- Hypoxic Zone
in the Gulf of Mexico
& Agriculture's Use of Nitrogen Fertilizer
in the Gulf of Mexico & Agriculture's Use of Nitrogen Fertilizer |
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Within the Gulf of Mexico is an area of low oxygen concentration (a hypoxia region) often known as "The Gulf's Dead Zone". In 1995 the areal extent of this problem was 18,200 km2. 1993 floods which flushed nutrients from midwest soils caused the hypoxic zone to double in size to about 7,000 square miles. Although the source of the problem via the Mississippi River is varied, Agriculture's present-day usage of fertilizer, including nitrogen and phosphate fertilizer, is a significant component.
From the Iowa Farm Bureau Spokesman, July 26, 1997, the article "Reduction in fertilizer use sought to reverse hypoxia in Gulf of Mexico" by Dale Johnson states:"Officials in the Gulf of Mexico want fertilizer usage throughout much of the cropping area of the Midwest reduced so that [hypoxia] can be reversed. Agriculture is a major contributor...with nitrogen concentrations expecially high from the corn-producing states of Iowa, Illinois, and Indiana".
"Hypoxia is not unique to the Gulf of Mexico and the Chesapeake Bay in the United States. Hypoxia is also found in the North, Baltic, Adriatic and Black Seas, Long Island Sound, and Japan's Seto Island."
Illustrated below, the Midwest is the largest continuous region in the nation of intensive nitrogen input. The nationwide annual total is estimated to be more than 11 million metric tons (mmt) in the form of commercial fertilizer (6.3 mmt), animal manure (2.8 mmt), legumes (1.1 mmt), domestic and municipal waste (.6 mmt), and atmospheric deposition (0.5 mmt).
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Smaller pockets in California, Texas, and the area
where Maryland, Delaware, Pennsylvania, and New Jersey all
converge are smaller areas of intensive nitrogen fertilizer
usage.
The chart below indicates that nitrate concentrations in the
Mississippi River did not begin to correlate with national
nitrogen fertilizer usage until about 1968, when nitrate levels
began to rise as the national usage of nitrogen fertilizer also
began to rise.
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Some may argue that the scales are different, that
the tracking is not exact, that the proportionate increases and
decreases are not the same, that the Mississippi River levels in
the 1950s were higher than those in the early 1970s, etc., etc.
But even with all these facts taken into account; the general
correspondence between the volume of nitrogen fertilizer used
since 1968 and the nitrate concentration measured in the
Mississippi River since 1968 is compelling. So let's take a look
at what can be done in U.S. Agriculture to address the Gulf's
Hypoxic Zone.
Some might recommend that acres be taken out of production and
put into set-aside programs, assuming that production alone is
responsible for the increase in the Mississippi nitrate levels
which come from Agriculture, but is that necessarily so?
Continuous alfalfa may seem more environmentally-friendly than
corn-following-alfalfa or corn-following-corn production; but
alfalfa fields are nitrate producers and corn is a
nitrate-absorbing crop. In effect, heavy-feeding corn is actually
a nitrate sponge, while alfalfa is a nitrate-supplier. So taking
more acres out of production is not necessarily a solution to the
Hypoxic Zone.
Others might say that growers should simply cut-back, that they
should make arbitrary 10%, 20%, 30%, etc., flat rate cutbacks and
that those cut-backs will solve everything.
But Catherine E. Woteki (Acting Under Secretary for Research, Education, and Economics in the Department of Agriculture) says "reducing inputs of agricultural chemicals may not always result in long-term water quality improvements".
While that statement prompts the reader to wonder about the USDA's particular Strategy for and Sincerity in Improving Water Quality throughout the Midwest and regions downstream, Crop Technology, Inc. (CTI), its customers, and the university, USDA, and other independent researchers that have evaluated CTI technology concur, but due only to the existence of Soil Doctor® Variable Rate Application technology. Absent Soil Doctor® technology, Ms. Woteki's views should trouble those concerned with the nation's water contamination problems, like the Hypoxia in the Gulf.
Blanket reductions --by growers who have been applying far less than recommended by the fertilizer industry-- may not result in long-term water quality improvements, only because arbitrary flat-rate cut-backs will still result in applying fertilizer to field areas which need absolutely no fertilizer, as they simultaneously rob from field areas that need 100% of the fertilizer rate. Blanket reductions by growers who have been faithfully following the "generous" recommendations of the fertilizer industry and those public sector scientists who promote those recommendations, however, can, of course, result in long-term water quality improvements.
But, we should not expect all growers to make arbitrary fertilizer cut-backs based on the practices of some, because arbitrary fertilizer cut-backs, by growers who do not follow the fertility recommendations of the fertilizer industry will, year-after-year, financially damage these growers and will have no long-term positive impact on water quality once these growers return to their normal practices. So what is The Solution for these Already-Responsible Growers?
Grid Soil Sampling: The purpose of
Precision Agriculture is to precisely address field needs on a
local, sub-field basis. Some try grid soil sampling to determine
those local needs, but grid soil sampling doesn't reliably work,
because it can't. Soils vary in orders of magnitude, often from
foot-to-foot, not just marginally and only once every quarter
acre. Crops are stationary with roots that outstretch little more
than a meter in diameter. Crops are not livestock which can walk
around and graze in the high nutrient areas ten feet to the west
or even five feet to the south. The nutrients must be within
their reach.
Soils are sampled as if they varied far less than they actually
do only because of the physical, and cost-effective limitations
of grid soil sampling. It is not that less than five soil samples
an acre is "good enough" for Agriculture, it is just
that less than five soil samples an acre is "the best most
can do".
Prescription Farming®
The Soil Doctor® System: With two different
soil sensing modes which enable growers to responsively vary,
foot-to-foot, the input of seeds and common agri-chemicals; the
Soil Doctor® System is the Only Complete Precision Farming
System in the World. On the market since 1990, the application
system integrates proprietary on-the-go, real-time soil
sensing into a one-step, continuously variable rate
technology.
Soil Doctor® System customers typically report fertilizer
cut-backs of 20%-40%-60%, while Maintaining --or even Increasing
yield. Cut backs like these --with associated Net Profit
Increases-- can easily be sustained year-after-year. Sustained
cut-backs, with Optimized Yields, will result in long-term water
quality improvements in the grower's local environment.
Because corn is a sponge for nitrate, applying fertilizer in such
a distribution that yield is maintained --while nitrate is
reduced-- is just better for the environment than simply reducing
nitrogen fertilizer usage at a flat rate/flat distribution and
accepting yield reductions.
