How Many Hectares a Day, Really
Quoting a large job forces you to answer an uncomfortable question: how many days will it take? Underestimate and you promise a date you cannot hold. Overestimate and the customer goes with whoever promised fewer days — who may not hold it either, but has already taken the work.
The trap is that almost everyone estimates from the spec sheet number, and that number describes a condition that never happens: the machine spraying continuously, without stopping, over an infinite, perfectly rectangular field.
The theoretical number, and why it is only the start
The instantaneous output of any application machine — aerial or ground — comes from two things: how wide the pass is and how fast it moves. The sum is theoretical ha/h = swath width in m × speed in km/h ÷ 10. A 7-metre swath at 20 km/h gives 14 theoretical hectares per hour.
Two warnings about that formula, and both matter more than the formula itself.
The width is the effective one, not the nominal one. Useful swath width is not the boom width or the machine's span: it is the width over which deposition stays within acceptable variation, measured in the field with water-sensitive paper or collectors. It is usually noticeably less than nominal, and it changes with application height, droplet size and wind. On top of that, you have to subtract the overlap you deliberately leave between passes so no strips go untreated.
The speed is sustained application speed, not top speed. And in aerial application with autonomous flight, you also have to subtract the turnaround time at the end of each pass, which covers no ground but does consume minutes and battery.
From the theoretical number to the real cycle
This is where the sum parts ways with the spec sheet. A machine does not spray continuously: it sprays in cycles. It flies or drives until the tank is empty, comes back, refills, and goes out again. What determines your day is the length of the full cycle, not the speed inside the pass.
Hectares per load come from tank capacity in L ÷ application rate in L/ha. And the cycle time is the sum of four things: spraying time, the round trip to the fill point, liquid refill, and battery swap or refuelling.
Application rate is the multiplier that rules: at twice the L/ha, half the hectares per load and twice as many cycles.
An example in round numbers. A 40-litre tank at 15 L/ha covers 2.7 hectares per load. At 14 theoretical ha/h, spraying those 2.7 hectares takes 11.4 minutes. Add 2 minutes for the round trip to the fill point, 2.5 minutes of liquid refill and 1.5 minutes for a battery swap: the full cycle is 17.4 minutes for 2.7 hectares, which is 9.3 real hectares per hour.
From 14 theoretical ha/h down to 9.3 real ones, and we have not even left the field yet. That is a field efficiency of 66%, well inside the typical range farm machinery references report for well-organised application work. If your refill takes five minutes instead of two and a half, the same machine drops to 8 ha/h: the bottleneck in a spraying operation is almost never the machine, it is the fill point.
Where your leverage is. Before buying more capacity, time your refill. Pre-mixed water waiting, a decent transfer pump, two battery sets in rotation and a helper dedicated to loading usually buy more hectares per day than an extra machine — at a fraction of the cost.
The whole day: what happens outside the cycle
The 9.3 ha/h in the example only apply while the machine is working. The day holds a lot more:
- Setup and teardown per field. Arriving, walking the ground, marking boundaries and obstacles, loading the flight plan or configuring the machine, and packing everything up at the end. Thirty to sixty minutes per field is realistic.
- Travel between fields. Pure dead time, and the reason grouping customers by area on the schedule is worth money directly.
- Mix preparation. Especially if a compatibility test is needed before loading.
- The weather window. This is the big one. You do not spray when you want: you spray when wind, temperature and humidity allow. In many regions that is five or six usable hours a day, not ten, and in some seasons it splits into two windows — early morning and late afternoon.
- Cleaning and rinsing at the end, especially when changing products.
With 5 hours of usable window, one field a day and the output above: 5 hours minus 45 minutes of setup leaves 4.25 working hours, which at 9.3 ha/h is about 40 hectares in the day. Against the 140 you would get by multiplying 14 ha/h by ten hours. The difference is not pessimism: it is everything the spec sheet does not measure.
The three numbers you should have written down
To quote without guessing you need three figures of your own, not the manufacturer's:
- Your cycle output in hectares per hour while working, split by application rate. Spraying at 10 L/ha and at 30 L/ha are two different businesses.
- Your average setup time per new field.
- Your usable window hours by season. This one comes straight out of history: how many effective hours you worked in March against how many in August.
All three come from the same place: the jobs you have already closed. If you record start time, finish time and hectares for every job, your real output appears on its own, and your next quote stops being a hunch.
The average lies. Do not estimate from a single average. A large, clean field near your base yields twice the hourly output of three small scattered ones. Keep at least two references — simple job and fragmented job — and quote with whichever resembles the field in front of you.
In short: the spec sheet gives you width times speed; your day is decided by refilling, setup and the weather window. Time one full cycle just once, subtract setup from your usable hours, and you will have a figure you can promise without fear — probably half of what the brochure says, and twice as credible.
General guidance only. Output varies with equipment, crop, terrain and conditions. Always quote from your own records.
Sources: ASABE (agricultural machinery field capacity and efficiency standards); University of Nebraska-Lincoln Extension; Penn State Extension.