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Soil phosphorus in the agricultural landscape (Transcript)

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Scene one

Shows an animation of a landscape featuring gum trees and a kangaroo, a tractor dispensing liquid, and a cow feeding on grass.

This scene is accompanied with the text "Management decisions, as well as soil characteristics and topography, all influence soil phosphorus availability, accumulation and losses."

Scene two

The scene zooms out to show an farm landscape showing two paddocks bound by fencing. One paddock shows rows of sown crop, the adjoining paddock with cows feeding on grass. A creek runs along the upper side of these two paddocks, and over the creek in the upper part of the animation we see paddocks of various shades of green to indicate different crops, grasses and/or soil types in the landscape. Some gum trees are also shown scattered throughout the landscape.

The scene is accompanied with the text "At the farm scale, phosphorus levels are affected by fertiliser and feed imports on to the farm, and removal of crops and animal products off the farm."

Scene three

With the same features as scene two, a tractor drives in from the left of screen onto the paddock showing rows of sown crop and distributes Phosphorus (P) fertiliser.

This scene is accompanied with the text "Soil phosphorus levels are often unevenly distributed within the farm landscape. More productive parts of the farm often receive more fertiliser phosphorus and animal manure. Steeper slopes and less productive parts of the farm may receive lower phosphorus inputs and consequently have limited soil phosphorus levels."

Scene four

The scene zooms in to show a close up of the cows grazing in the paddock, showing the addition of manure to the soil.

This scene is accompanies with the text "In grazing systems, animals spend more time in some paddocks, than in others. They also camp in particular places and congregate around sheltered areas and watering points. This can result in the accumulation of soil phosphorus from manure, some times well above the pasture and crop requirements."

Scene five

The scene zooms out again to show the farm landscape as described in scene two. This time the tractor drives off screen to the left of the paddock sown with crop, the tractor carrying a bale of forage crop. The tractor then reappears on the lower part of the screen and moves across to the paddock containing the cows. The tractor dissolves into the screen so you can see three bales of fodder lining the fence line of the paddock containing the cows.

The scene is accompanied with the text "Phosphorus and other nutrients can also be transferred around the farm by harvesting forages and crops from one part of the farm and feeding them to livestock in another."

Scene six

With the same features on screen as scene five, a legend appears denoting the colour green for optimum soil P levels, yellow for low soil P, and red for excessive soil P. The soil in the animation changes to reflect the areas of the farm landscape corresponding to this legend. The soil of the paddock containing the cows is red (excessive soil P), the soil of the crop paddock is green (optimum soil P), and the soils over the creek in the upper part of the farm landscape are shades of yellow and green.

The scene is accompanied with the text "These management practices will be reflected in the soil phosphorus levels. A regular soil testing program for your farm will greatly assist in better managing nutrients and increase the profitability of phosphorus fertiliser decisions."

Scene seven

The scene shifts to the right to show the creek flowing in to a pond. A swan swims on the pond. An arrow demonstrates the direction of flow of excess P from the soil into the creek and into the pond. The pond slowly shows a bright green shine to the water, demonstrating an outbreak of algae due to the excess P in the waterway.

The scene is accompanied with the text "While phosphorus plays an essential role in maintaining agricultural productivity, even small amounts of phosphorus in water bodies can lead to outbreaks of nuisance and toxic algal growth. This is called eutrophication and is a key challenge for agriculture around the world."

Scene eight

The scene shifts back to show the farm landscape as featured in scenes two, five and six above, and also including the pond to the right of screen. The tractor dispensing P fertiliser is present on the crop paddock, the cows are grazing with bales of forage crop available to them along the fence line, and the soil of each area of the farm landscape is shown as red, yellow or green depending on the levels of P in the soil as described in scene six. The bright green shine on the pond water is present also.

This scene is accompanied with the text "Phosphorus losses are associated with water and soil movement, and small losses from both agricultural and undisturbed landscapes are inevitable. A higher store of soil phosphorus can lead to higher concentrations of phosphorus in water leaving the farm. The closer the connectivity to water, the greater the risk of phosphorus losses and eutrophication. Appropriate management strategies to decrease phosphorus losses should therefore be targeted to these areas."

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