Advice for first time harvests

By Russell Armstrong

Winter is upon us and by now your Miscanthus crops will be dying back quite quickly. This is a very important phase in the development of the crop as nutrients in the leaves and stems are being pulled back into the rhizome to be stored ready for next springs growth.

In the next few months, you will be taking your first harvest. Harvesting is a contractor job and hopefully by now you have appointed one. If you need help with selecting a contractor please do contact us.

Ideally, when the cane is cut there will be little green left on the plant but in mild winters this may not be the case. The standing crop is unlikely to senesce more beyond the end of January so it should be cut as soon after this time as is possible. As a rule of thumb cutting usually happens in January or early February. However, with the majority of the UK fields now saturated after record Autumn rains harvest timing will be dictated by field conditions. It is critical to avoid damaging ruts and compaction as this is the factor that limits the productive life of a crop and if well managed the crop will perform for 20 years.

The self-propelled forager should be set to cut the canes to between 300mm and 450mm in length and leave the cane unsplit length-ways. Left like this in a swath it can be left for long periods to dry before baling.

In an average spring, the sun and wind will naturally dry the swath without needing for it to be turned before baling. In a wet spring turning the swath will aid drying but it adds costs and increases harvest losses so it needs to be justified. If you think your crop needs turning please speak to us or your contractor.

While standing, the crop will have dropped most of its leaves on to the soil. Please do not be tempted to rake this up into the swath. The leaves contain high levels of silicon and chlorine that the power stations find undesirable. Also, the leaf mulch will be wet and may be contaminated with soil and stones which may lead to bale rejections. The leaf mulch should be left on the ground to suppress weeds and to return nutrients and organic matter back to the soil.

Baling should only be done when you are certain that there are no green stems lefts in the swath and the crops meet the moisture specifications. You or your contractor should check the moisture content of the first 4 or 5 bales, and aim for average moisture content of 14% or less. Large 4×4 bales need to be 2250-2650mm in length, 1220-1320mm in height and 1150-1250mm in width. The smaller 4×3 bales should be 2500mm +/-150mm in length, 900mm +/-50mm in height and 1200mm +/-50mm in width. It is crucial that you produce bales within these size specifications because of the automated bale handling system at the power station.

Ideally, the bales should be removed from the field using a bale-chaser. These machines are equipped with large, low ground-pressure tires which reduce the risk of compaction and forming ruts. Most traditional flatbed bale trailers are equipped with super single tires which put much more pressure onto the ground (at least 5 times) than a bale-chaser. The extra contractor cost will be more than paid for by a more productive and longer lasting Miscanthus crop.

For more information, contact Russell Armstrong on 07535 649 111 or agronomy@terravesta.com

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