I’m currently doing a BSc at the Australian National University, double majoring in Environmental and Landscape System Science and Geography. Internet was asking me what I’ve learnt so far, so I made a list!
Although I still have a semester to go (and Honours!), here the five most important things to know about environmental science, brought to you by the Fenner School of Environment and Society and Internet’s questions.
5. Environmental Science is a Fashion Victim
There are fashion trends in everything and environmental science is no different. Back in the 90s the Big Thing in international environmental talks was sustainable development, with all all-star cast of the Brutland Report, Limits to Growth and the 1992 Earth Summit – the United Nations Conference on Environment and Development in Rio. Agenda 21 was born, nations who were at war with each other sat down and talked about sustainable development, Severn Suzuki was the *coolest person ever* and the triple bottom line was the new creed;
But today we all know that the Big Thing is climate change. Divest! Emissions trading schemes! Carbon dioxide! Fossil fuels! REDD+! Ice caps! More buzzwords!
One of my lecturers often laments this dramatic shift in focus; she argues that just looking at climate change is too simplistic as it doesn’t fully capture our degraded relationship with our home planet. How do we solve this problem? We study geography! Yay!
In a more physical geography sense, back in the 90s and early 2000s the Big Thing in land management in SE Australia was salinity. Salinity was set to become the Armageddon, the end of days, the Battle of Hogwarts. Salinity was It. However, the drought broke in the late 2000s and salinity never became the disaster it was meant to be. Lucky!
Now the big thing that everyone is researching and talking about and pulling their hair out about is overgrazing.
See Internet? Fashion victims.
4. Environmental Science will shift your World View
Especially if you study the more ‘society’side of it; human geography, human ecology, stakeholder based qualitative things, sustainable development etc. You will see our society in a new and increasingly complex way that will force you to realise the incredible inter-connectedness of it and, ultimately, the fragility of our inter-dependant gloabalised Western hegemony. Nowhere is this more evident than when considering the global food market.
In short, this will happen to you:
You can boost your marks by about 5 points by having a version of this paragraph in an assignment;
“There needs to be a strong emphasis on stakeholder collaboration and resilience building in light of a rapidly growing population and increasing threats from climate change.”
2. People don’t like anything that doesn’t fit their worldview
This makes point four harder to accept. The obvious example here is climate change; Australia being the intellectual backwater that we are, the media and politicians still talk like climate change is a debated idea, and still act as if it’s just a quite theory of little real world impact.
I experienced this first hand a few weeks ago when I was talking to a third year economics student whose father is a contractor. We were on an hour long bus trip and she was telling me how her father is contracted by farmers to put fertilisers on pasture and crops. I said something about paddock trees and how there aren’t enough of them to stop erosion and do all the great things they do and she launched into a tirade about those ‘bloody greenies’ who ‘don’t know anything about agriculture’ and are trying to ‘driver farmers into the ground’.
Yep, totally. Sorry if my three years of studying environmental science doesn’t quite fit in with your economics world view of ‘Cut down all trees, ???, profit!’.
‘Bloody greenies’? Seriously? Yes, I absolutely want to drive farmers into the ground. Because, you know, I find food overrated and I don’t actually want employment when I graduate after doing HONOURS IN SUSTAINABLE AGRICULTURE. (At this point Internet would like you to know that she hates those people. She said it, not me.)
Turns out trees do help with salinity! Picture: The Australian Academy of Science (but what would those bloody greenies know? They don’t study economics; their dads aren’t contractors!)
1. Goats and Fire
The most important thing I have learnt in the last three years is that if you have a problem – any problem – it can’t be solved by grazing it with goats, setting fire to it then grazing it with goats again.
Rangelands are used for very diverse purposes and have many associated management issues.
They cover 80% of Australia and comprise diverse ecosystems, such as woodlands, tropical savannah, shrub lands, grasslands and deserts. There are many land uses of rangelands, such as mining, tourism, Indigenous use and agriculture. The semi-arid areas are very important for grazing, and $4.4b is made annually from cattle, and a further $1.1b from sheep and wool.
Water ponding was used to reclaim scalded soils at two sites in the Nyngan locality. These sites are now 25 and seven years old and a Landscape Function Analysis was carried out on them to compare functionality and pond age, using a scalded site as a baseline.
Landscape Function Analysis
Landscape function analysis (LFA) is used to assess the functionality of rangelands. It uses visual indicators to give an indicator of 11 physical and biological processes to describe three key soil phenomena, and thus the overall functionality of that landscape (Tongway and Hindley, 2004).
An LFA was carried out on ponded sites in order to determine the effects of water ponding on landscape function in terms of stability, infiltration, nutrient cycling, soil carbon, and soil biomass relative to pond age.
I don’t know about you, but when I hear the word ‘pond’ I think of this:
Water ponding, however, is a practice used to reclaim scalded soils, which we’ve talked about before.
These soils develop due to clearing and overgrazing, causing an excess of sodium ions (i.e. >15%) which creates hard, concrete like surfaces called scalds. Neither water nor roots can penetrate these surfaces, leading to an absence of vascular plants in these areas, which in turn further disrupts the site’s hydrology. At this stage the landscape enters a new stable state that is X to agricultural use. A functional landscape experiences short tortuous flows of water through grass tussocks, whereas a dysfunctional has long straight flows around tussocks which loses resources such as water, soil, and seeds.
Water ponding is a highly successful practice that uses to reclaim these soils, a system that uses 0.4ha horseshoe shaped ponds to hold water and encourage plant growth by holding water on the surface. When a site is identified for water ponding, it is surveyed with a laser leveller in order to find potential positions for pond banks. Ponds are then laid out from the highest point in the scald and overlap like fish scales so water is not lost. They must be no more than 10cm deep or only reeds and rushes will grow, and wave action can destroy the banks. In order to ameliorate wave action, tunnelling, and dispersion there is a heightened buffer section between the banks and the pond. As the system is reliant on rainfall, water ponding may be less effective in times of drought.
Two water ponding sites were visited, one 25 years old and one seven years old. An LFA was carried out in four ponds at each site in order to assess the effect of water ponding on landscape function relative to pond age. This was done by laying down 15m transects at the back of ponds and collecting information on the fore mentioned 11 indicators in the patches (areas of vegetation) and interpatches (clear areas). Soil carbon and biomass were also measured.
Biomass was taken from a 30cm2 plot in the middle of the transect, oven dried and weighed.
The above results show that water ponding has a positive effect on landscape functionality. In every data set, treated sites performed better than the scalded control. In the case of nutrient cycling and infiltration, this difference was particularly significant. These two factors are both dependant on basal cover, litter origin and surface roughness among other things. The scald does not have these properties as it has no vascular plants and the dispersive soils create a smooth, hard crust that does not allow for the build-up of resources such as seeds, litter and water.
Water ponding allows water to sit on the scalds, which restores the swelling and cracking properties of the duplex soils (Thompson, 2008). Cracks allow windblown seeds to get caught in the micro-topography, as well as allowing water and root penetration of the surface. The seeds can then grow, restoring infiltration and nutrient cycling. This was indicated in the results; stability does not significantly increase with pond age, whereas infiltration and nutrient cycling do, suggesting that stability recovers first and is needed for nutrient cycling and infiltration.
There was no biomass on the scald, and differently aged ponds had similar amounts. This is because total biomass increases and plateaus relatively quickly; it can be up to a 20% increase in the first year.
Soil carbon increased over time and in comparison to the scalded site. Soil carbon helps to restore functionality by ameliorating soil structure and available nutrients (CSIRO, 20011).
It can be seen from the results that water ponding is successful in reclaiming scalded soils for use. Functionality of landscapes was seen to increase with age, but not significantly in regards to stability. It can also be concluded that, despite it’s irrelevance to agriculture, Amy and Rory’s story is wonderful and that the Last Centurion and the Girl Who Waited are heart warming in their (literally) undying love for each other.
Poor Pitt the Younger.
He must have had a rough time with geography at school, having to learn useless things like capital cities instead of awesome things like about methane clathrates, which are solid chunks of methane (a bit like ice) that sit on the ocean floor and in the permafrost that can be found in the northern parts of the northern hemisphere.
How are they related to geography? Well as we know, humans are massively changing the chemical composition of the atmosphere, which is causing the permafrost to melt, releasing all this methane. That’s pretty bad as methane has a global warming potential (GWP) of 72 over 20 years, making it exactly 72 times worse as a greenhouse gas than carbon dioxide over the same time period.
The tricky thing with the methane in the permafrost is that the more it melts the more methane will be released so it will get warmer so it will melt more so more methane will be released so it will get warmer so it will melt more … this could go on for a while. That’s what we call a positive feedback loop. They are bastards to model, so we don’t have a great understanding of them and climate change science is full of them.
So maybe Pitt the Younger was happy with his crappy geography classes, safe from the knowledge of methane and over grazing and erosion and land clearing and water pollution?
I think what I’m trying to say is that while a solid understanding of geography (or science in general) can be depressing (see discussion of methane, above), it is important have that knowledge and be excited about it (as PtY clearly wasn’t) so we can start solving those problems. The permafrost would still be melting even if we didn’t know about it, knowing about it helps as you need to identify a problem before you try to solve it.
Actually, really what I’m trying to say is that we should all watch Black Addder.
My assignment is still lurking around in the shadows of my Wednesday, so here we go, back into my developing field report.
So this morning we’re going to talk about grazing, specifically we’ll be talking about the merits of conventional versus organic versus time controlled grazing. I then have to decide which is the most sustainable, economically and environmentally, and then justify that decision.
Oxton Park, Buronga and Tulgani: Discuss the advantages and disadvantages of these various agricultural practices, and therefore which is the most sustainable (both environmentally and economically).
So grazing. Yeah.
We saw a conventional grazing system at Oxton Park. It’s an 8000 ha property with 200 ha set aside for grazing.
They had their soils classed and they have classes 1 – 5. Soil classing works like this; hazards are used to assess capability; the potential consequences of a hazard and the likelihood that that consequence will be realised. The LSC is based on the most limiting hazard. Soil classes go from 1-8. You can do anything you like with 1 but 8 is rubbish country. The assessment scheme is the major tool to assess the sustainability of land management practices. It follows on from one made for the Central West of NSW in 2008 (which was itself based on the US Dept of Ag scheme from the early 1950s). A Land and Soil Capability (LSC) assessment scheme is most suitable for broad scale assessment of land capability particularly for low intensity dry land agriculture-less so for high intensity use or irrigation.
So they graze on class 5. They crop for four years on classes 2 – 4 then graze for 15. This very long term thinking is in place as the farm is not a family farm but a business. They are playing with huge amounts of money and every paddock has a plan for it; they know what they will be doing there every year for about the next 20 years.
They run about 30 000 merino, mostly for superfine wool. 16 000 are pure merinos and 6000 are a quicker growing crossbreed that they use for meat, which is now worth more than wool. The meat sheep are exported if they’re more than 11 months old.
Wait, what’s superfine wool? How is it different to normal wool?
Good question Internet. Superfine wool is 18-19 microns thick, which is the diameter of the wool. Wool is also measured on it’s tensile strength, but the diameter is the most important factor and is dependant on the sheep’s age, breed, health and so on. Merinos are known for their superfine wool, which is used in thermal and luxury products.
They shear every ten months, generally in April and January. You need about 70mm of wool to make it worthwhile and you shouldn’t shear them in winter (really?!) or when they’re lambing.
This way of raising sheep is very high input, both in terms of money and time. You have to drench them and crutch them; you have to shear them, you have to move them from one paddock to the next.
The advantage is that you get a consistently high quality product, but the disadvantages are that if you run out of money or inputs the system will collapse. Also, because they’re grazing their sheep on class 5 land, it is reasonable to expect that the sheep’s diet isn’t great as the pasture in those paddocks may not be very varied. If this system was hit by a serious drought the farm would probably be fine financially but it’s anyone’s guess how the land would go after being managed to produce meat and wool rather than to produce pasture with the sheep as by products.
So what’s your conclusion?
Well Internet, it’s probably only sustainable financially as long as you have enough money to put into it and aren’t hit by a big drought; it’s very dependant on inputs. Environmentally it’s probably not that resilient, although good on them for understanding their soils and utilising them correctly.
Tune in next time for the same again, but with organic grazing!
The assignment doth continue so once more unto the breach, dear friends, once more …
The third thing to chat about soils at Gunyah is erosion.
Sodic soils (which we all know know are caused by too many sodium ions floating around) are also really prone to erosion.
This is because the soil has lost it’s structure and is really dispersive so when it gets wet it will run away easily. This also causes erosion.
Because water cannot infiltrate into sodic soils, the water moves laterally just under the surface, creating drains. These can’t be seen until they collapse into tunnels, and if they keep getting worse they may become erosion gullies (i.e. have a depth of >30cm).
Lastly, sodic soils may lose some topsoil due to dust.
So what did the farmer do?
Well Internet, he basically did the same as for salinity and sodicity; encouraged plant growth through the addition of manure, grazed lightly, and added lime in some places.
Lime is sort of the opposite to gypsum in that it raises pH rather than lowers it. In the case of Gunyah lime was most likely added as the soil was too acidic after years and years of super phosphates being added to perennial crops.
Soil pH is super important in agriculture as crops and pasture take up nutrients best when the pH is about 6.5.
The plants are important as their roots hold the soil and provide protection to it from the eroding powers of wind and rain.
Once you’ve treated your soil with gypsum it will form those nice little peds and all will be well on the farm.
It’s kind of simple, once you think about it carefully!
The craziest thing about all of this is that in the majority of cases it’s cheaper to buy new land than to rehabilitate your own land. So if you have sodic soils just, you know, fence it off and buy some new land. Nuts.
(Also, a really bad philosophy to get into. If we don’t take care of our land it’s not going to take care of us, and where else do you want to grow your food?)
That was the soils part of my assignment.
Stay tuned for when it gets crazy and I compare conventional, organic and time controlled systems in terms of grazing and cropping.