NE-132

**Title: Farm nutrient management and sustainability**
9:30	Opening
9:40–10:0	The structure of agricultural research in the Netherlands and the role of the Farm Management Group, Prof. Ruud Huirne (head of the Farm Management Group)
10:00–10:20	A short history of Dutch environmental problems related to agriculture and consequential policies, Paul Berentsen
10:20–10:50	The Dutch Mineral Accounting System and the European Nitrate Directive; implications for farm performance, Chirstien Onderstein
	Coffee break
11:10–11:40	Economic-environmental modeling of dairy farms, Paul Berentsen
11:40–12:10	A framework for measuring sustainability in dairy farming, Klaas-Jan van Calker
12:10–12:30	General discussion
12:30	Lunch

The group took lunch at de Leeuwenborch and by 1:30 left to visit 'De Marke' experimental farm for nutrient management. The visit was organized by Frans Aarts. The visit includes an overall presentation of the experimental farm objectives and history. A brief description of the farm follows:

De Marke, Experimental Farm for Dairy Farming and the Environment

De Marke, the Dutch Experimental Farm for Dairy Farming and the Environment, is located on sandy soil. Its goal is to develop a farming system characterized by optimum efficiency that can ensure clean soil, clean air and clean water. Since 1993, De Marke has played a major role in the discussion on efficient dairy farming within the constraints of stringent environmental targets.

Three institutions operate the farm collectively in a common interest: efficient dairy farming in a clean environment. These institutions are the Ministry of Agriculture, Nature Management and Fisheries, the Ministry of Housing, Physical Planning and the Environment and the farming industry, who are jointly responsible for the financing.

The main objective of De Marke is to develop and demonstrate an optimally cost-effective farm setup for dairy farming with sufficient land area which complies with future-oriented stringent environmental targets. Further objectives of De Marke are reducing energy use, reducing the application of crop-protection chemicals, lowering water consumption, and conserving and developing the natural environment.

Stringent environmental targets have been adopted which prescribe the maximum environmental loads on soil, air and water. These stringent environmental limits have been taken from the National Environmental Policy Plan (NMP), the Multi-Year Crop Protection Plan and other government papers, which determine how clean the Netherlands is to be by the beginning of next century.

For De Marke this results in the following environmental targets:

The group returned to Wageningen by 5:00 pm.

We met at 9:00 at the Plant Research International. The theme for the meeting was Systems research in dairy farming. The meeting was organized Herman van Keulen. The meeting included series of talks on dairy farming impact on the environment and the associated economic problems. Dr. Keullen discussed some of the group research methodology and system prototyping. Frans Aarts presented on applications of prototyping to dairy farming in the Netherlands. He discussed how De Marke links with the plant research group and discussed the experimental plans and the monitoring of water, chemical and energy flows. He also discussed the evaluation of the project and the expert knowledge that is used for continuous adaptation of the project. Considerable discussion was made on how the De Marke experience would be beneficial to US conditions.

Al Rotz presented DAFOSYM: A model for farm management evaluation followed by a presentation on applications of DAFOSYM to nutrient balances in dairy farming by Joe Harrison.

A general discussion was held on systems research in dairy farming: comparison of approaches and prospects for comparision.

The group had lunch at de Leeuwenborch and left at 1:00 to Amsterdam accompanied by Anne Houwers. The trip included a canal boat trip and visit to the historic city. We returned to Wageningen by 8:00 pm.

The group attended the 9:00 meeting of the Animal Production Systems Group members. The theme of the meeting was Sustainable development in practice: methodologies and applications organized by Henk Udo and Mike Grossman.

WIAS – Animal Production Systems meeting on:

Presentation outlines follow:

Programme:
9:00	Opening – Hank Udo
9:05-9:20	Assessment of Sustainable Development using Fuzzy Set Theory, Ton Cornelissen
9:25-9:40	Are Animal-Friendly Production Systems Sustainable? Erwin Mollenhorst
9:45-10:00	Environmental Decision Tools, Imke de Boer
10:05-10:20	Break
10:20-10:35	Measuring and Improving Sustainability in Aquatic Production Systems, Mark Verdegem 10:40-10:55 Greenness Attributes in the Green Piggery Project, Egbert Kanis
11:00-11:30	General Discussion

The aim of this meeting was to exchange information and to explore cooperation possibilities. ‘Wageningen’ participants in Systems Research in Dairy Farming:

Frans Aarts	Plant Research International – De Marke
Paul Berentsen	Farm Management
Paul Galama	Dairy Farming – De Marke
Arjan Reijneveld	Plant Research International
Jaap Schröder	Plant Research International
Henk Valk	Institute Animal Husbandry and Animal Health

The group left at 1:00 from WICC to visit the Dairy Farm of Wim Veldboom at Zeewolde (participant in praktijkcijfers-project). The visit included an introduction by a representative from the praktijcijfers-project and a tour of the farm.

The group conducted their business meeting at the WICC.

Jim Ferguson called the meeting to order at 8:45 a.m. and proceeded with members introduction. There were three new members at the meeting: Rhonda Miller (Utah State), Zhiguo Wu (Penn State), and Jeffery Hyde (Penn State).

Minutes of the last year meeting were approved. They were distributed via email by Jim Ferguson.

Paul Wangsness (NE132 administrative advisor) commented on the new paper work requirements for reporting. Paul will forward this information to Rabi Mohtar and Jim Ferguson.

Due to time constraints Ferguson commented that each station should limit its report to 15 minutes.

Henry Tyrrell (CSREES representative to NE 132) discussed the new reporting procedure. Details are available on the directors web site (D. McKinzie). Beside format changes, the annual report is due 60 days after the annual meeting, which is February 11 for NE 132. According to the new guidelines, the minutes of the meeting should be part of the report. Additionally, scientist with extension appointments can participate in regional projects. Henry indicated that NRI got a $13 million hit this year, and $20 million of its funds were directed to food safety. Three programs were eliminated including the Ecology Program. The good news is the IFAFS is back with a $120 million and a new RFP will be out soon. Funds will be available for multi state integrated applied projects where institutions can get full overheads. In the new fund, only land grant institutions can be a lead institution.

As far as other funds, formula funds are maintained at their previous level, special research funds are increased ($60-$100 million). Section 406 funds also increased especially food safety and water quality. Funding is also available to support regional water quality centers in coordination with EPA and USAD.

Henry invited the group to participate in the N-2001 meeting in Washington DC in Oct 14-19, 2001. The meeting is sponsored by the Ecological Society of America. The conference is funded by USEPA, USDA is looking at matching the EPA funds.

After some discussion, the group decided to hold next year's meeting at Purdue University for two days between the second and third week of November (meeting announcement).

Rabi Mohtar will be the chair for next year, Steve Herbert will be the secretary for the group for next year.

The group left the WICC at 12:00 for 'de Hoge Veluwe' accompanied by Marian Jonker, took lunch at pancake restaurant and visited the Kröller-Müller museum. The group returned to Wageningen by 4:30. At 5:00 the farm managemt group hosted drinks at the Leeuwenborch (PHLO-ruimte) and farewell dinner later at 7:00 at restaurant de Junushof.

Summary of station reports follow:

GRASIM Extensions (Nitrogen and Hydrology)

1. The current Nitrogen Stress Factor (NSF) in GRASIM that was developed using Penn State, University Park, data set is being modified. The previous empirical NSF formula limits the use of the model to other conditions. With the new modifications, NSF is only related to Nitrogen status in the soil and is physically based. This has been tested and documented (Chen and Mohtar).

2. Legume has been added to the model to simulate grass-legume mixture. This includes legume growth, nitrogen fixation, and nitrogen transfer from legume to associated grasses. This addition is under validation (Chen and Mohtar).

3. Sensitivity analysis has been conducted on the model. This helps to identify those most influential parameters and variables in the model, and facilitates the testing of the model (Mohtar and Chen).

4. Water routing and sediment component is developed based on the APEX (Agricultural Policy/Environmental eXtender) model (Chen and Mohtar)

GRASIM Extensions continued (Agro-forestry and Multiple Species)

1. WWW-based multipaddock version has been developed and validated (Mohtar, Chen, and Zhai).

2. Additional grazing schedules have been developed and tested (Zhai and Mohtar)

3. An ArcView interface for GRASIM was developed to address spatial and temporal distribution of input and output data. Evaluation is under way (Zhai and Mohtar).

4. Field testing of GRASIM is being conducted at Martell (W. Lafayette) and two additional sites, Penn State (H. Karsten) and American University of Beirut research farm (F. El-Awar).

5. Growth parameters matrix for a variety of plant species is being constructed using available crop growth data from literature, the three field sites, and FORADS. Parameter estimation methodologies are being used to estimate GRASIM needed parameters since field data collection cost is prohibitive (J. Cropper, Grazing Lands Technology Institute, USDA).

6. Grazing field trial under agroforestry system is being conducted under a FRA grant. Field data on plant growth, animal performance, nutrient cycling, are being collected and being used to quantify the tree impact on forage growth and grazing management.

Multimedia Application

A WWW-based Grazing modeling system and supporting materials were developed to improve user’s understanding of grazing systems. Using this tool, users are able to simulate, analyze, and optimize the impacts of the grazing activity on natural resources and water quality systems. This results in extended users knowledge and ability to improve natural resources and water quality protection, as well as improve the competitiveness of food production in agriculture. The developed case studies give users practical experience in real life systems modeling and expose them to environmental issues and water quality protection measures. The goal is to improve the user's understanding of the interactions between the various components of the water quality system: soil, water, crop, animal, chemical, farm management, and their interaction with climatic uncertainty. On-line documentation is available to help answer questions. Preliminary evaluation of the educational tool was conducted and the evaluation results showed that the tool is an effective way to provide education concerning complex environmental systems. The material is available for your use at this address: http://pasture.ecn.purdue.edu/~water/teach/src/teach.htm. If you have a specific case study that is not among the list we will be glad to add that to the list.

Contributors: E. C. Prigge, Div. Anim. & Vet. Sciences,

W. B. Bryan, Div. Of Plant & Soil Sciences

E. B. Rayburn, Cooperative Extension

1b. Herd Nutrient Utilization Strategies

Influence of time of supplement feeding and grazing activity on fiber digestion of cattle.

Prigge and Bryan – Supplementing concentrates to grazing cattle often results in a depression in fiber digestion which limits the utilization of this management for increasing the efficiency of production for lactating cattle. A study was initiated last spring and data collection was completed this summer. A concentrate supplement was fed to represent approximately 35% of total estimated DM intake and fed at either 700 or 1900 h. Grazing was allowed for a 12 h (700 to 1900 h) or 24 h period each day. Sward height on the plots was maintained at either 4 – 8 cm of 10 –14 cm. It is hopeful that the negative associative effect of concentrate supplementation on fiber digestion could be minimized by allowing time between the consumption of these two diet components. Variables measured were: grazing time, forage intake, and digestibility of DM, fiber, and crude protein. Growth rate and dry matter production of the pastures is also being monitored.

1d. Pasture and grazing

iii Methods of measuring and predicting pasture yield.

Generalized calibration for pasture plate meter use in the Northeast.

Rayburn – Research using plate meters to estimate pasture availability has shown variability of regression estimators due to season and pasture type; leading to the belief that calibrations of plate height to clipped sample yield are needed for each pasture and season. This retrospective study of 33 site years of plate meter research across four states, seasons of the year, and a range of pasture types found that forage density (forage mass per cm of height) accounted for the seasonal effect on plate meter calibrations. Much of the difference between pasture types was accounted for by pasture sod condition. Pastures, which had open soil at the base of the plants had lower forage density than stands having complete site occupation at the ground level. Such pastures occur due to being recently, being old hay fields, or containing non sod forming species. Tall fescue sods managed under good fertility and rotational grazing had higher densities than other mixed grass sods. By cooperatively using standard calibration-description protocol across a region it may be possible to provide producers calibrations that provide reliable estimates of pasture availability.

Publications

Two referred journals and 2 proceeding articles published.

B. Objective 2, Section 2c. Use of milk allantoin to estimate remen microbial protein flow. An Experiment was conducted to evaluate how quickly allantoin output in milk changed when a diet change occurred in lactation dairy cows. Cows were switched from a 40:60 or 60:40 forage to concentrate diet abruptly. Within 24-48 hours a change in milk allantoin output could be detected.

C. Objective 1, Section 1a, subsection ii. Corn silage was harvested at ~40% DM and stored in either a bunker silo or Ag Bag silo. When fed to lactating cows the bagged silage resulted in 2.75 pounds more 3.5 % FCM.

Data collected with bagged vs bunker stored corn silage can serve to help validate the advantage of the bagged system as simulated in SAFOSYM. In addition, it will help producers make more informed decisions about what storage system best meets their goals.

Objective 1a. Crop Growth and Conservation Strategies

In a recently completed simulated grazing study of 6 grasses and 24 grass-legume mixtures conducted under irrigation at Logan, Utah, mixtures yielded approximately twice as much as grasses grown alone. The presence of a legume increased dry matter and crude protein through the contribution of the legume, as well as through increased yield of the grass component. Averaged over three years, the highest-yielding grasses in the study were tall fescue, meadow brome, and orchardgrass, which produced 10.1, 7.4 and 6.0 Mg ha ^–1 y^-1, respectively, when no legume was included. The other grasses were Kentucky bluegrass and early- and late-maturing varieties of perennial ryegrass, and their yields when planted alone were 2.5, 3.8, and 3.4 Mg ha^-1 y^-1, respectively. Legumes used in the study were alfalfa, birdsfoot trefoil, white clover, and cicer milkvetch. Mixtures containing white clover were consistently the highest-yielding, averaging 11.9 Mg ha^-1 y^-1. Mixtures with alfalfa averaged 11.4, those with birdsfoot trefoil averaged 11.2, and mixtures with cicer milkvetch were consistently the lowest-yielding, averaging 9.2 Mg ha^-1 y^-1.

Usefulness of Findings

Based on the results of the clipping study and the comparability of specific grasses and legumes, a three-year long grazing study consisting of eight binary grass legume mixtures was established in 2000.Birdsfoot trefoil and white clover will be used as the legume component of mixtures.Birdsfoot trefoil has significant potential in the Intermountain West as an alternative to white clover for grazing, as it has never caused bloat in grazing animals and appears to be longer-lived than in warmer, more humid climates.The grass components of the mixtures will be tall fescue, meadow brome, orchardgrass, and perennial ryegrass.

Work Planned for 2001

Objective 1a. Crop Growth and Conservation Strategies

Objective 1c. Manure Application and Soil and Water Interactions

Soil nutrient levels will be determined and fertilization recommendations made accordingly. Leaf tissue samples will be collected and analyzed for nutrient composition throughout the growing season. Soil water samples will be collected biweekly during the growing season and analyzed for nitrogen and phosphorus. The fate of soil nutrients will be examined via leaf tissue samples, soil water samples, and soil analysis.

Publications

One referred journal and one abstract published.

Objective 1 a i. Nutrient uptake and nutritional value of crops.

Yields of corn cilage, alfalfa hay, and orchardgrass hay have been obtained from the field leaching experiment that includes various treatments (three crops each receiving Control, Fertilizer, N-based, and P-based dairy manure applications). Nutrient contents and removal by the crops are yet to be determined (we’ve just purchased a microwave digester and will analyze the samples this winter).

Objective 1 c ii. Characterize manure P for potential runoff loss.

a) Fecal samples collected from three feeding trials were tested in our lab for P characteristics. The feeding trials were conducted by Kohn at U. Md, Knowlton at Virginia Tech, and Wu et al. at the Dairy Forage Res. Center, respectively. We measured water soluble P for all the fecal samples. P fraction distributions were determined for selected samples.

b) Dairy and swine manures were amended with four types of power plant by-products to determine the impact on P solubility and fraction distribution changes as well as N balance. Incubations with the amendments have been completed; lab analyses are currently under way.

Objective 1 c iii. Nutrient efficiencies in different cropping systems.

With the field leaching experiment, we collected samples of manure, crops, soil, and leachate. We have measured some of the samples and have data on nutrient inputs (applications), P accumulation in soils as a result of the treatments. Determination of nutrient outputs in leachate and crops will be completed this winter. Upon the completion of the laboratory analysis, we will be able to compare the nutrient efficiencies of three crops (corn, alfalfa, and orchardgrass) with N- vs. P-based manure application strategy.

Objective2. Develop research-based information…educational materials in support of… agricultural consultants, and producers to strengthen the U.S. Dairy industry.

a) Classroom lectures and field trips offered in two courses.

b) Summer fellowship program was offered to two vet students, working on manure and bedding amendments for reduced nutrient losses and computer modeling of nutrient cycling on animal farms.

c) A 2+ day workshop at the PVMA annual meeting specifically on the issures of animal farm nutrient management.

d) Serial seminars at the Penn Conference (Veterinary Practitioners) on nutrient management, the environment, regulations, management options, veterinarians’ roles and opportunities.

Usefulness of Findings

1. P accumulation in soils – The N-based manure treatment resulted in increased soil test P accumulation after 2-yr’s applications compared to other treatments (Control, Fertilizer, or P-based manure rate). Soil test P (Mehlich-3 method) in 0 to 20 cm soil profile increased 18% in alfalfa, 34% in corn, and 8% in orchardgrass between Fall 1998 and Spring 2000 for plots receiving N-based manure. Surface soil P enhancement was not found in the other treatments.

2. Nutrients in leachate – nitrate-N concentrations averaged above EPA drinking water standard (10 mg/L) in corn and alfalfa receiving fertilizer or manure, but below the standard in orchardgrass regardless of nutrient treatments. P concentrations in leachate continue to be a concern, ranging from .05 to .13 mg/L (EPA critical values associated with accelerated eutrophication are 0.05 mg DP, 0.10 mg TP L^-1).

3. Fecal P fractionation from the feeding trials – P analysis of fecal samples from all three feeding trials indicated a similar pattern: Increasing dietary P levels resulted in not only higher excretion of total P in feces but more importantly an increased proportion of water soluble P fraction in feces.

Work Plan for 2001

Continue the field leaching experiment. Sample collection with continue with soils (nitrate and P), leachate, and crops. Crop rotation will be implemented at the end of Yr 2001 growing season.
Complete nutrient analysis of crop samples. Perform annual and rotational nutrient balance per treatment per crop.
Continue to explore fecal P characteristics as affected by dietary P levels and feed ingredients (in collaboration with Kohn, Wu, Knowlton).
(If funding available) we attempt to:

Install runoff collection devices in the lysimeter field so that both leaching and runoff losses of nutrients can be measured under the treatment scenarios,
Insert pan lysimeters for more accurate determination of P leaching loss,
Conduct lab trials to evaluate wick material for P retention potential.

Publications

Four referred journal articles, one abstract, and 1 proceeding published.
Title: An assessment of ammonia emissions from dairy facilities in Pennsylvania

Authors: James D. Ferguson, Zhengxia Dou, Charles Ramberg

Institution: University of Pennsylvania

School of Veterinary Medicine

Center for Animal Health and Productivity

382 West Street Road

Kennett Square, PA 19348

Ferguson@cahp2.nbc.upenn.edu

A survey of 747 dairy farms in Pennsylvania was used to construct demographics for the average Holstein dairy farm. The average Holstein dairy farm was composed of 69 lactating cows, 11 nonlactating, pregnant cows, and 52 nonlactating, nonporous (heifers) animals. Milk production averaged 27.4 kg (60.2 lb). Crop acres averaged 71.6 hectares. Milk production, crop acres and type and average county yields, and herd animal groups were used to construct a typical feeding program for these farms. Typical rations were constructed for 6 feeding groups (3 milk production groups, 1 nonlactating group, 2 heifer groups) to meet milk production, pregnancy and growth requirements. Rations were constructed based on three forage qualities (excellent, average, and poor) typically observed on PA dairy farms. Data for animal description (milk production, body weight, growth, and pregnancy status) and ration components and amounts consumed for each animal group were input into the excretion model of the Dairy Nutrient Planner computer program (DNP). Excretion of fecal N, urinary N, total P and K, and fecal dry matter were for each animal group was output and used to assess potential volatile losses of N. Work at the Marshak Dairy, New Bolton Center, indicates the majority of urinary N is lost as ammonia rapidly from dairy facilities. Based on this observation, the losses of N as ammonia were estimated to be 4.63, 4.62, and 4.28 metric tons per year for the farms with excellent, average, and poor quality forages.

Volatile losses of N may most reduced by controlling levels of urea in urine. Urinary N may be reduced through dietary manipulation of protein and carbohydrate sources. Conversion of urea to ammonia may be reduced by altering the pH of barn floors and gutters. Entrapment of ammonia may be accomplished by acidification of manure slurry.

PROJECT TITLE: Environmental and economic impacts of nutrient management on dairy forage systems

Objective 1a. Crop Growth and Conservation Strategies.

The Dairy Forage System Model (DAFOSYM) was used to evaluate the economic and environmental impacts of adding 50 acres of corn, barley, soybeans, or pasture to a 150 acre, 100-cow dairy farm in Wisconsin. The greatest benefit came from adding rotationally grazed pasture where annual farm profit increased about $20,000. Volatile nitrogen (N) loss from the farm increased 10%, but N leaching loss per land unit decreased 50%. Adding a bunker silo for more corn silage and 50 acres of corn, barley for feed grain and straw bedding, or soybeans for roasting and feeding all had similar impacts. Volatile N loss and N leaching loss per land unit were reduced about 15% and 20%, respectively. Annual farm profit was increased about $10,000 with more corn or soybeans and $14,000 with barley. All crop options reduced soil phosphorus (P) accumulation by 9 lb/acre/year.

A whole farm analysis was conducted to determine the potential long-term economic benefit and environmental impact of growing and feeding soybeans as a protein feed supplement. Representative dairy farms were simulated with alternative production strategies for 25 years of Pennsylvania weather. Production of soybeans as a cash crop increased annual farm net return by up to $55/cow when ample cropland was available to produce most of the feed requirement of the herd. With a more restricted land base, there was less economic benefit to shifting land from corn or alfalfa production to soybeans. When the soybeans were fed in a raw or roasted form, most of this economic benefit was offset giving an increase in annual net return of less than $15/cow. There was also little environmental benefit (reduced N loss or soil P accumulation) for growing soybeans as a cash crop or feed on dairy farms. In general, the current trend toward producing and feeding soybeans on dairy farms does not appear to provide substantial long-term economic benefit to the producer nor reduce the potential impact of the farm on it’s environment. However, under specific farming practices such as inefficient feeding of protein supplements or the production and feeding of high corn silage rations, economic benefit of up to $100/cow were obtained through soybean production and feeding.

Objective 1b. Herd Nutrient Utilization Strategies.

A representative farm with 400 Holstein cows (producing 11,000 kg/cow/yr) and their replacements on 300 ha of silt loam soil was simulated over 25 yr of Pennsylvania weather. Multiple simulations predicted the effects of animal density, herd production, and feeding strategy on N loss, P balance, and farm profit. Reducing the land area to 200 ha nearly doubled N losses and increased soil P accumulation by 15 kg/ha/yr with little change in farm profit. At 400 ha, the farm was near a long-term P balance with an N fertilizer requirement of 50 kg/ha. A 10% increase in herd production through the use of BST provided a small increase in N loss and soil P level; whereas, a 25% drop in production reduced N losses 10% and P buildup by 3.6 kg/ha/yr. Changing the breed to Jerseys while increasing animal numbers to maintain the same sale of fat corrected milk increased N losses 45% with a small increase (1.8 kg/ha/yr) in excess P. Compared to soybean meal as the sole protein feed, including a low RDP feed in rations reduced N volatile loss 35%, reduced N leaching loss 20%, and increased production and profit with little effect on soil P. Increasing the feeding of P to 20% above the NRC recommended level (common practice) increased the long-term buildup of soil P by 8 kg/ha/yr; whereas, a 20% reduction provided concurrent farm balances of both N and P. Shifting from low forage rations to maximum use of forage increased the purchase of alfalfa hay and reduced grain imports, which increased N losses slightly with little effect on P balance and farm profit. Changing from a corn and alfalfa rotation to all corn reduced N volatilization loss 14% and increased leaching loss 22% with little effect on soil P.

Objective 1c. Manure Application and Soil and Water Interactions.

No Progress to report.

Objective 1d. Pasture and Grazing.

DAFOSYM was used to simulate the economic effects of inaccuracies in estimating forage production on pasture. A representative grazing dairy farm was developed and the costs and return from “optimum” management were calculated. Different scenarios were then simulated including under or over estimating forage yield on pastures by 10 or 20%, under estimating yield by 10% in spring and overestimating by 10% in summer, and vice versa. All of the scenarios simulated resulted in lower returns compared to the optimum farm. Differences in net return compared to the optimum farm ranged from -$3 to -$80/acre/year. Underestimating pasture production resulted in less hay and silage being produced, more pasture being consumes, and more forage purchased compared to the optimum scenario. The opposite occurred for overestimation of pasture. Thus, achieving greater accuracy (to within 10% of actual pasture yield) in estimating pasture yields improves forage budgeting and increases farm net return.

Objective 1 e. System Integration.

Three grazing options were compared to a traditional corn and alfalfa based confinement feeding system for a Michigan dairy farm. To maintain a long-term phosphorus balance, 85 high producing cows and replacements were allowed on the 200-acre base farm. Converting 50 acres of alfalfa to permanent grass pasture increased the average annual net return by $41 /acre. Converting the entire land base to grass with more extensive use of grazing and a 10% reduction in milk production increased the net return by $68/acre and reduced nitrogen leaching loss by 50%. A low input system using all grass pasture, out wintering of animals, a spring calving cycle, and relatively low milk production allowed a phosphorus balance with about 50% more animals on the farm. This low input approach reduced animal facility, feed production, and manure handling costs and increased milk sales providing a $190/acre increase in the average annual net return.

A representative 200-acre Pennsylvania dairy farm using management-intensive grazing with spring calving was simulated over 25 years of weather to determine the effects of herd size and milk production level on profitability and P loading. Increasing herd size resulted in dramatic increases in P loading, while increases in per cow milk production levels increased P loading only moderately. To maintain an annual P balance, the more profitable management strategy was the smaller herd size (100 cows) with greater per cow milk production (17,000 lb). This was largely due to the decreasing proportion of nutrient intake used for animal maintenance as milk production increased. Therefore, there is economic and environmental efficiency in feeding cows grain for extra production while fully utilizing grazed forage.

Whole-farm simulation was used to estimate changes in economics and nutrient balances caused by management changes for farms in Denmark and the USA. The Danish farm at the northwest coast of Jutland has 73 ha of crop and pastureland, 54 milking cows producing 8571 L milk/year, and 60 young stock. The US farm located in central Pennsylvania has 100 milking cows producing 8790 L milk/hear, 85 young stock, and 81 ha of crop and pasture land. At the Danish farm, we simulated the effect of reducing the protein degradability of the protein supplement. Reducing the protein degradability did not affect net return but reduced N-volatilization by 19% and N-leaching by 8% compared to the base farm. Maintaining farm milk productivity by milking more cows of lower productivity resulted in negative economic returns and increased N-losses. The US scenario was changed from a year-round confinement operation to a system where cows were grazed from April to October. This change resulted in a 4% increase in net return and an 18% decrease in N-leaching loss.

Objective 2 a. Needs Assessment.

No progress to report

Objective 2 b. Information.

The planning and selection of equipment for harvest and handling of forage crops can greatly impact the performance and profitability of a farm. The type and size of equipment used affects the harvested yield and nutritive value of the forage crop as well as production costs. Through interactions with other parts of the farm, these effects can impact market value of the forage, animal intake and performance, delays in other farm operations, other production costs, and ultimately farm profit. Models were used to determine the range in harvest capacity, labor requirement and production cost of the major sizes and types of forage harvest systems. This information can improve the planning and selection of equipment to help assure a profitable operation that meets current and future goals of the farm.

Objective 2 c. Tools.

Distribution of the Dairy Forage System Model was maintained on the Internet at http://pswmru.arsup.psu.edu. Development of a new integrated Farm System Model was begun which expands DAFOSYM to include crop, dairy and beef farm options.

USEFULNESS OF THE RESULTS

DAFOSYM provides a teaching aid that illustrates the complexity and many interactions among the physical and biological components of the dairy farm. As a research tool, the model is used to study the effects of system changes on the performance, economics, and environmental impact of a farm or to determine a more optimum food production system. DAFOSYM analyses also provide dairy farmers and farm consultants with useful information for strategic planning.

WORK PLANNED FOR NEXT YEAR:

Two journals articles and six continuing proceedings were published.

PROJECT TITLE: Environmental and economic impacts of nutrient management on dairy forage systems.

PRINCIPAL LEADER: M. S. Allen

STUDENTS/STAFF: R. Longuski, D. Main, S. Mooney, M. Oba, J. Voelker, Y. Ying.

Objective 1b. Herd nutrient utilization strategies.

Effects of conservation method of corn grain and dietary starch content on DMI and productivity of lactating dairy cows were evaluated. Eight ruminally and duodenally cannulated Holstein cows (55+15.9 DIM; mean+SD) were used in a duplicated 4 x 4 Latin square design with a 2 x 2 factorial arrangement of treatments. Experimental diets contained either ground high moisture corn (HM) or dry ground corn (DC) at two dietary starch contents (32 vs. 21%). Mean particle size and DM content of corn grain were 1863 um and 63.2 %, and 885 um and 87.7% for HM and DG, respectively. All diets were formulated for 18% CP, and sources of dietary protein were alfalfa silage (50% of forage at DM basis), SBM, distillers grain, and blood meal.

Amount on OM truly fermented in the rumen varied from 7.7 (DG at 21% dietary starch) to 11.3 kg/d (HM at 32% dietary starch) among treatments. The HM treatment decreased DMI compared to DG in high starch diets (20.8 vs. 22.5 kg/d), while there was no difference in low starch diets (19.7 vs. 19.6 kg/d). This reduction in DMI is attributed to smaller meal size for HM compared to DG in high starch diets (1.9 vs. 2.3 kg of DM for high starch diets; 2.1 vs. 2.0 kg of DM for low starch diets). Faster starch fermentation for HM in high starch diets might result in satiety sooner. Milk yield was greater for cows fed high starch diets compared to cows fed low starch diets (38.6 vs. 33.9 kg/d) regardless of corn grain treatment. HM decreased 3.5% FCM compared to DG in high starch diets (35.7 vs. 38.7 kg/d), while there was no difference in low starch diets (35.7 vs. 35.4 kg/d). This is because of lower milk fat content for cows fed HM in high starch diets (3.05 vs. 3.59% for high starch diets; 3.95 vs. 3.73% for low starch diets). Milk protein content was lower for HM in high starch diets (2.98 vs. 3.02%) but higher for HM compared to DG in low starch diets (2.94 vs. 2.87%). Reducing ruminal starch fermentation by substituting DG for HM can increase productivity of lactating cows fed high starch diets.

True starch digestibility in the rumen was higher for HM compared to DG, and the difference was greater for high starch diets (71.1 vs. 46.9%) compared to low starch diets (58.5 vs. 45.9%). This interaction is attributed to a greater increase in digestion rate of starch for HM compared to DG in high starch diets (28.2 vs. 14.6%/h) compared to low starch diets (16.8 vs. 12.2 %/h). This suggests that ruminal starch digestion is limited by enzyme activities as well as substrate availability; ruminal contents of cows fed low starch diets may have insufficient amylolytic activity for maximal starch digestion when readily fermentable starch is available. Starch digestibility in the total t tract was not affected by corn grain treatment because of compensatory digestion post-ruminally.

Efficiency of microbial nitrogen production (MNE) was lower for HM treatment compared to DG (39.7 vs. 48.4 g/kg of truly ruminally fermented OM), but was not affected by dietary starch content. Within the data set of cow-period means, MNE was not related to daily mean ruminal pH or minimum ruminal pH (recorded every 5 sec. For 4 d per period). MNE was negatively correlated with rate of starch digestion (r=-0.55), which implies that energy spilling partially explains lower MNE for HM treatment. However, energy spilling does not appear to be from lack of ammonia because there was no relationship between MNE and ruminal ammonia concentration. Maximum rate for microbial protein synthesis independent from substrate availability might limit microbial N production. In addition, MNE was positively correlated with rate of passage for OM, starch, and NDF (r=0.77, 0.75, and 0.63, respectively). Rapid passage rate may decrease microbial turnover in the rumen, resulting in increased MNE.

Post-ruminal digestibility for non-ammonia-nitrogen was greater for HM compared to DG, and the increase was greater for high starch diets (74.3 vs. 68.7%) compared to low starch diets (71.2 vs. 70.6%). This might be attributed to greater microbial N excretion as feces due to enhanced starch digestion in the large intestine for cows fed DG compared to cows fed HM or to more resistant protein for DG compared to HM.

USEFULNESS OF THE RESULTS:

The results of this work will provide useful information to allow nutritionists to prepare more optimal diets for dairy cattle. It will also be used to refine the animal model of DAFOSYM which provides dairy farmers and farm consultants with useful information for strategic planning.

WORK PLANNED FOR NEXT YEAR:

Conduct study to evaluate effects of substitution of beet pulp for high moisture corn in low forage NDF diets on ruminal digestion kinetics, ruminal pH, microbial efficiency, dry matter intake and productivity of lactating cows.

Conduct a series of experiments to evaluate effects of propionate on feed intake.

Conduct a series of experiments to evaluate effects of sodium, potassium, and systemic acid-base balance on feeding and chewing behavior, ruminal pH, milk yield, and milk components of lactating cows.

PUBLICATIONS:

Nine journal articles were published.

Progress of the Work and Principal Accomplishments:

Objective 1a. Crop Growth and Conservation Strategies.

We continued to investigate various combinations of modified atmosphere (MA) and normal anaerobic storage for improving the preservation of true protein in alfalfa silage. Difficulties have been encountered in developing an MA system that works consistently. Work was initiated to study densities and losses in pressed bag silages.

We determined the variability of soil test P (STP) levels on dairy farm fields and response of alfalfa and corn to STP by sampling fields on dairy farms in MN and WI during 1999. STP levels varied widely, especially within fields as the mean STP level increased. STP did not affect corn yield and P uptake and 1^st cut alfalfa yeid, but 2^nd and 3^rd cut alfalfa yields improved as STP increased from low to optimum. Tissue P concentration in 2^nd and 3^rd alfalfa cuttings did not respond to STP but increased with STP in 1^st cut alfalfa. Alfalfa K increased with soil test P and K; STP and STK were highly correlated.

Objective 1c. Manure Application and Soil and Water Interaction.

Dairy urine (UN), feces (FN) and the undigested fiber component in feces (FUFN) were each enriched in ¹⁵N and applied to 16 soils.Inorganic N accumulated during the 24-week incubation period with UN, but FN and especially FUFN appeared to immobilize soil N. The ¹⁵N and difference methods gave different estimates of FN and FUFN mineralization. Estimates of UN mineralization were similar using both methods.

In a separate trial, we found that the land application of manure derived from dairy cows fed a high P diet results in runoff dramatically higher in soluble P than from plots amended with manure from cows fed a P adequate diet.

Usefulness of the Results

Objective 1a.

Forages showed little yield response to high soil test phosphorus and potassium, but high P-testing soils on dairy farms may produce forage that contains too much K to be safely fed. Fields with high STP are much more variable in STP level and need more sampling to adequately estimate mean STP.

Objective 1c.

Most dairy producers feed excessive P, dramatically increasing the cropland needed for recycling manure and affecting the number of cows a farm can keep or the duration a farm can operate before excessive levels of soil test P occur. According to new USDA-NRCS guidelines, manure should not be applied to cropland having excessive levels of soil test P. Our work also suggests greater potential environmental impact from P in runoff on farms where excessive P is fed.

Work Planned for Next Year

Objective 1a.

Work will continue to develop practical modified atmospheric techniques for preserving protein in alfalfa during ensiling. The study of density and losses in bag silos will be completed.

Distributed effort. We recently received funding for an IFAFS project entitled “Enhanced Integrated Nutrient Management on Dairy Farms”. This project seeks to (1) develop dairy diets that support high levels of milk production but produce manure N and P that is less susceptible to environmental losses, (2) identify how herd management and manure handling, storage and application practices affect nutrient cycles, (3) evaluate the effectiveness of conventional and alternative cropping systems for providing quality feed to the dairy herd and recycling manure nutrients, (4) develop tools for individual farmers, their extension educators and private consultants that assess where the greatest nutrient losses occur based on current farm management practices, and (5) develop curriculum for use in university education on nutrient cycling and nutrient management planning using dairy systems as the model. This project will contribute to Objectives 1a, 1b, 1c, 2b and 2c of the NE-132 project.

Publications

Three journal articles, three abstracts, and two proceedings were published.

Department of Animal and Avian Sciences

University of Maryland

College Park, MD 20741

E-mail: rkohn@wam.umd.edu

URL: http://www.inform.umd.edu/ManureNet

Evaluation of Protein Recommendations for Lactating Dairy Cows:

The objective of this study was to evaluate the National Research Council’s recommendations for feeding levels of rumen undegraded protein (RUP) for cows fed a one-group total mixed ration. Sixty Holstein cows were paired by parity (1 to 6) and days in milk (23 to 315) and were randomly assigned to one of two treatment sequences. Diets contained alfalfa silage (30% diet DM) and corn silage (26% diet DM), and were isonitrogenous (16% CP) and isocaloric (1.71 mcal/kg). Soybean meal, protected soybean meal (Soy Best^®), and urea were used to make ration protein fractions that were predicted to be 35% or 29% RUP. The 35% RUP diet was formulated to provide 98% and 105% of the average requirement for RUP and rumen degraded protein (RDP) respectively. The ration containing 29% RUP provided 79% and 117% of average required RUP and RDP respectively. All cows were group fed and high RUP diet during a 2-week pre-treatment period, and then were fed one ration for 4 weeks followed by the other for 4 weeks according to their assigned treatment sequence. Data were collected in the last week of each period. Mean milk production, milk fat, and milk protein were 32.6 kg/d, 4.35%, and 3.36% respectively with no treatment differences. Treatment response was not affected by degree of predicted RUP deficiency. The degree of expected deficiency was diminished for higher producing cows and increased for lower producing cows because the cows are the feed to meet their energy requirements. Thus lower producing cows ate less than predicted by NRC and higher producing cows ate more. National Research Council requirements for RUP may be too high for cows fed diets similar in energy to a one-group total mixed ration. Alternatively, estimates of RUP content of feedstuffs may be low.

Worksheets for Calculating Whole-Farm Nutrient Balances were Released

Excel worksheets were developed to rapidly calculate nutrient balances on livestock farms. This software has been demonstrated and made available for professionals to use on a farm-by-farm basis. It has also served as a workshop activity to demonstrate typical nutrient flows and control points on farms. This software is now being used to quantify typical nutrient flows on farms and to identify critical control points to reduce nutrient losses from agriculture. Recently the worksheets were made available on the internet at the web address: www.iinform.umd.edu/ManureNet/software/ The worksheets have been distributed to 25 locations in 11 states and 4 countries.

Usefulness of Findings

Current recommendations for protein feeding requirements are based on experiments conducted on individual cows. However, most farmers feed their cows in groups. Previous theoretical research suggested that using current recommendations for lead factors, protein may be overfed for grouped cows. The current study confirms that requirements may be lower for grouped cattle do to the interaction of energy and protein.

The worksheets for calculating nutrient balances have been used to demonstrate the extent of unaccounted for nitrogen and phosphorus on farms. These worksheets have been used to demonstrate the importance of farm management on water quality to individual farmers and extension educators.

Work Plans for 2000-2001

A field study is currently being conducted to introduce the use of milk urea nitrogen (MUN) to fine tune diets on dairy farms in Maryland. A comparison of laboratories for analyzing MUN is currently being summarized.

A total-collection feeding trial is underway to determine apparent digestibililty of phosphorus with two levels of dietary P. Changes in P retention during dry period, early, peak, mid and late lactation across 2 lactations is being measured.

Farm balance worksheets will be used to collect more data on farms in Maryland and these results will be summarized.

Environmental and Economic Impacts of Nutrient Flows in Dairy Forage Systems

Committee Meeting Minutes

The Netherlands, December 10-14, 2000

Sunday December 10

Monday December 11

De Marke, Experimental Farm for Dairy Farming and the Environment

Tuesday December 12

Wednesday December 13

Thursday December 14

Summary of station reports follow:

NE132 Committee Purdue University Research Report

The Netherlands, December 10, 2000

GRASIM Extensions (Nitrogen and Hydrology)

GRASIM Extensions continued (Agro-forestry and Multiple Species)

Multimedia Application

NE-132 Annual Report

West Virginia University

Objective:

1b. Herd Nutrient Utilization Strategies

1d. Pasture and grazing

iii Methods of measuring and predicting pasture yield.

Publications

NE-132 Regional Research Project: 2000 Annual Report

Joseph H. Harrison - Department of Animal Sciences

Washington State University

NE-132 Regional Research Project: 2000 Annual Report

Jennifer MacAdam, Rhonda Miller Utah State University

Objective 1a. Crop Growth and Conservation Strategies

Usefulness of Findings

Work Planned for 2001

Objective 1a. Crop Growth and Conservation Strategies

Objective 1c. Manure Application and Soil and Water Interactions

Publications

NE-132 Regional Project:2000 Annual Report

Z. Don and J. Ferguson, Univ. Penn

Objective 1 a i. Nutrient uptake and nutritional value of crops.

Objective 1 c ii. Characterize manure P for potential runoff loss.

Objective 1 c iii. Nutrient efficiencies in different cropping systems.

Objective2. Develop research-based information…educational materials in support of… agricultural consultants, and producers to strengthen the U.S. Dairy industry.

Usefulness of Findings

Work Plan for 2001

Publications

PROGRESS REPORT – REGIONA RESEARCH PROJECT NE-132

Pasture Systems and Watershed Management Research Unit

USDA/Agricultural Research Service

University Park, PA

December 2000

Objective 1a. Crop Growth and Conservation Strategies.

Objective 1b. Herd Nutrient Utilization Strategies.

Objective 1c. Manure Application and Soil and Water Interactions.

Objective 1d. Pasture and Grazing.

Objective 1 e. System Integration.

Objective 2 a. Needs Assessment.

Objective 2 b. Information.

Objective 2 c. Tools.

USEFULNESS OF THE RESULTS

WORK PLANNED FOR NEXT YEAR:

PUBLICATIONS

PROGRESS REPORT – REGIOINAL RESEARCH PROJECT NE-132 (Rev.)

MICHIGAN STATE UNIVERSITY

December 11-15, 2000

Objective 1b. Herd nutrient utilization strategies.

USEFULNESS OF THE RESULTS:

WORK PLANNED FOR NEXT YEAR:

PUBLICATIONS:

NE-132 2000 Illinois Station Report – M. R. Murphy

NE-132 Annual Report, 2000

USDA, ARS, U.S. Dairy Forage Research Center

Madison, WI

R. E. Muck, J. M. Powell

Objective 1a. Crop Growth and Conservation Strategies.

Objective 1c. Manure Application and Soil and Water Interaction.

Usefulness of the Results

Objective 1a.

Objective 1c.

Work Planned for Next Year

Objective 1a.

Publications

NE-132 Regional Project Report: December 11, 2000