Dr.
Praveen Kumar, Professor of Civil and Environmental Engineering at
the University of Illinois at Urbana-Champaign, gave a talk titled
The Water-Food-Climate Squeeze: Can we bio-engineer our way out? He
discussed the topic from an physical, biological, and climatological
prospective. He focused on a few fundamental problems such as how
will we feed people as our global population grows? Also, what
changes will occur to plants and crops do under climate change.
We
need to increase crop yield, improve water use efficiency, increase
albedo (reflectivity), and use the same amount of land for crops.
Interestingly Kumar showed that arable land is increasing in
developing countries but declining in developed countries, but the
ultimate takeaway is that cropland per person is decreasing fast.
Fifteen percent of terrestrial land is devoted to agriculture. With
water, the more we use in agriculture means there will be less for
consumption.
The
University of Illinois has conducted a field study growing soy and
corn crops at elevated carbon dioxide levels, focusing the talk on
the 550 ppm level, a likely concentration in the future. They found
that the plants had a clear increase in their temperature and
decrease in transpiration, as well as changing the chemistry.
Dr.
Kumar then ran a model to try and understand what is causing these
changes. It found that plant productivity is heterogeneously
distributed vertically, and we may be able to take advantage of this
to optimize production. It may be possible to find vertical
structures for a whole canopy that will allow increased productivity,
reduce water use, increase albedo, and increase photosynthesis,
simultaneously. When searching for a solution that could maximize or
minimize the key factors, it was found that optimal leaf area index
was less than existing, meaning that if we decreased the number of
leaves then it would increase the yield. Without making changes to
the genetics of the crops this result can have impacts on the amount
of food produced.
The
results are robust under present and climate change scenarios. The
science behind Dr. Kumar's research, as well as many other
scientists, is going to help agriculture continue to improve with or
without a changing climate. The future of the science is to look at
very fine resolutions, on the meter scale via remote sensing techniques such as LiDAR (Light Detection and Ranging), to find the
best ways to spatially grow crops with the natural topography. The
small-scale depressions and subtleties in topography will have
impacts on the hydrology and thus growth of crops differently. To
optimize the water use and land use, there will likely be assorted
crops planted in a single field based off the topography.
