These are background to some earlier posts:
Introduction
The Flexible Farming Systems project has been monitoring soil and crops in no-till and conventionally sown crops in the northern Wimmera and southern Mallee since 2006. The aim of this work has been to understand and illustrate how management may be different with the different establishment systems, and to highlight some of the issues that farmers may need to address as they adopt no-till and develop both systems to suit the apparent demands of climate change (or at least medium-term variability).
Methods
In May 2006 four of the six pairs of paddocks were surveyed with EM38. Maps and soil sampling were used to attempt to locate two parts of paddocks that were similar. The two remaining pairs were selected in July-August 2006 and similar locations selected on the basis of surface features. The sample area in each paddock was defined by four GPS locations describing a rectangle, 150-200 x 150-200m (map of paddocks and soil sampling locations here
). Four equal-spaced soil core samples were taken along each diagonal of the rectangle to 1.3m deep in 0-10, 10-40, 40-70, 70-100 and 100-130 cm horizons. The surface horizon was sampled separately from the deep core with six samples around each core. Because the initial (May-August) 2006 sample was taken in sown crop, all initial samples were inter-row to estimate the pre-sowing soil nutrient status. Subsequent sampling has been at random.
Table 1. Types of crop sown in each paddock in each year.
The aim of the work was to highlight relevant differences in management and the issues involved between ‘Till’ and ‘No Till’ paddocks. The results are displayed individually for each focus paddock, but it is important to remember that there is no replication of each paddock and also that any measurements are only from one point within the paddock. As far as possible, efforts are made to reduce errors but it only takes a small amount of random variation in 6 pairs to make a pattern! Nonetheless, over three years and multiple measurements some trends may stand out.