Keeping up with quality of soil essential chore
Afall in soil quality can significantly affect the environmental and economic sustainability of farming.
Such losses take considerable expense and many years to correct and can increase the risk of erosion by water or wind.
So safeguarding the soil for present and future generations is a key task for land managers.
Generally, not enough attention is given to the basic role of soil quality in efficient and sustained production, maintaining water quality and the effect of soil quality on the farm’s gross profit margin.
Farmers and land managers need to be able to identify and predict the effects of their short and long-term land management decisions on soil quality.
Reliable tools are needed to help make such decisions.
The Visual Soil Assessment (VSA), developed by well-known soil scientist Graham Shepherd, has been a good tool in assessing soil quality at farmer level and the results are easy to interpret and understand.
VSA provides a useful educational and vocational training tool for those unfamiliar with soil science.
It creates a better understanding of soil quality and its fundamental importance to sustainable resource and environmental management.
In particular, VSA has developed a greater awareness of the importance of soil’s physical properties (such as soil aeration) in governing soil quality and on-farm production.
Many physical, biological and, to a lesser degree, chemical soil properties show up as visual characteristics. Changes in land use or land management can markedly alter these.
Research in New Zealand and overseas shows many visual indicators are closely related to key measurement-based indicators of soil quality. These relationships have been used to develop VSA.
The VSA Field Guide helps land managers assess soil quality easily, quickly, reliably and cheaply on a paddock scale. It requires little equipment, training or technical skills. By assessing and monitoring soil quality with VSA, and following guidelines for prevention or recovery of soil degradation, farmers can improve their sustainable land management practices.
VSA presents visual assessment of key soil state and plant performance indicators of soil quality on a scorecard.
Soil quality is ranked by assessment of the soil indicators alone. This does not require knowledge of paddock history.
Plant indicators, however, require knowledge of immediate crop and paddock history.
Because of this, only those who have this information will be able to complete the plant indicator scorecard satisfactorily.
The new second edition of the VSA is a significant improvement partly because it is better able to assess soil condition and plant performance as a result of a more balanced assessment of soil chemical, biological and physical properties.
It is more strongly correlated to crop and pasture production and pasture quality.
The second edition considers key aspects of the subsoil and better addresses the ecological footprint of organic carbon dynamics and environmental issues, including greenhouse gas emissions and nutrients such as nitrogen and phosphorus getting into waterways.
Bala Tikkisetty is a sustainable agriculture coordinator at Waikato Regional Council. For further details or a demonstration of the VSA package, contact him on 0800 800 401 or email bala. tikkisetty@ waikatoregion.govt.nz.
Irrigation aid: Bala Tikkisetty, sustainable agriculture co-ordinator at Waikato Regional Council, says keep an eye on soil.