Hewitt Farming Co, winner of the 2017 John Grellman Shield

10 August, 2017

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Each season the CSD Extension and Development Team conduct a series of variety trials to evaluate the field performance of elite Australian cotton varieties. To celebrate the success of the best performing crops, CSD awards trophies to those growers who achieve the highest yield and best fibre quality.

In irrigated systems the trophy for the highest yield in a CSD variety trial is named after John Grellman, a cotton grower from Wee Waa and past Chairman of CSD.

The recipient for 2017 is Hewitt Farming Co, from Macalister on the Darling Downs, who achieved 14.49 bales per hectare, with a crop of Sicot 754 B3F.

The trial was planted on the 8th of October 2016, into a long fallow field off the back of chickpeas. With a full moisture soil profile and excellent temperature conditions, the soil temperature was measured at 19°C and continued to rise over the next seven days. Planting lines were evident within six days, and all seeds were out of the ground by ten days after planting. A final stand of 8.3 plants per metre was achieved from a 13 seeds per metre drop (64% establishment). Establishment ranged from 10 plants down to 8.5 plants per metre.

Pre plant nitrogen applied in the form of 110 kg/ha urea, followed by 41 kg/ha anhydrous ammonia, with an in crop cultivation

Early growth was steady due to some cool weather a few weeks after planting. Temperatures fell as low as 3.5°C to a maximum of 16°C, with 8 cold shock days occurring.

First flower occurred three months post-planting, with 10 NAWF; and the extremely hot weather experienced in January resulted in some shedding.

The crop received five in-crop irrigations, with rainfall from planting to first defoliation measured at 350mm. Rainfall in mid-January came in the form of a few storm events up to 70mm, and then some solid rainfall events (70mm and 130mm) again from mid-late March. The good conditions during March, combined with careful water management, allowed the crop to finish well, with the very top bolls filling well, resulting in an exceptional yield and quality result once the crop was picked in early April.

The crop was first defoliated on the 6th of April, and required a further two defoliations to fully remove the green leaf. The total rate for the three applications was 460ml/ha Dropp Ultra, and 3.5L/ha Prep.

By Chris Barry, Extension & Development Agronomist – Darling Downs and Central Queensland

Read the full case study HERE.