The Answer
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 that many of the visual indicators are closely related to key quantitative (measurement-based) indicators of soil condition.
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Visual assessment provides an immediate, effective diagnostic tool to assess soil condition, and the results are easy to interpret and understand. Compare a soil under well-managed pastoral grazing (on the right of the palm), and under poorly managed long-term continuous cropping (on the left). |
These relationships have been used to develop VSA. The VSA Field Guide has been developed to help land managers assess soil condition easily, quickly, reliably and cheaply on a paddock scale. It requires little equipment, training or technical skills. Assessing and monitoring soil condition on your farm with VSA, and following guidelines for prevention or recovery of soil degradation, can help you develop and implement sustainable land management practices.
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VSA provides a useful educational and vocational training tool for those unfamiliar with soil science. It can bring a better understanding of soil condition and its fundamental importance to sustainable resource and environmental management. In particular, VSA can develop a greater awareness of the importance of soil physical properties (such as soil aeration) in governing soil condition and on-farm production. |
VSA is based on the visual assessment of key soil 'condition' and plant 'performance' indicators of soil condition, presented on a score card. Soil condition is ranked by assessment of the soil indicators alone. It 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 score card satisfactorily.