Soil health
Abstract
Soil health
Summary
Soil Health is defined as the capacity of a living soil to function, within natural or managed ecosystem boundaries, to sustain plant and animal productivity, maintain or enhance water and air quality, and promote plant and animal health (Doran et al. 1996; 1998).
Sustainable production is a critical issue for winegrape growers in the Murray Valley. The concept of “soil health” has been recognised by growers for its potential to buffer extreme climate changes and has challenged current viticulture management practices. The aim of this project was to investigate and develop an understanding of the biological component of soil health. It was the expectation that this investigation would allow the development of techniques that could be used in the vineyard for improvements in vine health and fruit quality.
A literature review was commissioned to develop an understanding of soil health research relating to soil biology and viticulture. The review was finalised in January 2008 and covered the following headings:
1. What microbial populations are found in agricultural soils?
2. What conditions/ factors affect soil biota populations?
3. Effects of soil biota on soil health, vine health and fruit quality.
4. Measuring soil biota populations in the vineyard.
5. Soil biota testing facilities – Australian laboratories.
6. Interpretation of results.
7. Techniques to increase soil biota activity.
8. Recommendations for the Murray Valley.
In the 2007/08 season, a demonstration trial investigating four treatments (permanent sward, compost, microbial solution and compost plus the microbial solution) and a bare soil control began. The aim was to investigate management practices that may improve soil biology and thus positively impact vineyard productivity.
The trial suffered set backs in regards to water availability with only 43 % water allocation delivered to growers in the 2007/08 season. While the trial site was being irrigated by low level sprinklers irrigation, the permanent sward did not grow well. The trial results were varied, without showing clear treatment trends; however, the fruit quality results indicated that the compost treatment was improving vineyard water retention, resulting in larger berry size. This was confirmed through visual observation. The compost results were the only results consistent with the “expected” outcomes of this trial. The water and industry situations resulted in the demonstration trial block being placed on the market at the end of the season, causing a sudden end to the trial.
In 2008/09, a new demonstration trial was developed, looking at quantifying the type of biology in the soil, through principles of the soil food web and using new parameters to manipulate production outcomes. This trial investigated the multiplication and reintroduction of soil biology namely bacteria and fungi to create a favorable soil environment, with the expected results including an increase in soil moisture holding capacity, nutrient cycling capacity and suppression of disease.
This trial was delayed by the late arrival of equipment and still requires more work to develop plausible results, however the theory behind this trial shows merit and given longer-term application and observation this trial could produce positive results that may assist growers to reduce input costs and manage changes in climate.