Throughout South East Queensland there are a range of different crops which are grown for small cropping/ market gardening agriculture in a variety of different soils. These include beetroot, broccoli, cabbage, capsicum, carrots, cauliflower, celery, cabbage, garlic, lettuce, onion, peas, potato, sweet potato, pumpkin, corn, tomato and watermelon. These vegetables rely on the soil pH to be around 6-7.5, meaning they need a high percentage of organic matter in the soil and rely on good drainage, which means there needs to be a high percentage of sand in the soil.
The South east Queensland region mainly comprises of a variety of soils with diverse mineralogy. Black alluvial clays and clay loams are the most successful soils in the Lockyer valley region and consist of predominantly montmorillonite clay which is porous clay. This clay is highly fertile and has a slightly alkaline pH. The upper catchment tributaries and levee banks of the Lockyer creek are well drained and of a loamy texture however other alluvial soils in the region are not as well drained making them heavier. The Lockyer valleys production area lies on flat, slightly sloped and undulating soils and the area are sometimes subject to irregular flooding. The Lockyer valley and surrounding areas also occupy black soils which are dark grey to black cracking clays that are highly fertile and contain high percentages of humus; around 10%-20%. Black soils also contain sand and are good in structure as they have good depth and moisture holding capacity.
The soils of the Toowoomba range are deep and well drained red clay loams of predominant kaolinite clay which has a low shrink-swell capacity. This clay is highly fertile, both chemically and structurally and is acidic. After a few years of intensive farming, organic matter is important in improving nutrients and keeping the soils pH at a constant level.
The Eastern Darling Downs contains a variety of different soils with different characteristics such as dark medium clays and grey-brown alluvial clays exist in large areas of the eastern Darling downs where irrigation is available. Both these clays are Fertile, well-drained and alkaline. The eastern Darling Downs production areas are mostly slightly sloping which are well protected from cold winds.
Soil types in Australia
2.0 Aims
The aim of this experiment is to analyse four soils from South-East Queensland and determine which would be the most appropriate for small cropping/ market garden agriculture.
3.0 Methods
See appendix
4.0 Results
Part E - * wrong information calculated
Part G - * tap water instead of distilled water/ pH probe pin dodgy
Part I - * tap water instead of distilled water/ TDS probe pin dodgy
Part B - * wrong calculations
Problems
12/02/2010 - part B – Soil A group miscalculated their percentages however I corrected them but group A may still be wrong.
10/02/2010 - part F - Had to re-test 4 times because we added too much distilled water because of the inaccuracy of the bottle pump.
12/02/2010 –part E - one group from each soil A and D miscalculated their data
17/02/2010 –part G/I - Second group testing soil B used tap water instead of distilled water for both part G and I.
Group testing soil B used tap water instead of distilled water for both part G and I.
5.0 Analysis
Upon analysing the results, it is evident that for both part A and Part B soil classification, both soils C and Soil D have the closest theoretical soil classification characteristics. This is stated by , where it says loamy sand contains a high percentage of sand which helps speed up the infiltration rate. A good way to identify the soil types for soils is by using the soil texture triangle. Because both soils C and D are reasonably the same in their classification, it can easily be calculated that both are Loamy sand soils.
Whilst analysing at part C, it can be seen that soil A has a very quick infiltration rate of 23.3 seconds. As noted by , infiltration rate of the soil is vitally important for small crop production as the vegetables grown rely on good drainage, meaning the soil needs to have a high percentage of sand however in saying this, it also needs a good water holding capacity to hold nutrients. This coincides with part A and B’s soil classification results, soil A has been identified as being silty loam, therefore meaning it contains a good overall balance between sand, clay, organic matter but however a bit more silt in the soil. When looking at the data table, its looks as if soil A’s results for the infiltration rate is wrong as all the other soils have significantly large number compared to it. Although all soils have similar classification percentages, it can be seen that soil B has a very slow infiltration rate of 4.29:59’, and soils C and D have moderate infiltration rates of 2.04:18’ and 2.09:18’. Soil A’s results for infiltration rate may have been flawed as its rate is so minuscule compared to the other soils. Soil A is meant to be a silty loam, however according to , silt and clay are not permeable therefore hold water well meaning it should have a slow infiltration rate. This may be due to a flaw in the experiment, maybe because the group poured water into the funnel to quickly which resulted in water dripping down the side of the funnel and no through the filter paper.
Whilst analysing part D, it can be seen that soils B and D have lower water holding capacity then soils A and D. As noted by , sand is permeable however silt and clay are not. This therefore reflects the results for soil A as it is a silty loam meaning it has a good balance between the soils classification percentages. However it has a higher amount of silt throughout it which means it holds water as it is porous, hence its 35% of water holding capacity. All four of the soils have a fairly high water holding percentage therefore any of the four soils would be efficient.
Whilst analysing part E, whilst looking at the valid data it can be seen that soil D has the highest percentage of organic matter in the soil. As noted by , black soils occupy the Lockyer valley and contain high percentages of hums and organic matter. Soil D has the best organic matter out of all of the soil with 21.05% and Soil B had the least desirable percentage of organic matter with 6.63% and 5.93% for the two groups working on it.
Whilst analysing part F, it can be seen that all the soils have slightly acidic pH levels. According to , small crop vegetables rely on pH levels of 6-7.5, which means they need a high percentage of organic matter in the soil and rely on good drainage, which means there needs to be a high percentage of sand in the soil. From part E’s results, it can be seen that soil D has the highest amount of organic matter which then decreases the soils pH by adding acidic nutrients into the soil therefore it is plausible that soil D has the best pH level for small crops as it already has a lot of organic matter in the soil which then decreases the soil. Therefore if there wasn’t as much organic matter in the soil, soil D would probably have a much higher pH level which would be more suited for small cropping.
There were also numerous problems with this experiment. Everybody had to rely on the data from each other’s groups instead of each individual group doing every experiment and every soil. This caused many problems as there were a lot of groups which did not perform the experiments properly. This caused many variables and made it very hard to find a soil which was best suited to small cropping/market gardening.
6.0 Conclusion
It has come to a conclusion that soil D is the best soil for small cropping/ market gardening agriculture. This is because soil D has all the characteristics which enable it to grow well in the regions of South East Queensland including the Lockyer valley, Toowoomba and the Darling downs. Soil D’s classification enabled water to be infiltrated through the large pores in the loamy sand, resulting in 2.09:18’. Small cropping requires loamy soils, this means that soil D is the best soil as it comprises of a high percentage of sand, a high percentage of organic matter, a high water holding capacity percentage and a quick infiltration time.
Because of the high percentage of organic matter in the soil, soil D’s pH level is very low however if this organic matter wasn’t there, the soils pH level would be greatly increased therefore being the best of the four soils tested for pH levels. Although soil D has a high percentage of organic matter, there is enough sand in the soil to allow water to be drained out through the pores in the soil however still holding all the nutrients in the soil which are key elements for the production of vegetables. Because of this high percentage of organic matter in the soil, soil D’s water holding capacity is greatly improved. If there wasn’t so much organic matter, the soils infiltration rate would be sped up a lot because the soil is sand based which is very permeable. Because of all of these characteristics, soil D is the most plausible soil type for growing vegetables for small cropping/ market gardening in the South East Queensland region.
7.0 Reference
1. Mr. Reemeijer – science 21 teacher
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8.0 Appendix
Results for soils A1,B1,C1,D1