Management of water and nitrogen for controlling soil nitrate accumulation in pepper

Pot experiment was carried out for studying the effect of different N rates, irrigation methods (flood irrigation (F), drip irrigation (D) and subirrigation (S)) and amount on the growth of pepper and soil nitrate accumulation. Three levels irrigation amount of flood irrigation were set as 100%(F₁), 70%(F₂), 40%(F₃) of field capacity, respectively. N rate 0.3 g kg^-1 (N1), 0.6 g kg^-1 (N₂) dry soil was defined by middle N rate and high N rate. While N rate 0.3 g/kg dry soil and 70% of field capacity were designed on drip irrigation (N₂D) and infiltration (N₂S). The result showed that excessive nitrogen input could not increase the yield of pepper, but reduce the vitamin content (Vc). Under the same conditions of soil moisture, N₂ were higher than N₁ in productions and Vc. The max yield of pepper appeared in N₂S which was increased by 43.4% compared with N₂F₂. While the lowest of soil nitrate accumulation appeared in N₂D which was decreased by 22.3% compared with N₂F₂. The results of all indicated that the model of drip irrigation is the feasible management which caused higher Vc contents and yield but the lowest soil nitrogen accumulation.