Average theoretical potential maximum yields of winter wheat once again were estimated to be about 20 tonnes/hectare last season. The average UK yield was close to 8t/ha which is only 40% of the potential, while the highest yielding growers achieved more than 60% of this potential. Now is a good time to reflect what is limiting our potential on an individual farm and even field basis.
Certainly, when you talk to the highest yielding farmers in the ADAS YEN project, a common denominator between them are two key areas. Firstly, attention to detail in all aspects of growing the crop and secondly, focusing on improving soil health. Despite the wet and even snowy conditions throughout December and January, it has still been an excellent opportunity to wander round with a spade and assess our soils health. The wet conditions often exacerbate any underlying issues, allowing us to put plans in place to remediate. Effective drainage is the first thing we need to consider, as if there is nowhere for the water to go, it does not matter how good our soil structure is, it will still become waterlogged. These wet conditions will highlight areas needing priority and while new drainage systems may at first appear to be prohibitively expensive, without effective drainage, yield potential will always be compromised.
Simple steps such as walking ditches and identifying how effective our drains are working, can really highlight potential problems and show us where simple cleaning of the drain exit may suffice, or where jetting or some form of repair or maintenance may be required. It is also a good time to plan which ditches need cleaning – there may also be an opportunity on some fields to mole plough prior to any spring cropping if soils remain plastic at depth.
Having identified any improvements required in our drainage systems, the next focus is on our soil structure. Digging lots of holes over the last couple of months has proved fascinating, and has really highlighted areas which will need some remedial action when soil conditions allow. In some situations it has made us reconsider our whole establishment technique, as the wet conditions have really exaggerated the damage we have caused to the soil with certain cultivations.
The importance of tyre pressure has also proved incredibly important, and where tyre pressures have not been reduced, on some fields through simple investigation it is even possible to detect the damage caused by each pass of the drill tractor, let alone some of the more draconian damage from the likes of bale traffic. A winter like this really highlights the benefits of ‘well shod machinery’ and attention to detail.
Many of us will have attended the annual NROSO courses over the last couple of months. While there is some useful information in these courses, one slide really alarmed me when it suggested we should always look to use the coarsest spray quality we can. While I appreciate drift is a huge worry, I am concerned some companies are so concerned about losing approvals of key products, their advice to always use low drift nozzles can often compromise product efficacy. Low drift nozzles do have a major role to play and can be very effective in many situations, particularly by improving timing of applications where good coverage is required or with small targets such as small grass-weeds. As a rule their performance is likely to be inferior to a finer spray quality. The biggest influence on drift is the distance a droplet must travel to its target, hence boom height is key.
I would like to see more manufacturers focusing on better boom stability and providing the practical on-farm ability to maintain a lower boom height so we can reduce drift while also not compromising spray quality for specific tasks. In the meantime, if you must use low drift nozzles in a situation where good coverage is required, performance can be significantly improved by using application aids such as Remix with residual herbicides, or Velocity with fungicides.