Key Laboratory of Non-point Source Pollution Control, Ministry of Agriculture, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
USDA-Agricultural Research Service, Pasture Systems and Watershed Management Research Unit, University Park, PA 16802, USA.
Sci Total Environ. 2015 May 1;514:388-98. doi: 10.1016/j.scitotenv.2015.02.022. Epub 2015 Feb 11.
Identification of critical nitrogen (N) application rate can provide management supports for ensuring grain yield and reducing amount of nitrate leaching to ground water. A five-year (2008-2012) field lysimeter (1 m × 2 m × 1.2 m) experiment with three N treatments (0, 180 and 240 kg Nha(-1)) was conducted to quantify maize yields and amount of nitrate leaching from a Haplic Luvisol soil in the North China Plain. The experimental data were used to calibrate and validate the process-based model of Denitrification-Decomposition (DNDC). After this, the model was used to simulate maize yield production and amount of nitrate leaching under a series of N application rates and to identify critical N application rate based on acceptable yield and amount of nitrate leaching for this cropping system. The results of model calibration and validation indicated that the model could correctly simulate maize yield and amount of nitrate leaching, with satisfactory values of RMSE-observation standard deviation ratio, model efficiency and determination coefficient. The model simulations confirmed the measurements that N application increased maize yield compared with the control, but the high N rate (240 kg Nha(-1)) did not produce more yield than the low one (120 kg Nha(-1)), and that the amount of nitrate leaching increased with increasing N application rate. The simulation results suggested that the optimal N application rate was in a range between 150 and 240 kg ha(-1), which would keep the amount of nitrate leaching below 18.4 kg NO₃(-)-Nha(-1) and meanwhile maintain acceptable maize yield above 9410 kg ha(-1). Furthermore, 180 kg Nha(-1) produced the highest yields (9837 kg ha(-1)) and comparatively lower amount of nitrate leaching (10.0 kg NO₃(-)-Nha(-1)). This study will provide a valuable reference for determining optimal N application rate (or range) in other crop systems and regions in China.
确定关键施氮量可以为确保粮食产量和减少硝酸盐向地下水淋溶提供管理支持。在华北平原的一个 Haplic Luvisol 土壤上进行了一项为期五年(2008-2012 年)的田间淋溶池(1 m×2 m×1.2 m)试验,其中包括 3 个施氮处理(0、180 和 240 kg Nha(-1)),以量化玉米产量和硝酸盐从土壤中的淋溶量。该实验数据用于校准和验证基于反硝化-分解(DNDC)过程的模型。之后,该模型用于模拟一系列施氮量下的玉米产量和硝酸盐淋溶量,并根据该作物系统可接受的产量和硝酸盐淋溶量来确定关键施氮量。模型校准和验证的结果表明,该模型可以正确模拟玉米产量和硝酸盐淋溶量,具有令人满意的 RMSE-观测标准差比、模型效率和决定系数值。模型模拟结果证实了以下测量结果,即与对照相比,施氮会增加玉米产量,但高氮量(240 kg Nha(-1))并未比低氮量(120 kg Nha(-1))产生更多产量,并且硝酸盐淋溶量随施氮量的增加而增加。模拟结果表明,最佳施氮量在 150-240 kg ha(-1)之间,这将使硝酸盐淋溶量保持在 18.4 kg NO₃(-)-Nha(-1)以下,同时保持可接受的玉米产量在 9410 kg ha(-1)以上。此外,180 kg Nha(-1)产生了最高产量(9837 kg ha(-1))和相对较低的硝酸盐淋溶量(10.0 kg NO₃(-)-Nha(-1))。本研究将为确定中国其他作物系统和地区的最佳施氮量(或范围)提供有价值的参考。