At last it is that time of year when my Talking Agronomy contribution reverts back to practical in-field agronomy.
February is slipping away and the days are starting to lengthen and that classic harbinger of spring, the fertilser spreader, is starting to leave the barn.
Cold but dry weather has allowed some useful crop walking and I head into this season aided and accompanied by an enthusiastic young apprentice. Already, her grasp on the new technologies which are evolving in our role is helping me greatly, and I hope my teaching in other areas will give her a good foundation in the career she seeks.
Field-wise, winter has created its usual problems. When the frosts start the manganese begins to bite and there are many fields out there with extremely sick patches. Late-drilled wheats are blue with cold and in some cases have really been hammered by rooks, forcing down plant counts alarmingly. These will be candidates for that early shot of N. Hungry pigeons are now starting to ravage numbers of oilseed rape crops, but their defoliation seems to be even over whole fields rather than patches, which remain awkward throughout the season.
Charlock has had most of its leaves removed by the cold, but the stems look healthy enough to survive any last ditch attempts at chemical control. Danger from light leaf spot is forecast to be high and despite it being difficult to identify, we need to be vigilant.
Appropriate use of diagnostic kits helps greatly. It will be a difficult call with this crop as it could mean the potential for four fungicide treatments prior to harvest and an associated increase in costs. However, many fields show promise and the wrong call now will hold yields down to uneconomic levels.
Nitrogen/sulphur strategy will be based around green area index readings and in most instances the crop is already holding enough N to avoid very early applications and realistic reductions in overall usage could well be achieved. Where this is not the case, that important first dressing will have been completed by the time you read this.
Six months on from drilling, and halfway through their lifespan, I have many fields of wheat which are too forward for my liking. Thick, lush growth, high levels of disease innoculum coupled with above average tiller numbers present an interesting challenge for the spring. To try and sustain all these tillers is, perhaps, unrealistic. Likewise, to reduce them will also be a tough task, and will require careful tweaking of N inputs, timing and growth regulator chemistry. And above all it still needs to be standing at harvest.
Talk will soon turn to fungicide treatments in cereals and the choice of strategy for T0 applications. There are strong indications this year will give us a repeat of disease levels experienced last year. Spends not dissimilar to the price of a tonne of wheat have to deliver in order to stack up financially. Starting too early will lead to an additional spray application and treatment of leaves which have no worthwhile yield contribution.
It is crucial to keep those intervals tight, increase our usage of multisite protectants, and ensure T1 timings allow coverage of leaf 3. Cutting back during these early stages will put huge pressure on the efficacy and timing of subsequent applications.