Lancaster Report
Lancaster in the Chesapeake Bay
Identifying Lancaster county in the Chesapeake Bay Watershed
CENSUS NUMBERS
Bellow are reported numbers from the 2022 Ag Census for Lancaster County (FIPS 42071) in the Chesapeake Bay Watershed (NASS, USDA 2024).
Crop numbers reported on census 2022
The area harvested variable is reported in acres and the production of crops is reported in bushels or tons.
Animal numbers reported on census 2022
Model Numbers
In the model the data imported from census is changed to be useful to calculate the N input. The crops area and production per county is processed using satelite data and GIS software to represent the amount of crops that exists inside the portion of the county inside of the Chesapeake Bay Watershed. For the animals the data is also processed in this way, but it is also normalized to a year, instead of total product produced in the year.
CROPS
Area harvested in km2 of crops produced in Lancaster
Production in kg of crops produced in Lancaster
ANIMALS
Animal Sold per year
Number of animals population
This is calculated based on census numbers using coefficients from . The rationale is that assuming animals reported in the census are present on the farm year-round is not realistic. Most animals are only present for part of the year (cycles), so calculating annual impacts requires normalizing to an annualized population. The logic is explained below and is more elaborated in Kellogg, Moffitt, and Gollehon (2014)
Animal Cycles/year based on their type
| Animal Type | Days on Farm | Cycles/Year | Notes |
|---|---|---|---|
| Fattened Cattle | 146 | 2.5 | Feedlot finishing |
| Calves (beef & dairy) | 150 | 2.43 | Pre-weaning |
| Heifers (beef & dairy) | 150 | 2.43 | Replacement stock |
| Stockers (beef & dairy) | 200 | 1.825 | Backgrounding |
| Hogs for Slaughter | 182 | 2.0 | Grow-finish |
| Pullets | 162 | 2.25 | Layer replacement |
| Broilers | 60 | 6.0 | Fastest cycle |
| Slaughter Turkeys | 182 | 2.0 | Grow-finish |
Equations that transform census data into population of animals for the model
| # | Category | NASS Inputs | Formula |
|---|---|---|---|
| 1 | Fattened Cattle | CATTLE_ON_FEED_SALES |
sales / 2.5 |
| 2 | Milk Cows | CATTLE_COWS_MILK_INV |
direct inventory |
| 3 | Hogs for Breeding | HOGS_BREEDING_INV |
direct inventory |
| 4 | Hogs for Slaughter | HOGS_INV HOGS_BREEDING_INV
HOGS_SALES |
(total - breeding) / 2 + sales adj. |
| 5 | Chicken Layers | CHICKENS_LAYERS_INV |
direct inventory |
| 6 | Breeding Turkeys | TURKEYS_INVENTORY TURKEYS_SALES |
5% inv or 3% sales / 2 |
| 7 | Chicken Pullets | CHICKENS_PULLETS_INV
CHICKENS_PULLETS_SALES |
inv/2.25 + sales adj. |
| 8 | Chicken Broilers | CHICKENS_BROILERS_INV
CHICKENS_BROILERS_SALES |
inv/6 + sales adj. |
| 9 | Slaughter Turkeys | TURKEYS_INVENTORY TURKEYS_SALES |
95% inv / 2 + 97% sales adj. |
| 10 | Beef Breeding Herd | CATTLE_COWS_BEEF_INV
CATTLE_EXCL_COWS_INV |
beef_cows + bulls |
| 11 | Beef Calves | CATTLE_COWS_BEEF_INV
CATTLE_CALVES_SALES |
0.82 × beef_cows / 2.43 + adj. |
| 12 | Dairy Calves | CATTLE_COWS_MILK_INV
CATTLE_CALVES_SALES |
0.65 × milk_cows / 2.43 + adj. |
| 13 | Beef Heifers | CATTLE_COWS_BEEF_INV
CATTLE_EXCL_COWS_INV |
min(0.15 × beef_cows, avail) / 2.43 |
| 14 | Dairy Heifers | CATTLE_COWS_MILK_INV
CATTLE_EXCL_COWS_INV |
min(0.20 × milk_cows, avail) / 2.43 |
| 15 | Beef Stockers | Multiple cattle variables |
residual calculation / 1.825 |
| 16 | Dairy Stockers | Multiple cattle variables |
residual calculation / 1.825 |
DIET
AFIA Total amount of feed per animal commodity category in short tons
Average kg of crop fed to each animal type (For 1 animal)
Average kg of crop N fed to each animal type (For 1 animal)
Dry matter and N content available below were used to calculate the kg of N fed to each animal type based on the kg of crop fed to each animal type. Data was obtained from Algren, M et al. (2021)
Total kg of crop fed for each animal type in Lancaster (For all animals)
Based on the average value of crop kg fed to each animal type based on AFIA data we multiply the number of population in the county by the average crop fed to get the total kg feed for each animal type.
Total kg N in feed for each animal type in Lancaster (For all animals)
Based on the average value of crop N fed to each animal type based on AFIA data we multiply the number of population in the county by the average N fed to get the total N in feed for each animal type.
What is the net for feed based on their consumption by cattle
Is the manure produced by livestock in the region enough to fulfill crop needs?
Total N in manure produced, total manure N recovered, total manure N manure available
The following table of coefficients allow to calculate total N in manure (Algren, M et al. (2021)), total N recovered (Kellogg, Moffitt, and Gollehon (2014)) and manure available (Penn State Extension (2023)).
Total N in manure was calculated by multiplying annual kg N excrete coefficients by animal numbers.
Total N in manure recovered was calculated by multiplying Total N in manure by Manure mass recoverable and N recoverability percentages.
Ammonium concentration was used to separate Total N in manure recovered in Inorganic and Organic portions. Manure inorganic and organic portion were assumed to be applied in Fall and Spring. To calculate spring inorganic portion available to plants multiply it by spring inorganic available percentage (Fall is assumed to be all lost). To calculate spring and fall portions of organic N in manure applied available to plants multiply organic fraction by fall organic available and spring organic available.
Total kg N Plant Available is the pool of N available for plants. This total N plant available is distributed based on a ratio calculated based on a percentage of total N need of the crops (e.g., the crop that needs more N receives a higher percentage of that pool)
The value from N demand for crops in Lancaster is calculated based on the kg/km2 N demand of crops in Lancaster multiplied by the area of each crop in the county (previously mentioned).
The percentage of manure received is calculated based on the N demand of each crop divided by the total N demand of all crops in the county. This percentage is used to distribute the total N plant available to each crop by multiplying the percentage by total N manure available pool.