What’s the worth of magnesium as a nutrient supply for crops?

The Potash Improvement Affiliation (PDA) has up to date its potash, phosphate and sulphur suggestions for cereal crops.

It has additionally printed a brand new advisory leaflet which explores the worth of magnesium as a nutrient supply for wheat, barley, oats and different crops.

Trial work, carried out over the previous 30 years throughout the UK and Eire, has confirmed that inadequate potash has been utilized to cereal crops relative to the portions of vitamins eliminated in cereal grain and straw.

This has resulted resulted in an inevitable discount of soil potash reserves.

The same imbalance has developed for another essential arable crops and this additionally applies to phosphate.

These developments have continued and can result in severe penalties for yield and high quality.

The size of time earlier than monetary penalties happen will rely upon soil sort, manure use and the phosphate and potash reserves of particular person fields.

Crops

The world of cereals receiving no annual phosphate or potash in any respect has additionally elevated considerably in recent times with over 60% of the winter wheat space sown receiving no fertiliser phosphate or potash.

As solely round 20% of tillage soils are at an index the place phosphate and potash can safely be omitted for cereals, that is additional proof of imprudent cost-cutting.

It should not be assumed that as a result of cereals are identified to be environment friendly scavengers of phosphate and potash and since no visible signs are seen, that such cost-cutting is with out penalty.

Severe financial penalties can happen with none seen signs of deficiency. Soil phosphorus (P) and potassium (Ok) indices could decline solely slowly however as they fall under accepted threshold ranges, the dangers of yield and high quality losses improve.

In response to the PDA, such dangers are usually not price taking due to the important requirement of those vitamins for the upkeep of yield and high quality.

Potash impacts each yield and high quality of grain in addition to the overall well being and vigour of the plant.

Cereal crops want not less than as a lot, if no more, potash than another nutrient – together with nitrogen.

Potash is required in such giant quantities as a result of it’s the main regulator of resolution concentrations all through the plant.

It controls cell sap content material to keep up the turgor of the plant and helps the motion of all supplies inside the plant.

Potash provide is thus important for all nutrient uptake by the roots and motion to the leaves for photosynthesis and for the distribution of sugars and proteins made by the inexperienced tissue for plant development and grain fill.

Sulphur

Instantly accessible sulphur within the soil will be measured by laboratory evaluation.

However its susceptibility to leaching as sulphate and its variability each down the soil profile, and over time, implies that the traditional FOUR yearly soil evaluation regime will not be acceptable.

Each the natural processes and the leaching potential trigger soil sulphur ranges to range by month, and by 12 months.

Some analysis work has been performed by measuring sulphur in deep core samples taken for soil mineral nitrogen testing in oilseed rape crops.

Nonetheless, the predictability of potential reserves continues to be being decided.

As a result of routine soil evaluation can’t be used to foretell sulphur deficiency, plant tissue testing is typically advised.

For oilseed rape and cereals there may be the ‘Malate Sulphate’ take a look at which will be performed early within the crop’s life, however it could should be repeated later at stem extension.

Plant tissue evaluation nitrogen and sulphur concentrations may assist to present a information.

However the outcomes could not turn out to be accessible till too late to appropriate for the present crop.

Alternatively, grain evaluation for nitrogen and sulphur concentrations will be carried out. Though the outcomes will definitely be too late to affect that crop, they need to give good steering for future coverage.