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Potash News

The Potash Development Association publishes both technical Potash News items and shorter Blog items. Potash News provides the latest up to date information on Potash and its use, while blog items are shorter and more timely.

If you are in the UK or Ireland and are interested in receiving Potash News items through the post free of charge, then sign up on the contact page. Recipients of the Potash News can receive CPD points for BASIS, NRoSO, and Dairy Pro.

High Yields – are we keeping up with Potash offtakes?

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 […]

September 2014

Measuring potassium in soil and crop

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’, […]

June 2014

Nutrient recycling by grazing cattle

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 […]

October 2013

Fertiliser base dressings and timing

Nitrogen fertilisation for good yields can be effectively managed at SNS Index 0, because nitrogen fertiliser is applied each year to make good the supply from the soil and to meet the needs of the crop. But we cannot do this with potash (nor with phosphate) on P or K Index 0 soils because it […]

July 2013

What are the effects of potash deficiency?

We write ‘effects of potash deficiency’ rather than ‘symptoms of deficiency’, because so many of the negative effects of a shortage of available potash to crops are not clearly apparent, whereas ‘symptoms’ implies some visible effect. Of course severe deficiency has visible symptoms (Figure 1), but there can be many expensive negative impacts on the […]

March 2013

Calculator for estimating nutrients needed to correct soil deficiency

In the previous Newsletter it was noted that in many cases it could take between 10 and 20 years to change the nutrient status of a soil from Index 1 to 2 if only the additional 30 kg/ha as suggested in the Fertiliser Manual (RB209) is added to the crop offtake when making a phosphate […]

October 2012

Standard recommendations cannot make a poor soil good overnight

A crop receiving the rate of potash (or phosphate) recommended in the Fertiliser Manual (RB209) for a soil at Index 0 or 1 is still very unlikely to perform as well as it could on an Index 2 soil. The standard recommendation at phosphorus (P) or potassium (K) Index 0 or 1 is in two […]

July 2012

Good soil potash reserves are required for efficient nitrogen use

In the spring there is understandably much talk of nitrogen applications, growth regulators and how well crops have come through the winter. It is seldom accompanied by discussion of the importance of potash on the efficiency of nitrogen utilisation, on the ability of cereal crops to resist going down, or on the resistance of the […]

March 2012

Balanced nutrition shown by nitrogen:sulphur ratios

In a recent Newsletter the pattern of uptake of potassium and some other nutrients during the growing season was shown. The same French data-set also analysed the crops for the patterns of nitrogen (N) and sulphur (S) uptakes. The majority of the N and S in crops (other than the Brassicae, such as oilseed rape, […]

November 2011

Potassium uptake requirements of some crops

Fertiliser recommendations for potash (K2O) are usually based on removal or offtake of K2O at harvest. Some detailed results of measurements on K2O uptake during crop growth show that greater care is needed to ensure potash supply meets crop requirement. Difference between uptake and offtake The amount of a nutrient needed for full growth of […]

July 2011

Disappointing first cut yields due to drought are no reason to neglect potash and sulphur

Yields of first cut grass have been lower than average in many parts of the UK. Pockets of the south west and N Ireland aside, yields down by as much as 30% have been reported from Wales, Scotland and the midlands, north west and north east of England. Some grassland farmers may have delayed cutting […]

June 2011

Updated cereals recommendations and correction of K deficiency

The new revised PDA leaflet ‘Potash for Cereals‘ incorporates the changes to the recommendations for cereals in the updated Fertiliser Manual (RB209). For potash these relate to the reduction in the quantity of baled straw which is assumed to be removed per tonne of harvested grain (see PDA leaflet ‘Nutrients in Crop Material‘), now half […]

January 2011