Grain Management in Store Post Harvest
Tom Burns, Technical Manager
After a difficult harvest, the focus now turns to ensuring your Treated Grain is safely stored. If you are inclined to relax now that the grain is in, this article is to remind you that the next few weeks are crucial to maintaining the value of your crop. A little extra effort now will be well worth it.
Control the stored grain temperature at the following targets:
- Grain cooled to between 15-20ºC within 2-3 weeks of harvest.
- Grain cooled to between 10-15ºC within 4-6 weeks of harvest.
- Grain cooled to below 10 ºC within 8 weeks of harvest
- NEVER let grain temperature rise above 25 ºC
Why control the temperatures? These targets are framed to disrupt the reproductive cycle of insects and to prevent their growth within the grain heap.
How do you achieve these targets? Simply by blowing cold(er) air through the grain. The most effective cooling is achieved when the ambient air is at least 4°C lower than the grain temperature – generally at night-time in the weeks after harvest.
Monitoring Grain Temperatures
- Walk the grain with temperature probe and notebook in hand. Once the store is full, the grain temperatures should be checked at least TWICE weekly until the end of October. (Thereafter, until the store is empty, the temperature should be checked once per week.)
This means checking its temperature at regular spacings (approximately six meter squares) using a calibrated temperature probe. You should draw up a simple map of the grain pile marking the points where the temperature will be read. Ensure where relevant a point at the peak of the grain pile. The readings should be recorded each time and checked against the previous weeks readings.
- Install a Robydome® Temperature Monitoring System. In its simplest form, wireless temperature probes are inserted into the grain at regular spacings throughout the store. A signal indicating grain temperature is sent from each probe to a receiver and the readings for each probe can be downloaded using a handheld monitor. This in turn is transferred to a computer creating a permanent record. By using an ambient temperature sensor and enhanced controls, the system can also give fully automated control of grain aeration which is very effective and energy efficient. (Even with a fully automated system it is essential that somebody walks/ visually checks the grain once per week)
By monitoring and recording the grain temperatures you can then see how effective your aeration system is in achieving the targets set out above. If the targets are not being achieved, what can you do?
(Assuming the aeration system has been properly designed, installed, serviced and thoroughly cleaned before the harvest, and aeration only happens when ambient temperature is 4°C below the grain temperature).
- If the grain temperatures are even/similar across the store; aerate more i.e. for longer. You do not have to stop aerating if it rains, or if it is foggy as it is not possible to dampen the grain if the ambient air temperature is 4°C lower than the grain temperature.
- If the grain temperatures are uneven i.e. a hotspot, there may be a problem with a duct or fan in that area. The duct needs to be checked to ensure no grain has leaked in effectively blocking it. Unblocking it may be possible or not. An alternative solution may be to increase the aeration in that area by increasing air supply to adjacent ducts or using augur fans at the top of the pile.
- In some situations, a “crust” may have formed at the top of the pile preventing good/even aeration. This crust is caused by warm air coming up through the grain condensing in the cold grain at the top of the pile. It is essential to break up this crust using rakes or a “Grain Stirrer”
As the air coming up through the grain will be warmer than ambient it needs to be removed from the airspace above the grain or condensation will occur on the cold surfaces, e.g. the roof and will drip back down on the grain. An extractor fan should be fitted at the highest level to remove/change the air in the space above the grain so that its temperature is the same as the ambient air.
Regular Monitoring, (daily temperature readings plus twice weekly visual inspection) is the key to preventing problems getting out of hand and ensuring safe grain storage.
Adesco personnel will also visit your stores in the coming weeks but you should not wait until then to discover a problem as that may be too late to prevent losses.
Finally, a reminder to ensure you have a good pest control programme in place and working.
Any questions feel free to email Tom on email@example.com
or any of the Adesco grain team at firstname.lastname@example.org, email@example.com, firstname.lastname@example.org