Additionally, modern agriculture harms the environment in several ways. Dangerous poisonous chemicals are used as pesticides. Also, when too much water is drawn from the underground reservoir, particularly during drought years, the damage is often long-term and irreversible. The water issue is especially important. Its availability often determines the population size that an area can support.
Agriculture is actually a water-intensive industry.
In other words, the population size that a country with a given quantity of water can support will shrink as the agricultural component of the country's economy grows. But financial considerations are not always the deciding factor in economic activity. Political concerns, as well as survival, may override purely economic considerations. The clearest example of this is security. Agriculture, being the means of insuring a population's food supply, has national strategic importance even if it requires special assistance.