What are the environmental consequences of the current methods involved in planting crops and raising livestock?

Question

What will be an ideal response?

Answer 1

Growing crops has major environmental consequences. The soil loses nutrients as each crop is harvested, so fertilizer is applied. Some nitrogen in the fertilizer is released as a gas that contributes to greenhouse gas emissions. With rain or irrigation, fertilizer leaches into ground water or runs off into the waterways where it stimulates algae growth, which depletes oxygen and kills aquatic plants and animals.
To protect crops against weeds and pests, farmers apply herbicides and pesticides, which pollute the water and kill native plants, native insects, and animals that eat those plants and insects. Ironically, with continued widespread use of pesticides and herbicides, pests and weeds become more resistant. Consequently, farmers must use more pesticides and herbicides. These chemicals pose hazards for farm workers who handle them, and the residues can create health problems for consumers as well.
Finally, when fields are irrigated, the water evaporates, but the salts do not. As salts accumulate on the soil surface, plant growth fails. Irrigation can also deplete the water supply over time as much of the water taken from surface waters or from underground evaporates or runs off. Excessive irrigation can dry up rivers and lakes and lower the water table of entire regions. A vicious cycle develops. The drier the region becomes, the more farmers must irrigate, and the more they irrigate, the drier the region becomes.
Consumers are not typically aware of the environmental impact of eating meat, but raising livestock takes an enormous toll on land and energy resources. Animals raised in large concentrated areas such as cattle feedlots or hog farms create environmental problems when huge masses of animal wastes are produced. The ammonia from their wastes pollutes the air and is a major cause of acid rain, which damages plants, acidifies soils, and pollutes waterways. In addition to urine and manure, animals produce large quantities of methane—a greenhouse gas that contributes to climate change. In an effort to prevent contamination of air, soil, and water, the US Environmental Protection Agency offers incentives to livestock farmers who clean up their wastes and allow inspections.
In addition to the waste problems, animals in feedlots must be fed, and grain is grown for them on other land. That grain may require fertilizers, herbicides, pesticides, and irrigation, too. In the United States, more cropland is used to produce grains for livestock than to produce grains for people.