Well formulated chemical products could slash sprayer filling time and improve efficacy, according to Paul Miller, application specialist for NIAB TAG.

In trials carried out with BASF products, some advanced formulations more than halved sprayer filling time and improved deposition of product on the plant, he told delegates at the Association of Independent Crop Consultants (AICC) conference last Monday (10 January).

Ease of rinsing was the biggest time saver with the newer formulations used, but pack size and design also had an impact.

Pendimethalin product Stomp Aqua – in new foil-less packaging – was the fastest product tested, reducing filling time of a standard sprayer by 57%, said Prof Miller. Can opening time was more than halved with the new foil-less packaging, he noted.

Stomp 400 – in standard foil packaging – was the slowest product tested, taking over twice as long to open, pour and rinse a 10-litre container compared with Stomp Aqua.

Because of its higher pendimethalin content, fewer Stomp Aqua containers were needed to fill the sprayer, further cutting filling time, he said.

Adjusting application volumes to avoid part packs also improved loading time, said Prof Miller. “Handling part packs can involve an added 50 seconds for measuring contents and one additional rinse cycle for the measuring jug.”

The tests were carried out under controlled conditions, with products on the bench ready for operators to pick up, but gave an accurate comparison between products, he noted.

Operator skill also made a considerable difference to the speed of sprayer filling, and further guidance or training could bring slower operators up to speed, he said.

Deposition of chemical on wheat ears was also improved with more advanced formulations, said Prof Miller.

Trials comparing a variety of epoxiconazole formulations including existing suspension concentrate formulation Opus with a new emulsifiable concentrate BAS480 EC showed significantly better leaf coverage with the latter, he said.

Suspension concentrates contain granulated chemical products suspended in water. These leave a residual deposit on leaves, which gradually penetrates the leaf surface with the help of an adjuvant.

In emulsifiable concentrates, the active ingredient is dissolved in an organic solvent which is then dispersed into the water component in droplets. When applied, these products embed themselves into the waxy leaf layer.

The study did not look at the relationship between deposition and efficacy.

BASF studies also showed reduced product drying time, with the EC formulation taking 10 minutes compared with 16 minutes for the SC product.

Time-saving tips

Saving time when filling the sprayer meant products were more likely to be applied when they would be most effective, said Prof Miller. For boom sprayers, work rate depended on water volume used, boom width, spraying speed and ability to operate in a wide range of conditions.

“As you reduce water volume and increase speed and boom width work rate goes up.”

But work rate was also limited by the number of tank fills that could be achieved in a day, he said. Most sprayers could take on water quickly, making chemical loading time the limiting factor.

Ease of product pouring and rinsing and the number of containers needed to fill the tank was, therefore, crucial to increasing filling speed and achieving the maximum number of fills in a day.