Tracts of land were used for producing crops long before anyone kept records of the physical and chemical properties of the soil. It is impossible to go back in time and analyse the effects agriculture had.

Now using a computer simulator, a soil scientist, has compiled a yearby- year effect of 100 years of agriculture on claypan soils in American farms. Claypan is a dense, semi-permeable layer in the subsoil. The data will help develop strategies to protect and restore soil fertility.

He analysed soil properties of two claypan fields—a never-farmed and a field under cultivation for a century. He also made use of satellite images and photographs taken between 1930 and 1990 of the land.

Considerable changes were found in soil fertility and pesticide runoff throughout the century, including 39 per cent drop in corn and 75 per cent drop in soybean yields.

Source: Down To Earth
Date: December, 2010