Evaluation of N environmental risks on Andosols from an intensive dairy farming watershed using DNDC

• Published in: The Science of the total environment Vol. 512-513; pp. 659 - 671
• Main Authors: Deng, Meihua, Bellingrath-Kimura, Sonoko D, Zeng, Lin, Hojito, Masayuki, Zhang, Tianzhu, Yoh, Muneoki
• Format: Journal Article
• Language: English
• Published: Netherlands 15.04.2015
• Subjects: Crops; Dairying; Environmental Monitoring; Hordeum vulgare; Japan; Leaching; Manure; Mathematical models; Models, Chemical; Nitrogen - analysis; Nitrous oxides; Rice; Sand; Soil (material); Soil - chemistry; Soil Pollutants - analysis; Texture; Zea mays; Japan, Honshu, Tochigi Prefect., Naka R; Japan; DNDC; Paddy rice; Intensive dairy farming; N environmental pollution; Upland; Andosol
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2015.01.047

Manure nitrogen (N) in the livestock sector has become a key driver of environmental change. The denitrification-decomposition (DNDC) model was used to evaluate N pollution strengths on Andosols with intensive dairy manure application in Upper Naka River Watershed, Japan. The calibrated model was capable of predicting Andosol N flows because the simulated soil mineral N content, soil nitrogen oxide (N2O) fluxes, denitrification rate, and crop N uptake matched the patterns and magnitudes of the field observations from a wide range of soil textures, as well as manure management and cropping systems. The simulations showed that current intensive manure application systems caused low crop N use efficiency and a large amount of NO3(-)-N leaching and N2O emission. The crop N use efficiency was 27%-42% and 37%-55% of input N for uplands and paddy rice, respectively. The uplands showed much more serious N environmental pollution risks with N leaching 123-362 kg N ha(-1) yr(-1) and N2O emissions 6.53-11.8 kg N ha(-1) yr(-1) than that in the lowland paddy rice with N leaching 17.4-103 kg N ha(-1) yr(-1) and N2O emissions 0.59-2.77 kg N ha(-1) yr(-1). Forage rice/barley crop systems have high N cleaning capability due to the greater crop N uptake which reached to 304 kg N ha(-1) yr(-1). High precipitation stimulated more NO3(-)-N leaching. Sandy soil also showed higher N leaching and was unsuitable for paddy rice. Slurry application stimulated more N2O emission than compost manure. To mitigate the current high N pollution, the critical N application rate was recommended to be approximately 380, 470, 640, and 390 kg N ha(-1) yr(-1) for loam sand planted with maize/grass, loam soil with maize/grass, forage rice/barley, and rice/fallow with winter manure application, respectively.