ARTICLE INDEX
Volume 4, Number 5
October 1994
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THE IDAHO NUTRIENT
MANAGEMENT SPECIFICATION
In 1990 the U.S. Department of Agriculture's Soil Conservation Service (USDA-SCS)
in Idaho began the development of a nutrient management specification for the SCS
field office technical guides. The intent was to establish voluntary BMPs to
protect water quality. Even though voluntary, the management guidelines were to
be designed so that all environmental concerns were adequately addressed. An
initial committee consisting of representatives from SCS, University of Idaho,
USDA-Agricultural Research Service, Idaho Soil Improvement Committee, private
consultants, industry agronomists, fertilizer dealers, and producers was put
together in the spring of 1990. This committee developed Idaho's nutrient
management specification. More than 90 percent of the document was put together
with unanimous consensus. However, when an issue or a numerical value could not
be resolved by consensus, SCS made the ultimate decision. The specification
requires use of the latest research and technology and uses the University of
Idaho crop fertilizer guides as the basis for fertilizer recommendations. This
document has received widespread exposure in Idaho and has generated much
controversy. The document is not perfect, but it is an excellent starting point
for nutrient management programs in Idaho. The goal of the committee was to
develop guidelines whereby producers, the fertilizer industry, and
conservationists could position themselves to meet water quality needs without
having to be regulated. The nutrient management specification has five parts:
(1) a general specification section, (2) nitrogen (N), (3) phosphorus (P), (4)
organic wastes and manure, and (5) operation and management. The general portion
of the Idaho nutrient management specification contains the following:
Although somewhat controversial, this voluntary nutrient management specification has several positive aspects. Perhaps most important is that the plan is research-based. Nitrogen management relies on University of Idaho fertilizer guides. In addition, there is adequate flexibility for growers to supplement original nutrient applications with justification based on additional soil and/or plant tissue tests during the growing season. And last, this plan is based on a combination of proven N management BMPs.
The down side of the nutrient management plan is that under conditions of poor management a grower must spend more money for diagnostic purposes to justify additional fertilizer applications to fields. The plan also assumes that the University of Idaho fertilizer guidelines are up-to-date. This requires a solid university commitment to a continuous soil test correlation research and extension program.
The fact that this plan is a voluntary effort will allow refinement with time.
Some states have already enacted laws limiting fertilizer use in especially
vulnerable areas. The authors of this paper predict, however, that sometime in
the not-too-distant future nutrient management planning will no longer be
voluntary unless producers and the fertilizer industry together are willing to
apply fertilizer according to research-based technical criteria such as the Idaho
Nutrient Management Specification.
(R. L. Mahler, University of Idaho, and F. G. Bailey, SCS)
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SOME CRP CONTRACTS EXPIRE IN
1995
Ten-year contracts on the first 2 million acres of sensitive land taken out of
agricultural production under the Conservation Reserve Program (CRP) will expire
in 1995. According to the Soil and Water Conservation Society (SWCS), without a
new plan for that land, much of it (and the other 34.5 million acres protected by
later CRP contracts) will return to intensive cropping, reversing environmental
benefits to water and wildlife.
According to program experts, most of the land now under contract will be subject to compliance with conservation practices such as conservation tillage if the land is returned to use. However, there is some question as to whether these practices would be protective enough of the most environmentally fragile land.
The program, which pays farmers an average of $50 an acre annually to keep highly erodible land in long-term vegetative cover, was established in 1985 under the 1985 Food Security Act. According to the SWCS policy position released in January, "A major impetus for the program initially was the need to help reduce surplus agricultural commodity supplies that were lowering food and feed grain prices and increasing the federal government's farm program costs. The program was designed to provide other important environmental benefits, including soil erosion control, improved water quality, wildlife habitat enhancement, and increased recreational opportunities."
While the program has unquestionably benefited the environment and farm economy, "those benefits have not been determined with any degree of accuracy, and they need to be," said the SWCS in its policy position. The USDA's Economic Research Service estimated the 1990 value of the CRP's environmental benefits to be between $6 billion and $13 billion over the life of the contracts. According to the policy paper, the program's $2 billion price tag excludes administrative costs and the value of the savings it brings to other agricultural support programs.
SWCS Recommends Refocusing on Conservation Priorities
The SWCS recommended extending the CRP program with some critical modifications.
First, it said, the full focus of the program should be redirected toward natural
resource conservation, rather than agricultural commodity supply management. That
way, lands under new contracts can be prioritized with regard to environmental
benefits and payments adjusted accordingly.
Protection of water quality is a central theme in the SWCS's proposed policy. "Riparian corridors, buffer strips along streams, habitats for threatened and endangered species . . . should be given high priority for continued enrollment," and lands important to water quality, but not currently enrolled, should be targeted in a revamped program, said the conservation society.
Long-term or permanent easements, similar to those that protect wetlands under
the Wetlands Reserve Program were proposed by SWCS as a lasting solution, as well
as some built-in flexibility for new contracts that would allow lower-impact uses
of less-sensitive lands.
(Adapted from EPA News-Notes, No. 36)
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GROUNDWATER POLLUTION
PREVENTION: VOLUNTARY BMPs FOR AGRICULTURE
(This is the third in a series of articles on the potential effectiveness of
the voluntary approach to reducing agrichemical contamination of
groundwater.)
At least five questions must be asked in determining how conducive a given
environment is to voluntary change:
Several studies indicate that groundwater quality perceptions are linked to health concerns. If the justification is related directly to health, it may be much more motivating than if justification is based upon environmental interests or presented in a preventive context.
4. Do farmers sense that viable alternatives to current practices
exist?
Perhaps not surprisingly, survey findings have indicated that farmers have
varying views on the question of viable alternatives. In a 1988 northwestern Iowa
study of farm operators engaged primarily in corn, soybean, and hog production, a
large majority (86 percent) indicated that they would like alternatives to their
current dependence on agricultural chemicals. At the same time, a smaller
majority (58 percent) also indicated that, for now, they felt chemical products
were their best alternatives for controlling weeds, insects, and disease. These
results suggest interest in--but less than strong recognition of--existing
alternatives.
A 1988 study by the Wisconsin Rural Development Center found that 58 percent of Wisconsin farmers felt that they had already cut back on chemicals as much as they could.
In northeastern Iowa, where farming diversity is greater in both crop rotations and livestock enterprises than elsewhere in the state, 58 percent of farmers felt refinements in their own pesticide and fertilizer management would be beneficial to the profitability of their own operations, and 67 percent felt that refinements in their livestock waste practices would be beneficial to profitability. Yet few were making changes.
According to the survey, commercial nitrogen and herbicide use was nearly unanimous. Estimates of total nitrogen availability far exceeded crop needs. When Iowa corn farmers were asked how a herbicide ban would affect their operations, most felt a major reduction in yields would occur. If current tillage practices were continued, the average estimated decline was 22 percent. If alternative tillage and cultivation were practiced, the estimate was an 18 percent decrease. Although most (92 percent) of those in the survey currently cultivate, a majority (52 percent) said that the added costs of additional cultivation would offset savings for herbicides.
For many farmers, the findings point to a sense of entrapment. Their strong dependence on chemicals has evolved over a period of years. Their machinery, labor, management, and markets for products constitute an integrated production system.
Reduction in chemicals is viewed as a major shock to the operating system as well as to output and profits. The economic woes in the farm community during the 1980s prompted a retrenchment in risk taking. Experimenting with alternatives, including those that focus on fewer chemical inputs, is defined as risk taking and a departure from existing practices. In this setting, aggressive experimentation is unlikely without a support system.
There is every reason to believe that Idaho farmers have views similar to those surveyed in Iowa and Wisconsin. The perception that attractive alternatives do not exist retards responses to perceived environmental problems.
5. If alternative practices are modeled and nutured, do they become
acceptable?
For at least two generations, research on the adoption of farming practices has
documented the importance of on-farm trials as enticements for adoption. Today's
messages about less dependence upon chemicals and greater dependence upon
mechanical and cultural practices is as much a shift as was the trend toward
chemical inputs 40 years ago. For some, it is defined as turning back rather than
just turning in another direction.
When Iowa farmers were asked in 1988 what changes they were making or experimenting with regarding nitrogen rates and herbicide use, 12 percent said that they were cutting back on nitrogen fertilizer rates. One in five had either experimented with or was regularly banding herbicides.
In one targeted area, Iowa's Big Spring Basin, Extension programs have encouraged a number of practices designed to protect groundwater. In that location, about 50 percent had reduced fertilizer application and about 25 percent had reduced herbicide use. Reasons farmers gave for making changes included attempts to reduce input costs (98 percent), and concern about groundwater quality, health, and safety (84 percent). Those findings are very encouraging for a voluntary approach.
The Idaho Response
Two federally funded and locally supported five-year projects that are designed
to accelerate the transfer of technology necessary to protect groundwater while
maintaining farm profitability are located in Idaho. The first project called the
Idaho Snake-Payette Rivers Hydrologic Unit Water Quality Project comprises over
840,000 acres in Canyon, Gem, Payette, and Washington counties. The second
project, called the Mini-Cassia Water Quality Demonstration Project, comprises
over 1,900,000 acres primarily in Cassia and Minidoka counties. These five-year
projects are incorporating water, nitrogen, and pest management into an
integrated system that will successfully protect water quality without mortgaging
the farm.
(Adapted from Groundwater and Public Policy. Series No. 10 by Steve Padgelt
from Iowa State University)
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CHEMIGATION
Chemigation is the process of applying an agricultural chemical to the soil or
plant surface through the irrigation water. This is a very efficient and
economical method of applying pesticides and fertilizers since it saves the
expense of another application. Chemigation requires some sort of injection
system so the chemical can be applied uniformly to the field. When fertilizers
and pesticides are applied in the irrigation water there are many serious
potential problems that may develop unless the system is well designed and
maintained.
If nitrates are found in groundwater the source may be some natural phenomenon such as feedlot drainage, a poorly designed and maintained septic system, or a problem with chemigation. When pesticides are found in groundwater they are a direct result of people using pesticides improperly.
Since our irrigation water source can be a well, surface irrigation ditch, or public drinking water supply, we are primarily concerned about the possibility of contaminating these water sources.
These can become contaminated if:
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GROUNDWATER QUALITY MONITORING
(This is the last of a two part series on Idaho's groundwater quality
monitoring program.)
A Groundwater Quality Monitoring Program for the state of Idaho was developed as
part of the Groundwater Quality Plan created from the Groundwater Quality
Protection Act of 1989. The framework for the development of a three part
monitoring program was based in part on the recommendations expressed by Idaho
groundwater experts and on input from the Groundwater Quality Council.
The three parts were designed to complement each other by allowing different degrees of quantity of data. The three parts differ in purpose, scale, and duration. Knowledge gained from each part can and will be used to improve the other parts.
Statewide Monitoring. The statewide or Ambient Groundwater Quality Monitoring Network will characterize the water quality of the state's aquifers. This part of the program is also designed to identify long-term trends in groundwater quality. Any potential water quality problems detected will be evaluated by the regional and local monitoring parts of the overall program.
The network design is based on subdividing the state into about 20 hydrogeologically similar regimes. Existing wells and springs will be used as monitoring sites because construction of dedicated wells would be prohibitively expensive. Monitoring sites will be distributed statewide throughout as many aquifers as possible; however, major aquifers will be emphasized. Within each regime, areas of greatest groundwater vulnerability will receive the greatest number of monitoring sites.
Initially, all groundwater samples will be analyzed for inorganic, radioactive, and bacterial constituents as well as pesticides, nutrients, and volatile organic compounds. Monitoring sites will be re-sampled on a 1 to 3 year schedule depending on the initial water quality results. If these screens indicate constituent values above the normal range; additional analysis may be performed.
Regional Monitoring. The purpose of regional monitoring is to acquire data to address trends in greater detail or higher resolution than the statewide ambient network is designed to provide. Whereas the statewide network may only select 3 to 6 wells in a particular county, a regional project may select 50 to 200 wells in the same area. This approach is used in areas of high vulnerability or areas of particularly intensive land uses that may impact groundwater.
Another screening tool that will be used in the selection of regional monitoring project areas is the groundwater vulnerability data being prepared as a cooperative effort between the Idaho Department of Health and Welfare, the Idaho Department of Water Resources, the United States Geological Survey, and the Soil Conservation Service. Composite maps of vulnerability data rank areas that are potentially susceptible to groundwater contamination. These maps have been prepared for the entire Snake River Plain. Studies are expanding the data base to include other major aquifers in Idaho.
Regional monitoring is most useful in evaluating nonpoint source ollution impacts; that is, those dispersed and individually low impact sources that may cumulatively degrade groundwater quality. Monitoring will identify contaminants that need to be addressed by the implementation of Best Management Practices (BMPs). Regional and/or local monitoring, in conjunction with the application of BMPs, will reveal whether BMPs are effective. Existing BMPs can be refined and new BMPs can be designed to protect the quality of the groundwater if adequate monitoring is an integral part of the process.
Local Monitoring. The third part of the groundwater monitoring program is called local monitoring and it involves data collection at the greatest degree of detail. Local monitoring most effectively addresses the legislative mandate to monitor "point(s) of use" and "point(s) of contamination."
Local monitoring involves sampling at and around individual sites of known or suspected contamination. It is this type of contamination that creates the greatest impacts on public health and raises the greatest degree of concern among the public. The primary purpose for local monitoring is the investigation of point source pollution; those contamination incidents where a discrete point of release and zone of contamination can be identified. Typical examples are a leaking underground storage tank, a chemical spill on the land surface, a ruptured petroleum pipeline, or leachate from a landfill.
In other instances, local monitoring may be used when there has been no contamination. Instead, monitoring is conducted to ensure that impacts are not occurring or to give an early warning if slight increases in contaminants are noted. Examples of this are the monitoring conducted at landfills and around underground storage tank areas. Monitoring of this type is often required as a condition for obtaining a permit for an activity.
Information System for Groundwater Quality Data
The Idaho Department of Water Resources (IDWR) already maintains a geographic
information system (GIS) for the state. The Groundwater Quality Protection Plan
directs the IDWR to include groundwater quality data in the GIS system and that
this data be accessible to the public. There are potentially many users of this
data management system including state and federal agencies, consultants,
industry, environmental and political organizations, and the general public. In
general, the system will be designed to be easy to use by persons with varying
computer skills.
The information system, proposed to be called the Environmental Data Management System (EDMS), must be useable for determining long-term trends. The system will include data collected specifically for the state-funded monitoring programs and data from other sources, including historic data. Data to be entered into the system must be certified and then categorized according to its level of confidence. Certification involves a verification procedure that assures the data residing on the IDWR system is correct. The organization that submits data must certify that the data are accurate and free of entry errors. The basic system will emphasize the greatest amount of flexibility at the user level. It will provide both on-line access and analysis and/or download capability for processing on another work station or personal computer.
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COMPOST TO PROTECT WATER
QUALITY
Composting and the use of compost can reduce nonpoint source pollution as well as
enhancing plant growth. Yet, despite the benefits, the use of compost could be
greatly expanded, according to a 1992 study.
Adding compost to soil helps reduce soil erosion by improving soil tilth, increasing water penetration, and increasing soil moisture retention. Not only does the use of compost reduce runoff from fields, but the addition of compost improves the physical, chemical, and biological properties of soils, increasing the aeration and drainage of dense soils, and the waterholding capacity and aggregation of sandy soils, according to soil experts. Compost also promotes plant growth, and research has shown that turfgrass applications and some field crop applications of compost suppress plant disease, reducing the need for fumigation. The composting process reduces the bulk of organic waste materials and helps overcome the high cost of transportation and application. The heat produced during composting destroys pathogens and weed seeds that are present in raw organic materials.
Despite these positive factors, only two percent of the current market demand for soil products is being met by compost. According to the study, done for the Composting Council by Battelle Institute, the potential demand for composted materials is over a billion cubic yards per year.
The potential demand is actually far greater than the potential supply of compost. According to the study, composting all organic waste, including 50 to 60 percent of municipal discards, agricultural residues, biosolids, food residues, yard trimmings, and tree barks would produce about 100 million cubic yards of compost, or about 10 percent of the potential U.S. market.
"Clearly, the challenge is to develop markets, not to create them," concluded Gary Hyatt's paper on the study, presented at the American Society of Agronomy 1993 annual meeting.
According to the study, the four sources of compost and their corresponding potential and current supplies are as follows.
| Compost source | Potential supply (cubic yards) | Current supply (cubic yards) |
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| Municipal organics | 60,000,000 | 2,000,000 |
| Biosolids | 6,000,000 | 4,000,000 |
| Horticultural residues | 30,000,000 | 10,000,000 |
| Agricultural residues | 6,000,000 | <600,000 |
| TOTALS | 102,000,000 | <17,000,000 |
The Battelle study identified nine types of application. The applications were ranked according to the expected ease of penetration of the potential market:
| Application | Potential Compost demand (million cubic yards) | Current
demand penetration (percent) |
|---|---|---|
| Landscaping | 2.0 | <20 |
| Delivered topsoil | 3.7 | <5 |
| Bagged/Retail | 8.0 | 80 |
| Landfill final cover | 0.6 | <5 |
| Surface mine reclamation | 0.2 | <5 |
| Container nurseries | 0.9 | 50 |
| Field nurseries | 4.0 | <l |
| Sod production | 20.0 | <1 |
| Silviculture | 104.0 | <1 |
| Agriculture | 895.0 | <1 |
| TOTALS | 1,038.4 | <2 |
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Comments to webmistress: karenl@uidaho.edu
All contents copyright © 1997-2003. College of Agricultural and Life Sciences, University of Idaho. All rights reserved. Revised: January 3, 2003