A field experiment was conducted on two soil types in the Changsha suburb of Hunan Province to study the effects of hydroquinone (HQ),dicyandiamide (DCD) and thiourea (TU) on the nitrate content in soil and pakchoi and on the yield of pakchoi.

• 通过田间试验；对湖南长沙地区的红菜园土和冲积菜园土两种土壤条件下氢醌(HQ)、双氰胺(DCD)和硫脲(TU)3种硝化抑制剂对土壤和小白菜硝酸盐含量及小白菜产量的影响进行研究.