Soil fertility and fertilization practices affect accumulation and leaching risk of reactive N in greenhouse vegetable soils

Abstract

Elevated soil fertility levels induced by continuous chemical fertilizer and (or) manure application may affect N loss potential and redistribution within soil-crop system. A 49-d packed soil column experiment with a factorial design of three soil fertility levels and four fertilization treatments was conducted to evaluate the effects of soil fertility and fertilization treatments on the accumulation and leaching risk of reactive N. The results showed that the 49-d cumulative leaching loss of total reactive N ranged from 176.3 to 499.0 kg N ha−1. The cumulative leaching losses of total dissolved nitrogen (TDN) and dissolved organic nitrogen (DON) in NPK treatment were significantly higher than those in other three treatments in fertility level I and II soils. The cumulative leaching loss of NO3−-N was significantly greater in NPK + M or NPK treatment than in CK treatment in fertility level I or III soils, and it was remarkably greater in M treatment than in other three treatments in fertility level II soil. In total, 64.0% of TDN in soil leachate existed in the form of DON, and 35.1% was nitrate-N among different soil fertility and fertilization treatments. These results indicated that DON was an important component of N leaching loss and could not be neglected in sustainable development of vegetable greenhouse soil.