Improving the efficiency of nitrogen use and reducing ammonia emissions from Pennsylvania dairies

2010 Annual Report for LNE09-286

Project Type: Research and Education
Funds awarded in 2009: $179,940.00
Projected End Date: 12/31/2012
Region: Northeast
State: Pennsylvania
Project Leader:
Dr. Alexander Hristov
Pennsylvania State University

Improving the efficiency of nitrogen use and reducing ammonia emissions from Pennsylvania dairies

Summary

The project continued with the 12 cooperator dairies identified in Year 1. All dairies agreed to continue their participation in the project. As planned, a spring’10 sampling event was executed between April 7 and 28th.

Meetings were organized and the objectives of the next stage of the project, i.e. reduction in dietary crude protein concentration and further monitoring of ammonia emissions, were explained to participating farmers and their consulting nutritionists. The crude protein concentration of the lactating cow diets was reduced in fall’10. Diet composition was monitored for at least 2 wks before a fall’10 sampling and data collection event was executed. Average crude protein concentration of the diets was 15.9%, which was within our target of 1%-unit reduction (compared to Year 1, i.e. 17%).

Ammonia emissions were measured twice following the reduction in dietary protein. Milk production and income-over-feed costs were monitored before and after the reduction in dietary protein. Farm nitrogen balance data were collected throughout the year for all participating farms.

Preliminary analysis of the barn floor ammonia emissions data indicate a 50 to 90% reduction in emissions in all participating farms, compared with the emissions measured in fall’09 and spring’10. These results are only preliminary and must be interpreted with caution.

Objectives/Performance Targets

Reduce whole-farm nitrogen inputs on 50 Pennsylvania dairies, representing 5,000 cows and 10,000 acres by approximately 150 tons/yr and reduce ammonia emissions from these dairies by 50 tons/yr while maintaining or improving profitability as measured through Income Over Feed Cost.

Accomplishments/Milestones

The project continued with the 12 cooperator dairies identified in Year 1. All dairies agreed to continue their participation in the project. In early spring’10, samples of the total mixed rations (TMR) fed at the dairies were collected and analyzed for chemical composition.

Based on these analyses, it was determined that the crude protein concentration of the diets of all dairies was meeting the goal for this project (17% or above). Therefore, sampling was scheduled and executed between April 7 and 28th, 2010.

In late summer-early fall’10, the project team organized several meetings with the farms consulting nutritionists and cooperator dairymen. At these meetings, the objectives of the next stage of the project, i.e. reduction in dietary crude protein concentration and further monitoring of ammonia emissions, were explained. All nutritionists and farmers agreed to continue their participation. One farm was removed from the study due to inconsistencies in diet formulation. Thus, the project continued with 11 farms.

The crude protein concentration of the lactating cow diets was reduced in fall’10, after the new forages were harvested and the corn silage was relatively stable. Protein content of the diets was monitored for at least 2 wks before sampling and data collection. Average crude protein concentration of the diets was 15.9%, which was within our target of 1%-unit reduction (compared to Year 1, i.e. 17%).

The fall’10 sampling and emission measurement event took place between Nov 8th and Dec. 15th. The farms were visited weekly and feed, manure, and milk samples were collected before and after the dietary protein reduction. Ammonia emissions were measured twice following the reduction in dietary protein. Milk production and income-over-feed costs were monitored before and after the reduction in dietary protein.

One farm had consistently dietary crude protein levels of 17% or above. Samples were collected from this dairy, but were not processed and emission data were discarded. The team is working with this particular producer to schedule another sampling event in early spring’11.

Farm nitrogen balance data were collected throughout the year for all participating farms. Preliminary analysis of the barn floor ammonia emissions data indicate a 50 to 90% reduction in emissions in all participating farms, compared with the emissions measured in fall’09 and spring’10. These results are exciting, but must be interpreted with caution. Factors such are ambient temperature play an important role in ammonia emissions from manure and cannot be controlled on the farm. The laboratory emission data (i.e., independent of environmental factors) are still being processed and were not available to be included in this report.

The on-farm sampling and measurement event will be repeated in spring’11.

Impacts and Contributions/Outcomes

All project activities planned for 2010 have been completed. Farm samples and ammonia emissions were collected/measured in spring and fall’10.

The most critical event was to persuade the participating farmers and their consulting nutritionists to reduce the crude protein of the lactating cow rations. This task has been accomplished successfully and all farms continued their participation in the project (except one removed by the project team). Preliminary analysis of the barn floor ammonia emissions data collected after the reduction in dietary protein concentration indicate a 50 to 90% reduction in emissions in all participating farms, compared with the emissions measured in fall’09 and spring’10. These results are only preliminary and must be interpreted with caution.

Collaborators:

Dr. Gene Schurman

exs10@psu.edu
Dairy Extensiojn Educator
Pennsylvania State University
827 Water Street
Indiana, PA 15701
Office Phone: 7244653880
Dr. Ken Griswold

keg16@psu.edu
Dairy Extensiojn Educator
Pennsylvania State University
1383 ARCADIA ROAD, ROOM 140
LANCASTER, PA 17601
Office Phone: 7173946851
Dr. Eileen Wheeler

efw2@psu.edu
Professor
Pennsylvania State University
0228 AG ENGR BLDG
University Park, PA 16801
Office Phone: 8148653552
Dr. Sarah Dinh

skd16@psu.edu
Dairy Extensiojn Educator
1383 ARCADIA ROAD, ROOM 140
LANCASTER, PA 17601
Office Phone: 7173946851
Virginia Ishler

vishler@psu.edu
Dairy Manager
Pennsylvania State University
324 Henning
University Park, PA 16801