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| Effect of fulvic acid-modified bentonite on nitrogen leaching and nitrogen use efficiency |
| Received:July 20, 2020 |
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| KeyWord:fulvic acid modified bentonite;isothermal adsorption;NH4+-N leaching;NO3--N leaching;nitrogen use efficiency |
| Author Name | Affiliation | E-mail | | KONG Bai-shu | College of Resources and Environment, Shandong Agricultural University, Tai'an 271018, China | | | JIAO Shu-ying | College of Resources and Environment, Shandong Agricultural University, Tai'an 271018, China | jiaoshuying@sdau.edu.cn | | LI Yong-qiang | College of Resources and Environment, Shandong Agricultural University, Tai'an 271018, China | | | SHEN Yu-wen | Institute of Agricultural Resources and Environment, Shandong Academy of Agricultural Sciences, Ji'nan 250100, China | | | LI Ye | College of Resources and Environment, Shandong Agricultural University, Tai'an 271018, China | | | ZHANG Zi-xu | College of Resources and Environment, Shandong Agricultural University, Tai'an 271018, China | | | FU Chun-yu | College of Resources and Environment, Shandong Agricultural University, Tai'an 271018, China | |
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| Abstract: |
| This study aims to investigate the effects of fulvic acid-modified bentonite on nitrogen leaching in brown soil and urea-nitrogen utilization under three nitrogen levels. The adsorption properties of fulvic acid-modified bentonite for NH4+-N and NO3--N were studied by conducting isothermal adsorption test. Soil column leaching test and maize pot experiment were conducted to determine the effects of applying fulvic acid-modified bentonite on nitrogen leaching and nitrogen utilization under different nitrogen application gradients. Herein, three nitrogen reduction gradients were set up, i.e., farmers' conventional fertilization(CN), nitrogen reduction by 15%(CN1), nitrogen reduction by 30%(CN2), and 0.2% fulvic acid-modified bentonite was added to the three nitrogen reduction gradients(XCN, XCN1, XCN2), respectively. The results showed that the adsorption process of NH4+-N and NO3--N by fulvic acid-modified bentonite can be well fitted by Langmuir model, with maximum adsorption capacity of 27.28 and 43.37 mg·g-1, respectively. Compared with CN treatment, NH4+-N leaching loss of XCN treatment decreased by 13.5%, whereas NO3--N leaching amount of XCN, XCN1, and XCN2 treatments decreased by 38.13%, 18.56%, and 35.75%, respectively. The fulvic acid-modified bentonite could significantly increase nitrogen retention in soil and nitrogen use efficiency of the maize grain. Compared with the treatment of CN, CN1, and CN2, the nitrogen use efficiency of XCN, XCN1, and XCN2 increased by 7.94%, 10.07%, and 79.17%, respectively. Fulvic acid-modified bentonite can effectively reduce soil nitrogen leaching and improve crop nitrogen use efficiency under nitrogen reduction, which has a potential agronomic value. |
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