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514 results on '"Luo, Jiafa"'

41. Spatio-Temporal Analysis of Net Anthropogenic Phosphorus Inputs (NAPIs) and Their Impacts in Ningxia Hui Autonomous Region Using Monte Carlo Simulations and Sensitivity Analysis.

Author

Ma, Hua, Liu, Xiaotong, Lei, Qiuliang, Luo, Jiafa, Di, Hongjie, Du, Xinzhong, Zhao, Ying, Zhang, Xuejun, and Liu, Hongbin

Subjects
PHOSPHATE fertilizers, MONTE Carlo method, NONPOINT source pollution, STATISTICS, LAND use
Abstract

This study employed the Net Anthropogenic Phosphorus Inputs (NAPI) model to assess the impact of human activities on phosphorus input in a watershed, analyzing county-level statistical data and NAPI model parameters from 1991 to 2020. The Monte Carlo method was used for a quantitative analysis of the model parameters' effects on each NAPI component and the overall simulation results. The sensitivity index method identified each component's sensitive parameters. The study found that the lowest NAPI value was 454 kg/(km2·a) in 1991 and the highest was 1336 kg/(km2·a) in 2003. NAPI in Ningxia showed an overall upward trend from 1991 to 1999, a slight decrease from 1999 to 2003, and a slight increase from 2003 to 2020, with fertilizer being the main contributing factor, accounting for 77.4% of the total input. On a spatial scale, NAPI in Ningxia was significantly correlated with land use patterns, showing higher values in the northern and southern regions compared to the central part. The NAPI values derived from Monte Carlo simulations with appropriate parameters ranged from −24.83% to 31.49%. The study highlighted the net food and feed imports component as having the highest uncertainty, impacting simulation results within a range of −23.89% to 53.98%. It was observed that the larger a component's proportion in the NAPI model, the more sensitive its parameters, with the phosphorus fertilizer (Pfer) component's parameters being notably more sensitive than those of the food/feed phosphorus input and the non-food phosphorus input (Pnf) components. These findings can inform phosphorus pollution control policies in Northwest China, while the selection of sensitive parameters provides a useful reference for future NAPI research in other regions. [ABSTRACT FROM AUTHOR]

Published
2024
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42. Increases of N2O emissions due to enhanced nitrification in a sandy loam soil under long-term manure application.

Author

Liao, Xia, Müller, Christoph, Sun, Heyang, Yuan, Junji, Liu, Deyan, Chen, Zengming, He, Tiehu, Jansen-Willems, Anne, Luo, Jiafa, and Ding, Weixin

Subjects
POULTRY manure, SANDY loam soils, CATTLE manure, NITRIFICATION inhibitors, SOIL leaching
Abstract

15N tracing was carried out on sandy loam soil amended with (i) mineral nitrogen-phosphorus-potassium fertilizer (NPK) alone, (ii) half mineral N and half N from chicken manure (HFC), or (iii) half mineral N and half N from cattle manure (HCM), for 8 years. Cumulative N2O emissions during incubation were 30.2 µg N kg− 1 in the NPK treatment, which increased to 37.8 and 51.3 µg N kg− 1 in the HFC and HCM treatments, respectively. The majority of N2O emissions in all the treatments were attributed to nitrification (81.0% in the NPK treatment, 83.0% in the HFC treatment, and 85.1% in the HCM treatment). Compared with NPK, HCM treatment caused a significant increase in the gross rate of nitrification, while HFC treatment slightly enhanced the rate of dissimilatory NO3− reduction to NH4+. Additionally, HFC treatment achieved higher gross rates of organic N mineralization, and both HFC and HCM treatments had higher NH4+ mineralization-immobilization turnover (MIAT) rates than NPK treatment. The results suggest that application of cattle or chicken manure increased soil NH4+ availability. The gross rate of NO3− adsorption in the HCM treatment was greater than that in the NPK treatment, while the release of adsorbed NO3− in the HFC treatment was slower than that in the NPK treatment, indicating that application of cattle or chicken manure lowered the potential for NO3− leaching in soil. Overall, combining cattle or chicken manure with mineral fertilizer decreased NO3− availability but increased NH4+ availability, leading to higher N2O emissions through nitrification. Our results suggest that organic manures should be applied with nitrification inhibitors in sandy loam soil containing low organic carbon to increase soil fertility and mitigate N2O emissions. [ABSTRACT FROM AUTHOR]

Published
2024
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