Video | Agriculture | Confidence | Economy | Energy | Employment | Finance | Media | Property | RBNZ | Science | SOEs | Tax | Technology | Telecoms | Tourism | Transport | Search

 

Visual Soil Assessment, a practical technique

Visual Soil Assessment, a practical technique for soil monitoring

By Bala Tikkisetty
Sustainable Agriculture Coordinator
Environment Waikato
Hamilton East

Protecting the physical properties of soil is vital to successful sustainable farming. This is because these physical properties control the movement of water and air through the soil, and the ease with which roots penetrate the soil.

Damage to the soil can change these properties and reduce plant growth, regardless of nutrient levels.

Loss of soil quality (soil degradation) can significantly affect the environmental sustainability of the soil, and the economic sustainability of farming.

And decline in soil physical properties takes considerable expense and many years to correct, and can increase the risk of soil erosion by water or wind.

So safeguarding the soil for present and future generations is a key task of land managers.

Generally, not enough attention is given to the basic role of soil quality in efficient and sustained production, and maintaining water quality and the effect of soil quality on the farm’s gross profit margin.

There is every need for farmers and land managers to be able to identify and predict the effects of their short and long term land management decisions on soil quality.


Therefore, reliable tools are needed to help make decisions that will lead to sustainable land management.

The Visual Soil Assessment (VSA), developed by well known soil scientist Graham Shepherd, has been a good tool in assessing soil quality at farmers' level and the results are easy to interpret and understand.

VSA also 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 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 managements can markedly alter these.

Research in New Zealand and overseas shows many visual indicators are closely related to key quantitative (measurement-based) indicators of soil quality. Actually, 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 on your farm 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. 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 scorecard satisfactorily.

Each indicator is given a visual score of 0 (poor), 1 (moderate), or 2 (good), based on the soil quality observed when comparing the paddock sample with three photographs in the field guide manual.

The scoring is flexible, so if the sample you are assessing does not clearly align with any of the photographs but sits between two, a score in between can be given, for example 0.5 or 1.5. An explanation of the scoring criteria accompanies each set of photographs.

Because some soil factors or indicators are relatively more important for soil quality than others, VSA provides a weighting factor of 1, 2 or 3. For example, soil structure is a more important indicator (a factor of 3) than surface relief (a factor of 1).

The score you give each indicator is multiplied by the weighting factor to give a VS ranking.
The total of the VS rankings gives the overall ranking score for the sample you are assessing. Compare this with the score ranges at the bottom of the page to determine whether your soil has good, moderate or poor soil quality.

The VSA package has been recently updated by adding some more important indicators. The second edition of the VSA is a significant improvement on the first edition 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 as well as physical properties. It is more strongly correlated to crop and pasture production and pasture quality, considers key aspects of the subsoil and better addresses the ecological footprint of organic carbon dynamics and environmental issues, including greenhouse gas emissions and nutrient loading (such as N and P) into water ways.


ENDS

© Scoop Media

 
 
 
Business Headlines | Sci-Tech Headlines

 




Digitl: Bumper year ahead for NZ IT sector

Gartner says New Zealand spending on technology products and services will grow 7.4 percent this year. The company’s latest forecast says the market will total NZ$15.3 billion in 2022... More>>



Fonterra: Lifts Forecast Farmgate Milk Price Range

Fonterra Co-operative Group today lifted its 2021/22 forecast Farmgate Milk Price range to NZD $8.90 - $9.50 per kgMS, up from NZD $8.40 - $9.00 per kgMS. This increases the midpoint of the range, which farmers are paid off... More>>

Federated Farmers: NAIT Levy Increases Must Achieve Accurate, User-friendly System
Nobody welcomes extra costs but if OSPRI is to catch-up on under investment in the NAIT platform and deliver on its workability and farmer support, levy increases are probably necessary, Federated Farmers says... More>>



Skoltech: Study Probes Earth’s Turbulent Past To Explain Where Oceans Came From

The origin of water on our planet is a hot question: Water has immense implications for plate tectonics, climate, the origin of life on Earth, and potential habitability of other Earth-like planets. In a recent study in Physical Review Letters, a Skoltech professor and his Chinese colleagues suggest... More>>


Statistics: Household Net Worth Grows In The September 2021 Quarter But At A Slower Pace Compared To March 2021

Household net worth grew by $60.7 billion in the September 2021 quarter compared with the June 2021 quarter, Stats NZ said today. This represents an increase of 2.5 percent, a similar result to the June 2021 quarter, which was up $60.6 billion or 2.6 percent... More>>

TradeMe: Job Market Ends 2021 On A High With Record Number Of Vacancies
The New Zealand job market finished 2021 on a high note, with the ball still firmly in the job hunters’ court, according to the analysis of 69,600 vacancies listed on Trade Me Jobs for the quarter ending 31 December (Q4)... More>>