In addition to corn stover and wheat straw, other grain crop residues such as barley, oat, rye, rice and grain sorghum straws (i.e., leaves, stalks, chaff) can also be used for bioenergy and bioproducts. Acreages of these crops are limited and, with the exception of rice, generally widely distributed geographically. In total, about 37 million dry tons of these straws were produced in 2005. Not all of these quantities can be removed from the field. Crop residues play a vital role in maintaining soil characteristics (e.g., soil organic matter and soil moisture), controlling erosion and chemical runoff, and ensuring the long-term productivity of the soil. Sufficient quantities of straw must be left on the field to maintain these functions--the quantities needed will depend on the conditions under which the grain is produced (i.e., crop rotation, tillage and other management practices, soil type, field characteristics such as slope, climate, etc.). Few studies have examined the available quantities and collection costs of these grain straws.
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