Choosing the right target DM% for your farm
The following procedure is designed to identify an initial target DM% to consider. Once that target DM% is identified consider varieties within 2% either side being within five days either side of the selected harvest date e.g. the target DM% is 35 then consider a range between 33-37 which represents a 10 day window.
Identifying the correct DM% range:
- In Table A - select the conditions which apply to the proposed crop and enter the DM% score in the end column.
- Select the regional score from Table B, insert them in Table A and add up to total.
- Once the target DM% range has been identified refer to 'choosing a variety list' below
Remember that planning for a late harvest date so that you can use higher yielding, lower dry matter varieties, may work in an average season but leaves less leeway in a bad one.
| Harvest date | 15-22 Sept | 23-30 Sept | 1-7 Oct | 8-15 Oct | SCORE |
| DM% | 6 | 4 | 2 | 0 | |
| Sowing date | 15-22 Apr | 23-30 Apr | 1-7 May | 7-15 May | |
| DM% | 0 | 1 | 2 | 3 | |
| Altitude | 0-5 m | 50-100 m | 100-150 m | +150 m | |
| DM% | 0 | 1 | 2 | 3 | |
| Soil type | Light | Medium | Heavy | Very heavy | |
| DM% | 0 | 1 | 2 | 3 | |
| Rainfall | Low (10-27") | Medium (28-39") | High (40+") | ||
| DM% | 0 | 1 | 2 | ||
| Regional score | From Table B | ||||
| TOTAL |
| Regional area | Dry matter score |
| Scotland and Northumberland | 32 |
| Northern England (Borders to Nottinghamshire) | 30 |
| North Midlands (Nottinghamshire to Hertfordshire) | 28 |
| North and mid Wales | 30 |
| South Midlands, East Anglia and Welsh Borders | 26 |
| South Wales | 28 |
| South East and southern counties | 24 |
| Somerset and Dorset | 26 |
| North Devon and Cornwall | 30 |
| South Devon | 28 |
Choosing a variety list
Favourable DL applies to regions with a rating of 28 or less in Table B. In these conditions, later maturing varieties may be favoured.
Less Favourable DL applies to regions with a rating of more than 28 in Table B and at other sites where the altitude or other previously mentioned factors necessitate an early maturing variety.