A new cotton sampling system developed by Agricultural Research Service scientists helps growers determine the different fiber qualities produced by their cotton plants throughout a harvested field.

ARS plant physiologist Gretchen Sassenrath worked with technician Ray Adams in the ARS Application and Production Technology Research Unit at Stoneville, Miss., to design a method of spatially sampling cotton during harvesting operations. The system helps determine what underlying factors, such as soil moisture, may be affecting the fiber properties.

Soil properties will alter the moisture and temperature in a small area of a field, changing the individual microclimate for that area. For instance, if areas of a field have changes in soil quality, varying temperatures or different amounts of water collecting throughout it due to terrain features, cotton fiber properties may vary.

Adams built a cotton sampler that attaches to the picker's chute. A lever switches a paddle gate in the picker chute and, every 20 seconds, diverts some of the harvested cotton into a sampler chute for collection and later analysis. The cotton sample is harvested from a known area of the field. Fiber properties are then incorporated with the position data and entered into the database for spatial analysis.

The system works alongside the cotton yield monitor, a device that measures the quantity of cotton at any given position in the field. The yield monitor is equipped with a Global Positioning System receiver to compute position, speed and time.

The data from the yield monitor and the fiber properties are then entered into the geographic information system (GIS), a database that processes geographically-based information. A GIS map shows growers which areas of their fields need more attention and which areas are producing cotton bolls with the best fiber properties. Once the cotton fiber properties have been determined, the value of the cotton lint is calculated from the same tables that farmers use when selling their cotton.

ARS is the U.S. Department of Agriculture's chief scientific research agency.