Wednesday, 5 February 2014
So Wheat Crops - How are you looking after the Winter?
One of the key wheat growing lessons I learnt from my Nuffield travels was the need to get the plant population right in order to set the crop up to optimise yield. Too thick i.e. too much biomass and the crop has a greater risk of lodging and if it stays upright then there will be less light interception lower down the plant canopy. On thinner land more plants will be competing with each other for moisture later in the critical grain fill period. Obviously the crops planted at Overbury were done before my travels so I have been keen to take a look at what was planted and what has survived the winter.
Dominic Swainson (Agrii) came out to start the assessment process with me. We had a 50cm by 50cm square which we randomly threw across the field and where it landed, as long as it wasn't in a tramline or something, that's where we took our plant count from. The target is to try and achieve 100-125 plants/m2 which in theory could produce about 4.5 tillers each totalling between 450-550 ears at the end of the day. What we found was the variability of plants during the counts. I think I will have to do more to get a more accurate picture but it took a surprisingly long time. Once we had located the area, we picked out all of the plants (very well rooted), counted them, and the tiller numbers per plant and got our averages.
There were some tremendous variability in survival rates in relation to seeds/m2 planted and that varied per planting machine, soil type and establishment technique. The field of KWS Croft, shown here had a seeding rate of 103Kg/ha planted on the 21st September, which meant we were planting 190 seeds/m2. When we came to do the plant counts we averaged 114 plants/m2 which meant we lost 76 seeds/m2 or 40%! So there a statistic on it's own, how do you calculate field loss, either through stone content, soil type, slug pressure (after oilseed rape) and then winter kill. Don't forget this winter has been so mild soil temperatures at 800' above sea level are still average 4 degrees and on this free draining land we have lost very few plants through the winter period.