Space-based crop monitoring a key to food security

April 30, 2014 by Marea Martlew
Photosynthetic activity in the US Midwest. Credit: NASA

(Phys.org) —To face the challenges of climate change, and human impact, world food production needs to double by 2050 making accurate and reliable estimates of agricultural productivity – measured as global gross primary productivity (GPP) – a global priority.

An international collaboration, involving UTS remote sensing specialist, Professor Alfredo Huete, has made this goal more achievable by using a breakthrough methodology that has the potential to significantly improve the monitoring of global crop productivity.

The results of the research, recently published in Proceedings of the National Academy of Sciences (PNAS), show that new space-based observations of , using chlorophyll fluorescence data, will provide more reliable projections of and the impact of climate on crop yields.

The research outcomes are especially timely because new satellite missions in 2014 and 2015 are expected to further improve the potential for this type of monitoring and provide unique data sets for the better management of critical agricultural resources.

Currently the best estimates for GPP use direct measurement of carbon dioxide exchange from a series of micrometeorological instruments attached to towers over agricultural fields. However these flux towers tend to sample relatively small areas and are concentrated in North America and Europe. To overcome these shortcomings scientists are now utilising advances in spectroscopy to monitor photosynthesis in terrestrial plants from space, with highly encouraging results.

"Photosynthesis is the primary source of energy for all life on Earth and generally speaking this process places an upper limit on the supply of food and fuels from our agricultural systems. However it has been very difficult to assess photosynthesis rates over the breadbaskets of the world until now," Professor Huete says.

The authors of the paper said the research gives a unique global perspective on crop photosynthesis by monitoring sun-induced chlorophyll fluorescence (SIF) across the world's croplands. This shows that remotely sensed SIF data provides a direct measure of the productivity of cropland and grassland ecosystems.

Professor Huete explained that SIF is a by-product of photosynthesis that is emitted as an electromagnetic signal in a particular "spectral window" of 650-850 nanometres. Improved instrumentation aboard satellite platforms associated with the Global Ozone Monitoring Experiment-2, for example, means that SIF monitoring can now be done at higher resolution, more frequently over a much bigger area of the world and without the need for additional information or complicated modelling.

"This is really a breakthrough because SIF data is giving us realistic estimates of photosynthetic uptake rates over large cropping areas such as the American corn belt and the intensively fertilised Indo-Gangetic Plains. This means we can improve current models of the global carbon cycle which tend to substantially underestimate productivity in these regions."

Explore further: Seeing photosynthesis from space: NASA scientists use satellites to measure plant health (w/ Video)

More information: Luis Guanter, Yongguang Zhang, Martin Jung, Joanna Joiner, Maximilian Voigt, Joseph A. Berry, Christian Frankenberg, Alfredo R. Huete, Pablo Zarco-Tejada, Jung-Eun Lee, M. Susan Moran, Guillermo Ponce-Campos, Christian Beer, Gustavo Camps-Valls, Nina Buchmann, Damiano Gianelle, Katja Klumpp, Alessandro Cescatti, John M. Baker, and Timothy J. Griffis. "Global and time-resolved monitoring of crop photosynthesis with chlorophyll fluorescence." PNAS 2014 111 (14) E1327-E1333; published ahead of print March 25, 2014, DOI: 10.1073/pnas.1320008111

Related Stories

Studying photosynthesis, from outer space

March 24, 2014

Plants convert energy from sunlight into chemical energy during a process called photosynthesis. This energy is passed on to humans and animals that eat the plants, and thus photosynthesis is the primary source of energy ...

Satellite shows high productivity from US corn belt

March 31, 2014

Data from satellite sensors show that during the Northern Hemisphere's growing season, the Midwest region of the United States boasts more photosynthetic activity than any other spot on Earth, according to NASA and university ...

Sugar responsible for shoot branching in plants

April 7, 2014

(Phys.org) —A University of Queensland study has overturned the long-held belief that plant hormones control the shape of plant growth, and shown instead that this process starts with sugar.

Recommended for you

How wind sculpted Earth's largest dust deposit

September 1, 2015

China's Loess Plateau was formed by wind alternately depositing dust or removing dust over the last 2.6 million years, according to a new report from University of Arizona geoscientists.

Climate ups odds of 'grey swan' superstorms

August 31, 2015

Climate change will boost the odds up to 14-fold for extremely rare, hard-to-predict tropical cyclones for parts of Australia, the United States and Dubai by 2100, researchers said Monday.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.