Which sprayer nozzles for liquid fertilizer: streamer nozzles
Teagasc names streamer nozzles as the fertiliser nozzles needed to apply liquid nitrogen through a sprayer. The Hypro ESI Six-Stream is a fertilizer spray nozzle of this kind: it delivers six identical fluid streams, and its low-pressure distribution chamber reduces atomisation and leaf burn.
Before you ask a supplier for a quote, write down what the job needs: the product, the liquid volume per hectare, working width, outlet spacing and forward speed. Keep the nutrient quantity (kg N per hectare) separate from the liquid volume, because they are two different numbers. Ask the supplier to name the whole nozzle assembly, including holder, cap, seal and strainer, not only the tip, and keep the fertiliser set clearly marked so nobody picks a tip by its familiar colour or by a similar flow size.
The Hypro fertilizer nozzles in this range have large outlet holes that help prevent plugging, wear-resistant orifices, a FastCap fitting, sizes 015 to 20, and compatibility with PWM systems. The ESI is an advanced fertilizer nozzle capable of both pre- and post-emerge fertilizer applications. Ordinary crop-protection tips are covered in the sprayer-nozzle guide.
How the chart reads: pressure, flow and gallons per acre
The Hypro ESI chart is in US units: pressure in PSI, flow in GPM, application rates in gallons per acre and per 1,000 ft², with a 20-inch nozzle spacing and speeds from 4 to 20 MPH.
Read these headings before you copy a value into a farm worksheet, and do not mix a pressure column from one unit system with a flow or speed column from another. If your sprayer works in metric units, ask for the metric technical sheet and keep the original chart next to any converted worksheet.
| Information on the chart | What to write in your selection note |
|---|---|
| Nozzle size | Full code and nozzle family |
| Pressure | Unit and the operating value you chose |
| Flow rate | Unit and whether it is water or solution |
| Application volume | Quantity per stated area |
| Speed | Unit and the column you used |
| Nozzle spacing | The spacing the table assumes, compared with your boom |
Liquid fertilizer spray nozzles and solution density: the 1.13 factor
Nozzle catalogues are written for water. 28 percent N solution has a specific gravity different from water, so the nozzle must be sized by multiplying the water flow by a conversion factor of 1.13, the square root of the specific gravity of 28 percent N solution. In the Iowa State example, each of 24 nozzles would deliver 1.02 gal/min of water, so the nozzles chosen for 28 percent N solution must deliver 1.15 gal/min of water equivalent when picked from a catalogue.
Ask the supplier for the actual specific gravity of the solution you will buy, and write down the calculation with its input values and units. Do not confuse nutrient concentration with density or with the liquid volume you want to apply. If a different product is delivered later, repeat the calculation instead of keeping the old factor because the new product sounds similar.
Sprayer pump, hoses and valves for a spray nozzle for liquid fertilizer
Liquid fertilizer needs high volumes: 150 lb N/acre as 28 percent UAN solution is an application of 50 gal/acre. The capacity of the pumps, hoses, nozzles and fittings to deliver that flow is the second limit after the nozzle.
A pump capacity below 40 gal/min and, in particular, 1/2-inch distribution hoses to boom sections are probably inadequate on larger sprayers. Older centrifugal or roller pumps may not deliver high flow without being overhauled or replaced. In the Iowa State example a 1/2-inch hose to the boom sections would cause an unacceptably high pressure loss and restrict flow, while 30 ft of 3/4-inch hose carrying 8 gal/min loses about 3 psi.
Keep your spray records in one place. Free to start.
The specification of diaphragm check valves and solenoid valves to the boom sections has to allow the desired flow, and the check valve on each nozzle should be checked when nozzle flow approaches 2 gal/min.
Give the technician the pump model and a sketch of the boom plumbing: sections, hoses, valves, return line and controller. Ask them to assess whether that circuit can deliver the planned flow at working pressure. If the displayed rate, the measured delivery and the technician's findings disagree, write down what you saw and how you measured it, and fix the supply problem before you raise the pressure further.
Boom width, overlap and section control
With liquid fertiliser there is little or no room for over or underlapping. Boom widths have to be measured accurately, otherwise the edge of the boom can receive double the rate or none, which stripes the crop and loses yield. Auto steer on the tractor when drilling and section control on the sprayer are necessities to avoid overlap or non-application of liquid fertiliser.
Check the outlet spacing and coverage at the boom ends and on any section that has been altered or replaced, and do not copy last season's settings into the controller until you have done so. Measure the full working width, not the folded transport width. Ask the service agent to demonstrate how the controller handles speed changes, section shut-off and headland turns with these tips, and note any adjustment made and who made it, so the next operator does not depend on memory.
With UAN the headland is more accurate than with a spreader: little or no product goes into hedgerows, and with a spreader the outside metre of the crop can get less than optimum fertiliser.
Work rate, weather and nitrogen loss
Applying a given quantity of nitrogen as liquid took 20% longer on the Wicklow farm than as granular fertiliser. Applying liquid is the most forgiving fertiliser option in windy conditions, and moving from solid fertiliser at 30 metre tramlines to liquid nitrogen increased the number of days on which nitrogen could be applied.
Liquid must not be applied onto wet crops that will be dry within a few hours, for example on a dewy morning. In very dry conditions the urea part of UAN can potentially be lost, in the same way as solid urea. Shallow incorporation of liquid nitrogen reduces potential volatilisation loss.
Cleaning, seals and mixing with herbicide
Equipment should be cleaned and rinsed at the end of each day. If spraying runs over several days and daily rinsing is difficult, Viton seals in the check valves avoid rapid seal deterioration. When herbicide is applied in the same pass, the herbicide and the fertiliser must be checked for antagonism.
If a stream pattern looks wrong, note which outlets are affected and what you see, and whether it began after a parts change, a different product or a changed setting. Read the markings on the parts rather than describing them by colour. Do not enlarge an outlet or modify a chamber to make a pattern look like the brochure; ask the supplier for the approved replacement cap, seal and insert instead.
Irish rules for spreading chemical fertiliser
The Good Agricultural Practice Regulations require chemical fertiliser to be spread as accurately and as evenly as possible. Chemical fertiliser must not be spread when the land is waterlogged, flooded or likely to flood, frozen or snow-covered, or when heavy rain is forecast within 48 hours, and not within 2 metres of a surface watercourse. On the Wicklow farm the investment in concrete-bunded storage tanks for liquid nitrogen ensured that potential spillages are retained.
Next step
Connect the nozzle and flow choice to the crop-nutrition plan; for ordinary crop-protection tips and mixing see the sprayer-nozzle guide and tank-mix compatibility.