PDA News
The PDA publishes both technical News items and shorter Blog items. PDA News provides the latest up to date information on macronutrients and their use, while blog items are shorter and timelier.
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Potash use on grass
It has been well known for decades that grass can take up and, if cut for silage or hay remove from the field, very large amounts of potash. Typical potash removal values shown in the Nutrient Management Guide (RB209) are equivalent to around 2% K in dry-matter, sometimes higher in fresh grass and lower in […]
October 2018
Consider nutrient removals more closely this season
The implications of plant potash levels on drought stress are often discussed during the spring due to the role potash plays in enabling efficient water usage in plants and improving crop tolerance to drought. Drought conditions are not only related to potassium levels in the plant but may also have an impact on nutrient levels […]
July 2018
Nitrogen & potassium Interactions
Justus von Liebig’s Law of the Minimum states that yield is proportional to the amount of the most limiting nutrient, whichever nutrient it may be (Figure 1). Nitrogen is the nutrient that most frequently provides the largest response, suggesting that this is usually most limiting. However, the plant available potassium status of a soil has […]
April 2018
Time to reflect on last year’s yield and nutritional program
Winter is a good time for many to reflect back on last year’s yields and nutritional programs to identify areas of change that may need correcting going forward. Where applications of phosphate and potash were made based on estimated yields and assumptions on straw management, actual offtakes could be very different, which unless corrected could […]
January 2018
Magnesium as a nutrient for crops and grass
Dr Ian Richards, Independent Consultant, Ecopt. Introduction The 13 or so essential nutrients for plants are grouped, in fertiliser regulations, into primary nutrients (nitrogen, phosphate and potash), secondary nutrients (calcium, magnesium, sulphur and sodium) and micronutrients (manganese, copper, boron etc) according roughly to the amounts needed by crops. Don’t be deceived by the term ‘secondary’; […]
December 2017
Change of PDA staff
Our Coordinator, Peter Hoey, is leaving PDA and we are delighted to say that Ian Matts is taking over from December 1st. Ian is well known in the nutrient industry having done over 10 years with Yara Fertilisers, lastly as Technical Manager for UK and Ireland. He is now an independent agronomist/consultant, and also the […]
November 2017
Grass yields: measure to manage
To misquote a saying slightly “if you don’t measure it, you can’t manage it”, this is very important for grassland where production is so often not measured directly because grass is grown to feed livestock, rather than sell directly as a product. As a result of not measuring, the benefits of certain grassland management decisions […]
November 2017
Review of potassium as a nutrient (IFS)
At their 2016 agronomic conference the International Fertiliser Society (IFS) hosted a comprehensive and detailed review of potassium management in soils and crops by Johnny Johnston, of Rothamsted Research. Containing a host of data from long term trials run by Rothamsted, this is an excellent reference guide for advisers. You can read the abstract of […]
September 2017
Sulphur as a nutrient for crops and grass
Introduction Sulphur is an essential nutrient for all plants, and certain crops are more vulnerable to deficiency than others. Historically, in the UK sulphur was deposited on land from the atmosphere in quantities which were adequate for our crops. However, as the burning of UK coal (high S) in power stations was switched to imported […]
September 2017
P & K for wholecrop cereals
With the arrival of the new Nutrient Management Guide (RB209) from AHDB, the Wholecrop Cereal recommendations for Phosphate and Potash have been included. In the past, in the absence of good information on Wholecrop generally, advisers have often used “grass for silage” recommendations instead, reflecting the greener nature of under-ripe cereals cut for Wholecrop silage. […]
August 2017
Maize and rye for AD plants
With the huge increase in area producing forage maize and rye for anaerobic digesters, it seems timely to remember a couple of the nutrient issues that arise which can be different from normal growing practice. Firstly, harvesting often occurs earlier with the crop being greener than for normal animal feed purposes. The implication being that […]
August 2017
P & K calculator revised for 2017
With the arrival of the new AHDB Nutrient Management Guide (RB209) and its revised values for P & K offtakes, and the inclusion of more crops, we have updated our P & K Calculator accordingly. The P & K Calculator is a free tool for farmers and crop nutrition advisors in England, Wales and N […]
June 2017