Effects of different irrigation and fertilization strategies on soil inorganic N residues in open field of vegetable rotation system

Effects of different irrigation and fertilization strategies including conventional treatment and recommended treatment following balancing method on the total yield of five seasonal vegetable rotation system (amaranth-spinach-cauliflower-amaranth-spinach) and the changes of soil Nmin residue were compared in North China Plain in this paper. The results showed that there were no significant differences in marketable yield between conventional and recommended nitrogn treatments except for cauliflower in 2000yr. In conventional nitrogen treatments with different irrigation regimes, much soil nitrate was accumulated and leached down to the depth of 150～180cm after four seasonal vegetable experiments. However, no obvious nitrogen leaching was monitored in the combination with recommended water and nitrogen treatments.