Articles, Blog

Water and Irrigated Agriculture

Welcome, this is the Water and Irrigated Agriculture
portion of the Water, Civilization, and Nature MOOC: Addressing Water Challenges of the 21st
Century. Hi, my name is James Pritchett. I am a professor in Agricultural and Resource
Economics at Colorado State University. I’ve been trained as an Ag Economist working in
the area of agriculture and water resources. Not only how we can use that on the farm but
also what it means to local communities in order to have that irrigated agricultural
base. Maybe even at a broader base, understanding policy issues that influence irrigated agriculture
and water resources. That’s the perspective that you’ll get from me today, is thinking
about things like an Ag Economist. We’re really going to provide you with an
overview of several agricultural economic issues and agricultural issues as it relates
to water resource economics. It won’t be in terrible depth or in terrible rigor, but instead
it’s an introduction to issues. You’ll have the opportunity to dig a little deeper into
those issues by enrolling in other courses. Here’s some key takeaways that I want you
to think a little bit about. First, by the end of this session I want you to understand
that water is a complex natural resource. It joins people, food, fiber, culture, industry,
and the environment all together. It’s important to think of water as being this interconnected
activity or set of activities so that when you change one it alters all of the others.
These activities are influenced by external forces, things like climate change and the
laws and institutions that we use to allocate water. The way that agriculture uses water
will have to necessarily change in the future because of those external forces that I mentioned.
We’ll talk a little bit about some of the things we can do in order to take advantage
of the opportunities in the future and to fend off some challenges. Opportunities do
about for meeting those agricultural water challenges, but all of those are going to
require collaboration, by individuals within the watersheds and by different stakeholder
groups. Let’s get started thinking a little bit about water and irrigated agriculture.
The first thing I’d like to do is give you a snapshot of how water is used in irrigated
agriculture. Important to note that agriculture uses water throughout the supply chain. For
instance, feed lots will use water in order to produce cattle, but we’re mainly focusing
on the crop side of things with this presentation, so that’s where the emphasis will be, will
be on irrigated agriculture. I wanted to give you a kind of hydrologic
view from the hydrologic cycle, a view of how water is used in irrigated agriculture.
The diagram that we have sort of represents and upland slope on the left-hand side and
a river system that runs downhill to where there is an ocean down at the far right-hand
side and a municipality. Rain falls in those upper uplands and is collected in lakes and
streams, maybe even reservoirs in that area, then the water trickles down so that it can
be used by farms. Surface water, using that water that flows down through the river system
is one way that water can use farms. But also that water will percolate down into the groundwater.
Those forms may use wells, high capacity commercial wells, in order to pump water up and irrigate
crops with those. Whether it be via surface irrigation or via the groundwater irrigation,
there will be water that will apply to farm fields and those will make its way back into
the river system. It won’t be completely used by the crop. That water can flow back into
the system and be reused and reused again and reused again as it travels downstream
until eventually it meets that water area. One thing that’s true is that if agriculture
uses water it can use it from two different sources, that being the surface water and
the groundwater, that agriculture’s use of water can be used by others, and agriculture
can use the return flows of water that comes from other farms and comes from other cities.
There’s really a complexity of uses that take place.
We’ve gone so far as to categorize these uses of water in agriculture into a variety of
different areas. One of those areas that we categorize water into is blue water. That’s
fresh surface water or flowing water and groundwater that’s been preserved in the ground level.
This is water that we’re going to bring up, that we’re going to use for crops. This is
different than green water. Green water is precipitation that falls down and that doesn’t
runoff the land or isn’t used to recharge groundwater. It doesn’t flow into the stream,
instead crops use it where it is. Crops use that water in an evapotranspiration process
in order to grow, grow foliage or grow grain. The last type of water classification is grey
water. That’s the fresh water that we use in order to assimilate a load of pollutants.
Actually, to dilute those pollutants in discharged water. The three different water uses: blue
water, green water, and grey water. One thing that I think we want to take away is that
water is really distributed throughout the world in varying amounts. That can both be
in terms of green water which is in the upper portion of the map of the world where you
see green water distribution. Darker colors of green represent more water. Blue water
distribution which is also spread out unevenly, that’s the flowing surface water and some
groundwater. Darker shades of blue indicate more blue water. Grey water is also unevenly
distributed but one thing you might notice is it really fits with populations because
we use our freshwater to discharge in areas where there tends to be heavy populations.
Water is spread unevenly through the world. Yet, with the exception of grey water, it
doesn’t always match up with where the people are which can lead to water stresses. Irrigated
agriculture needs to be located where that water is and in areas where there is significant
population or other competing uses for those types of water, that’s where we might have
some scarcity. One of the things that’s also true about agriculture
is among that water that’s available, the green water, the blue water, and the grey
water, among that water that’s available, agriculture really is the largest user of
water and withdrawals the most. In this chart, produced by the FAO, you can look at for the
world that’s the far left-hand side of the charts and different other areas or sectors,
what their withdrawals are by the type of industry that’s there. Agriculture is the
very darkest brown. Sort of the middle brown is industrial use. Municipal use is the lightest
shade of brown. Agriculture worldwide will extract or withdrawal about 70% of the water
that’s available within the word as a percent of all water withdrawals. Different regions
use more or less water for agriculture depending on how much is available and how much is actually
fed as precipitation and to extent that they have industrialized sectors. In developed
countries like western and central Europe, you see that on the far right-hand side of
the chart, they tend to use more water as a percent of withdrawals for industrial use
and municipal use compared to their agriculture. But in the least developed countries, which
is the far right-hand bar, those countries tend to use most of their water for agriculture.
Really, agriculture is generally an important base industry in those countries so that makes
sense to us. Agriculture is by far the largest water user and it uses it in order to produce
crops that later go to feed those individuals in municipalities. I think one thing that
is true is that individuals often think that cities use the most amount of water but in
truth their withdrawals are small compared to what we use for food which is an indirect
demand of water in those cities. Why is irrigation important? Why do we need
that much water in agriculture and why is it important that that persists?
I think one thing that is important that’s on the front of everybody’s mind is that we
use irrigated agriculture in order to meet global food needs. It’s true that dry land
agriculture, agriculture where precipitation or green water just feeds that, that does
provide some of the water that we have. Let’s look at this diagram, that will help us out
some because we’ll look at rainfed agriculture versus irrigated agriculture and find out
that irrigated agriculture is actually the area that uses water to produce the most food
for this system. On the left-hand side of the diagram we have precipitation. 100% of
precipitation falls down, some to land and soil. About 65% goes there; that’s green water.
Then, 35% goes to lakes, rivers, and percolates down into the groundwater. That’s blue water.
The green water can be used for rainfed agriculture. Precipitation falls, plants take it up, then
they evapotranspirate that and use it to produce some of its foliage, some of its crop. For
that rainfed agriculture, about 80% of the agricultural land produces about 60% of the
food. When it comes to the bottom portion of that diagram where we have blue water and
gray water, lakes, rivers and groundwater give that blue water and gray water from return
flows from domestic and industrial water use also contribute to irrigated agricultural.
Irrigated agriculture only has 20% of the agricultural land but it produces 40% of the
food. You can see that there’s really an increased productivity that is associated with irrigated
agriculture because you can use water more intensively to produce crops that go on to
meet global food needs. The other thing that’s true about this is that rainfed agriculture,
well that faucet can turn off every once in a while. We can have droughts. Then cropping
suffers. But when it comes to irrigated agriculture, to the extent that we manage the supplies
within reservoirs and within lakes, and to the extent that we can economically extract
that from groundwater, irrigated agriculture is a much more reliable supply of food. Not
only does it produce more food per acre because of its intensive production, but also it’s
more reliable and that reliability is really important for meeting global food needs.
The other way that water short areas are able to attain water is not necessarily through
a direct flow or reservoir or by a pipeline, but instead they may virtually ship water
to areas where there isn’t much by shipping food. We grow food in areas where water is
abundant or very efficient in the use of water, and ship those to areas where perhaps where
they’re not as abundant or not as suited for producing agriculture. That’s what this chart
shows, is global water savings associated with international trade. If you can ship
the products, then in essence you’re shipping water from one area to the next. In the left-hand
side of that chart, in the United States there’s a lot of blue water that’s used in western
irrigated agriculture and that can be shipped to areas around the world including Japan
and other spots on the far right-hand side of the chart where more less-suited agricultural
areas are found and less water is available for agriculture. Virtual water, shipping from
one place to another, is another way we can meet those global food demands and one of
the reasons why irrigated agriculture in one part of the world is important for feeding
other parts of the world. I mentioned earlier that irrigated agriculture
is really more productive in producing goods relative to rainfed agriculture when you compare
everything on a per acre by per acre basis. I think in the United States this really shows
up in terms of the revenues and the value of market, marketed agricultural products
that are sold when you compare irrigated farms to dry land farms. Let’s take a look at this
chart produced by the Economic Research Service using statistics from the National Agricultural
Statistics Service. Let’s look for evidence that irrigated agricultural production might
be more efficient or more productive on a per acre or per farm basis than dryland farms.
The far right-hand side of this chart is dryland farms. The middle portion of the chart is
irrigated farms. All farms represent that first column on the left-hand side, after
the labels. If we look at the market value of agricultural products sold, measured in
thousands of dollars, that’s that first row. For all farms in the United States in 2007,
that appears to be more than $297 billion of agricultural products that were sold, or
about $143 thousand per farm. Irrigated farms relative to what that average is, they produced
about $344 thousand and that’s a mix of irrigated and dryland cropping, or if it’s just irrigated
cropping, that’s about $349 thousand, so a greater value of crops have been produced
in those areas. It’s especially true in the United States that if you produce a higher
value of crop, you’re more likely to have irrigation because you have more at risk associated
with the value of that crop. It’s also true when you compare that to dryland farms, that
far right-hand column, that the value of market goods sold is only about a third for the dryland
farms compared to those irrigated farms. In terms of producing the assets or producing
the values of crops, it’s much higher with irrigated cropping compared with dryland cropping.
The same thing is true when you look down. If you can skip down to that first, second,
third, fourth row, where total farm expenses are, irrigated farms make more purchases of
inputs because it’s associated with higher yields. You need more seed, you need more
fertilizer, frankly you’ll probably need more pesticides and herbicides in order to produce
the value of that crop. Irrigated farms production expenses are about $309 thousand per farm
in 2007. Dryland farms that’s only $77,000. If you think of irrigated agriculture as also
supporting other industries that provide inputs into those industries that provide things
like fertilizers and pesticides and labor and equipment, then irrigated farms actually
generate a higher economic multiplier for the local community compared to what those
dryland farms are. Why is irrigation important? It’s important for meeting global food demands.
Irrigation is important for producing food and shipping it to areas where they might
have a deficit of water. Irrigated agriculture is important in terms of productivity relative
to what we do in dryland production. Quite frankly, we wouldn’t be able to meet global
food needs or generate as much economic activity if we didn’t have irrigated agriculture available
to us as an agricultural community. There are things that are not directly contributed
to irrigated agriculture but are also important because agriculture exists and sort of relates
my first example to that idea of economic activity.
In order to orient you though, I wanted to tell you a story of Colorado in particular
and what irrigated agriculture means in Colorado. This is a map of the state of Colorado. It’s
a snake diagram that depicts river systems in Colorado that’s been produced by the State
Engineer’s Office in the state of Colorado. Colorado being a headwater state has a lot
of different river systems. They include the Yampa, the White, the Colorado, the Gunnison,
the Dolores, the San Juan, the Rio Grande, the Arkansas, and the South Platte. On the
left-hand side of Colorado, that’s what we call the West Slope. It has a population of
about 578,000 people and has about 860,000 irrigated acres. But 80% of all of Colorado’s
precipitation whether it be falling as green water that crops can use or blue water and
more often blue water whne it comes to reservoirs and streams and also groundwater, about 80%
of the water actually falls on the Western Slope where there aren’t as many people. The
numbers that you see in each of those river systems represent the amount of flow, on average,
for those river systems at the state line. The Yampa has one and half million acre feet
of water per year. The Colorado, our really big river system, has four and half million
acre feet per year. Let’s compare that to the East Slope, where there’s almost four
and half million people in terms of population, that’s the right-hand side of the chart. There’s
about 1.7 million irrigated acres and a lot less flow of water when it comes to this blue
water in streams. The South Platte is the largest river system, it has about 400,000
acre feet a year at that state line. But, much water gets reused. Some of it gets transferred
from the West Slope to the East Slope. Colorado is like a lot of other states in that they’ve
used direct flows of irrigation water in order to produce agriculture in a variety of different
areas. Those areas are generally defined by the water basins. Pay attention to where the
South Platte is in the upper-right hand corner, the Arkansas in the lower right-hand corner,
the Rio Grande which is in the central part of the lower part of Colorado, and the Colorado.
I want to talk about the economic activity that’s generated by each of those river systems
with respect to agriculture. We were commissioned in order to do a study
to look at this for some of our state leaders who were grappling with how much water can
be kept in agriculture and how that might be done. We have a region in the Arkansas,
the Republican River Basin which is part of that South Platte, the Rio Grande which is
in the central lower part of the state, and the South Platte which is in that upper right-hand
side. It gauged the importance of irrigated agriculture to the local economy; one of the
first things we did was measure agriculture’s receipts relative to the local GDP. Farm gate
receipts, sales that are made at the farm, relative to all the regional sales that take
place. You might think of regional sales as being the GDP for that region or the gross
domestic product. In the Arkansas River Basin, remember that was in the lower right-hand
part of Colorado, about 31 cents of every dollar’s sales can be attributed to farm gate
receipts or sales that happened right at the farm gate. In the Republican that’s 37%. In
the Rio Grande it’s very high, that’s about 48%. In the South Platte, that’s very low,
that’s about 2%. It’s an interesting statistic. Comparing the Rio Grande to the South Platte
because the South Platte contains two of the most agriculturally productive counties in
the United States. Because this is farm gate receipts divided by regional sales, it’s true
that there’s an awful lot of other things going on in the South Platte, including our
state capitol Denver and other large municipalities. Even though those sales are quite large from
farm gates, they’re small relative to the rest of the economy. Another way to measure
this economic activity of irrigated agriculture and what that might mean to a state is to
look at how much is generated per acre of irrigated cropland. When we assessed that
value we found that in the Arkansas in 2006, a time of lower prices than today, we found
that there were about $428 per irrigated acre versus in the Rio Grande look at that number,
almost three times as much, $1127. The difference has to do with what crops are irrigated within
that region. In the Arkansas, there’s generally lower value forage crops, things like alfalfa
hay that are grown in that area. That alfalfa hay is generally marketed to cattle which
is not necessarily a high end market for that hay. Compared to the Rio Grande, there’s an
additional economic activity, about $1127 that is attributed to high value crops like
malting barley for beers and potatoes, table potatoes, that get sold all over the United
States. That doesn’t tell the whole story of economic
activity that’s generated. One of the spillovers that’s associated with irrigated agriculture.
Not only is there direct activity which is those sales at the farm gates, there’s also
indirect effects. These are the industries that I talked about that agricultural sales,
the dollar revenue, helps to support in the local community. That includes fertilizer,
seed, and chemical sales. But the economic activity only includes the margin or the profit
that’s produced in that area if the industry is headquartered in that area. We wanted to
make sure we attributed it specifically to the area in which it is. It also includes
transportation, trucking that takes place, real estate services, and agricultural consultants
who might scout for pests for instance. Indirect effects are one source of economic activity
related to sales but that even goes further. For those folks that are working on the farms
or working in the local businesses, the wages that are spent at the supermarket or the pharmacy
or in the dentist’s office, those are called induced effects. Those are also associated
with economic activity for irrigated agriculture. When does irrigated agriculture tend to generate
a lot of economic activity? When you produce high value crops that are sold outside of
a region that brings income in. Or, you’re able to produce crops that might replace imports
that would come into your region. It also is associated with when you use a lot of locally
produced inputs, that tends to generate a higher economic activity. Local support industries,
you tend to use their local labor in order to produce those things. That’s when you produce
that higher economic activity. Irrigated agriculture is important in that we meet global food demands.
It’s important in the sense that we can shift water to places where we’re in deficit. But
irrigated agriculture is also an important base industry to a local community. If water
shifts around or if there’s less available to us, that might affect that base economic
industry adversely. That’s one of the things we pay attention to as we think about water
and agriculture. It’s also true that agriculture uses water
in a consumptive way, but doesn’t use all of the water that way. Also, water might be
available because you have to ship from one place to another for non-consumptive types
of uses. One of the important non-consumptive uses of agricultural water is water that’s
used by recreation. Those are things like fishing, you see our fly fisherman in the
picture up above. Boating, rafting, touring- that might be folks that are travelling up
and down in kayaks or touring up and down the river system so they can see wildlife-
and hiring guides who can enhance a tourist’s experience by being able to see what takes
place. Those are all direct activities that also inject economic activity into the local
economy. Those spawn indirect activities just like we had for the agricultural inputs before.
That’s the purchase of supplies for each of those industries from local shops. When folks
come to that area so they can raft or they can boat or fly fish, they stay in a hotel
or a motel and that recreation industry might not exist without those agricultural water
deliveries that we get to recreate on, restaurants, and fuel purchases. Spillovers are not just
because of the consumptive uses of water in agriculture that supports local industries
but also the non-consumptive uses that exist because agricultural water is used and it’s
stored and it’s conveyed. At the same time, that conveyance may create
positive environmental effects. Those might include induced wetlands so that as irrigation
takes place, the runoff runs back to a river system and riparian areas are developed that
might not exist otherwise. That creates habitat for important species that might be valued.
Riparian areas for healthy ecological systems may be created as a result. Landscapes that
people enjoy may be part of the beyond the farm gate benefits of having irrigated agriculture.
That nexus with the environment isn’t all positive. Sometimes negative spillovers are
created because of irrigated agriculture. In particular, that might take place because
as chemicals or fertilizers are applied to irrigated farmland, and if that water that
is used to irrigate should lift those chemicals or that fertilizer off and put them into a
streambed or into a river system, or maybe even further on into an ocean, it can impair
the environment. An important part of addressing challenges for irrigated agriculture is to
look at what are the different ways that water quality can be improved. This chart gives
you an idea of wetlands water quality state and what those changes are by continent. The
eutrophication or the agricultural pollution or water quality loyal, that percent change
is measured on the vertical axis on that left-hand side. We take a look at it by continent, Africa,
Asia, Europe, in the Neotropics, in North America, and Oceania. We also have lines drawn
across for average agricultural pollution and average eutrophication of quality. As
impairment takes place, there’s changes in water quality and agricultural lands because
that land has been irrigated and because inputs are used more intensively, it can also harm
the environment as well. Beyond the farm gate there may be those negative spillovers. We
looked at spillovers related to the economy, to recreation, to the environment, all positive
and negative. That’s some of the things we don’t get a grasp on when we think of agriculture
just as food production and how it relates to water.
Things are going to change. One of the things we said at the outset, one of the key things
we wanted to takeaway was that there are external pressures that are going to change the way
we do agriculture and the way that we use irrigation.
Changes are already taking place in the United States. I like this chart as a way to describe
some of the changes that are taking place. I’ve circled some instances that are very
important to us. This map is created from US Agricultural Census data. The Agricultural
Census is just like a population census, forms are sent out to individual farms and they
write down what they do in terms of agricultural production, whether they use irrigated production
or not, the types of crops that they grow, the age of the producer, and other types of
demographic information. When we get a census then, we can look at changes over time. This
census takes place every five years. This chart shows in particular irrigated lands,
which farmers use irrigated lands, and the change from 2002 to 2007. Blue dots represent
additional irrigated agriculture. Red dots represent a decrease in irrigated agriculture.
Both of those dots represent changes of one thousand acres. What I’d like to do is start
on the far left-hand side and describe some external pressures that are tending to dry
up irrigated lands. Those are the red dots that you see. Down in the lower left-hand
portion of the United States, in southern California and also accompanying parts of
central Arizona, there’s been a decrease overall, a net decrease in irrigated lands. That’s
a direct result of increased demand from growing population areas. As individuals move into
the western United States, homes are built and those homes and households need water
resources. One of the easiest ways to get water resources is to buy them in private
market transactions from farmers. As a result, that water is transferred off the farmland
or the houses are actually built on that farmland. But now the water instead of being used in
irrigated crops are used in homes. That’s part of the decrease in irrigated acres. That’s
a little different than the green circle that you see in the center of the page up in northern
Colorado. In some of those areas we’ve seen a decrease in irrigated acres in part because
of population growth that’s taken place in Denver, in part population is a pressure.
But also because the way laws have been applied in Colorado changed so that individuals who
had wells that were connected to river systems had to go through additional steps and take
on additional expense to use those wells. They couldn’t take on that expense, the laws
had changed, so they shut down those wells and that constituted a dry up along the South
Platte River Basin, which is a basin we discussed earlier. That’s why those irrigated acres
have dried up in those areas. Let’s shift down to Texas which is lower below that dot
where you see I’ve circled some other areas, especially within the panhandle of Texas.
Recall that there were two sources of blue water. One was from surface water irrigation,
rivers and streams. The other was from groundwater. Well, there’s not a lot of rivers and streams
in that part of Texas, but there is a lot of groundwater that gets pulled from the Edwards
Aquifer and from the Ogallala Aquifer in order to irrigate farmland. As individuals have
captured more and more of that water, they’ve had to go deeper and deeper in order to get
it. The cost of the energy to pump that water up relative to the value that’s created by
irrigated agriculture, well that’s gotten to be the case where it’s a losing proposition
for those farmers. So, they’ve shut down those wells and those irrigated acres have transitioned
to dryland agriculture or gone back to native grasses. Population changes can tend to reduce,
that’s an external pressure on agricultural water as it shifts to municipal use. Laws
are changing in how we apply water and that may make water less available for agriculture.
Overuse may be one of the pressures that take place if we withdrawal water from aquifers
at a rate that’s faster than it gets replenished. That may cause a decrease in irrigated agriculture
or may cause irrigated agriculture to try to use water more wisely in order to conserve
water in different ways. Climate change is another means by which irrigated
agriculture will feel some pressure related to its water. When we think about climate
change we think about precipitation change which I’ve gotten this figure that’s in the
middle of the page, but also in changes in temperature. Increased temperatures generally
associated with climate change, and also longer growing seasons so you can grow more crops
and also we may see more intense storms, and more intense drought events. All of those
things might take place. Generally those will increase the demand that agriculture has for
water so that the amount of crops you can produce in an area may go up provided that
there’s water supplies, but that’s going to induce increased water, too. We need to pay
attention to climate change as an external pressure that will make us use water more
wisely just like population, changing institutions, and depleting water at unsustainable rates
may change how irrigated agriculture uses its water.
The last innovation that I think has taken place in the last several decades and may
continue into the future is the use of biofuels or using agricultural crops in order to meet
future fuel demands just like we need to meet future food demands. If we’re going to be
growing more agricultural crops for that purpose, we’ll also need to use water in the production
of that fuel. There’s a water and energy and agriculture nexus in that sense. But also
we’ll have to grow more crops as fodder for those biofuels. One thing we’ve tried to do
is look at that ethanol water footprint in Colorado just so we understand how much additional
water is needed. The ethanol water footprint in Colorado, most of our plants operate at
about 3.5 gallons of water are needed to produce a gallon of ethanol. That’s been squeezed
down to about 3 gallons in some of our more efficient plants. Gasoline, just as comparison,
uses about 2.5 to 8 gallons of water depending on the technology used in order to produce
gasoline. Of course, ethanol is mixed in with gasoline as a fuel we use in our automobiles.
In Colorado’s three plants, we produce slightly more than 400 gallons per minute, which means
we need to use 595 million gallons per year of water within those plants, which is about
1,825 acre feet of water within a year. Picture an acre as being about the size of a football
field, and picture about 12 inches of water being the amount used, 1825 football fields
being the amount needed within the plant when producing ethanol .That’s pretty small. Think
about the surface water that was on the snake diagram earlier, the four and half million
acre feet that are produced within the Colorado River Basin or even the 400,000 acre feet
that are produced in the South Platte Basin. The key though is that’s just the water used
within the plant. The crops that are needed to grow fuel stock to go into those ethanol
plants, well that’s a different story. We calculated that, too. In Colorado, consumptive
use of water, the amount of water that’s needed by the crop in order to produce that grain
is about 1.5 acre feet of consumptive use. A bushel of corn needs about 2600 gallons
of water. One bushel produces about 2.8 gallons of ethanol in Colorado. One Colorado ethanol
facility draws about 20.5 million bushels per year of grain, so the grain footprint
of an ethanol plant in Colorado is about 20.5 million bushels which is a footprint of about
163,000 acre feet of consumptive use water for irrigation. That’s compared to 1800 acre
feet needed just within the plant. So, quite a bit more used when we grow those crops.
That’s about 108,000 acres of corn. It creates an interesting competition with other sectors.
That’s what that chart on the right-hand shows. If we add ethanol to production in Colorado,
there are other industries that need to use those crops and tradeoffs are going to take
place about where we route that corn and probably more importantly, where we route that water.
Ethanol is going to compete against the dairy industry, the fed beef industry, lamb industry,
poultry industry, and the swine industry. All of those need about 222,300 bushels of
corn, or a little over a thousand acres, 1.179 thousand acres in order to produce the corn
that’s needed in all those industries. The truth is in Colorado we can only supply about
148,000 bushels of corn and only have about 785 thousand acres of corn within the state
in those years. That means there’s a deficitbetween what total use is and what’s produced in Colorado.
Where does that come from? It comes from other states that ship it in. Virtual water is being
shipped into Colorado to supply a growing ethanol industry as well as animal industries
in order to meet the food demands of people all over the world. That’s another example
of virtual water. Colorado’s total draw for ethanol, just from those three plants, is
about 325,000 acres of corn or about 490,000 acre feet of CU for irrigation in other places.
External pressures tend to include growing population is one thing we’ve talked about,
we’ve talked a little about climate change, we’ve talked a little about using water faster
than it can be replenished in groundwater, we’ve talked about changing institutions or
laws that affect water allocation and that will influence agriculture’s use of water,
and lastly we’ve talked a little bit about fuel uses or new agricultural uses increasing
agricultural demand. What can we do in order to mitigate some of the effects or some of
the things that we think are changes taking place. Where can we go from here? That’s what
I’d like to cover next. One place that we’re focusing a lot of attention
are on the agronomics side of things. Is it possible for us to produce more crop per drop?
If we’re going to meet the growing needs of population worldwide, we’re going to have
to find effective ways to use water. If we can create crops that can use less water to
produce the same amount of grain, we’ll be ahead in terms of meeting those needs. This
is kind of a neat chart that shows how water is used, green water and blue water in the
plant, where it’s stored, how it comes to the plant, where it’s stored, and how it exits.
We get green water via rain that is transpired and used by the plant and irrigation that’s
applied to the plant. That goes through transpiration which is yield and some evaporation that takes
place, and some of the water runs off, and then some flows down into groundwater. This
is kind of a water balance equation describing the water equation of how it’s used in agriculture.
The places that we’re trying to improve things are 1) enhancing the ability of soil to store
water for longer periods of time so it’s made available to the plant. We can do that in
a lot of different ways. By increasing the organic matter of that particular soil or
managing the soil differently. If we till the soil less often or not at all, we’re more
likely to preserve some of that water within the soil scape. We can also reduce the runoff
by encouraging infiltration in the soil. We can do that by amending the soil as well.
We may also work within the plants genoma, the genetics of the plant, so that it needs
less water in order to produce that yield. Or, in the case of a drought, there isn’t
much yield decrease because less water is available. Genomics is an important way to
be able to do that, too. We also focus on how the crop grows so that it spends more
of its energy and more of its water filling the grain rather than growing the plant material
itself. This is one of the opportunities we have in scheduling when irrigation might be
applied. We’ll schedule that irrigation so it takes place in that grain-fill periods
rather than in the foliage-growing periods, so there are some opportunities in order to
be able to use irrigation more wisely in agriculture. Not just at the plant level, there are other
opportunities for us to reduce withdrawals of agricultural water from streams and help
to enhance the environment and make more water available to others. That’s by improving our
methods of conveyance so there’s less losses taking place, and improving our methods of
application so there’s less runoff taking place whenever we’re timing that. One of the
interesting things that the US National Agricultural Statistics Survey does is to sample farmers
and find out what types of technology they’re using in the fields and then benchmark how
that technology changes over time. That’s what this chart shows. There’s a percent of
total irrigated acres measured on that vertical axis in each of the years that this type of
survey has taken place. You can see how traditional irrigated acres, by furlough irrigation, are
flooding the fields is tending to decline over time. More efficient drip and trickle
irrigated acres are being seen as we look across agriculture. That’s a savings in terms
of the application of water. Less has to be withdrawn, whether that be withdrawn from
groundwater or that be withdrawn from surface water systems. The one thing I’ll say is that
improving efficiency can leave more water in the groundwater or it can leave more water
in the stream but it also has unintended consequences. Remember one of the spillovers of irrigated
agriculture is producing those induced wetlands. If there’s less runoff that’s taking place
or less water being applied, there may be fewer induced wetlands and that may have negative
effects as well. In general, this is a way that we might be able to increase yields relative
to the amount of water withdrawn rather than the water consumptively used within the industry.
There are other opportunities, too, for us to enhance environmental effects. In that
upper left-hand corner, we’ve looked at opportunities to alter the timing of pumping within Colorado
so that we can enhance habitats and stream flows rather than draw down those stream flows
at important reproductive times for endangered species like the Brassy minnow. In the upper
right-hand side, we’ve got a group of farmers that are talking about the different types
of systems that we might use to conserve the application of water but also changing crop
rotations from, say a wheat which is in that far top part of the picture underneath the
sprinkler relative to another crop that’s more water using. By using different types
of crop rotations, we can use water more wisely and perhaps share that with other types of
institutions like cities and the environment. We can also improve water quality by using
htings like vegetative buffer strips to reduce fertilizer runoff. We have government programs
that help us to be able to do that. We can enhance water quality so it’s more usable
by municipalities and it’s also better for the environment. We can take care of our headwater
areas that are in the lower left-hand corner where, if we restore forests, especially after
the advent of fires, we can improve water quality so it’s easier used by agriculture
and the environment and by municipalities. There’s some different ways that we can approach
some of the challenges of the future that we face because of external pressures going
forward. This has really been an introduction to a
lot of issues related to water and agriculture. I hope we’ve been able to drive home some
key points about the complex nature of water as it’s used in agriculture, and how that
relates to other industries, the way that agricultural water will necessarily have to
change because of climate change and increasing populations, and also because of the way institutions
are changing, and because of some of the other challenges that we face. But those challenges
have created opportunities for us, opportunities related to genomics, related to increased
technology, the way we manage water systems, and the way we take care of water systems
so we can meet those future challenges.

Leave a Comment

Your email address will not be published. Required fields are marked *