Project Delivery: Warren Catchments Council
Contact: Wendy Wilkins (SWCC – Bridgetown). Ph: 9761 4184
Website: SWCC Sustainable Agriculture
Start Date: May 2014 End Date: Dec 2017
Site ID: IN2.1.004
Size Are Ha: 4.5
The overall aim of this trial is to utilise the symbiotic relationships between diverse plant species with soil micro flora and fauna to improve soil condition and increase productivity. A range of variables will be assessed to demonstrate improvements achieved by the treatment sites in comparison to control sites (usual practice).
Two trials will be conducted. Each will compare production and environmental consequences of growing the current pastures system to a pasture with high diversity and a substantial proportion of perennials. The two trials will be initiated at different times of the year to measure any differences in pasture composition or productivity as a consequence of the order of establishment of the summer and winter components.
The trial is progressing well. Further soil and pasture testing has occurred.
A field walk was held on March 22, 2016. The agronomist advising the farmer on the trial and the farmer undertaking the trial spoke.
The Agronomist described the reasoning behind the trial (ways in which the symbiotic plant/microbe relationships builds soil fertility and soil structure both of which is a critical need post-potato growing and harvesting, actions that cause significant soil disturbance); outlined the trial design and reported on progress to date (supported by statistical analysis of data results). This data demonstrated a strong correlation between TOC and TN – an economic advantage: the more in the soil, the less needing to be applied, hence the need to build soil organic matter through (traditionally) green manures or permanent roots in the soil.
The landholder hosting the trial and extension activities, described the typical post-potato crop – rye/clover hay crop to mop up excess nutrients. He noticed soil pH lowering, low CEC impeding soil’s ability to hold on to nutrients and recognised soil disturbance reduced carbon and damaged fungi and other biology.
The plan to introduce perennials was to extend the shoulders of the season. The root exudates from the extended green bridge provide food for biology over the summer months. The trial was experimenting with a diversity of species.
The presenters also spoke of challenges faced in establishing the pastures, despite irrigation: residual nitrates, germinating purslane and double-gee infestation. Annuals proved to be better at competing with weeds, perennials generally had trouble competing with the annuals, leafy turnip shading out other species.
At the field day held in March the participating farmer indicated how happy he is with the practice by saying he is putting his whole farm to perennial pastures.
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