Effect of different fertilization managements on nitrate accumulation in a Mollisol of Northeast China

In a continuous spring maize system in Northeast China, the accumulation and succession characteristics of nitrate in Mollisol with four fertilization treatments, including no fertilization (CK), farmers’ conventional fertilization (FC), recommendation fertilization (RF), and controlled release fertilizer application (CRF), were compared over a 6-year field plot trial. On average, the RF and CRF treatments decreased nitrate nitrogen by 16.6 and 39.5 % in the 0–90 cm soil layer, respectively, and maintained a relatively high maize grain yield, as compared to the FC treatment. The accumulation of nitrate nitrogen was more obvious in the CRF treatment compared with the other fertilizer treatments under the arid climate. However, the high precipitation resulted in the leaching of nitrate nitrogen into the deeper soil layer in all the fertilizer treatments. The maximum of nitrate nitrogen in the 0–90 cm soil layer was 81.4 kg N/ha at a nitrogen fertilizer rate of 250 kg N/ha in the long-term trial, which was within the rational and safe level for groundwater. The best fertilization strategy to decrease nitrate accumulation in soil should consider both soil characteristics and precipitation.