Crop rotation British Agricultural Revolution. The rotation between arable and ley is sometimes called ley farming. George Washington Carver (1860s–1943) studied crop-rotation methods in the United States, teaching southern farmers to rotate soil-depleting crops like cotton with soil-enriching crops like peanuts and peas. In the Green Revolution of the mid-20th century the traditional practice of crop rotation gave way in some parts of the world to the practice of supplementing the chemical inputs to the soil through topdressing with fertilizers, adding (for example) ammonium nitrate or urea and restoring soil pH with lime. Such practices aimed to increase yields, to prepare soil
Reuse of bottles contain the chemical Bisphenol A (BPA), which is made from polycarbonate and which shares resin identification code 7 with other plastics. Another chemical found in plastic drinking bottles is phthalate. Both of these chemicals are controversial because they are known endocrine disruptors, which can interfere with the body's hormonal system. A study by the Harvard School of Public Health (HSPH) found that participants who drank from polycarbonate bottles – which is the plastic commonly used in disposable plastic water bottles, other plastic drinking bottles, and baby bottles – for just one week showed a two-thirds increase in their urine of