Farm Table says:
What is the problem?
During the 1990’s there was a fundamental change in cropping systems in the medium rainfall zone of south-eastern Australia towards continuous cropping (fewer pastures, resulting from decreased wool prices), reduced fallowing and the development of non-cereal cropping options such as canola and high-value pulses. There has also been a progressive shift away from mechanical cultivation to conservation cropping practices.
What did the research involve?
The SCRIME (Sustainable Cropping Rotations In Mediterranean Environments) experiment was established in 1998 on a Vertosol soil in a 425 mm rainfall environment in the Victorian Wimmera to assess how rotation and tillage practice influence long-term crop productivity and the underpinning soil resource.
What were the key findings?
Since 2004, seasonal conditions have ranged from several years of drought and crop failure to a 1 in 200-year rainfall event. Results indicated that fallowing consistently produced higher wheat yields than continuous cropping, whereas the use of a green manure (vetch) did not. Long-term tillage (zero vs conventional) practice had no significant effect on the grain yields of wheat. The inclusion of a green manure or a 3-year lucerne phase produced significantly greater soil C and N whereas fallowing resulted in lower N and C compared to other treatments.
Increased soil total N and C did not necessarily result in higher plant available N levels at sowing. Results from SCRIME demonstrated the value of long-term trials to understand the complex inter-relationships between management, crop productivity, and the soil resource.