Week 3
Photosynthesis converts water + carbon dioxide to oxygen and an organic substance.
Photosynthesis also requires additional nutrients (such as magnesium).
Efficency of converting light into dry matter varies...
Ecosystem Productivity
| Perrennial crop Annual Crop Evergreen Forest Deciduous Forest | 3-8 kgs dry matter/m2/year 2-3 kgs dry matter/m2/year 2 kgs dry matter/m2/year 1.5 kgs dry matter/m2/year |
Perspiration, decomposition and combustion.
Special Environmental features of WA... (North to Monkey Mia, South to Esperance)
- mediterranean climate: mild, wet winter; Hot, dry summer.
- unique flora and fauna with unusual biology
-> highly susceptible to invasive pests and Diseases
- Extremely impoverished soils, highly saline lowlands (ancient landscape)
- fire prone: exploited by aborigines
- low elevation: no mountains
- rivers dry up in summer
- unpredictable: droughts/floods etc
Challenges for european farmers in australia...
- crop failures: infertile soils, low productivity due to rabbits, roos, droughts, salinty.
- stock losses: aboriginal hunting, poisoning, dingoes, drought, flooding.
- property losses: fire, cyclones.
Ecological consequences...
- 90% of the wheatbelt was cleared killing off over 90 plant species
- wind erosion destroys topsoil
- weed invasion
- crops not adequately using soil, therefore rising water table levels.
Ecological consequences of clearing native vegetation for agriculture...
- reduced rainfall
- increased salinity
- increased wind and water erosion
Smaller sized plants in crops do not reduce the wate table as large trees do, resulting in salinity etc.
posted by Mel Binks @ 8:51 PM
1 Comments:
I was sitting in our study the other morning, about 8am working on the computer and I came to a realisation. Even though it was a freezing cold morning outside, I was sitting in trakkie pants and a tank-top and wasn't cold. The sunlight was streaming through the window stright into the room, and I had the door closed. When I left the room, I notcied a dramatic change in temerature, and it made me realise how much of a change natural 'solar heating' can make, and how seriously overlooked it is in housing designs of today.
As heating and cooling now is so easy for us with reverce cycle air-conditioning, I think the only way to convince people to incorporate this window-positioning into everyday housing design would be through the wallet. Even though temerature control in houses these days is simple and quick, it is also quite expensive.
If we can publicise simple things like window positioning within the design of the house, and even the inclusion of gas heating even with reverce cycle systems, simply to even slightly reduce the amount of electricity consumed in the average household. Like I said in an earlier post, if we can get small changes slightly reducing the resource consumption of the everyday household, the effects should be substantially more visible than one or two houses being entirely sustainable.
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