Soil quality issues for horticulture include erosion, compaction, structure decline, salinisation, acidification and pollution by toxic chemicals. HAL funds a number of projects in the soil health area, including research into soil structure, nutrition and soil borne diseases.
The Vegetable industry has implemented a healthy soils project that includes a practical guide for soil management called the Soil Interpretation Ute Guide; an instructional CD/DVD based on the Ute Guide for those growers with limited English; and a Soil Interpretation and Management Course.
This course aims to help vegetable growers learn more about their soil profile, to identify and interpret soil structure and chemistry, to restore or improve the health of the soil and to select the appropriate crop types for the soil with the least impact on the broader environment.
Nitrogen and phosphorous application is an ongoing soil fertility issue for horticulture. The nitrogen and phosphorous status of soils varies greatly between regions and requires different application rates in different areas.
Farmers are increasingly recognising that soil fertility and fertiliser applications need to be carefully managed to achieve production targets without causing environmental damage.
Signposts address the issues of soil salinity and acidity. Dryland salinity is not a significant issue for the horticulture industry.
Irrigation-induced salinity resulting from both over-irrigation and under-irrigation is a more significant issue for the industry. Improving water use efficiency is a key strategy to ameliorate this problem. Actions include modernising irrigation infrastructure, upgrading irrigation technology, improving scheduling and ensuring water reuse.
In the case of soil acidity, audit data suggests that this is an issue in almost half of the horticulture production area. Soil acidity can be corrected by the application of lime in the form of agricultural lime or dolomite. There is presently no industry data on the extent of liming in horticulture.
Water use and quality
Water is a key resource for the horticulture industry for both permanent and annual plantings.
HAL established the Horticulture Water Initiative as an industry level strategy in 2003. It has also invested in partnership projects with other national irrigation R&D funders to address key issues facing the industry.
The key water quality issue for horticulturalists is preventing fertiliser leakage to surface and ground water both on and off farm. Presently, there is no industry level data on water quality issues.
Greenhouse gas emissions
The most compelling current issues in the minds of both consumers and the general community are the contribution of industries to the conservation of biodiversity and greenhouse gas (GHG) emissions (or conversely GHG or carbon sequestration).
Sources of GHGs in horticulture include nitrous oxide from soils particularly fertilisers, nitrous oxide and methane emissions, field burning of agricultural residues and carbon dioxide from the operation of fossil fuel machinery.
Improving the efficiency of energy use and more effective fertiliser management are key actions for the industry to reduce GHG emissions. Some growers are members of the Greenhouse Challenge Plus, a partnership with the Australian Government to improve energy efficiency and reduce GHG emissions.