1- defined soil health (100 words)
2- what are the risk factors for salinity, soil acidity, nutrient, rundown and soil structure decline?(700 words(
3- how did you identify the soil health problems? ( 700 words)
4- what soil health problems does the farm have? )150 words)
5 to the most serious soil health problems identified how should John and michelle. (180 words)
6- conclusion (100 words)
You decided the following actions and information were important to answering the questions
posed. Note: There were some questions that were redundant as they have been answered
in stage 1. Also it is the following year!
Answer the following questions
How did you identify the soil health problems?
What soil health problems does the farm have?
To the most serious soil health problems identified how should John and Michelle respond?
Reply to Stage 2
John did not have any recent soil tests from the affected paIDocks. Usually the agronomist
interpreted the tests for him, and he had followed their advice. In the past he had not had any
obvious nutritional problems with the forage and wheat crops so he believed it would be same
result this time too. Hence, he decided against more soil testing because of the expense ($300)
and also not to do plant analysis: for one reason it was too late and the other reason was he
wasn’t sure how reliable it was. By happy coincidence he’d had chap from Dept of Agriculture,
Fisheries and Forestry based in Gunnedah, as part of a soil survey team conduct some soil
testing for a soil mapping project on his properties. Their website had some great information
on soil health: http://soilquality.org.au/
They had identified two main soil types: dermasols where grazed pastures are located and
vertosols where the winter crop of durum wheat, and forage oats each had been planted in
separate paIDocks, after a summer bare fallow. John has not kept yield records for each
paIDock but made sure he was meeting his contract targets, and usually found that when he did
compare yields they were close to the district average.
John thought the chap who surveyed both of his soils seemed objective and had no vested
interest. The information provided was difficult to interpret, but with the aid of the
accompanying test advice he thought he could make some sense of it. He referred John to the
web site to assist in interpretation of the results http://www.environment.nsw.gov.au/soils,
and John later found the DPI website to be useful too
It seemed the soil tests showed that organic matter levels in the vertosols were lower than he
had assumed and in some areas were less than 1%, also there were patches of bare ground on
the lower parts of the paIDock were the crop had not germinated evenly, and resulted in
depressed yield. The soil pH levels of the vertosols were marginally acidic at depth with a soil
pH of 4.5 (tested in 1:5 Ca Cl2 soln), with adequate levels of available N, high levels of
exchangeable aluminium, and deficient in available P. Exchangeable sodium percentage was
increasing with depth and hence the potential for hardsetting in the A2 layer.
For his pasture paIDocks on the dermasols soil tests showed that organic matter levels were
higher than he had thought and were less than 3%. However, even though he thought the soil
pH was close to neutral it had dropped to 5.0 (1:5 CaCl2 soln) in the surface layers, and he
2013 Stage 2 Reply Werris Creek Farm Soil Health Identification 1
wondered if this had contributed to the low clover establishment. The lower pH and high iron
levels may have contributed to the nutrient deficiencies.
John, and his father before him, had been fertilising the crop and pasture paIDocks regularly
over the last 40 years because it was phosphate deficient, although the release of phosphate
was slowed due to relatively lower soil pH, especially in the sub-soil of the vertosols. John had
never used lime, as it was quite expensive, but he uses a type of superphosphate that has some
Calcium in it.
The vertosols due to its high clay content throughout the profile are well buffered compared
with the dermasols which have a higher proportion of sand. The vertosols soil pH is less likely
to be affected by changes in land management, but it is particular acidic in the subsoil (eg due to
product removal, heavy rainfall events over summer, and type of fertiliser application). Also,
John had been using nitrogen fertiliser, sulphate of ammonium as a source of N, on the
vertosols after visiting a field day where the production figures spoke for themselves. John had
grown durum wheat as it was fetching a high price but did not realise it was more sensitive to
low soil pH than other wheat varieties.
Lower in the landscape where the wheat and forage crops were grown the water table had risen
significantly and was 3 m from the surface. John realised there was salinity about, but especially
further west, and thought it more likely waterlogging from recent rains was leading to
depressed forage yields rather than soil salinity problems. John had examined the water quality
irrigation guidelines on the DPI website:
and believed that for an unregulated creek it was well within the acceptable standards (< 280
µS/cm (low-salinity water threshold) and 280-800 µS/cm (medium-salinity water threshold). The
quality of the bore water was becoming more saline, and the EC values were increasing
compared withlast year, and John relied on the bore water for irrigation and stock water.
For the Landcare group soil salinity and soil acidity were a priority as they could be easily
monitored, but other issues such as soil structure decline were not considered as important. The
Caring for Our Country proposal the Landcare group had submitted the previous year had been
supported, so the work on “Corridors of Green” would continue.
John has dug an area of his oat forage crop to examine the soil more closely and found the root
ball was severely stunted in its development, especially between the A2 horizon. John had
hoped the past 10 yrs of minimum tillage, using narrow tynes and maybe less than 3 passes of
the scarifier (which tends to reduce the stubble by 20%)(see Soil Erosion notes) had improved
the soil structure, but maybe the vertosols required different strategies. John had been careful
not to go and plough the area too soon after the rain had fallen in summer. For both soils, the
chap from the government had shown him how aggregates from the B horizon placed in
rainwater had disintegrated slowly and made the water cloudy, indicating a dispersive subsoil.
John felt that maybe more frequent examination of his soil structure was in order, but what
could he do?
John was glad the market was short of durum wheat due to the drought the previous year, so he
may still get a good price even if the yields were down. John had sold his crop for a good price.
The drought had been on and off since 2002. John had attributed to the drought to the pasture
decline on the dermasols, and the pasture species not recovering, however he had noticed a
2013 Stage 2 Reply Werris Creek Farm Soil Health Identification 2
decline in the clover component (subterranean variety) and an increase in the more acidtolerant native grasses, as well as more flat weeds. John had been monitoring
the grazed paIDocks and on average it was 65% with a range between 50 to 70%. The contour
banks had held up against the summer storms. John had decided to renovate the upper
paIDocks where the pastures were looking rundown, and used the storms to assist in pasture
establishment, especially with summer active species such as Rhodes, Green Panic and Digiteria.
John had gradually built up stock numbers but was mindful that the drought was not completely
over. The autumn dry had been followed by some much needed soaking rain, which helped the
establishment of the seeded pasture and forage crops.
2013 Stage 2 Reply Werris Creek Farm Soil Health Identification 4
EM311_511 PBL Questions Stage 1 2013
Questions asked by students for lecturer to answer internal
Compiled 19 June 2013 (externals), 9 July 2013 (internals) no %
irrigation and drainage control measures for farm? Are the crop’s drip irrigated?
How much water required for irrigation?
2 size of property 3 100
3 Relative proportions of each land use on the farm, and soil associated with it? 3 100
4 % under remnant bush – size, type, condition and location? 3 100
5 surrounding land uses? Management issues of neighbours? 3 100
6 Stocking rate? Type of stock? 3 100
7 What are their tillage practices? Conventional or no-till? 3 100
8 Use of fertiliser? Other chemicals and pesticides? 3 100
9 Area of crop? Rotation history? 3 100
10 land use history? Clearing and land use and land management change 3 100
11 Level of education? Background knowledge 3 100
Waste management? Do they discharge into creek? Mine or Livestock ipmact on
water quality? 3
13 Do you exclude stock from rivers and riparian zone, what access to water ? 2 67
14 water allocation during drought? Source? Quality? 2 67
15 Composition of pasture? 2 67
16 Practices during drought? (integrity and duration) 2 67
17 What erosion control measures have been undertaken? E.g. Windbreaks, stubble
18 extent of farming experience locally and farm management? 2 67
19 How close to mine? Intensive livestock 2 67
20 have practices changed over time? 2 67
21 Topography 1 33
22 Are they members of landcare? 1 33
23 any invasive species? Any weed problems? 1 33
24 Weather? Rainfall, Wind exposure, temperature 1 33
25 Any riparian revegetation taking place? Condition of- regeneration and erosion
26 How old are they? 1 33
27 grazing strategy? Cell grazing or set stocking? 1 33
28 Do they monitor the soil, water and vegetation quality regularly? 1 33
29 Bushfire risk? Burning of stubble? 1 33
30 What is their financial situation? Subsidies?
31 How much of the farm affected by flood?
32 soil and water pH levels?
33 Are they aware of environmental change?
34 Flow rate of the Mooki River
35 ground cover and types percentages?
36 Any endangered species?
37 Depth to water table, EC of water, access to ground water
38 type of foIDer? Drought and salinity tolerant?
39 How much water is stored in dams?
40 Is there a succession plan for the farm inherited or purchased?
2013 Stage 2 Reply Werris Creek Farm Soil Health Identification 5
EM311_511 PBL Questions Stage 1 2013
41 What are the drought subsidy?
42 Ownership goals and objectives? (financial and other)
43 Has the biodiversity been affected?
44 Are they willing to change farm practices to aIDress drought?
45 Family farm
46 Do they have a property management plan?
47 What is their relationship to the agencies?
tenure of the property
49 Do they seek professional advice?
Areas students need to investigate no %
1 Climate of area
2 Do they have any acidification or salinity? 1 33
3 How did floods and drought periods affect the land?
4 What forms of land degradation ocured on farm before? 1 33
5 Land suitability and capability classes of property?
6 Has it been farmed sustainably?
Areas students need to investigate, but did not identify
1 What is a drought considered to be?
2 Is farm rehabilitation worthwhile?
3 What is the general influence of the drought?
4 How erodibility and erosivity of the two soils?
2013 Stage 2 Reply Werris Creek Farm Soil Health Identification 6
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In this section you will find detailed information, including national overviews and state and regional level assessments, fromthe
2000-2002 National Land and Water Resources Audit theme assessments.
Australian Agriculture Assessment 2001 – Soil acidification: an insidious
soil degradation issue
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