Asst/Professor Matthias Leopold: Soils

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En provenance du cours de University of Western Australia

Discover Best Practice Farming for a Sustainable 2050

49 notes

University of Western Australia

Discover Best Practice Farming for a Sustainable 2050

49 notes

The Discover Best Practice Farming for a Sustainable 2050 Course is based on a clear vision: imagine best practice farming for 2050, start to implement these strategies now, all the while making sure it will still be profitable. At UWA we're doing just that with the Future Farm 2050 Project, set on a mixed-enterprise farm in Western Australia and we want you to learn how it can be done in your part of the world. Although this course is based on agriculture, it's not only about farming. It is a multi-disciplinary course that addresses a wide range of issues confronting the industry, including rural communities, rural infrastructure and conservation of biodiversity in agriculture. By completing this course you will understand that feeding and clothing the planet requires a multi-disciplinary approach and upon completion you will be able to explain best practices of sustainable farming and apply them in new contexts.

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Water and Soils

Welcome to the second week of "Discover Best Practice Farming for a Sustainable 2050". This week you will gain an understanding into the importance of soil and water and its careful management.

Professor Graeme Martin - Introduction to Water and Soils1:18

Asst/Professor Matthias Leopold: Soils8:11

Interview with Emeritus Professor Lynette Abbott6:17

Dr Matt Hipsey: Water14:26

Rencontrer les enseignants

Graeme Martin
Professor
School of Agriculture and Environment

[MUSIC]

My name is Matias Leopold.

I'm originally from Germany, and I'm working now for

the University of Western Australia in the context of soil science,

geomorphology and landscape evolution.

Which also connects me with the future farm projects with the topic of soils.

Farming has been a part of human for more than 10,000 years.

Many things have changed during this time and humans first started to grow crops.

We have developed new plant varieties.

We apply organic or artificial fertilizers and

we use mechanical aids and innovations such as remote sensing techniques.

To help modernize modern agriculture, to produce large parts of our daily food.

What hasn't changed much in the past 10,000 years is the place where we grow

our crops.

The vast majority is still produced in terrestrial soils.

So the survival of mankind actually relies on soils, just as it relies on water.

The world population is rising more and

more which means we need to grow more crops in soil.

Have you ever asked yourself,

how does soil free farm got there in the first place?

What is required to form a soil and can we take it for granted?

Or are soils under threat?

To start answering these questions we first have to have a look at

where we can find agricultural soils in the world.

Here you see a map of the world where the intensity of the blue color highlights

the percentage of arable land compared to the overall land area in this country.

Nearly everywhere in the world we find areas or

soils which are agriculturally used for crops.

And it seems as some countries do better than others.

France, for example, using 33% of their land for crops.

Whereas, the US only uses 16%, China 11%, and

countries like Canada, or Brazil, or Russia, even below 10%.

So is this the solution for the big challenge we face in the near future with

the prognosis of a rising world population?

Isn't it obvious?

We simply increase the arable land and grow more crops.

Well, unfortunately, it's not that easy.

And to understand why, we have to take a closer look at soils and

their abilities, as well as their functions in the ecosystem.

So what is the soil?

Well, first, it is product of nature that has developed over time.

And if you would take a soil profile you quickly discover that the soil is

not only the small bit you can see on the surface it can have diverse colors and

structures with depth and we call these all together a soil.

The famous Russian soil scientist Dokuchaev

describes soil in a very simple formula which is S =

the functions of (SPM, C, R, O, T, and HI).

So soil is the function of soil forming factors which change from place

to place on the globe such as the factor of soil parent material.

Which is the inorganic minerals, the weathering products from a granite,

or a volcanic rock, or a limestone, or the local sediments.

The factor of the local climate.

Whether you're in the tundra, the midlatitudes,

the dry savannahs, or the rainforest.

There is the salt forming factor of topography of a landscape.

Whether you have a soil on a steep mountain face or a flat lowland.

Also the variation in organisms which are often closely linked to climatic changes.

And the time, the factor of time with certain processes like

weathering of rocks could take place.

And more and more important, the factor of human impact.

If you build a house and a road and seal the surface with the soil below,

it is useless for agriculture.

A simplified, but maybe better understandable way of describing

soils is to look at where they sit within the ecosystem.

So the Earth ecosystem is an interaction of several spheres, such as the biosphere.

So all the living plants and animals and bacteria.

The lithosphere, which are the inorganic components such as the rocks and

sediments.

The atmosphere with the gasses and mainly rainwater together with

the energy fluxes Such as temperature or solar radiation.

And last but not least, the hydrosphere with the water and lakes and

streams and most important is groundwater in soils and sediment.

The area where all spheres interact is defined as the critical zone or

the zone that sustains life on earth.

The pedosphere or the soil zone is located in the center of the critical zone.

It is extremely thin compared to the dimensions of the earth and

the atmosphere, which is only about 1 to 2 meter thickness.

In other words, our soils are extremely thin and thus extremely vulnerable.

Its lower boundaries fall by loose sediments or hard rocks and

its upper boundaries form by the vegetation and the atmosphere.

It forms over a long period of time, hundreds to thousands of years.

Once lost or destroyed it won't come back by natural processes during your lifetime.

Here you see a variety of different soils from different regions in the world.

The different colors are an expression of

the different soil forming factors that led to this pattern.

The physical, chemical and biological properties vary enormously in soils.

Remember, not every soil is suitable for cropping.

Arable soils are limited on Earth.

Within the future farm concept, it asks us for intelligent management decisions

now in order to provide sustainable functions for soils in the future.

We want to provide optimal bulk densities for example for our crops.

Increased the water storage capacity, the nutrient availability.

Increase and manipulate in a beneficial sense the carbon storage abilities.

And last but not least, we want to provide healthy soil biology for our crops.

On the right hand side, you see a couple of different soil property maps of

the UWA future farm invest in Australia.

These maps show the difference in clay contents, bulk density,

pH values, or carbon contents.

You can see just by the color variation that there are differences.

Because of this natural variability, we need to use and

treat these areas differently to sustain the productivity of our soils.

Remember, soil is the place where agriculture, and thus food production,

starts.

We cannot afford to lose our soils, because remember,

soils are part of the critical zone upon which humanity utterly depends.

[MUSIC]

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