Soil management

Eyre Peninsula soil is a critical asset to agricultural productivity and natural biodiversity. The characteristics of soil are one of the key factors that determine where different crops may be grown and the natural distribution of native plant species. The soil also provides habitat for a range of plants and animals including burrowing mammals, marsupials and reptiles, invertebrates and microbial organisms.

The Eyre Peninsula region has 15 main soil groups ranging from calcareous soils, hard red-brown soils over alkaline sub soils, deep loamy textured soils, and deep sands to ironstone soils. For further information about Eyre Peninsula soils and soils limitations, Enviro Data SA is a source of useful information.

Below is a sample of maps outlining key land management attributes from Enviro Data SA.

Southern South Australia land types

South Australia soil erosion potential 

Southern South Australia water erosion potential

Southern South Australia water repellence

Southern South Australia current and future potential acidity

The importance of soil

Soil is important because it:

  • is one of the primary features that determine vegetation types and land suitability for primary production uses;
  • is home to fungi, bacteria, burrowing animals, invertebrates and other animals that provide ecosystem services, such as recycling nutrients and binding soil particles; and
  • has physical, biological and chemical properties that affect the moisture, nutrient and biota levels on which plants depend.

Soil degradation can be caused by:

  • clearance of vegetation;
  • disturbance by cultivation for the sowing of crops and pastures;
  • soil disturbance for weed control;
  • stubble removal practices such as burning;
  •  over-grazing by domestic stock;
  • crop failure or poor growth;
  • grazing, burrowing and hoof impacts of pest animals such as rabbits, deer and goats; and
  • use of the land that causes inadequate protection.

Degradation of soil can result in:

  • reduced soil fertility;
  • poor plant establishment;
  • reduced productivity of crops and pastures;
  • loss of native plant species that cannot grow under altered conditions;
  • susceptibility to invasion by weeds tolerant of degraded soils;
  • increased recharge of groundwater;
  • increased acidification of soils;
  • increased dryland salinity; and
  • susceptibility to erosion by wind and water.

Degradation of soil can also result in susceptibility to erosion by wind and water which comes with further challenges.

Wind erosion can smother plants and seed reserves; be a health hazard to people, causing breathing difficulties and reducing visibility for traffic; and lead to soil deposition in creeks, rivers and the marine environment which can smother aquatic plants and life forms and alter the hydrology.

Healthy soil management

Healthy management of soil includes:

  • managing the risk of wind and water erosion through sustainable management practices, particularly the occurrence, intensity and timing of tilling and the quantity and nature of surface cover;
  • managing the impact of water erosion through contour banking and flood control dams; 
  • managing soil acidification through the application of lime; and
  • modern agricultural weed management practices that are selective and integrated.

How we can help

We have gathered a range of resources that land managers can use to help manage their soil.

Land use potential

  • This document provides background and overview information for the land use potential spatial datasets, based on regional-scale soil and land mapping undertaken by the South Australian Government. It shows the land use potential for agricultural crops in southern South Australia.
  • This three-page document is about understanding your soils and their constraints.

Healthy soils

Soil is the most valuable natural asset on any property. Without a well-functioning soil, landscape health will be poor. Soils have three key aspects to their condition: physical, chemical and biological. All are important and each influences the other. Healthy soil which is in good condition across all three areas, results in well-performing soil ecosystem processes which drive the productivity and sustainability of agricultural soils. The following resources may be useful in soil management.

  • There is great interest by farmers in improving their soil condition and health; and it is likely that biological products can play at part in helping them achieve their aims. Farmers test biological products but can't always tell if they worked or not. This soil biology paper (2017) focuses on monitoring the effectiveness of biological products by reviewing what measurements can be taken to help evaluate biological products in research and on-farm trials.
  • This clip from the Ag Excellence Alliances features a Senior Research Officer with SARDI, discussing her disease suppressive soils research. As part of this research, a rotation trial was established on grey calcareous soil at Streaky Bay to determine if disease suppression could be achieved in these types of soils.
  • This Rapid Assessment of Soil Health (RASH) manual is a landholders guide, published by NQ Dry Tropics, to help assess soil health across a range of land types. This RASH scorecard and groundcover worksheet can be used in conjunction with the manual. The manual demonstrates how to quickly assess some key aspects of soil and land to determine if the soil is healthy or has constraints.
  • In 2017, a soil biology project begun on the Eyre Peninsula to increase the understanding of soil biology in EP farming systems. This is the report from this soil biology project which included sampling a number of regional soil types; using biological assays to identify biology present in local soils; and identifying and examining the impact of soil treatments on microbial biomass.
  • This Soil Smart Booklet is a farmer's guide to agricultural soil properties and their management.

Protecting soils (wind and water)

Soils cleared for agriculture on Eyre Peninsula have a range of management and production limitations including shallow sandy soils, calcareous sandy soils, deep salacious sands and sand over clay. Large areas of these sandy soils - about 550,000 ha - are prone to increased risk of wind erosion due to a number of inherent characteristics which restrict crop germination and growth; and consequently surface cover for protection against wind erosion.

The map below shows the wind erosion potential for the Eyre Peninsula.

 

Subsoil constraints

Addressing subsoil constrains using current research techniques have a number of beneficial outcomes including increasing depth productive soil layers, increasing soil organic carbon levels, addressing sodic soils and managing non wetting sands.

  • A 2019 project in Darke Peak focused on managing subsoil constraints for improved productivity. Read the 14-page report.
  • Buckleboo Farm Improvement Group (Big Fig) hosted a talk in 2017 about strategic tillage on dune-swale soil systems with a case study of the northern Yorke Peninsula presented by agronomist Chris Davey.
  • The latest innovative tillage machinery research was discussed in 2017 at a talk hosted by the Buckleboo Farm Improvement Group (Big Fig). This 34 minute talk is presented by Dr Chris Saunders of the Agricultural Machinery Research and Design Centre, School of Engineering.

Managing soil acidity

Soil acidity is a significant issue on Lower and Eastern Eyre Peninsula with more than 186,000 hectares (7%) of agricultural land in the region prone to acidification. Projects on Eyre Peninsula suggest that the rate of acidification is occurring faster on average with current farming practices, than historical estimates and that, if not treated with adequate applications of lime, a further 509,000 ha (19%) in the region is at risk of acidifying over the next 20-50 years (Forward and Hughes 2019).

Find out more about soil acidity and its potential implications on this fact sheet from soilquality.org.au. The Ag Excellence Alliance website is also a source of information and includes a soil acidity in South Australia page including maps, case studies, lime cheque and calculators.

The map below shows the current and potential acidity of the Eyre Peninsula region.

Useful resources on managing soil acidity:

Acid sulphate soils

Acid sulphate soils are found in saline, waterlogged environments including coastal swamps and inland areas. They are persistently bare areas of land recognised by being agriculturally unproductive and environmentally damaging.

This four-page document from the Department for Environment and Water is about managing acid sulphate soils in other areas of South Australia but has some general information about the issue.  

Dryland salinity

Dryland salinity affects an estimated 20,400ha of the Eyre Peninsula. Early Landcare groups made substantial progress in addressing the spread of salt scalds and encroaching salinity. In recent times however, we’ve seen an increase in saline affected soils.

These reports may be a useful reference for managing dryland salinity:

  • The Holman family was one of ten farming businesses across Eyre Peninsula who developed a next generation farm plan as part of the “Future Farm Landscapes” project, identifying key areas that needed action and had opportunities for the ongoing development and sustainability of the farm business. Read the case study of the Holman's project , in which it was identified that the low production deep sandy soils were at risk of crop failure 50% of the time; and to increase productivity of these areas, they undertook delving and clay spreading.
  • Saltland Pastures for South Australia is a do-it-yourself manual for the selection, establishment, management and evaluation of saltland pasture systems.

Mallee seeps

Seeps on the Eyre Peninsula are growing as a result of modern farming systems, landscape and seasonal factors. Take action early to keep land productive and prevent degradation occurring.

  • Seeps are a growing problem across SA. This report is about how seeps are formed and key management strategies.
  • NDVI mapping can be used to identify the extent of seeps and the potential for that seep to spread. This 10-page report from 2019 , details results from NDVI map technology being used on two properties.
  • Sites on two farmers’ properties in the Kimba district were established to investigate and demonstrate the dynamics and potential strategies in managing mallee seeps. Read the site report (2020).

Murray Mallee farmers have been addressing mallee seeps for a number of years and have prepared case studies and newsletters detailing the results. Below is a selection of their publications.

Managing Sandy soils (clay spreading, delving and spading)

An estimated 19% (521,000 ha) of land cleared for agriculture on the Eyre Peninsula has moderate to severe water repellence, and without careful management has a moderate or higher wind erosion risk. Clay spreading and delving, if done well, will encourage crop root growth deeper in the soil profile, increasing the plant’s ability to uptake minerals, trace elements and seek out moisture and increase yields and profitability. These soil improvement practices are costly and must be planned to consider individual paddock constraints in order for benefits to be realised. It’s not a one–practice-fits-all and that’s why we are keen to share lessons learnt and highlight the parameters farmers need to consider.

The following information details soil improvement processes and options:

Managing Clay Soils

Clay at the surface or further down the soil profile are sodic or dispersive, with fairly poor structure can be difficult to manage. The structure breaks down when it gets wet which limits root growth deeper into the profile. So the difficulty that we have with this dispersive clay, it can be very hard to work the paddock. When the soil gets wet the structure breaks down and it becomes very slippery and when it dries out it forms a sealing layer like concrete.

This clip from Ag Excellence Alliance is about using gypsum to improve soil and increase water use, yields and profits.

Education resource - Soil activities

Learn more about soil basics with our Soil Activity Pack for kids and adults who want to learn the basics. Adapted from the South East Landscape Board, the Activity Pack contains some great information on why soil is important, what it is, and soil types to help you out with the first three activities:

Activity 1 – Comparing apples and earth

Activity 2 – Soil Texture: the manipulative test

Activity 3 – Dirt Shake: determining soil types

Unleash your inner soil scientist will these activities.

 

More information