How did irrigation eventually lead to a food surplus?

Answer 1

Ash is partially correct. In the simplest explanation, irrigation allowed for the cultivation/growing of fruits, vegetables, cereals, etc. in places that they couldn't/wouldn't have been before irrigation; irrigation allowed mankind to practice agriculture in far more/new places than previous which would lead to more crops/food being produced. In primitive societies without irrigation, crops can only grow in those areas where they get enough water supply from rain (and in some cases in areas along rivers and lakes) which the crops need to grow. As societies advanced through the development of irrigation, they simply transfered a constant supply of fresh water to more and more areas allowing far more land to be used to produce food. I know in Michigan and parts of the Midwest we do have a much greater supply of freshwater than most other places with our abundance of lakes, rivers, streams, etc. and many farmers took advantage of this fact by building their properties in places with a constant supply of fresh water; other farmers without a source of water on their farms then would need to find other ways of providing/diverting water to their crops such as building canal ditches off nearby sources of water in case they didn't receive enough rain during the year. Just look at California as a prime example of how irrigation can create a food surplus. They have many large-scale farm operations that can grow various crops all year long due to the constant warm temperature and sunshine not found in Northern parts of the US; however many of these farms get very little rain during the year and also have no source of freshwater nearby to substain the crops. Through irrigation techniques, man has simply brought the required water to this area and has created a huge agricultural industry there where there could be none without irrigation and this area also provides an enormous amount of foodstuffs which helps the US have a food surplus.

Answer 2

when irrigation was created it was an easier way to water crops so they could effectively grow more crops