Nutrient Management on Maine Dairy Farms

Objective 1: Determining Farmer Needs
The initial activity to address Objective #1 was the development and implementation of a nutrient management survey. The purpose of this survey, sent to all Maine dairy farmers in January, 1995, was to provide a snapshot of current nutrient management practices on Maine dairy farms, along with information on herd size, crop acreage, and crop mix. The survey demonstrated that many farms currently use standard nutrient management tools (like soil and manure testing), and indicated a need for additional education on the use of these and other tools. An additional survey to assess dairy farmer implementation of Best Management Practices (conducted by John Jemison, UMCE Water Quality specialist, 1997) confirmed that successful nutrient management would depend on farmers first adopting simple testing strategies to assess nutrient status and using relevant information to make specific short- and long-term nutrient use decisions. Although both surveys supplied useful guidance to this SARE project, farmer needs clarified during educational programs and (especially) study circles or discussion groups were of much greater importance. In these cases, many needs were determined to the farm level rather than the industry level. Additionally, these needs were reflected in the topics or questions addressed by on-farm research projects carried out via this SARE project. Broadly stated, these needs fall into the following nutrient management issues:

1. Use of testing technologies in making management decisions
2. Crop nutrient removal and the fate of excess soil nutrients
3. Alternative uses of manure and integrated crop-livestock systems
4. Economic value of manure and whole-farm nutrient decisions

Objective 2: Addressing Farmer Needs with On-Farm Research and Educational Programs

On-farm research was the central focus of this SARE project. Within each of the areas mentioned above, the following will be briefly described: educational programs developed, on-farm research projects that developed local information regarding specific nutrient questions, experiment station research projects to supplement the research database, and publications or learning aids developed. Examples of significant research results are also provided within each section.

Use of testing technologies in making management decisions: A critical initial focus of this project, which continued through four years, was on developing farmer skills in accurately accounting for the nutrients on their farm, via numerous testing technologies, and using this information to make informed management decisions on nutrient use. There were many educational programs developed focusing on this topic, simply because it is central to effective nutrient management. These programs include (here and elsewhere, the primary collaborators are identified in the right-hand column):

1995:
North Turner--Soil testing as a management tool--SWCD
Augusta--Answering nutrient questions on the farm--SWCD
Augusta--Nutrient research in Maine--Dairy Seminar
Belfast--Nutrient management decisions on the farm--Extension
South Paris--Nutrient management and crop fertility--DHIA
Gorham--Identifying nutrient problems on the farm--SWCD/NRCS

1996:
Farmington--Managing nutrients: manure, feed, fertilizer--SWCD
Houlton--Managing nutrients: manure, feed, fertilizer--SWCD
Lewiston--Nutrient testing strategies--Sludge applicators
Lewiston--Corn leaf testing to manage nutrients--SWCD
Bangor--Nutrient testing strategies--Sludge applicators
Skowhegan--Interpreting soil and manure analysis--SWCD/Americorp
Farmington--Maintaining yield and reducing costs--SWCD

1997:
Lewiston--Crop fertility and nutrient management--Short Course
Skowhegan--Crop fertility and nutrient management--Short Course
Belfast--Crop fertility and nutrient management--Short Course
Bangor--Crop fertility and nutrient management--Short Course

1998:
Waterville--Steps in managing manure effectively--SWCD

Approximately 650 Maine farmers, along with numerous farm advisors from industry and government, participated in these programs. The materials used to develop these programs came from three primary sources: published research, and on-farm research and experiment station research conducted as part of this project. There were seven on-farm projects that focused on using testing technologies to make management decisions. Like all of the on-farm trials conducted through this project, the goal was to define site-specific questions on nutrient management, and aid farmers in obtaining reliable information to answer these questions. Research topics addressed included: necessity of sidedress N application to corn following manure application (3 trials), rate of manure application, boron fertilization for alfalfa fertilized with only manure, and potato petiole sampling to determine N needs following manure application.

Several studies addressed farmer concerns that manure could not supply sufficient N to corn. The implementation of these studies involved soil and manure analysis, calculation of agronomic application rate, PSNT testing to evaluate N status, and final yield and crop nutrient content. Three similar studies, where N was applied at different rates after manure, are summarized in Figure 1. Corn yield increased with N rate only following the destruction of a grass sod. The PSNT from the other two trials indicated that an N response was unlikely, and none was observed. Typical N application rates on these farms was 50-100 lb N/acre; these testing strategies reduced production costs and environmental N loads.

Other on-farm research trials demonstrated that: alfalfa yield and winterhardiness was not increased with elemental boron (B) application, even on sandy-textured soil that received only manure; liquid dairy manure could replace synthetic fertilizer in potato production, but established testing strategies for potatoes were not very effective in evaluating N status from organic sources; different manure resources on a single farm (ie: fresh vs. aged manure) can be used effectively for corn production and forage crop seedings only if manure nutrient content is determined. All of these research results contributed to the effectiveness of the educational programs discussed above.

Fact sheets were developed to describe how to take a manure sample, and how to interpret a manure analysis. These publications supplement existing fact sheets on soil testing and PSNT; the first printing of 2,000 copies of these fact sheets were distributed, and a second printing was recently made available. Popular press articles in the New England Farmer reached a wider audience on this topic.

Crop nutrient removal and the fate of excess soil nutrients: The amount of nutrients present in the soil is a reflection of both past nutrient applications and crop removal. In many areas, dairy manure and other nutrient sources have been applied in excess of crop requirements, leading to very high soil test levels of phosphorus (P), which is a surface water quality concern, and potassium (K), which is related to nutritional problems in transitional cows. Producer questions were directed at several aspects of this broad issue, including: yield affects (increases or decreases) from excess soil nutrients, the effect of soil nutrient level on plant nutrient level, and the potential nutrient removal by common forage and grain crops. In addition, there was a broad need to outline the potential fate of excess soil nutrients, including environmental impacts of N and P.

Numerous educational programs and discussion groups addressed these issues, throughout the duration of this project. The need to develop long-term relationships with farmers was particularly evident here, when the negative impacts of agricultural practices were discussed. Some of the educational programs, attended by 340 Maine farmers and advisors, included:

1995:
Farmington--Excess nutrients and nutrient imbalances--SWCD
Turner--Reviewing on-farm trials on high nutrient sites--SWCD

1996:
Lewiston--Review of the 1995 TOOLS trial--Agway
Lewiston--Review of TOOLS – discussion group--SWCD
Augusta--Developing BMPs for high P sites--Dept. of Ag
Bangor--Cation and anion balance in soils--Seminar

1997:
Augusta State-wide conference on NPS pollution
* N and P loss from agriculture
* How Maine farms manage nutrients
* Success stories from Maine farms
Clinton--Crop nutrient removal on a large dairy farm--Dept. of Ag

On-farm research trials to address this issue were truly a collaborative effort, involving UMCE, Androscoggin County SWCD, Maine Department of Environmental Protection, and Agway. Beginning in 1995, eight individual corn fields were intensively sampled (8-10 fixed points per field), to develop a database that included: soil test nutrient level and pH, PSNT and leaf chlorophyll status (at 6-leaf stage), ear-leaf N and P, total crop yield and moisture level, end of season plant nutrient concentration, and total crop nutrient removal. This provided a database with more than 80 data point for each parameter. Most of these fields were in an area that has historically received large poultry manure applications on dairy farms. This database was very effective in demonstrating that: high or excessive nutrient levels had no impact on crop yield (Figure 2), and crop removal was closely tied to yield (Figure 3). This implies that other management factors control yield on these high nutrient sites, not soil nutrient levels.

Additional, more basic research was stimulated by these field evaluations, concerning the availability of P (and N) from different livestock manures, and estimating different P pools in the soil. A 100 days laboratory incubation, using dairy, beef, poultry and swine manures, was conducted. In addition to the typical soil test P levels, water soluble and anion exchange membrane (AEM, an estimator of bioavailable P) pools were quantified over time. This research clearly shows that there are substantial differences in P availability between manures, and the water soluble and AEM-P decline over time as P moves into less available forms (Figures 4 and 5).

There were several particularly noteworthy aspects of the effort in Androscoggin County. First, all of this activity was collaborative with an US-EPA funded Integrated Crop Management (ICM) project, with SARE project PI contributing nearly 70 days of effort in this area. Second, it was the first successful demonstration of ‘study circles’ in Maine, following the SARE Professional Development conference in Waterville Valley NH, in 1995. These study circles developed and continued for three years. And lastly, this collaboration was recognized was selected as one of four showcase presentations at “Productivity and Conservation: Working Toward Common Goals.” This November, 1997, conference was sponsored by the Reilly Memorial Foundation, NRCS, and CSREES, explored “locally led agricultural and natural resource projects to learn why they are working and to document important exportable techniques.” The roles of on-farm research, farmer-based study circles, and the need for local information, all of which were supported (financially or otherwise) by this SARE project, were discussed during this presentation. Lessons learned from this and other selected projects were subsequently used in round-table discussions with Agriculture Secretary Glickman.

A statewide conference on agriculture and non-point source pollution was held April 1, 1997, in Augusta ME, bringing together many of these same issues in nutrient management. The development of this conference was spearheaded by a farmer (Adrian Wadsworth), was very involved in the Androscoggin County ICM program and the on-farm evaluations of nutrient removal sponsored by this SARE project. The conference was planned jointly by farmers, Maine Farm Bureau, NRCS, Cooperative Extension, and Maine Departments of Agriculture and Environmental Protection. The primary goals of the conference were to (1) present a realistic appraisal of agricultural NPS (mainly from nutrients and sediment), (2) update farmers and others on current or pending legislation at state and federal levels; and (3) showcase farmer successes in dealing with these issues. The Nutrient Management area of the conference and proceedings was developed largely by people involved with this SARE project, and one of the farmer presentations (George Nuite) has been a cooperator with this project. This conference, in turn, stimulated the development of a Manure Management Task Force by the Maine Department of Agriculture, that evaluated possible voluntary and regulatory solutions to nutrient pollution. This SARE project has provided information to this task force directly and indirectly. This farmer-led task force eventually developed nutrient management legislation in Maine, which will be implemented in coming years.

Alternative uses of manure and integrated crop-livestock systems: On many farms, it is possible to increase the nutrient use efficiency of nutrients from manure, and reduce or eliminate purchased fertilizer nutrients, by implementing many of the testing strategies discussed above in making management decisions. On other farms, however, the animal density is sufficient that other avenues must be explored, including export of manure to other crops or other farms. This SARE project has been very involved in efforts to stimulate the integration of dairy farms with other farms (especially potato farms), with movement of manure and nutrients between farms. This clearly represents a challenge beyond teaching farmers and advisors about technologies and individual management decisions; instead, it focuses not only a farm system but many times on a multi-farm systems. This has been addressed via a number of educational programs and discussion groups, including:

1995:
Augusta Integrating crop and livestock production--MOFGA
Caribou--Examples of crop-livestock integration
Newport--Study Circle: Integrating Dairy and Potatoes
Bangor--Study Circle: Integrating Dairy and Potatoes
Exeter--An example of dairy-potato integration--ASA Tour

1996:
College Park MD--Hayfield response to manure & fertilizer--NEBASA
College Park MD--The role of manure in forage production--NEBASA-CCA
Orono--Manure and fertilizer use on hayfield--Conservation Tour
Exeter--Manure vs. fertilizer for potato production--Conservation Tour

1997:
Corinna--Dairy-potato integration workshop--NRCS, SWCD
Bangor--Manure in potato cropping systems
Orono--The need for long-term cropping system research--Univ. of Maine
Portland--Practical Partnership Conf.: dairy and potato--SARE

1998:
Caribou--Rotations and amendments in on-farm trials

These programs and tours were attended by nearly 700 people. The use of on-farm research information, and the presence of farmers as educators, were the common elements of nearly all of these activities. The former was used to answer specific field or farm level nutrient questions, while the latter (along with discussion groups) dealt largely with the interpersonal relationships needed to successfully integrate farms.

The use of manure as an alternative nutrient source for potato production was evaluated in four on-farm trials. Three trials showed that manure nutrients could be substituted for fertilizer without yield reduction, and that fertilizer applied in addition to manure generally had little impact on yield or quality. These and other collaborative studies with ARS also show that the petiole nutrient status (especially for N) may not accurately reflect nutrient availability from manure. In the Figure 6, petiole N is clearly lower for potatoes fertilized with manure, but yield was unaffected. An additional, 3-yr on-farm experiment also demonstrated the positive impact of manure on soil physical properties, increasing 3rd year potato yield by approximately 20%, compared to an identical (but non-manured) crop rotation.

These on-farm trials played a critical role, perhaps more critical than those described in the previous sections, because of the potential economic loss associated with making incorrect decisions in potato production. The high economic value, and the high production costs, of potato means that farmers must be confident that yield and quality will not suffer as a result of using alternative nutrient sources like manure. Although these trials did not answer all relevant questions in this regard, they have succeeded in stimulate tremendous discussion in this area.

Economic value of manure and whole-farm nutrient decisions: Please see Objective 4, below.

Objective 3: Graduate Student Research Projects
Three graduate students participated directly in this project. George Van Vlaanderen (M.S., 1997) evaluated the use of PSNT, leaf chlorophyll (SPAD) early and late in the season, ear leaf N, and post-harvest stalk nitrate, to further refine N fertilization of corn. Although these studies, over a wide range of N levels (0-350 lb N/acre) confirmed earlier research that PSNT and V6-SPAD were about equally effective in identifying N responsive sites, it also documented that the relationship between the soil-based PSNT and the plant-based SPAD was not particularly strong, with correlation coefficients (r) of only 0.50.

The substitution of manure nutrients for fertilizer nutrients, and the effects on crop nutrient status and yield, were primary concerns in evaluating alternatives uses of manure. The long-term use of liquid manure on perennial forage crops, long overlooked in favor of spreading on corn ground, was re-evaluated by Eric Giberson (M.S., 1999). He looked at yield, quality, and species composition in unfertilized and N-fertilized controls, along with fertilization with NPK fertilizer or liquid dairy manure. This study has entered its fifth year with continued support from Potash and Phosphate Institute. Yield through the first four years can be summarized in the Figure 7 (nutrients were not applied in 1997, where residual response was measured). Initial yield differences between fertilizer and manure have narrowed, and crop nutrient removal and soil test P and K are virtually identical for NPK and manure treatments.

The relative efficiency of fall versus spring manure application, for corn silage production, was evaluated by Mark Hutchinson (M.S., 1998). Mark is a high school teacher in Thorndike, ME, who returned to obtain an interdisciplinary M.S. in Environmental Sciences, supported by a Christa McAuliffe Fellowship. In two on-farm trials, Mark evaluated crop response to timing of manure application and N rate, along with measuring potential N leaching using suction lysimeters. Retention of manure N was reduced by early (versus late) fall applications of manure, requiring an additional 50-60 lb fertilizer N/acre to maintain yield. Both late fall (November) and spring (May) application of manure supplied sufficient N to meet yield goals, as evidenced by the lack of fertilizer N response in both treatments.

Objective 4: Economics and Whole-Farm Systems
The progress we made in addressing this topic area, and conducting economic evaluations of on-farm trials, was hampered somewhat by the departure, in 1996, of the Farm Management specialist in Cooperative Extension. It is clear, however, the long-term changes in how manure and fertilizer nutrients are managed require that 1) the value of nutrients in any form are recognized, and 2) nutrients are viewed within the context of the entire farm (or farms), not on a field by field basis. The development of partial budget scenarios has not been particularly useful in these regards. This SARE project has consistently addressed these two broad requirements.

A framework for evaluating the economic value of manure, and how it is profoundly influenced by management decisions, was initially developed for a 1996 SARE Professional Development conference (Sustainable Animal Production, Fairlee VT). This program focused on the potential for increasing or decreasing the economic value of manure based on the use of farm-specific information and management practices (ie. time and method of application, etc.). The primary goal was to begin to think of manure as an economic resource, not a waste. This program was subsequently delivered numerous times in Maine, at a Northeast Certified Crop Advisor training in New York, and was developed further as a UMCE Fact Sheet.

This SARE project has also continued to support the refinement of UMCE Nutrient Balancer software. This software allows farm-specific information to be collected and stored, and whole-farm and field-by-field nutrient budgets to be developed and refined. It is commonly used in educational programs, in conjunction with the database developed by this project. The most recent revision will be available July, 1999, will be broadly distributed as Maine’s nutrient management legislation is implemented over the next two years. (This program is briefly illustrated in the Attachments.)