Growers have to pay more attention to their soils and consider introducing biostimulants to their input armoury, in order to help crops maximise their full potential. Intensification of farming systems has slowly eroded the organic component of some soils with the worst impact being felt on land where root crops such as carrots, sugar beet and potatoes have been included in the rotation. 

According to Norfolk independent agronomist John Purslow there is no quick fix to this problem which has taken the last 20 years to create and could easily take the same length of time to repair.

“We are at cross roads in agriculture where I think we will have to view agriculture differently because current thinking is unsustainable. Growers chasing yields are going in the wrong direction. We have to look to the soil and to the plant itself for more answers and not necessarily rely on the agchem bottle and bagged fertiliser,” he says.

“I’m not an advocate of cutting nitrogen rates, but without good rooting the nitrogen applied will not be utilised efficiently. For example, oilseed rape needs 30kg N/ha in the autumn to sustain the crop through the winter.”

Research carried out by the University of Nottingham on root biostimulants demonstrates a benefit to both soil quality and plant performance.

“It’s not a panacea when considering biostimulants. They can’t be used on every crop and be expected to achieve a yield increase every time. But all crops at some point in their growth cycle drop into the stressed category and it’s on these crops where the biggest impact is likely to be felt,” says Mr Purslow.

He accepts that the concept of a root biostimulant is a hard sell but what growers cannot afford to have is a failed crop. “We saw too many of those last autumn,” he says. “So anything that helps minimise the risk of failure has to be exploited. Better rooting helps utilise fertiliser uptake and water retention.”

Over the last four years or so Mr Purslow has changed the way he looks at crops and how its full potential can be best exploited. He is now more focused on attention to detail on a field by field basis, with soil testing and tissue analysis playing a pivotal role in how decisions are being made. 

Mr Purslow has been using a biostimulant from OMEX called Kickstart on oilseed rape crops. Last year, where many crops failed due to the appalling weather conditions during the establishment phase, he saw a dramatic improvement in the condition of some of his crops where the product had been applied.

“The denitrification of soils caused by the breakdown of cereal stubbles in the soil after harvest can have a detrimental impact on the establishment of the following crop such as oilseed rape. Seed drilled into stubbles in these situations often just sits there doing nothing. It is in this type of scenario where I think a biostimulant can be very effective.

“I have seen work carried out by the University of Nottingham on biostimulants and I was most impressed with the increase in root biomass where OMEX Kickstart had been used.  The benefit of these products is underestimated.”

Phosphite – the key component of Kickstart – has been well researched and its ability to boost root growth is well documented. Root exudate is a key component of soil carbon, says Mr Purslow.  Without good rooting a crop will not recover in the spring.

“Kickstart is another tool in the grower armoury, which at £4-5/ha I think is much better value for money than other comparative biostimulants on the market,” he says. “Professor Rossall at the University of Nottingham pretty much exploded the myth that other phosphites are as good as Kickstart.”

Although visually the effects of biostimulants can be quite dramatic, the jury is still out on whether this follows through to yield. Other factors such as seasonal variation, seed variety, pesticides and soil type can all play a role in boosting yield.

“What we can say with some level of certainty is that by increasing the organic content of the soil and restoring a natural balance we are giving the crop the best chance possible of achieving its potential,” concludes Mr Purslow.