The influence of different establishment methods on performance of early-drilled winter wheat

Abstract

The increased popularity of earlier drilling dates in the autumn for winter wheat crops has resulted in the use of lower seeding rates. These lower seeding rates have highlighted the fact that many conventionally drilled crops have quite uneven seed, and subsequent plant distribution, along the drill rows.

This project investigated the impact of different establishment methods, conventional drilling, precision drilling and broadcasting on plant distributions and subsequent yield performance.

Spatial assessments of plants and general visual observations indicated that, whilst precision drilling produced the most uniform plant distribution along rows the most effective spatial arrangements (equal distances between plants in all directions) were produced by the broadcasting methods. However, there did not appear to be a consistent relationship between any of the spatial arrangements and subsequent yield performance. Eight establishment methods were evaluated at two locations in each of the three seasons. The control establishment method was a conventional air-assisted drill, using 200 seeds/m2 with a drilling speed of 6 to 9 kph. A total of 16 of the 42 treatments produced yields which were significantly different from that of the control treatment in the six trials. However, only three of those significant responses were increases in yield and 13 of them were significant yield decreases compared to the control treatment.

Margins (£/ha) were calculated for each of the treatments on the basis of the cost of the establishment method plus the cost of the seed subtracted from the value of the grain yield (valued at £65/tonne). Over the three seasons margins ranged from £490 to £769/ha. The two treatments which produced the overall highest margins (averaged across the six trials) were broadcasting using 100 seeds/m2 and broadcasting using 200 seeds/m2. Precision seeding (at 200 seeds/m2) was the third highest average margin and the control treatment produced the fourth highest margin.

Many growers will criticise the broadcasting method as it does not have good depth control of seed, can compromise autumn herbicide decisions and does not have the same pleasing appearance as drilled crops. However, there is no escaping the fact that it can be significantly cheaper to broadcast rather than drill crops.

There has been a marked lack of investment in broadcasting methods by the industry. This study suggests that broadcasting does present opportunities for cost saving and that further development investment should be considered.