and Melissa Gorst, a 2nd year agricultural degree student, won our prize with this essay.
Grass cut regularly, as silage, haylage or hay, removes very large amounts of potassium (K). Unless this is replaced, soil K concentrations will fall. In recent years there is evidence of an overall increase in the number of grassland soils below target index (2-), as well as a decline in the use of potash fertiliser. This situation is not sustainable and grass yields will fall unless corrected.
Having worked out the rate of nutrient potash required for a crop or grass, and considered the timing of the applications, we now have to select a suitable fertiliser product or other source, such as organic manures, to apply to the soil or crop. Then we have to apply it effectively to suit the crop being grown.
As growers and advisers we need to know how much potash we should apply to ensure crops thrive in terms of yield and quality. Previous articles have described the way soils hold potash and how the plants use it. This article takes us on to the reality of deciding how much, and when to apply […]
Ian Matts, Company Agronomist, Yara UK Potassium is one of the major nutrients required by all crops and is present in large quantities in the plant in the form of the cation K+. It plays a major role in achieving the maximum economic yield, as part of a balanced approach to crop nutrition, as well […]
Dr Paul Hargreaves, SRUC, Crichton, Dumfries. The application, use, efficiency and loss of nutrients including K and P can vary with soil type. Soil type is generally determined by the texture of the soil, which is a measure of the proportions of the following three particles: sand, classified as having a particle size between 0.05mm […]
The Fertiliser Manual (RB209) gives recommendations for phosphate and potash applications for arable crops and grass based on that needed to replace the amount that will be removed from the soil by crop offtake at harvest. In addition, where soil analysis is below target, it adds a small amount to build up the soil reserves […]
At a time when a crop is looking at its best, as is usually the case at this time of year, there may be little incentive to think about deficiencies. However crops can appear to be perfectly well fed yet still be deficient in potash. This ‘invisible’ deficiency is often referred to as ‘hidden hunger’, […]
Grazing livestock return most of the nutrients they consume to the soil. This sounds good but a glance at any grazed pasture will show that the recycling is not done very well. There are many patches where dung or urine has been deposited but most of the field is unaffected. In paddock grazing systems where […]