Summary

SECTION 7.4

AGRICULTURAL LAND PREPARATION

(This page last updated on November 19, 2014)

Emission Inventory Source Category
Miscellaneous Processes / Farming Operations

Method Summary: This category includes estimates of the airborne soil particulate emissions produced during the preparation of agricultural lands for planting and post-harvest activities. Operations included in this methodology are discing, shaping, chiseling, leveling, and other mechanical operations used to prepare the soil. This update incorporates current activity data, based on 2005 harvested crop acreage for most of the state, and 2007 farmland acreage for San Joaquin Valley. 

Activity Data Source: For most regions, the county-specific crop acreage is from USDA National Agricultural Statistics Services' (NASS) annual summaries of harvested crop acreage for 2005, as reported by California County Agricultural Commissioners. For the San Joaquin Valley Air Basin, 2007 farmland acreage from the California Department of Conservation’s Farmland Mapping and Monitoring Program (FMMP) was allocated to the various crops based on NASS harvested acreage reports for 2007. For all regions, information about the operation type, quantity, and the time of year that land preparation operations occur is from agricultural crop calendars, which were developed in consultation with growers and other agricultural experts to accurately reflect current California growing practices. 

Emission Factor Source: The operation specific emission factors were based on extensive field testing by the University of California, Davis. In consultation with agricultural experts, twenty crop specific emission factors were developed by summing acre-pass weighted emission factors for land preparation operations, and were then assigned to all California crops. 

Temporal Data: Land preparation activities are assumed to occur primarily during the day, seven days a week. The monthly activity profiles were derived for each county by summing the monthly crop emissions. The monthly emissions were calculated based on crop specific calendar profiles, which reflect the percentage of land preparation activities that take place for each crop in each month.

Changes in Method and Emissions Estimate: The emission factor equation uses an updated particle size profile. Temporal profiles were updated to reflect current land preparation activities and new growth surrogates were developed.  

Date of Last Update: December 2013

Growth Parameter: Growth in this category is based on projections of harvested crop acreage or farmland acreage and varies by region. 

Statewide Emissions Summary 
(2007 — Annual Average Tons/Day, Uncontrolled)

Click to download the full methodology (1.37 MB) in PDF format   Area Source Top Page             Search ARB Programs / Topics