Throw away the calendar and manage your crops by growth stage if you want to get the most economic use from your agronomy programme over the next few months, says ProCam. The atrocious conditions endured by most growers earlier this season mean backward crops now have even less time to complete their growing cycle and timely management of agronomic inputs will be essential to protect margins. Nothing had a chance of growing in March and early April and, with time short between now and harvest, agronomic decisions moving forward could have a significant impact, warns the companys Dr Tony John. Some producers are questioning whether cutting back on fungicides is the way to deal with the shorter growing season, but all the evidence suggests otherwise. With levels of septoria inoculum presenting the same potential threat as last year, depending on the weather in the next couple of months, reducing fungicide use could be disastrous. The challenge is to get crops already in the ground performing as well as possible so they fulfil their potential and deliver as much yield and margin as they can, he says. Correct use of fungicides always produces a return on investment. Our 4cast Agronomy database shows that over the last ten years a full fungicide programme has delivered on average a one tonne per hectare yield response and in many cases significantly more.
Over those years, analysis of the data shows that as fungicide investments have increased from 100 to 120/ha, yields have increased in an almost linear manner.
In a bad year with a high disease threat, such as 2012, the yield response can be as much as 5t/ha to a full fungicide programme so this is certainly not the year to consider cutting back. Remember, its cost per tonne of production that is important rather than outright costs per hectare.
In fact, growers may need to use PGRs and fungicides at higher rates than they would normally consider this year, he continues.
PGRs are essential in helping the plant get roots down and to encourage tillering to get shoot numbers correct so it has the foundations for healthy growth. Fungicide use should be focused on keeping disease out of crops so plants are able to put all their energy into maximising yield rather than fighting disease.
Key to achieving good control this year is managing the crop by growth stage rather than date, he says.
Weve got a much shorter growing season to deal with and so we would say focus on growth stage and leaf emergence, irrespective of what date they emerge at these may even be as close together as two weeks.
That will give you the right intervals and make sure applications take place at the right time for the plants. The key priority is the same as every year to keep the flag leaf clean and free from disease and then ensure leaves 2 and 3 are kept free from disease, too.