The use of intensive farming techniques are creating not only localized ecological disasters but in many places having impacts across way sections of the countryside. Intensive farming designs limit the range of habitats, inputs to the system particularly those used for soil fertility and pest control determine the impact on species within the habitats. Intensive farming substitutes rather than enhances the natural biological production processes. Livestock and arable enterprises are separated breaking the cyclical processes characteristic of natural ecosystems. The lack of diversity of crops and animals narrows the range of natural plants and animals on the land. Autumn and winter-sown cereals decrease the availability of food for wild birds at the start of the crucial breeding season and thus limiting the range of wild birds, hares and other small mammals. The large farm size further limits the size of animal populations because field boundaries are smaller, fewer and farther apart. Habitats within boundaries, especially hedgerows, are important to many wild flowers, insects, birds and mammals. Oversowing land decreases the populations of insects. Soil fertility is decreased because of intensive farming techniques. Soil invertebrates are fewer where inorganic fertilizers are used and crop residues are burned. Weed control is more efficient further limiting the range of species of plants and animals. Intensive farming causes more nitrate and phosphate pollution of surface waters. Soil erosion is greater. Leaching rates are greater. Animal wastes are in surplus where animals are raised intensively. Soils are effected negatively also. Soil organic matter levels are lowered decreasing the availability of water and some nutrients to plants. Trace elements are lost or used up. The buffering capacity of the soil is disrupted increasing pH fluctuations. Substrate is lost further decreasing fertility. Continuous cropping of autumn and winter-sown cereals promote erosion because the soil is exposed during the wetter part of the year. Soil flora and fauna are lost with their ability to cycle nutrients within the soil and their contribution to the suppression of plant diseases. The continuous use of chemicals has enabled the development of pesticide resistant insects, weeds and microbes. Plants that are chemically fertilized may look lush, but lush growth produces watery tissues, which become more susceptible to disease; and the nutritive quality suffers.
The intensification of agriculture during the green revolution with its the reliance on antibiotics and hormones in feeding animals in so-called animal factories (i.e. chicken, pigs) as well as on irrigation and chemical inputs in crop fields has led to serious health and environmental problems. Much of Asia, for example, faces problems of severe salinity, pesticide misuse and degradation of natural resources. It is therefore not surprising to see the ever increasing development of opposition against any further biotechnological applications, especially those arising from genetical modification of microbial, plant and animal cells.
Agriculture as it is currently practised is a global disease, because it wastes the soil through erosion, burns up more energy than it produces in food and requires the extensive use of agricultural chemicals, whose side-effects are largely unknown. Studies show that farmers who apply few or no chemicals to crops are usually as productive as those who use synthetic fertilizers and pesticides.
The use of agricultural chemicals is not in itself harmful. The level of use remains quite low in many regions where the response rates are high and the environmental consequences of residues are not yet a problem. The issue is that the growth in the use of these chemicals tends to be concentrated where they tend to do more overall harm than good.