On the basis of the eight-season vegetable rotating experiments (1999-2001), the open field experiments with rotating system of cauliflower (Brassica oler. L., var secalinuni) - catch crops including sweet corn (Amaranthus spp.) and amaranth (Zea mays L.) - spinach (Spinacia oleracea L.) were conducted in Beijing suburb in 2002, in order to study the dynamic change of nitrate leaching affected by different water and nitrogen inputs. Balanced irrigation and fertilization treatments were introduce...