Video - Interview - Greg Shea, WA Department of Agriculture and Food

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Del curso dictado por University of Western Australia

Agriculture, Economics and Nature

136 calificaciones

University of Western Australia

Agriculture, Economics and Nature

136 calificaciones

Sound economic thinking is crucial for farmers because they depend on good economic decision making to survive. Governments depend on economic information to make good policy decisions on behalf of the community. This course will help you to contribute to better decision making by farmers, or by agencies servicing agriculture, and it will help you to understand why farmers respond to policies and economic opportunities in the ways they do. You can use this course to improve your skills and knowledge, and to assess whether this is a subject that you'd like to study further. The course includes high-quality video lectures, interviews with experts, demonstrations of how to build economic models in spreadsheets, practice quizzes, and a range of recommended readings and optional readings. Assessment is by a final exam. The key economic principles that we’ll learn about can help us understand changes that have occurred in agriculture, and support improved decision making about things like agricultural production methods, agricultural input levels, resource conservation, and the balance between agricultural production and its environmental impacts. There are literally thousands of agricultural economists around the world who work on these issues, so there is a wealth of knowledge to draw on for the course. Watch a brief video about our course here: https://www.youtube.com/watch?v=T_IeYGpeqV8

De la lección

The economics of land conservation

Week 4 focuses on evaluating land conservation practices, weighing benefits and costs correctly, non-economic factors, and provides an example in conservation agriculture.

Video - Interview - Greg Shea, WA Department of Agriculture and Food6:31

Conoce a los instructores

Professor David Pannell, BSc(Agric), BEc, PhD
Head of School of Agricultural and Resource Economics
University of Western Australia
Jacob Hawkins, BA(Biol), MESM, PhD
School of Agricultural and Resource Economics
University of Western Australia

[MUSIC PLAYING]

DAVID PANNELL: Today, we're out in the wheatbelt

of Western Australia near the town of Merredin,

and I'm speaking to Greg Shea who's

a development officer with the West Australian

Department of Agriculture and Food.

Welcome, Greg.

GREG SHEA: Great to be here, Dave.

DAVID PANNELL: So we're going to talk about soil acidity, which

is a big problem in the wheat part of Western Australia.

So can you tell us a bit about what's behind soil acidity?

What causes it?

GREG SHEA: Well, really, it's the result of agriculture.

Over time, the long-term effect is

that there's an imbalance in the system,

and the soils start having their chemistry changed.

And the result is that the roots of the crop

are compromised by the soil acidity.

DAVID PANNELL: OK.

So what sorts of farming actions cause it?

Fertilizer application?

GREG SHEA: Mainly nitrogen-- and use of legumes over time

and also leaching of nitrogen.

So it's an imbalance that happens in the soil--

as well as the export of any agricultural commodity

from a farm.

So over time, that just creates the imbalance.

DAVID PANNELL: And how widespread

is it in Western Australia?

GREG SHEA: It is very widespread in Western Australia.

We've got millions of hectares affected.

And a lot of soil has got a problem

in terms of subsurface acidity.

That's where it expresses itself.

So crops really do have a problem filling the grain

at the end of the season as a result of the soil acidity

problem.

DAVID PANNELL: So the result's lower yields?

GREG SHEA: Absolutely.

Yes, and quality.

And so it's just a major factor in crop production.

DAVID PANNELL: How much lower yields are we talking?

GREG SHEA: Well, if we ameliorate the soil acidity,

then we can get responses of 10% to 40%.

It depends on the seasonal conditions.

DAVID PANNELL: So what are the options

that farmers have to try and manage it?

To try and reduce these impacts?

GREG SHEA: Well the main one is to bring the use of lime

into the farming system.

And that is a product which-- when it reacts with the soil--

reverses the effects that have happened over time,

and the soil acidity is reduced.

It does take time to actually work,

but that is the main thing that we get the growers to use.

DAVID PANNELL: So they're applying lime-- a bit

like a fertilizer?

GREG SHEA: Absolutely like a fertilizer.

Yes, they do.

And it's something that's been promoted for many years.

But growers have been hesitant in some cases

because it's usually cheap to buy,

but the transport cost is often the major factor.

DAVID PANNELL: OK.

So how about the economics then over all?

Do the economics of applying lime

stack up in certain situations or not?

GREG SHEA: Well, it's a really tough one

in the lower rainfall areas, David,

because the yield potentials aren't as high.

We often have more drought, and so the effects of soil acidity

are worse because, as I say, it's

working about the roots are affected.

And obviously, there's a long way from the sources of lime--

usually, crushed limestone or lime sand.

So there is a big question for the farmers.

It's only in the last few years that the tonnage

of lime to use in the wheatbelt has kicked up in amount.

DAVID PANNELL: I imagine that when you're applying lime,

you're bearing a cost up front and then there's

benefits for carrying down the track.

GREG SHEA: Yes.

DAVID PANNELL: So that could also

be a factor that farmers are considering?

GREG SHEA: It's the big factor.

Apart from circumstances which are relatively rare

and which we're still investigating,

the general experience is it's four

or five years until the actual lime is exerting its effect

and the crop yields start improving.

So it's that delay that is really crucial in why the take

up of lime by farmers is restricted.

Because they see it as something where the budget is often

under stress, and it's the first thing that gets

knocked off the list.

DAVID PANNELL: Right.

Right.

So what's the Department of Agriculture and Food

doing in terms of research or extension

to try and address the acidity problem?

GREG SHEA: Well, it's in all areas, actually, David.

And the main thing is getting growers

to make sure they make the correct decisions about which

kind of lime source they use for their farm-- depending where

their farm is relative to where the sources of lime are,

liming agents.

And also just a planning process in terms

of working out where the resources should be allocated

on the farm-- between fertilizers and lime.

Because often we find that once liming is taken up

and the soils are improved, particularly phosphate

fertilizers, you can actually use lower amounts of phosphate

because that correction that's happening in the soil.

So there are savings to be made.

And also just putting together where the paddocks are located

on the farm where the biggest responses to lime will occur.

So it's targeted lime.

It's not one time of lime over the whole farm.

It's more like 2 and 1/2 or 3 tons of lime--

DAVID PANNELL: Per hectare.

GREG SHEA: --per hectare-- on the areas

which are most likely to be responsive quickest

so that economic issue is dealt with.

DAVID PANNELL: So can you explain a bit more

about the phosphorus story?

You mentioned that they might be able to cut back

on their phosphorus application?

How does that work?

GREG SHEA: Well, the background to it

is-- I haven't mentioned before because I

was talking about soil acidity.

But the actual effect in the soil

is that aluminium becomes more available in the soil

as a result of soil acidity.

DAVID PANNELL: And aluminium is toxic to plants.

GREG SHEA: Aluminium is toxic to plants.

So most plants that we grow don't like aluminium

in the soil solution.

And so the end result is the roots

are restricted in their growth, and therefore, they

can't explore the soil for the reserves of phosphate

which have built up over the years.

And so therefore in those situations,

you're generally putting on phosphate

to meet the plant's requirements.

So once it's sorted out, with liming and the soil

acidity becoming less of a problem,

then that action is reversed.

And it's not so responsive to applied p,

because they're already getting it from the soil.

DAVID PANNELL: OK.

Thanks, Greg.

That's been very interesting.

GREG SHEA: Thanks, David.

It's been great talking to you.

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