The stock record in your office lists 40 tons of urea in the shed. If you count 52 tons and sized the rice order on the record’s 40, you buy 12 tons you already own: US$ 6,000 at the example price of US$ 500 a ton used below. The stock record is the notebook or spreadsheet where you log each input in and out. Count every input in the shed before you close the purchase, not on the morning you apply it, and subtract what you find from the order. The case below is a rice farm near Stuttgart, Arkansas.
When does the count have to happen to change the order?
Before the order closes. In a farmdoc survey, 271 corn farmers from several states were asked how they price nitrogen, and 82% said they normally buy forward. Forward buying means committing to the purchase and the price ahead of use, and farmdoc notes it may require the farmer to take delivery. The order therefore closes well before the input goes on the field.
A count on application day still has a use: it finds the missing jug before the sprayer is due. It cannot change the order, which closed long before. The count that changes the order is the one taken a week or two before the purchase closes, while you can still change what you buy.
Buying early to lock a price is a legitimate choice, and the trade is yours: the discount against the money tied up. Langemeier counts prepaid fertilizer and seed among a farm’s current assets, money that stays tied up until the crop uses the input. If you buy early, move the count to the purchase date.
What does a wrong stock record cost, and in which direction?
The record can be wrong in two directions. Compare it with your count for each input and write which way the gap runs.
| Which way the gap runs | What happened | What it costs |
|---|---|---|
| Record above the count | Stock left the shed without an entry | You reorder late and run short in the middle of a field job |
| Record below the count | Stock came in or came back without an entry | You buy again what you already own, and tie up cash, or take on debt, for it |
The example farm sows 800 acres of rice and plans 130 tons of urea for the crop. The quantities and the price are made up for the example.
The gap can also run the other way. If the record lists 40 tons and you count 28, the 90-ton order leaves the farm 12 tons short, and you find out when the spreader stops. Each field job has a window, the dates you plan to run it in; counting the inputs it needs before that window opens finds a shortage in time.
How far can the record drift from what is in the shed?
Far, when nobody counts. No public study found here measured it for crop inputs in a shed, so two nearby measures follow, and neither is your shed’s.
Destro and colleagues simulated warehouses at five performance levels. They defined record inaccuracy as the difference between the physical stock and the logged stock. In the best-run warehouse it rose from 0.10% to 4.55% in a year with no counting, and stayed at 0.13% with one person counting on a planned schedule.
On a farm, Arce-Cordero and colleagues tracked mineral supplement in five large dairies in the western United States. Average shrink was 2.0%, the share lost in storage and loading, with a range from 0.37% to 3.25% across farms. Dairy minerals are not urea, but a shed that lost the same share of the example farm’s 130 tons would be missing 2.6 tons, about US$ 1,300.
The count is right only for the day you took it. The next bag that leaves without an entry restarts the drift, so repeat it before each purchase. Most exits from the record are first written in your field log, the note of each field job and the input it used, and a bag emptied without an entry is where the gap starts.
What do you count first, and how long does it take?
An afternoon, for the inputs of the next purchase only. Not the whole shed at once. Work with the purchase list for the coming season and the record open beside a notebook in the shed.
The count does not tell you how much to buy or when, which stays your decision, nor how to store an input better, which is for you and your agronomist. A sheet with a date and a name is what lets the next person read it. Buying from a count you took yourself, rather than from a record you hope still holds, is worth doing for every input the farm reorders. On the farm management page you will find where this sits in the rest of running a farm; the other planning articles cover the plans the purchase leans on.