Fertilizer Spreading Advice

Yara has joined forces with SCS Spreader and Sprayer Testing Ltd to bring you the latest advice on how to successfully spread your fertilizer to achieve the best results.

Solid fertilizer application

Make the right fertilizer choice

1. Conduct a broad spectrum soil analysis in conjunction with a nutrient management planto help decide which fertilizer is the most appropriate for a crop’s needs.
2. Use a true uniform compound fertilizer to ensure all the nutrients are contained in each granule and there is no segregation in the hopper.  The benefit of this is an even spread of all nutrients across the whole spread width so that all of the crop gets the correct nutrition to meet its needs.

Check fertilizer quality

1. Check that all the fertilizer to be applied comes from the same batch, particularly if taking delivery on several dates or if there is a carry over of old stock. The same fertilizer can sometimes be produced at different factories, each with different characteristics which means two batches of the same product could have different spread settings and may need to be tested separately.
2. Fertilizer should have consistent characteristics to achieve an even spread, so check it before you put it in the hopper. Fertilizer can degrade with age, old stock versus new stock may need different settings. Blends can segregate during spreading and how you store it can have a bearing on the quality; we advise you to stack fertilizers no more than three bags high to prevent compaction.

Get the timing right

1. Spread the nutrients at the right time – when your crops need them most. Trial data has shown that crops benefit from a spring application of N, P&K and S as that is when their demand for these major nutrients is at its highest, getting your crops off to a great start. 
2. Heed the weather! Strong winds may well effect your spread pattern, especially if you’re spreading lighter prills. If it is too windy to spray, don’t spread either! Keep an eye on humidity levels too, on a damp day fertilizer can absorb moisture which will affect flow rates. Damp or humid conditions will also affect sulphur products causing them to build up on the vanes quicker than in dry conditions.

Spreader maintenance

1. Regularly check your spreader for wear and tear as it will have an impact on your spread pattern. Replace parts where appropriate and follow the manufacturer’s maintenance advice.
2. Check the PTO read-out on the screen in your tractor compared to the PTO shaft. In many cases the readout is not the same so your spreader is not operating at the PTO speed you think. 
3. Clean the spreader regularly, both during and after use.
4. Pay particular attention to the spreader vanes and clean these everytime before refilling your hopper. This is especially important when using fertilizers containing sulphur. Over time, sulphur fertilizers are known to leave deposits on the spreader vanes which can create a build-up or cause blockages which will lead to uneven spreading. Yara and SCS both recommend using a 'WD40' type product and rag to clean vanes. Oil based lubricants dissolve sulphur build up quickly.

When spreading fertilizers containing sulphur it is recommended to regularly clean the spreader vanes using a rag with a 'WD40' type lubricant to avoid a build-up of deposits.

Get your settings right

The correct setting of a spreading machine is determined by the physical properties of the fertilizer. Particle size distribution, bulk density and flow rate particularly influence the setting.

1. Spreader manufacturer's tables are are a guide only. These are based on tests under ideal conditions in test stations and give information on how to set the spreader for optimum, even spreading at the desired application rate (kg/ha) and at a specific working width, however these are a guide only. 
2. To achieve optimum spreading conditions, you should perform a tray test using your particular combination of spreader and fertilizer. A separate test should be conducted for different fertilizer. NOTE some fertilizer products vary depending upon where they’ve been produced and may need testing separately. Always check the directions on the bag of fertilizer
3. Machine height: Ensure the disc or spout on a mounted spreader is at the correct height above crop (see manufacturers guide) and that it is mounted correctly

Fertilizer application advice and guidance

1. Forward speed: Speed plays an important role in achieving a constant application rate, so the correct gear must be used. With machines which rely on PTO or ground drive to operate the disc, always travel at the recommended forward speed. Variations will produce uneven spread and alterations in rate.
2. Bout width: It is most important to drive a correct working width. The manufacturer’s handbook will give this information for the type of fertilizer which is to be used. For full-width distributors each bout should match up with the previous one. 
3. Headlands: It is usual to leave enough space for two bouts around the field. With lateral spread machines it is essential that the ‘switch-on’ and the ‘switch-off’ of fertilizer is aligned to avoid double-dosing or missing. Use the headland disc or border device supplied with the machine. Take into account application restrictions on field margins and set the headland device accordingly.

Liquid fertilizer application

Liquid fertilizer can be applied through an existing farm sprayer and can give an immediate improvement in the accuracy of both nitrogen and NPKS applications.

1. Application accuracy: Across the full boom width however wide, over the entire field with the correct amount applied per hectare, at the end of bouts by reducing overlaps and especially at the field margins right up to the crop’s edge - and no further.
2. Benefits include: More even crops, reduced overlapping on headlands, less fertilizer wastage, less risk of lodging and diseases, easier combining, more consistent grain samples and higher yields