Non-tillage establishment of oilseed rape using the 'Autocast' technique

Abstract

This study examined a novel method of sowing oilseed rape that involves spreading the seed into the stubble of the preceding crop as it is harvested. Demonstrations were set up to show growers how the system worked and user comments were recorded by means of a survey.

The quest for a more reliable method of establishing oilseed rape that would enable growers to predict plant populations continues. Non-tillage methods provide another approach to establishment. The Autocast method of establishing the crop was largely successful in the three consecutive wet autumns of the project.

Slug damage was the greatest problem and it is likely that the pest is more of a problem with this method than with more conventional methods. This is because they can feed undetected on the soil surface but underneath the straw mulch. In a survey, slugs were identified as the cause of most crop failures or severe crop damage. Damage was worse on headlands. Slugs also hit crops that had been conventionally established on the same or neighbouring farms but there were no direct comparisons.

Soil conditions were critical to success; if there was no surface tilth as a result of compaction poor establishment was likely. The self-structuring clay soils (eg Hanslope series) are therefore most appropriate candidates for using this technique. In wet seasons, however even on these soils care has to be taken to ensure that there is no surface compaction. Using a non-tillage technique on soil types prone to capping is risky.

An advantage from not disturbing the soil surface was the absence of an autumn flush of weeds. In many cases a broad-leaved herbicide was not required representing a considerable saving in growing costs.

Autocasting produced a considerable saving in the cost of establishment and a major saving in time at a busy period of the farming year. However several growers commented on the additional management time after sowing, some of which was associated with learning a new system.

Guidelines for the use of this approach to oilseed rape establishment are presented.