Sustainable Agriculture: From Sweet Sorghum Planting and Ensiling to Ruminant Feeding.

Abstract

A large proportion of food is composed of crops and meat besides vegetables and fruits. The production of crops and meat needs a large area of land and other resources, such as water, chemical fertilizer, and pesticides. The growing world population increases the demand for food security. Moreover, developing countries with highly dense populations have dramatically changed food composition from mostly crops to more meat and milk, which has forced the adjustment and optimization of agricultural production structure to supply the demand caused by these dramatic changes. For example, after 40 years of economic reform in China, the living standard has considerably increased and is reflected by the stark changes in food demand. From 1990 to 2012 human consumption of crops in China declined by 38%, while consumption of meat and milk increased by 226% (Louie et al., 2015). Considering that the Chinese population totals 1.4 billion, one-quarter of the world s population, this rapidly increasing demand for animal-derived foods and products increases the need for more grains used as feed. Over the last several years, total grain output in China reached 0.6 billion tons per year, more than half of these being used as animal feed.\nMass production of livestock has caused many negative environmental consequences. In particular, feeding chickens and pigs not only produces large amounts of fecal waste but also causes large quantities of antibiotic contamination of water and soil in China (Zhang et al., 2015). Moreover, increased production of grains results in large amounts of crop straw left in the field. Unfortunately, burning the straw in the field, the widely adopted method used for post-harvest treatment of straw, has caused severe air pollution. Straw returning back into soils also potentially increases the rate of occurrence of plant diseases and insect pests in the subsequent season of crop growth.