KWS' new online maize seed rate calulator is now available on the company's website
KWS’ new online maize seed rate calulator is now available on the company’s website.

A free, online seed rate calculator to help maize growers make decisions on seed rates, row spacings and seed volume orders has been launched by plant breeder, KWS.

Growers using the KWS seed rate tool enter their target plant density, crop area and planned row spacing into the calculator. It will produce a seed rate recommendation and total seed quantity required by area or by hectare, as well as a projected deposition distance.

John Burgess of KWS said the the seed rate tool was extremely simple to use and was available to all UK growers, regardless of whether or not KWS maize varieties had been selected.

“It can be helpful to enter a range of differing figures, to manipulate the end result and decide on the best policy,” he added. “Under normal conditions, a 95 per cent field emergence can be assumed. For early sowing or under difficult conditions, the number of seeds sown should be about 10 per cent higher than the required plant density.”

The KWS seed rate tool is set at a default that uses a target plant density of 95,000 plants/ha for a crop area of 20ha and a row spacing of 50cm. This will produce a recommended seed rate of 100,000 seeds/ha, a required seed volume of 2.0 units/ha and a total required volume for the given area of 40 units. It also gives a projected deposition distance of 20cm.

Meanwhile, the same figures entered for a 75cm row spacing will give similar results, but with a deposition distance of 13.3cm.

“The manipulation of plant numbers offers a number of advantages, as individual plants can access more light, with a potential boost to grain quality and silage quality,” Mr Burgess said. “Each plant will also have access to more water and that can be useful in a dry season. For example, a five per cent reduction in seed rate can increase starch content by one to two per cent.

“Low seed rates can also bring forward harvest date by up to 10 days because of the boost to individual plant productivity. However, there may be a deficit of about 300kg/ha of fresh weight yield due to the lower plant numbers.”

A range of row widths and seed rate combinations for maize have been trialled by KWS since 2017.

“We have looked at row width and plant population in conjunction with Vaderstad. Maize has been planted at a seed rate of 100,000 seeds/ha with 50cm row spacings, which is a fairly high seed rate at a relatively narrow row width. Rates as low as 80,000 seeds/ha were sown at the same row width,” Mr Burgess added.

“The advantage of narrow rows is the ability to tramline, which allows easier herbicide application without running over the crop. Narrow rows also make for better drill utilisation across multiple crop types. Our findings to date haven’t uncovered any yield or quality penalty for the narrow row systems.”