Xin Zhang1, Guangmin Xiao1, Roland Bol2, Wenliang Wu1, Fanqiao Meng1
1 College of Resources and Environmental Sciences, China Agricultural University, No. 2 Yuanming Xilu, Haidian, Beijing, 100193, China, mengfq@cau.edu.cn
2 Institute of Bio- and Geosciences, Agrosphere (IBG–3), Research Centre Jülich, Jülich, 52425, Germany
Abstract
During the past three decades of agricultural intensification in China, crop production has increased greatly. However, intensive agriculture is under pressure to reduce environmental pollution and improve nutrient use efficiency. We undertook a 35-year study in the Huantai county to analyse the temporal dynamics of N efficiency, losses and driving factors during this process. From 1982 to 2002, N partial factor productivity (PFPN) and N uptake efficiency (NUpE) increased 2.0-fold and 1.8-fold, and then stabilised from 2003 to present (PFPN at 36.4 kg grain kg-1 Nfert, and NUpE at 0.57 kg Nplant kg-1 Nfert+min). Similarly, decreases were observed in reactive N losses intensity (32.0 to 10.7 kg N Mg-1 grain), land intensity (0.13 to 0.06 ha Mg-1 grain) and N uses intensity (49.2 to 24.6 kg N Mg-1 grain), and then were stable from 2002 to 2014. Nitrogen utilization efficiency (NUtE) was stable at about 42 kg grain kg-1 Nplant during the 35 years. Apparent N use efficiency (ANUE) increased from 42.1% in the 1980s to 60% in 2010s. The increase of N use efficiency and decrease of N losses depended much on optimized fertilization, mechanization farming and crop straw incorporation. This highlighted that with the introduction of improved farming practices, a sustainable agricultural intensification was achieved in developing countries like China.