Nutrient Reduction Workgroup:
Nutrient management planning on dairy farms, with a focus on nutrient source reduction, is vital for farm economic sustainability and water quality improvement. Previous studies at Cornell University have reported that 60 to 80% of nitrogen and phosphorus imported onto dairy farms remains after accounting for all nutrients that leave. Long term and sustainable nutrient reduction will only occur by reducing nutrient imbalances i.e., decreasing imports and/or increasing exports. As two thirds or more of the imported nutrients to dairy farms come in purchased feed, significant reductions in nutrient imports can be accomplished with changes in ration and crop management. Several studies have demonstrated, and it is widely accepted that precision feed management can reduce manure nutrient excretions, including volatilized ammonia, an important atmospheric pollutant. In addition, nutrient mass balances can play a key role in providing benchmarks for monitoring farm nutrient management performance. Adaptive Nitrogen Management tools assist in achieving benchmarks by adjusting fertilizer rates based on weather conditions, stalk nitrate levels and soil nitrogen pools. It stands to reason that those farms that export the most nutrients while importing the least, are the most efficient, profitable, and environmentally friendly.
To that end, the Nutrient Reduction Workgroup, coordinated by the USC Ag Coordinator, was developed to reduce Nitrogen and Phosphorus loading into the Upper Susquehanna River watershed. It is a basin-wide coordinated partnership of scientific and technical experts encompassing Districts, Universities, Cooperative Extension, Farm Bureau, North East Dairy Producers Association, New York State Ag and Markets, New York State Department of Environmental Conservation, and the USDA Natural Resources Conservation Service. Elements include mass nutrient balance, precision feed management (PFM), and adaptive nitrogen management (ANM) to reduce nutrient losses on dairy farms through farm benchmark analysis and nitrogen testing. A brief description of each approach is outlined below:
Mass Nutrient Balances:
Source control relies on understanding a farm’s nutrient budget. Mass balance analysis (difference between nutrients entering the farm through feed, fertilizer, fixation etc. and the amount leaving the farm through sales of milk, meat, animals, crops, manure etc.) can determine excess nutrients based on nutrient inputs and outputs. Mass balancing information is useful because it:
Provides important baseline information for all planning and many implementation projects
• Prioritizes practices where excess nutrients are documented
• Has outreach potential by showing nutrient loading to farmers in a more understandable format
• Demonstrates economic and yield benefits that should attract greater farmer participation
• Can be used to develop a mass balance for a watershed
• Can be used as a tool for documentation if nutrient trading is initiated
The USC and Cornell University have conducted mass balances on 60 farms under a pilot project to streamline how to develop a more extensive application. Because this process is a precursor for precision feeding/forage management and an aid for targeting many management practices, it is a key planning tool.
Precision Feed Management:
New York has proposed to implement Dairy Precision Feeding with 50% of the dairy animal units. Many of these animal units will be under CAFO operations, which represent over 40% of the total dairy animal units in the NYS watershed. The 10 years of experience with PFM in NYS has led to the development of professional capacity to implement PFM on farms, especially in the Upper Susquehanna. In NYS, Cornell Cooperative Extension (CCE) in partnership with the USC has developed the interest and expertise to implement PFM on dairy farms, and has a demonstrated track record of doing so. Since 2007, through the efforts of CCE and the USC, over 100 farms in the Upper Susquehanna have already been engaged in some form of PFM assessment and implementation through PFM pilot projects. At present CCE and the USC are developing the next phase of PFM implementation, a coordinated basin wide strategy to implement PFM in a consistent, quantified manner. All of the CCE agricultural field staff working in the Upper Susquehanna Basin in NYS are participating in developing this strategy and will be involved in its implementation. Having locally based extension and SWCD professionals involved in bringing PFM to farms will enhance farmer participation in the program and successful adoption of this BMP.
Over the next two years several projects are already in place that will build upon the success of PFM over the last 10 years. For example, the Natural Resources Conservation Service has entered into an agreement with Cornell Cooperative Extension of Delaware County to develop feed management plans on dairy farms in the designated priority areas of the Chesapeake Bay Watershed Initiative (CBWI). Under the agreement, CCE of Delaware County will develop 18 feed management plans and conduct several outreach meetings to inform producers about the benefits of feed management and to make them aware of the pilot opportunity. The purpose of this project is to refine and evaluate the planning process, and increase the awareness among farmers of the benefits of feed management. Furthermore, the USC just received a Chesapeake Bay Small Watershed Grant that will expand on past research to minimize N and P loss by working with 3,000 cows on 20 farms. Precision feed/forage benchmark analysis will be used to determine specific nutrient management challenges that will result in documented manure nutrient reductions and farm nutrient accumulations (mass balance).
Participants step through a precision feed/forage management checklist of seven benchmarks that assesses nutrient efficiency of dairy cows on the farm. These are:
1. Forage Neutral Detergent Fiber (NDF) equal to or greater than 0.9% of body weight in lactating herd diet
2. Greater than or equal to 60% of lactating herd diet is forage (dry matter basis)
3. Greater than or equal to 60% of lactating herd diet is home grown (dry matter basis)
4. Ration P within 5% of NRC
5. Diet CP: less than or equal to 16.5%
6. Milk Urea Nitrogen (MUN): less than or equal to 12
7. % dead or culled cows less than 60 days in milk will be less than or equal to 5%
A project technician works with the dairy producer and their feed consultant to calculate these benchmarks from farm data, which helps monitor protein and phosphorus levels in the diet and promote the use of high quality homegrown forages. Farms not attaining the benchmarks go through a problem solving process and a plan to implement permanent changes to management practices are developed. Forage tests and new benchmarks are generally run four times a year.
Agricultural Modeling and Training Systems non-linear optimizer with precision scale heads:
The AMTS non-linear optimizer, a mathematical algorithm used to optimize rations, can balance rations on limiting N and P excretion as its objective function. To date, very few software developers have offered non-linear models and even fewer offer non-linear optimizers. The USC also promotes the effectiveness and affordability of the optimizer when used with LMI scale heads. Typically, high capital costs have put electronic scale heads out of the reach of small and medium sized farms. However, the LMI scale head purchase cost is 1/10 that of products currently available and is a cost effective investment for all farm sizes. Furthermore, the scales allow a seamless interface between AMTS software implementation of the CNCPS 6.1 rumen model (used in Precision Feed benchmarking) and on the farm delivery of more precise, balanced rations. Dairy rations for amino acids can also be balanced.
Adaptive Nitrogen Management Tools:
We promote the use of Adaptive Nitrogen Management (ANM) through the use of two nitrogen tests and soil nitrogen status modeling software. The ANM targets farms growing corn in the Upper Susquehanna Watershed. We promote the use the Illinois Soil Nitrogen Test (ISNT) to indicate fields that should need no additional nitrogen for the corn crop. A second test is the corn stalk nitrate test (CSNT) at the end of the growing season to verify if the nitrogen rate used was optimal. We will use the Cornell U. computer model “Adapt N” that utilizes farm data and local weather conditions to predict sidedress nitrogen needs for a corn crop during the growing season. The use of these tests and model result in a more precise nitrogen management plan. A technician coordinates sampling of project participant fields by sampling the fields or by working with crop consultants and environmental planners who do sampling. Sampling occurs with an ISNT taken ahead of 2nd year or greater corn fields to determine if additional nitrogen is needed or not. Producers would supply the necessary information to run the Adapt N model during the growing season to know how much additional N, if any, would be needed for sidedressing. This is followed by the corn stalk nitrate test at the end of the season to determine if nitrogen applications were correct. Small strips of additional nitrogen would be applied in fields as a check to verify that the optimal rate of nitrogen was applied. Participants supply the crop, manure and fertilizer history to confirm the results and develop accurate N management plans.