Chen Xin

Phosphorus Leaching from a Gley Meadow Soil in Relation to Soil Fertility Level and Fertilizer Application

The influence of fertilizer application on leaching of phosphorus in a gley meadow soil at low-, medium and high-fertility levels was studied using unsaturated intact soil columns. The soil column at each fertility level received three fertilization treatments (control [CK], manure [M] and chemical fertilizer [F]). The results showed that the leaching loss of DTP from the soil column was induced by the P input from either manure or chemical fertilizer application, and the extent of leaching loss of P was also positively related to the soil fertility level. In addition, the DTP concentrations in the leachates from the fertilization treatments all exceeded the critical value for water eutrophication (0.02 mg P/L). This suggests that applications of manure and chemical fertilizer at proper rates with close consideration of the soil fertility level are essential to reduce the leaching loss of DTP to the environment.

Accumulation of Soluble Organic Nitrogen under Intensive Vegetable Production Pattern in Northeast China

Field experiment was conducted to investigate the accumulation of soluble organic nitrogen under intensive vegetable production pattern in Northeast China. The results showed that the amount of soil soluble organic nitrogen was increased by 114.2% and 184.2% in the treatments M1 and M2 compared with CK, and its corresponding percent accounting for the total soluble N was increased by 74.9% and 123.7%, respectively (P <; 0.01). This suggested that the substantive application of organic manure significantly elevated the accumulation of soluble organic nitrogen, and then extended its leaching risk into deeper soil layers under the intensive vegetable production process.