Increased nitrogen use efficiencies as a key mitigation alternative to reduce nitrate leaching in north china plain

• Published in: Agricultural water management Vol. 89; no. 1; pp. 137 - 147
• Main Authors: Li, Xiaoxin, Hu, Chunsheng, Delgado, Jorge A., Zhang, Yuming, Ouyang, Zhiyun
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 16.04.2007; Elsevier Science; Elsevier
• Series: Agricultural Water Management
• Subjects: Agricultural and forest climatology and meteorology. Irrigation. Drainage; Agronomy. Soil science and plant productions; Best management practices; Biological and medical sciences; corn; crop rotation; evapotranspiration; fertilizer rates; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; grain yield; Irrigation. Drainage; leaching; Lysimeter; Nitrate leaching; nitrate nitrogen; Nitrogen fertilization; nitrogen fertilizers; Nitrogen use efficiencies; Nitrogen, phosphorus, potassium fertilizations; North China Plain; nutrient management; nutrient uptake; nutrient use efficiency; Physical properties; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Soil and water pollution; soil chemical properties; Soil science; soil water balance; Soil-plant relationships. Soil fertility. Fertilization. Amendments; Triticum aestivum; Water and solute dynamics; Water balance; winter wheat; Zea mays; China; Asia; China, People's Rep., North China Plain; China, People's Rep; Nitrogen use efficiencies; Nitrate leaching; Water balance; Lysimeter; Best management practices; North China Plain; Nitrogen fertilization; Irrigation; Soil transport processes; Cultivated soil; Nitrates; Inorganic element; Temperate zone; Environmental engineering; Semi arid zone; Irrigated farming; Water engineering; Soil science; Soil interaction; North; Pollution by agriculture; Cultural practice; Underground leaching; Intensive farming; Nutrient recovery; Nitrogen; Leaching; Soil management; Mitigation; Pollutant; Inorganic anion; Plain; Inorganic nitrogen; Decrease; Alternative method; Water pollution
• ISSN: 0378-3774; 1873-2283
• DOI: 10.1016/j.agwat.2006.12.012

The Northern China Plain (NCP) produces over 20% of the national grain production. Best management practices (BMP) for intensive irrigated cropping systems of the NCP are based on large nitrogen (N) applications without accounting for N budgets. There are concerns that non-scientific based BMPs may be impacting underground water resources. We conducted the first study in this region, located at the Luancheng Experimental Research Station that measured the effects of N fertilizer rates on nitrate-nitrogen (NO 3-N) leaching losses. From October 1, 2001 to September 30, 2004, we used a water balance approach with a neutron probe, weighing lysimeter, and suction cups located at 1.8 m depths on a winter wheat ( Triticum aestivum L.)–corn ( Zea mays L.) rotation to monitor NO 3-N leaching. Residual soil NO 3-N, yields, and N uptake by aboveground biomass were also measured. Corn received two surface broadcast applications every year of 50, 100, 150 and 200 kg urea-N ha −1 for the N 200, N 400, N 600, and N 800 treatments, respectively. The first broadcast application was at seeding and the second at tassel. Similarly, winter wheat received two surface broadcast applications, initially as a pre-plant and a second application at the jointing stage of growth in spring. We monitored NO 3-N leaching losses for the N 200, N 400, and N 800 treatments. Average NO 3-N leaching losses during wheat–corn season were 6, 58, and 149 kg NO 3-N ha −1 year −1 for the 200, 400, and 800 kg N ha −1 year −1 treatments, respectively. The NO 3-N leaching increased with N applications ( P < 0.05) and were in agreement with the NO 3-N concentrations of 12, 74, and 223 mg NO 3-N L −1 for soil water at 1.8 m depths for the 200, 400, and 800 kg N ha −1 year −1 treatments, respectively. Higher than needed N fertilizer applications increased the NO 3-N leaching losses and reduced the N use efficiency (NUE) without yield increases. We propose that there is a need for a new scientifically based BMP approach for the NCP based on N budgets that credits soil NO 3-N before planting, N mineralization from soil organic matter, and other potential N sources as a key mitigation alternative to increase NUE and reduce NO 3-N leaching in this region.