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January 2007

Environmental Effects of MAEAP Verification

Analysis of the environmental impact of the Michigan Agriculture Environmental Assurance Program on the phosphorus mass balance and phosphorus index of farms revealed that verified farms reduced their phosphorus pollution potential. Many of the changes implemented in an operation were due to increased knowledge and understanding of agronomic conditions, of water flow, of animal management, and of environmental regulations as well as the maintenance of more accurate records.

Carrie Vollmer-Sanders
Sandra S. Batie
Christopher A. Wolf
Dept. of Agricultural Economics

The Michigan Agriculture Environmental Assurance Program (MAEAP) is a voluntary program created in 1998 by multiple Michigan governmental, industry, and university entities. MAEAP’s purpose is to assist livestock producers with the management of nutrients, particularly manure. A livestock farm must have an accurate and complete Comprehensive Nutrient Management Plan (CNMP), which the livestock producer must implement in order to become MAEAP-verified. Those livestock producers who follow the pollution prevention strategies outlined in their farm-specific CNMP may be able to reduce the risk of pollution discharges, nuisance complaints, and lawsuits. However, to date, the total participation in the MAEAP program has been small relative to potential participation. This article explores the environmental outcomes associated with MAEAP verification.

To determine the environmental impacts of MAEAP, in-person interviews were conducted with 29 producers from farms that were MAEAP-verified or soon-to-be MAEAP-verified as of January 1, 2005. The 29 producers interviewed represented 63% of all MAEAP-verified livestock producers at that time. The number of MAEAP-verified farms has increased steadily since the time of this research. As of December, 2006 there were 173 Livestock, 122 Farmstead, and 63 Cropping MAEAP-verified farms.

Concentrated Animal Feeding Operations (CAFOs) and Animal Feeding Operations (AFOs) of fewer than 1,000 animal units were examined separately. Among dairies, 700 mature dairy cows or 1,000 heifers are considered 1,000 animal units and were classified as CAFOs.


Interview questions and farm-specific CNMP information were combined to determine the environmental changes and outcomes that resulted from becoming MAEAP-verified. There were changes in CAFO regulations and availability of EQIP cost-share funds during the timeframe referenced in the survey. For example, a livestock producer may have needed to alter management strategies or to purchase capital investments due to the regulation changes or their own business needs. However, if a surveyed livestock producer attributed a change on the farm to becoming MAEAP-verified, then we assumed this attribution was valid.

Two measures were used to examine environmental impacts: the change in farm operation phosphorus (P) mass balance and the change in field P-Index scores. The Michigan P-Index used in this study is still being field tested prior to it being adopted by any governmental agency, university, or MAEAP. Although not released for public use at the time of this research, it was utilized as a measurement tool. For this discussion of P balance and P-index, P refers to P2O5.

Both methods were used to quantify farm environmental outcomes that occurred through MAEAP verification. The assumption was that if there was an improvement in either of these measures, then the amount of P entering Michigan waters should be reduced.

Cropland P mass balance

The P balance is a measure of how much the net import of P must change for the farm to avoid over-application. Because P can lead to harmful plant growth such as algae in freshwater systems, it must be applied at appropriate agronomic rates.
Phosphorus mass balance scores were calculated by subtracting P associated with crop sales, animal sales, manure moved off-farm, and other “exported” P from the amount “imported” onto the farm through commercial fertilizer and feed purchases. Several variables were used to calculate the cropland P mass balance.
The amount of P in manure

  • The total quantity of manure
  • The number of spreadable acres below 300 lb. of P per acre
  • The amount of P the crops on those spreadable acres would use during a growing season
  • The amount of manure moved off-farm

Any farm will either be in phosphorus mass balance or out of phosphorus mass balance given the spreadable acres available. If the calculations from this research revealed an operation had a phosphorus mass balance score that was within plus or minus 20 percent of the initial pounds of phosphorus consumed by crops, then that farm was considered to be in balance. This range was the result of potential errors in calculating phosphorus in manure, soil phosphorus, and crop uptake. If a farm was out of balance, it had a positive score, signifying that the crops could not consume all of the phosphorus that was applied via manure application and not enough manure had been sold off-farm.

The average dairy farm examined generated more P than the crops could use (was out of mass balance) before implementation of the CNMP and MAEAP verification (Table 1). At least one farm in our survey with other livestock species was out of mass balance before becoming MAEAP-verified. After becoming MAEAP-verified, all farms in the survey had an average P mass balance score that was below zero and, therefore, in mass balance. Ninety-two percent of the 23 farms for which a P mass balance score was calculated were in mass balance after becoming MAEAP-verified. It is expected that farms that are in mass balance have reduced their farm’s potential for soil P build-up and eventual runoff into surface water.

After becoming MAEAP-verified, CAFOs, that on average were in deficit to begin with, decreased P mass balance by an average of 23,750 lb. of P (Table 1). AFOs had a much smaller change in mass balance, but still had a decrease of P mass balance after verification. Two CAFO operators sold some animals, an action that aided these farms coming into or below the P mass balance. The average dairy operation went from a 3,595 lb. surplus to a 20,411 lb. deficit. To achieve this outcome, the average dairy farm spent $5.96 per animal unit annually on management actions that affected the P mass balance score. Actions that directly altered the cropland’s P mass balance for this research included acquiring additional spreadable acres, moving manure off-farm, and recuding fertilizer and feed purchases. These actions were taken because applying manure to the appropriate fields can influence the operation’s cropland P balance.


A P-Index was calculated in addition to the mass balance calculation. P-Index differs from a mass balance calculation, in that it addresses the transport and source of P on each field and takes into consideration streams that hold water part of the year, field slope, and the field’s hydrological group. The P-Index was calculated using information within the CNMP and was used to estimate the potential for P runoff, but did not include the volume of amount in any potential runoff.

Prior to MAEAP verification 12 farms determined to be at high risk for P pollution had an average score of 18.5 on the P-Index, slightly above the 18.0 threshold under which a producer could spread more manure or commercial fertilizer. The farm averages ranged from 27.7 to 8.7. After these farms became verified, the P-Index score on these same fields ranged from 20.5 to 7.7. This result reflects the adoption of environmentally beneficial practices to decrease P runoff. After the dairy operations became MAEAP-verified, an average P-Index score of 14.9 was achieved, which signified a lowered potential for P runoff on the high risk fields.

To lower the P-Index score of a field, the livestock producer could have made several different management changes or planted a buffer strip or grass waterway. A change in the P-Index score usually resulted from decreasing P runoff potential through less soil erosion (by adopting practices such as planting buffers or grass waterways, and observing setbacks), applying manure over a growing crop, incorporating manure into soil, or applying less manure or commercial P.

More livestock producers chose to implement buffer strips, change crop rotation, or alter tillage practices rather than change the method or amount of P that was applied to a field. The most common change made on a field was adding buffers or setbacks, which also increased the distance to surface water.

Costs and equipment changes

About 44% of producer annual costs per animal unit incurred on the high risk farms were attributable to changes made that affected the P-Index ($3.42 of $7.76). Of the high risk farms, there were no CAFOs that received cost-share for any capital investments eligible for EQIP cost-share. On average, the 12 high risk farms received more cost-share per animal unit (average costs of $91.17 per animal unit) than did the other surveyed farms ($54.96 per animal unit). This comparison suggests that larger amounts of cost-share were provided to the farms with the highest potential to pollute surface water from a field.

If a farm was considered high risk according to this study’s criteria, the livestock producer was more likely to change the equipment used to spread manure, add more manure storage, and put rain gutters on the buildings than if the farm was not categorized as high risk.

There were some other differences between the livestock producers with farms having high risk fields and others surveyed. For example, those operators with high risk farms disagreed with the statement, “Even though clean water benefits the public, producers should pay for the majority of mandatory environmental practices to ensure pollution prevention,” more strongly than did the average livestock producer. The 12 high risk farms also had a larger animal unit per acre density than did the 13 other farms in which a CNMP was collected compared with where density was 0.6 animal units per acre.


This analysis of the environmental impact of MAEAP on the P mass balance and P index of MAEAP-verified farms revealed that verified farms reduced their P pollution potential. Ninety-two percent of farms surveyed were in mass balance after they became MAEAP-verified. The 12 high risk farms, after becoming MAEAP-verified, had P-index scores below the threshold, which indicated that a lower risk of P runoff potential from a field had been achieved. Many of the changes implemented on an operation were due to increased knowledge and understanding of agronomic conditions, of water flow, of animal management, and of environmental regulations as well as by the maintenance of more accurate records.

Over 5,000 livestock producers have attended MAEAP Phase 1 education sessions and may be implementing the knowledge gained from these educational sessions without going through the MAEAP verification process. Thus, it is difficult to conclude exactly how much of an impact MAEAP has had on improving environmental outcomes.

MAEAP has introduced a Progressive Planning Initiative that will involve more small and medium-sized livestock producers in pollution prevention aimed at future verification. As of April 30, 2006 over 500 livestock producers had signed up for this step-wise approach, 80% being dairy operations. As the program grows, it will be worthwhile to continue to evaluate the effectiveness of MAEAP in obtaining improved environmental outcomes.





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