Strengthen roots to reduce drought damage

Using biostimulants to encourage deeper roots could help crops fend off the threat of drought and heat stress, says an agronomist.

Agronomist Mike Stoker, from biostimulant specialist Orion FT says “Plants that accumulate more silicon have been shown to grow longer roots. In periods of drought this gives silicon treated plants a significant advantage.”

“This is especially true for leafy plants like brassicas, and research published by Reading University shows plant mortality of a kale crop being halved through the use of silicon biostimulants.”

Rainfall in some counties was just 16% of the average expected amoung during March, according to Met Office figures. The highest March temperature of 21.3C also suggests that plants will be experiencing heat stress.

Photosynthetic efficiency helps determine how plants manage drought and heat stress. In trials, spinach crops treated with silicon had a higher chlorophyll content and improved photosynthetic efficiency in temperatures of 42C for 24 hours.

“Silicon applications under drought conditions maintain plant nutrient balance and improve the uptake of nitrogen, phosphate, potassium, calcium, magnesium, iron, copper and manganese.

“This makes silicon applications a viable option to improve plant water status and maintain plant water balance under drought stress conditions.”

Annual loss

Some cereal crops will be threatened by the potential drought conditions faced this year. The Agriculture and Horticulture Development Board suggests 10% of wheat yield is lost annual due to insufficient soil moisture.

This figure grows in the driest years, says the AHDB. Some 30% of the UK’s wheat acreage is grown on drought-prone soils.

As a result, crops can frequently fail when water supply does not keep pace with crop demand, especially during critical stages of yield formation.

“Cereal crops can benefit from an application of silicon in spring to help root development when the crop needs water the most,” says Mr Stoker. Silicon added to an existing tank mix can help crops during dry weather.

How to tackle willowherb this spring

Growers are being urged to watch out for willowherb and take steps to tackle the weed in cereal crops this spring.

Willowherb has become a more prevalent issue in recent years – possibly due to the shift towards minimal tillage or no-till methods. But failure to address the issue could result in costly yield losses at harvest.

“These practices help soil structure, but they also provide an environment where certain weeds – including willowherb – can thrive,” says Mathew Hutchings, senior commercial technical manager at FMC.

Lack of deep soil cultivations allows perennial weeds like willowherb to spread and establish roots deep in the soil, says Mr Hutchings.

Managing willowherb

“Changes to crop rotation patterns may have also caused the spike in willowherb being identified by agronomists. The lack of options for control in some crops, especially those that are less competitive, may allow willowherb to spread and become more prevalent.”

The waxy coating on willowherb leaves acts as a natural barrier that can prevent some herbicides from being absorbed effectively by the plant, says Mr Hutchings. This is particularly true when glyphosate is applied to the surface of the leaves.

The waxy layer can repel the herbicide, reducing its ability to penetrate the plant tissues. But a sulfonylurea herbicide will tackle the weed by quickly slowing down the rate of growth, before they become competitive.

“The most effective way of tackling willowherb, and other broadleaf weeds this spring, will be to use sulfonylurea herbicides (SU) with the active ingredients metsulfuron and tribenuron,” says Mr Hutchings.

SUs have been a key component of the arable toolbox for 40 years and to this day they continue to prove themselves on-farm, he adds.

They include products such as Ally and Max SX, with an enhanced spectrum of weed control.