Chapter 1 - Introduction

Abstract

Agricultural crop residues, such as straws of wheat, barley, rice, maize, oats, rye, and cotton, as well as sugarcane bagasse and other residues, represent an enormous underutilized energy resource, which has a great potential as feed for ruminants and also as raw materials for paper, chemicals, and other technical products. Straw, the aboveground part of the cereal plant, comprises about half the total dry weight of the crop. Straw has been valued as the most useful by-product of cereal production, and it has been used for feeding livestock, bedding, growing mushroom, and so on. Farmers in many of the chief cereal-growing countries of the world burn or plough the straw into the field directly as a fertilizer. With the development of science and technology in the recent decades, especially with the exploitation of petroleum, straw is regarded as little more than an embarrassing companion to the grain crop. One of the most traditional utilizations of straw is as feed for livestock. Various physical, chemical, and biological treatments have been applied to improve utilization of straws. Physical treatment is carried out mainly to increase the surface area, which would enhance the attachment of bacteria. Processes such as milling, grinding, chopping, and steaming have long been used to improve the feed value of straw.