Grazing and crop production are affected by the quality of pastures and soils type. Vegetative cover and soil health will influence the quality of groundwater and run-off water entering watercourses.
While a cover of grasses and herbaceous plants will filter run-off as effectively as perennial woodland vegetation, seasonal baring or overgrazing will lead to increased and more turbid run-off.
Perennial grasses (both native and exotic) provide more consistent vegetative cover than annual species. Native grasses are efficient water users and have higher biodiversity value than introduced grasses.
The compaction of soils by livestock or machinery is a major factor in soil degradation. Excluding livestock and machinery from seasonally waterlogged areas will lessen this impact.
In an intensive grazing enterprise (where the maximum carrying capacity of a holding is approached or exceeded for part of the year), cell or strip grazing will maximise pasture productivity. The longer that livestock graze a given area, the more the pasture is trampled and the soil compacted.
There is often a fine line between what is a drainage line and what is a watercourse. The management of pasture within minor watercourses should consider the seasonal sensitivity of such areas. A property fenced to land class, or the use of temporary fencing, can relieve pressure on seasonally waterlogged areas.
Vegetative cover is an essential factor in the maintenance of healthy soils. Natural mulch is important in maintaining soil micro-organisms and in returning nutrients to the soil.
However, with intensive use, the maintenance of productivity will require the introduction of various elements. Soils should be monitored for essential elements (N, P, K), pH, trace elements and salinity to ensure that they remain productive.
How does it affect you and your catchment?
The maintenance of pastures should reflect the carrying capacity of its soil, land class and water resources.
A significant threat to agricultural production in the Mount Lofty Ranges Watershed is acid soils. High soil acidity (low pH) will lead to the leaching of nutrients (including trace elements) and may result in the degradation of riparian environments and water quality. The development of toxic acid sulphate soils in low lying areas may occur in certain geological provinces.
Productivity often means the export of alkaline products (fodder, manure, crops and livestock) off the land. Managing acidification, particularly in already acid soils, involves the conservation of alkaline materials or their introduction through the application of products such as lime (CaCO3). Expert advice should be sought before treating your soils.
The application of fertilisers may be useful in treating other identified soil nutrient deficiencies. Effective soil conservation and sustainable productivity ultimately relies on an understanding of the dynamic relationship between soils, water, vegetation and animals.
Management Options
- Familiarise yourself with the basics of soil and pasture biology.
- Monitor the health and productivity of your soils and pastures.
- Actively promote healthy and productive soils.
- Seek advice from experts on how best to achieve these goals.
- Do not overgraze your pastures.
- Fence your property to land class for grazing purposes.
- Exclude livestock from seasonally waterlogged areas.
NOTE:
Sourced from Adelaide & Mount Lofty Ranges Natural Resource Management Board