# Presentation: 478110

## Whole Farm Simulation and Nutrient Management

**USDA, Agricultural Research Service**
**University Park, Pennsylvania**

**C. Alan Rotz**

## Descriptive Information

**                     ****Integrated Farm System Model**
**Purpose: Research and teaching tool for long-term evaluation of farm production systems**
**Contact Person: Al Rotz**
**Stage of Development: Recent versions available on the Internet; Continuing development**

**Descriptive Information**

## Focus and Scale

**Focus: Whole-farm (Soil, crops, animals, equipment processes, etc.)**
**Scale: Whole-farm**
**Area of Concern: Nitrogen losses (volatilization, leaching and denitrification) and phosphorus balance**

## Integrated Farm System Model

**Soil**

**Establish**

**Crop**

**Harvest**

**Storage**

**Animal**

**Manure**

**Grazing**

**Volatile loss**

**Milk sold**
**Animals sold**

**Purchased feed,**
**bedding, etc.**

**Feed sold**
**Volatile loss**

**Fixed**
**   ****nitrogen**

**Volatile loss**
**Purchased**
**   ****fertilizer**
**Runoff &**
**  ****Leaching loss**

## Weather

**Weather**

## Crops

**Alfalfa pasture, hay and silage**
**Grass pasture, hay and silage**
**Corn grain and silage**
**Barley, wheat, oats or rye grain, silage, or mulch**
**Soybean grain**

## Crop Growth

**Phenological stage**
**Yield**
**Nutritive content**
**Nutrient uptake**

## Harvest

**Machinery use**
**Timeliness of operations**
**Fuel and labor use**
**Harvest losses and nutritive changes**

## Storage

**Types of storage**
**Storage losses and nutritive changes**
**Silo capacity and fill**

## Feeding and Use

**Feed allocation**
**Balanced ration**
**Machinery, fuel, and labor use**
**Animal intake**
**Production**

## Manure

**Quantity and nutrient content**
**Bedding and feed loss **
**Nitrogen volatilization and loss**
**Machinery, fuel, and labor use**
**Timeliness of operations**
**Date to begin tillage**

## Tillage and Planting

**Type of tillage (sequence of operations)**
**Machinery, fuel, and labor use**
**Timeliness of operations**
**Planting date**

## Soil

**Predominant soil type**
**Moisture balance in soil profile**
**Nitrogen balance in soil profile**
**      ****Leaching**
**      ****Mineralization**
**      ****Denitrification**
**Farm level balance of P and K**

## Economics

**Annual production costs**
**Annual incomes**
**Annual net return**
**Mean and standard deviation in costs**
**   ****and returns across years**

## Environmental Impact

**Nitrogen loss to atmosphere**
**Nitrogen loss to ground water**
**Phosphorus accumulation**
**Potassium accumulation**
**   **

## Risk

**Cumulative probability**

**Cost or return**

## Application

**Users: Researchers, Teaching faculty, Extension, NRCS, etc.**
**Format: Windows (version 95 and up)**
**Documentation: Integrated help system**
**User guide – Guidance on input, output and use**
**Reference Manual – Description of model including major equations and references**

## Regional Application

**Primarily developed and validated for the northern temperate regions of the U.S.**
**Has been used for a number of locations in Canada and Europe**
**Most recent version can simulate**
**      ****areas in the southern hemisphere**

## Recent Applications

** ****Alternative strategies for manure handling**
** ****Protein supplementation strategies for dairy cattle**
** ****Soybean production and feeding on dairy farms**
** ****Small grain production and use on dairy farms**
** ****Pasture and confined feeding systems**
** ****Reduced levels of grain feeding**
** ****Intensity of pasture management**
** ****Global climate change**
** ****Corn silage processing**
** ****Robotic Milking**

## Model Use

## Inputs

**Farm parameters**
**Machinery parameters**
**Weather data**

## Farm Parameters

**Crop types & areas**
**Predominant soil type**
**Equipment and structures used**
**Number of animals at various ages**
**Animal feeding & maintenance strategies**
**Harvest, tillage & manure handling strategies**
**Prices for various farm inputs and outputs**

## Machinery Parameters

**Size**
**Age**
**Initial cost**
**Field speed**
**Operating capacity**
**Power requirements**
**Repair factors**

## Weather Data

**Daily data for solar radiation, maximum and minimum temperature, and precipitation**
**Weather files are available for many locations across the northern U.S., Canada and Europe**
**Weather files can be created                  for other locations**

## Outputs

**Summary tables**
**Report tables**
**Parameter tables**
**Optional tables**

## Summary & Report

**Crop yields & quality**
**Feeds produced**
**Feeds bought and sold**
**Milk or meat produced**
**Manure produced**
**Labor, fuel & equipment use**

**Performance Output**

## Summary & Report

**Volatile N loss**
**Leaching N loss**
**Denitrification N loss**
**N concentration in groundwater**
**P balance**
**K balance**

**Environmental Output**

## Summary & Report

**Manure handling costs**
**Feed production costs**
**Other farm costs**
**Income from milk, meat and animals sold**
**Net return or profitability**

**Economic Output**

## Optional Output

**Daily values of crop growth and development**
**Pasture availability by month **
**Suitable days for fieldwork by month **
**Daily values of forage harvest operations**
**Annual summaries of machine, fuel, and labor use **
**Animal group characteristics and diets**

## Example Application

**Whole Farm Management to Reduce Nitrogen Losses from Dairy Farms**

**C. A. Rotz**
**J. Oenema**
**H. van Keulen**

## Objectives

**Objectives**

**Calibrate and verify our farm model through simulation of the De Marke farm **
**Evaluate these N conservation practices on simulated 100- and 1000-cow dairy farms for southern Pennsylvania**

## De Marke Farm

**8,600 kg/cow**
**57 young stock**
**55 ha of land**
**Grass, corn and triticale**
**Deep sandy soil**

**De Marke Farm**

## Nitrogen Conserving Technologies

**Efficient protein feeding**
**Low emission barn floor**
**Covered manure storage**
**Manure injection**
**Grass catch crop**

## Model Calibration

**Soil organic N in grassland**
**N volatilization from pasture**
**Animal intake of forage**
**Base temperature for corn growth**

**Model Calibration**

**Simulation of De Marke farm for weather years 1996-99**

## Nitrogen Balance

**Nitrogen Balance, kg**

## Model Evaluation

**Reduced grazing time and area**
**More clover in pasture**

**Model Evaluation**

**Simulation of De Marke farm for weather years 2000-01**

## Nitrogen Balance

**Nitrogen Balance, kg**

## Pennsylvania Farm

**100 cows**
**8,600 kg/cow**
**67 young stock**
**100 ha of land**
**Corn, alfalfa and grass pasture**
**Medium silt loam soil**
**Daily manure hauling**

## Nitrogen Conservation Technologies

## 100 Cow Farm

**Loss or balance, kg/ha**

## 100 Cow Farm

**Cost or return, $/cow**

## Pennsylvania Farm

**1000 cows**
**11,300 kg/cow**
**770 young stock**
**600 ha of land**
**Corn and alfalfa**
**Medium silt loam soil**
**Long-term manure storage**

## 1000 Cow Farm

**Loss or balance, kg/ha**

## 1000 Cow Farm

**Cost or return, $/cow**

## Conclusions

**The IFS model satisfactorily reproduced the long-term feed production and use and the N and P flows of the De Marke dairy farm**
**Simulation of N conservation technologies on Pennsylvania farms illustrated that N loss, primarily in the form of ammonia emissions, could be reduced by about 35%**
**The cost of this technology exceeded the value of the N saved, causing a reduction in annual net return of about $80/cow**

## Limitations & Usefulness

## Limitations

**What limits the tool from use by a wider audience?**

**Model complexity!**

## Limitations

**Identifiable weaknesses in terms of technical abilities?**

**Other crops**
**Other animal species**
**Subtropical regions**
**Need for further validation/verification**

## Limitations

**Aspect of nutrient management fulfilled by the model?**

**Integration with other aspects of the farm (Performance and economics)**
**Ability to evaluate nutrient management in whole farm systems**

## Usefulness

**Gaps in the abilities of the model to balance nutrients or predict nutrient outcomes?**

**Phosphorus loss**

## Usefulness

**Quality of results with respect to nutrient handling?**

**Nitrogen volatilization**
**Nitrogen leaching**
**Denitrification**
**Unaccounted nitrogen loss**

## Usefulness

**Confidence level in the output?**

**Practical expertise is required to use the model**
**Some calibration/verification is helpful**
**Simulated nutrient flows and losses are at least as accurate as measured values**

## Usefulness

**Has there been any field validation?**

**Farm level validation is very difficult**
**All component models are carefully evaluated, verified, or validated**
**Many farms have been represented with the model with at least reasonable results**

## Usefulness

**Who has used this tool and in what capacity?**

**Researchers**
**Teaching faculty**
**Extension faculty/specialists**
**Machinery industry**
**Producers, etc.**

**Estimated number of users???**

## Usefulness

**Has the tool been useful in meeting regulatory requirements or policy?**

**Not directly**
**Provides a great educational tool that could influence farm design/regulation**
**Use of the model for this purpose could be abused**

**Does the tool produce a nutrient management plan?   ****No**

## Future Plans

**Validate beef component**
**Upgrade N volatilization loss**
**Predict P loss  (crops, diet, tillage, etc.)**
**Upgrade pasture model (multiple plant species)**
**Add carbon balance?**
**Add other animal species?**

## Model Availability

**Model Availability**

**http://pswmru.arsup.psu.edu**

## Pasture Systems and Watershed Management Research Unit

**Pasture Systems and Watershed Management Research Unit**
**University Park, Pennsylvania**

**Agricultural Research Service**