Agriculture’s Troubled Waters

Growing up in New England and being exposed to the wilderness as a young Boy Scout, I thought all streams had soap suds in them. I believed nobody could drink water from a stream but only from a faucet. It was taken for granted that polluted streams were a necessary byproduct of the expansion of manufacturing during the previous decades.

Since that time, rivers and streams have gotten cleaner in New England and in the U.S. due to the Clean Water Act of 1972 which regulated point source pollution. In the subsequent decades, other laws were passed at both the federal and state levels to address non-point sources of pollution and to set water quality standards.

Today, most attention is focused on the Total Maxi­mum Daily Load (TMDL) of permitted contaminants in water, especially in the context of watershed management. States are being tasked to implement remediation plans in response to their TMDLs for pollutants. Since the agricultural lands are non-point sources, they have come under intense scrutiny because of fertilizer practices that introduce nitrogen, potassium and phosphorus into ground water.

In recent years, water quality has gotten more attention in many states due to the practice of “hydraulic fracking,” which uses large amounts of water, sand and chemicals in the deep drilling for natural gas. Because of our nation’s past experience with water quality and industrialization, questions have been raised about the long-term effect of fracking near streams and other water bodies.

I started this article talking about pollution because water quantity has never been a big concern in the past in the U.S. Yes, there have been significant droughts affecting parts of the country.  But the affected regions always bounce back over time to normal precipitation patterns.

That said, there have been number of disquieting trends in weather and water usage that, when coupled with pollution issues, present a number of future challenges to agriculture. Before addressing these challenges and possible solutions, a few facts may be in order to put everything in context.

Weather is on the forefront of everyone’s mind because of the extreme events being experienced this winter not only in the U.S. but around the world. An unusually dry winter is contributing to persistent dry conditions in the Southwestern U.S., while the Midwestern and Northeastern parts of the country have been dealing with frigid cold and above normal moisture. Weather terms like “polar vortex” are becoming part of the everyday lexicon. In recent years, warmer summers are becoming the norm for most of the country.

The drier conditions have resulted in record fires and declining snowpack in the Rocky Mountain States, while recurrent, high frequency moisture has both hindered and helped the Northeastern states. Globally, the story is the same. While Brazil is baking in the Southern Hemisphere, Great Britain is experiencing widespread flooding and China is facing its coldest winter in decades.

All these extreme weather events are occurring at a time when the global population is rapidly increasing along with its competition for water, energy and food resources. It is not hard to understand that if the snowpack declines in the Rocky Mountains, then there are less seasonal headwaters to feed rivers and reservoirs. With diminishing water resources, distribution must be prioritized among people, manufacturing and agriculture. Historically, this competition for resources results in people needs coming first, followed by protecting manufacturing because of jobs, and, lastly, agriculture.

The snowpack also affects the long-term viability of aquifers located beneath states east of the Rocky Mountains. Since it takes many years to replenish aquifers with snow melt and seasonal rain, these water reserves, like the Ogallala aquifer, can be viewed as a non-renewable resource. The intense mining of these reserves through irrigation has put certain productive agricultural lands at risk of having no water in the future.

Besides quality concerns and the competition for quantity, there is water usage. Since there are varying kinds and amounts of natural and manmade chemicals and particulate matter, water may be safe for one type of use, such as watering a lawn, but not for another, such as drinking.

The World Health Organization (WHO) has addressed usage head on by developing indices that range from 0 to 100 where the low end is poor and the upper end is excellent. Examples of usage indices are the Drinking Water Quality Index (DWQI), a Health Water Quality Index (HWQI), and an Acceptability Water Quality Index (AWQI). The purpose of each index is to give the public some relative measure of quality for a particular type of use, such as drinking.

Separating sources of water based on their usage can be helpful for a community. Recycled water leaving a wastewater treatment plant can be safely used for irrigating vegetation. The recycled water saves money for a landscaper and at the same time reduces the demand for drinking water. While salinity and alkalinity are commonly tracked in irrigated agricultural soils, an unknown number of exotic and unreported chemicals may be present in some underground water. Over time, agricultural usage of water will come under increased scrutiny by discerning consumers, who will want to know where crops are grown and with what water source.

The water challenges facing agriculture are on several fronts. First, growers near populated areas have to compete with people and businesses for water resources. This is especially true in regions experiencing prolonged dry conditions. Second, in high competition areas, growers may have to settle for recycled or brackish water as sources for irrigation. Third, as farmlands are targeted as sources of non-point water pollution, especially in sensitive watersheds, growers may be enlisted to participate in control programs. Fourth, changing weather patterns, whether short or long term, that result in excessive heat and/or drought conditions may force growers to scale back their operations or switch to less productive crops.

Lastly, downstream processors and consumers who are conscious about where and how crops are grown may demand records of production practices including the source, amount and quality of water.

While there are challenges, there are solutions. One solution is the genetic modification of plants to strive in brackish conditions or use less water while maintaining the same amount of growth. A second is to use irrigation equipment and practices, such as schedules, to conserve water. A related third solution is to use soil sensors or imagery to zone irrigated fields for variable rate applications of water. Variable-rate applications may use the same amount of water as applied to a whole field, but deliver less moisture in some zones and more in others based on the pattern of crop growth across a field. A fourth solution is deficit irrigation which is designed to sustain crop yields while saving water.

Solutions outside of irrigation include the use of natural and artificial surface covers to retard soil evaporation and thus conserve ground water. Also, the leveling of land to minimize slope runoff, and the use of basins to catch runoff, may also be employed. There are many other innovative solutions for water conservation on a farm, but choosing them depends on the crop, its geography, surrounding environment, water source and production practices.

All agricultural stakeholders, be they individuals or organizations, can be part of the water solution. ZedX, Inc., my employer, is an information technology company that has been developing information-based products and services for the agricultural community for over 26 years. The company strives to give growers and their trusted advisors a more holistic solution for water management by providing models and decision-support tools that range from multi-county watersheds down to a single irrigation pivot.

By inputting virtual local weather data into a soil moisture budget and coupling it with a crop development model as part of an irrigation schedule, daily recommendations can be made as to how much water needs to be applied to a field. Since precipitation and evapotranspiration are accounted for in a schedule, irrigation can be withheld when ground water is replenished through rainfall. This withholding of irrigation not only translates into a savings of water but also into a savings in dollars for energy and labor.

The graphical output of a simplified irrigation schedule using the water budget approach is shown in Figure 1.

Irrigation Schedule Graph

It illustrates the interplay of precipitation, evapotranspiration and irrigation in the management of crop water requirements. As can be seen in the figure, the available water in a soil is the sum or budget of precipitation minus evapotranspiration plus irrigation. If a budget drops below a certain threshold due to the loss of water by evapotranspiration, then irrigation must be added to the soil. If there is precipitation, then irrigation can be reduced or withheld according to the budget.

The available water can be presented as a fraction of the maximum water stored in a soil. This fraction fluctuates daily as shown in the figure between a preset, crop-dependent, lower threshold of 0.7 and a maximum of 1.0 (field capacity) according to the precipitation, evapotranspiration and irrigation budget. An irrigation schedule begins just before planting and ends just before harvest. The amount of irrigated water is a function of soil texture and rooting depth, crop type, irrigation method and the capacity and efficiency of a system making applications. It is adjusted during a growing season based on root growth, crop stage and canopy size.

A schedule, as a water management tool, not only takes the guesswork out of the timing and amount of an application but also provides peace of mind because a grower knows that the water needs of a crop have been met. When coupled with soil sensors or imagery, a schedule can become a precision agricultural tool for prescribing variable rate irrigations.

The take-home message for this article is although we live on a planet with 71% of its surface covered with oceans, we must never lose sight that our local water sources can be limited and at risk for contamination. By understanding soil properties and crop water needs and employing the appropriate tools and practices, a grower can manage water resources intelligently and sustainably into the future.

WEBINAR ON DEMAND: Take the Challenge: Water Quality and Agriculture

Topics:

Leave a Reply

State of the Industry Stories

Fertilizer Tender close-up
MicronutrientsHow Micronutrients Fit Into 2017 Fertility Plans
January 10, 2017
Where do micronutrients stand going forward in fertility plans? For one thing, Tim Mundorf, Field Representative with Midwest Laboratories, says Read More
Fertilizer application
State of the IndustryCautious Optimism On Fertilizer In 2017
January 10, 2017
What kind of fertilizer rates are growers and retailers looking at in 2017 and beyond? According to stakeholders CropLife magazine Read More
Asmus Farm Supply crop protection products in storage
State of the IndustryCrop Protection Products Market: Complexity Begets Opportunity
January 10, 2017
While other key market segments in agriculture continue to see tumultuous shifts in sales volumes going forward (large equipment sales are Read More
Pioneer corn seed in storage
Special ReportsState Of The Seed Industry: Better Later Than Never
January 3, 2017
Traditionally, the majority of the nation’s grower-customers made their seed planting decisions in the late fall. Normally, when folks attended Read More
Trending Articles
PrecisionAg Vision Conference
Precision AgPrecisionAg® Vision Conference: Focused on the Future
June 13, 2017
PrecisionAg® is pleased to announce the return of its PrecisionAg Vision Conference, October 10-12, 2017. Based on overwhelmingly positive response Read More
Redbanded-stinkbug-on-soybean-Photo-credit-Thomas-County-Ag
Crop InputsExperts: Mild Winter, Early Planting Will Increase Soybean Insect Threat
June 12, 2017
Higher than average temperatures this past winter affected much of the nation, especially the South and Midwest. The National Centers Read More
Eric SfiligojMonsanto ‘Picks Its Battles’ by Nixing Deere Deal
May 23, 2017
Having been in the trade journalism game since the mid-1980s, I remember several watershed moments during my career. One of Read More
Migrant farm workers
LegislationTrump: Immigration Crackdown Won’t Impact U.S. Agriculture
May 16, 2017
President Donald Trump said he would seek to keep his tough immigration enforcement policies from harming the U.S. farm industry Read More
AGCO Ratliff featured
Eric SfiligojRemembering Robert Ratliff
May 15, 2017
With all the fast-paced happenings in agriculture this spring, with multiple mergers in the works and planting season in full Read More
Case sprayer nozzle closeup
EquipmentSpray Application: A Nozzle Renaissance
May 2, 2017
If you had asked four-decade ag veteran Mark Bartel, President of Wilger Inc., just a few years ago what lay Read More
Latest News
Young Corn Plants
Eric SfiligojLaunching New Seed Traits: Wait on China . . . Or Else!
June 26, 2017
In life, no one likes the waiting game. In agriculture, however, playing the waiting game is very important – especially Read More
Monsanto sign
Crop InputsMonsanto Speaks on Dicamba Issues in Arkansas
June 26, 2017
Monsanto’s Chief Technology Officer, Robb Fraley, issued the following statement following the Arkansas State Plant Board’s proposal to ban dicamba, Read More
Corn Field
Seed/BiotechCorn Insect Bt Technologies Offer Cost-effective, Proac…
June 26, 2017
When farm economics are challenging, farmers look for ways to bolster profit margins, including reducing input costs. Some may think Read More
Crop InputsArkansas Plant Board Votes to Ban Dicamba — Now W…
June 23, 2017
The Arkansas State Plant Board has voted to pass a proposed emergency rule to ban the use of in-crop dicamba, Read More
Engenia soybeans
Crop InputsBASF: ‘Closely Monitoring’ Dicamba Situatio…
June 22, 2017
BASF, whose Engenia herbicide is the target of more than 200 drift complaints in Arkansas, emailed the following statement to Read More
ManagementConsolidation Update
June 22, 2017
Editors Paul Schrimpf and Eric Sfiligoj discuss progress on manufacturer consolidation, and another big move for Midwest cooperative Central Valley Read More
Palmer pigweed seedhead in cotton
Crop InputsThreat of Dicamba Ban Looms in Arkansas
June 22, 2017
The Arkansas State Plant Board has rejected a proposed ban on the use of dicamba herbicide, but a procedural error Read More
Potash Agrium
Crop InputsAgrium-PotashCorp to become Nutrien upon Merger Complet…
June 21, 2017
Potash Corporation of Saskatchewan Inc. and Agrium Inc. have announced today that once the anticipated merger transaction closes, the new Read More
Crop InputsMidwestern BioAg Hosts TerraNu Fertilizer Plant Opening…
June 20, 2017
Last Friday, Midwestern BioAg was joined by over 80 local farmers, media and staff to celebrate the grand opening of Read More
Soybean Field
Industry NewsAligned Ag Distributors Names New President
June 19, 2017
Aligned Ag Distributors LLC announced this morning the appointment of Mary Tolke to the position of President/CEO, effective July 1. Read More
ManagementPlotting Corn, AGCO/Asmark’s Applicator Training Center…
June 15, 2017
Editors Paul Schrimpf and Eric Sfiligoj talk about their recent visits to Columbus, OH, and Bloomington, IL, along with an Read More
Seed/BiotechDow AgroSciences Announces Launch of Enlist Corn for 20…
June 14, 2017
Enlist corn will be commercially available in the U.S. for the 2018 growing season. Dow AgroSciences announced the launch today Read More
ASMARK AGCO Applicator Training Center
EmployeesAsmark, AGCO Open Training Center for Beginning Applica…
June 13, 2017
AGCO Corp. and the Asmark Institute have opened a new Applicator Training Center, created in a collaboration between the two Read More
Power to Do More Contest Winners
HerbicidesDow AgroSciences Announces Three Winners in Power to Do…
June 13, 2017
Thousands of votes have been cast and three farmers have been awarded the power to do more with a $10,000 Read More
Frogeye leaf spot
FungicidesStrobilurin-resistant Frogeye Leaf Spot Threat Looms wi…
June 13, 2017
Heavy spring rainfall throughout the South and Midwest delayed planting and created the perfect environment for diseases like frogeye leaf Read More
PrecisionAg Vision Conference
Precision AgPrecisionAg® Vision Conference: Focused on the Future
June 13, 2017
PrecisionAg® is pleased to announce the return of its PrecisionAg Vision Conference, October 10-12, 2017. Based on overwhelmingly positive response Read More
CHS St. Paul, MN fertilizer terminal
LegislationICGA Praises President Trump’s Remarks on Waterwa…
June 12, 2017
Illinois Corn Growers Association President Justin Durdan, a farmer from Utica, issued the following statement regarding President Donald Trump’s comments Read More
Wheat Growers
UncategorizedWheat Growers Names Tracy Linbo as Senior Vice Presiden…
June 12, 2017
Wheat Growers has hired Tracy Linbo as Senior Vice President of Agronomy. Linbo joins Wheat Growers after having served 10 Read More