Straw

Straw is the dried mature crop plant that remains after collecting seeds/fruits. It is commonly known as the dried stalks (vegetative parts) of the mature cereal crop plants (rice/wheat/maize/barley/oat) that remain after harvesting and removing grains. It is an agricultural byproduct, and its nutritional value is inferior since it is harvested after maturity. The digestibility of straw is very low, about 40%. Rice straw and wheat straw usually contains 14 – 20% moisture (depending on the season), 35–40% cellulose (a type of digestible carbohydrate), 15 - 20% lignin (an indigestible carbohydrate), 12–14% silica (a mineral which interferes with straw digestibility), and 4% crude protein which is mostly indigestible, no vitamins but contains traces of minerals of which potassium is the highest (1.2%).

Although the uses of straw are diversified, only 20% of its production is used worldwide, but it varies from country to country. Its important use is as animal feed. Although its nutritional quality is poor, it is used as necessary roughage feed for ruminant animals in cereal-producing developing countries where green grass cultivation is scarce. In some countries in Asia and Africa, straw is extensively used as part of roughage feed for ruminant animals. Other uses of straw are; bedding for livestock, as biofuel substitute for coal, as construction of the roof of houses in poor communities in some countries, manufacturing handicrafts (dolls, hats, cat’s houses, mats, baskets, etc.), spent straw of cattle house are used to make compost (biofertilizer), as materials for manufacturing bioplastic, as packaging materials and so on. Because of the various uses of straw, it is foreseeable that in the future, although its use as animal feeds will be drastically reduced, its other uses will continue or may even be increased due to technological development. [Md. Ali Akbar]