Growers must now manage crops by growth stage rather than date

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’s Dr. Tony John.

The atrocious conditions endured by most growers in recent weeks 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 the time between now and harvest is shorter than ever, so making less than wise decisions regarding your agronomy moving forward could have a significant impact,” he warns.

“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 innoculum 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 show 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/ha 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 5.0 tonnes/ha to a full fungicide programme so this is certainly not the year to consider cutting back.

“Remember, it’s 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 says.

“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, Dr. Tony John says.

“We’ve got a much shorter growing season to deal with so rather than say T0 needs to go on on 25th March, T1 on 25th April, T2 on 25th May and T3 on 15th June, 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.

“Crops that may be thinner than ideal due to the season will respond to day length and temperature and start the process of stem elongation and continue going through the growth stages without further tillering.

“Because of the lower shoot density and thinner canopy, sunlight will be able to get through to the lower leaves more than usual and in these crops the lower leaves will contribute more to final yield than normal. It is, therefore, essential these leaves are kept clean.

“The bottom line is that plants must be kept fed, free from disease and in the type of condition that will allow them to keep growing and make best use of whatever daylength and temperature is available.”