Frequently Asked Questions

About Pastures from Space Plus

Does Pastures from Space Plus require high internet speed connectivity?

Pastures from Space Plus does not require excessive internet downloading to operate. To test how Pastures from Space Plus will work with the internet connection in your area, try the free demonstration farm on the homepage, as the requirements and functionality will be exactly the same as it will be with your own farm.

Does Pastures from Space Plus have the same important features as the previous version?

Yes, and more. It still offers Pasture Growth Rates, Feed On Offer, Total Dry Matter, NDVI and rainfall data, but with the addition of hi-res Landsat 8 imagery.

How do I know if my farm is covered by Pastures from Space Plus?

Pastures from Space Plus is intended for use by properties located within the intensive agricultural regions of southern Australia.

How is Pastures from Space Plus different to the previous version?

PFS Plus now includes the facility to map your own paddocks, saving you money by not needing a consultant to do it for you. Also new in PFS Plus is a quick and easy-to-read summary report on all of the paddocks showing the PGRs, FOOs and change in FOO for the week.

The report can be sorted on either of these or by paddock name. There is also a stocking rate calculator for each paddock which uses the actual PGR and FOO data reported for the paddock, taking away a lot of the guess work.

PFS Plus also includes the option of 30m resolution satellite imagery showing the current PGR, FOO and greenness (NDVI) levels within paddocks.

This is a vast improvement on the 250m resolution data.

Are you working on a version for agronomists to access?

Yes. We are currently working on a multi-licence version for agronomists. We ask that you register your interest with our account manager Roberto.Hofmann@landgate.wa.gov.au.

About Pastures from Space Plus satellite imagery

What is all the white on the Landsat image?

It is the cloud cover seen by the satellite as it passes over your farm.

Can the satellites see through cloud cover?

No, although there may be ways around this. One method is to use the next or previous data, or images may be taken from another satellite. The satellite images are used in combination with other data not constrained by cloud cover, such as rainfall and temperature readings.

What is MODIS imagery?

MODIS imagery has a resolution of 250m, i.e., each pixel is 250m x 250m or 6.25ha. MODIS imagery is processed weekly (on Wednesdays).

What is Landsat 8 imagery?

Landsat 8 imagery has a resolution of 30m, i.e., each pixel is 30m x 30m and orbits over the same region every 16 days (7 + 9 days in overlapping regions). However, because of this low orbital frequency, a cloud free composite image is often not possible and therefore the data is not used in the determination of weekly PGR, FOO and TDM values. Therefore, the Landsat 8 imagery is provided for visual assessment purposes only and must be considered as supplementary information only.

What are the benefits of me using Landsat 8 imagery?

Landsat 8 has benefits for both pastures and crops. With Landsat 8 imagery, you can see the differences within a paddock. For example, you can see which parts of a paddock are growing better than others, which parts of a paddock are being grazed more heavily than others and which parts of a paddock are recovering faster post-grazing. You can see which parts of the paddock are more productive than others, and hence where fence lines are better located. You can see which paddocks are performing better than others (on both sides of the fence). You can see where weeds are germinating following unseasonal rainfall and potentially which parts of the paddock are having moisture penetration issues.

Using Pastures from Space Plus

Can I download the data/export to Excel?

Not in this version. It is being evaluated for future releases. In the meantime, in-built charting tools allow past performance to be seen, at a glance.

Can I add my own rainfall data?

Not in this version. It is being evaluated for future releases. Currently we use Bureau of Meteorology (BOM) data.

Glossary

What does ‘daily green-feed intake’ mean when calculating my stocking rates?

This is how much green feed (in kg) an animal will eat per day.

How can I identify those scenes that are affected by cloud cover?

A percentage cloud figure is displayed adjacent to each capture date.

Can I add extra paddocks once I have registered my farm?

Yes, but it will cost more if you decide to add additional paddocks after your initial signup. A further set-up fee will apply.

If I delete paddocks from my farm, do I get a refund on my subscription?

No. Your subscription is for a 12 month period. You can change the number of paddocks at subscription renewal.

Can I view/interrogate individual pixel values?

Not in this version. It is being evaluated for future releases

Is there a geo-locator feature indicating where I am in relation to the satellite image?

Not in this version It is being evaluated for future releases

How do I identify paddock areas or management zones?

Once you register, you will be prompted to draw your paddock areas. The aim is to draw paddocks or management zones that you treat as a management unit. You will then be able to monitor the change in growth for these zones each week and back to 2004.

What is NDVI?

It is the Normalised Difference Vegetation Index. NDVI is a satellite-derived index which is sensitive to the amount of chlorophyll covering the ground. Essentially, NDVI shows how green the ground appears from the satellite.

Does NDVI show digestibility of vegetation?

NDVI will show which parts of a paddock is greener, but does not necessarily show digestibility. However, some farmers have noted that with the Landsat 8 images of NDVI, they can see which regions of a paddock are being grazed more than others.

Does a higher NDVI value indicate the greener the vegetation is in a paddock?

Yes. The higher the NDVI value, the more of the ground is covered by green vegetation. An NDVI of ~20 is when the ground is totally bare or the grass has completely dried off. An NDVI of ~80 is when the ground is completely covered in green vegetation.

What is the saturation point for NDVI?

NDVI saturates when the feed on offer gets to about 2500 kg/ha (for annual pastures).

What is the best way to use weekly NDVI data?

The best use of weekly NDVI data is graphing it for paddocks with similar crop or pasture type.

Graph a group of pasture paddocks in a single year to see which are greener, and which ones are recovering better post-grazing. It's also good for comparing a single paddock over multiple years and hence identifying analogous seasons.

What happens when I have high of green biomass but the satellite image shows all pink (meaning no PGR)?

It means that the biomass is growing at less than 10 kg/ha/day, or not at all. If there is new growth coming through underneath dead material then that would be shielding the new growth from being seen by the satellite.

The PGR model relies on BOM’s 5 km resolution climate data. When there is a combination of low bureau-estimated rainfall and high evaporation over a period PGR will think that soil moisture has all but gone and show a PGR = 0.

What is Feed on Offer® (FOO)?

This is an estimate of how much ‘green’ feed (in kg dry matter/hectare) is available in each annual pasture paddock.

Why are my FOO values considerably lower than actuals?

This can be caused due to several reasons:
  • Paddocks are too small and the relatively large pixels are detecting areas of lower FOO outside the paddock.
  • A pasture paddock is in its first year out of crop and the dead crop stubble is masking out the underlying green pasture.
  • The FOO values are only sensitive to green biomass and don't detect dry biomass. This can happen if pastures haven't been grazed and have dead material build up on top, again, masking out the underlying green pasture.
  • Different pasture species are growing in the paddock than the annual pasture species that the FOO model was derived from.
  • The conditions were too cloudy during the week and new growth hasn’t yet been detected by the satellite.

Why doesn’t the FOO index go higher than 1500 kg/ha?

A typical benchmark in our area is to have a minimum of 3000 kg/ha FOO at haying off.
The FOO calculation saturates at approximately 2500 kg dry matter per hectare. Once the ground is fully covered by green biomass it’s difficult for the satellite to measure FOO levels above this. You can see the estimated FOO value in the paddock report, or in the paddock information window at the bottom-right of the screen when you move the mouse over the paddock.

Does FOO only pick up green FOO?

Yes, the FOO reported in PFS Plus only detects green FOO.

Does PfS Plus provide a total of combined FOO and TDM for the whole property?

No. We haven't developed whole-of-property information because a lot of farms are a mixture of pasture and cropping. Including cropping paddocks in the property-level calculations would skew the numbers.

What are Pasture Growth Rates® (PGR)?

This is an estimate of how quickly (in kg dry matter/hectare/day) the pasture is growing each week.

How often is the PGR information updated?

The 250m resolution data is updated weekly (usually on Wednesday afternoons). Landsat 8 orbits over the same region every 16 days and is processed when made available by the USGS. In overlapping regions, Landsat 8 orbits every 7 + 9 days.

What is Total Dry Matter (TDM)?

This is an estimate of the gross primary production, or the total amount of pasture (in kg dry matter/hectare) that was grown over the year.