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Objective Nitrogen loss from soils is a pervasive environmental issue facing agricultural production in many countries. In this paper, we studied the combined effect of rainfall and fertilization on nitrogen loss via surface runoff from paddy fields in attempts to improve nitrogen management and reduce the nonpoint source pollution of rice production in Southern China. Method The experiment was conducted from 2019 to 2021 in a paddy field in Zhejiang province. It consisted of four nitrogen treatments: conventional nitrogen fertilization (N18), reduced nitrogen fertilization (N15), organic fertilization (OF). Without fertilization was the control. In the experiment, we measured surface runoff, total nitrogen concentration in the surface runoff. The rainfall data were obtained from a weather station on the experimental site. Result Annual rainfall and annual nitrogen loss were closely correlated, but linear regression analysis showed that daily rainfall and total nitrogen did not correlate significantly. Considering the delay between rainfall and nitrogen loss vial the surface runoff can make piecewise average daily rainfall positively correlated to nitrogen loss, with the regression coefficient ≥0.36. The effect of fertilization on nitrogen loss from the runoff was ranked in the order of N18>N15>OF>CK. Structural equation showed that, when considering the delay between rainfall and nitrogen loss, the piecewise average daily rainfall, the runoff volume, rainfall interval, the interval between rainfall and fertilization, fertilization amount, and fertilizer types were the factors affecting nitrogen loss, with their standardized total effect being 0.264, -0.126, 0.078, 0.033, and -0.038, respectively. The rainfall affected nitrogen loss more than the fertilization, and the piecewise average daily rainfall and rainfall interval were key factors affecting nitrogen loss. Conclusion For rice-wheat rotation cultivation in Zhejiang Province, a short rainfall interval affected nitrogen loss via surface runoff from paddy fields more than an increase in rainfall. Applying organic fertilizer in the wet season can reduce nitrogen loss from the runoff. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

(Objective) The China meteorological assimilation driving datasets is a database built up over the past decades specifically for application to the SWAT model (CMADS) in data-poor regions. This paper studies its application in upper reach of the Kaidu river in Northwestern China. (Method) We assessed two aspects. The first one is to assess the performance of the CMADS dataset in terms of estimating precipitation, maximum and minimum temperatures. The second is to compare the simulated results using the CMADS dataset and ground-true meteorological data.(Result) 1 The CMADS dataset is accurate for estimating temperature with its correlation with ground-true data being more than 0.9, but is less accurate for estimating daily precipitation, with its correlation with ground-truth data being 0.59. However, the correlation between calculated and measured monthly precipitations was high, reaching 0.84. 2 The simulated runoff using SWAT combined with CMADS dataset was in general more accurate than the results simulated using SWAT combined with the ground-truth data, indicating that, for regional hydrological modelling, CMADS dataset is more accurate than point-measured data. 3 Using the CMADS overestimated the baseflow and the lowest flow and underestimate the peak flow in model calibration stage, while underestimated the peak flow and overestimated baseflow slightly in model validation stage. In general, the runoff calculated using the CMADS was acceptable, except in a few extreme cases.(Conclusion) Testing the CMADS dataset against the upper reach of Kaidu river basin shows it is accurate and reliable. It can be used to simulate hydrological processes in regions short of measured meteorological data. [ABSTRACT FROM AUTHOR]

Copyright of China Rural Water & Hydropower is the property of China Rural Water & Hydropower Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)