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| Effects of biogas slurry application on nitrogen leaching in rape fields with typical yellow soil in Guizhou, China |
| Received:October 18, 2021 Revised:December 27, 2021 |
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| KeyWord:biogas slurry application;yellow soil;rape;nitrogen leaching;application rate threshold |
| Author Name | Affiliation | E-mail | | SUN Fangfang | College of Agriculture, Guizhou University, Guiyang 550025, China | | | JIANG Tao | College of Agriculture, Guizhou University, Guiyang 550025, China | | | CHENG Jianbo | Institute of New Rural Development, Guizhou University, Guiyang 550025, China
Guizhou Engineering Research Center for Technologies in Control and Recycling of Livestock and Poultry Breeding Waste in Mountain Area, Guiyang 550025, China | jbcheng@gzu.edu.cn | | HE Tengbing | College of Agriculture, Guizhou University, Guiyang 550025, China
Institute of New Rural Development, Guizhou University, Guiyang 550025, China
Guizhou Engineering Research Center for Technologies in Control and Recycling of Livestock and Poultry Breeding Waste in Mountain Area, Guiyang 550025, China | | | QIN Song | Soil and Fertilizer Institute, Guizhou Academy of Agricultural Sciences, Guiyang 550006, China | | | WANG Guoying | Guizhou Agricultural Ecology and Resources Protection Agency, Guiyang 550001, China | | | HONG Jianming | Yuping Agricultural and Rural Bureau, Tongren 554330, China | |
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| Abstract: |
| Biogas slurry is commonly applied through irrigation in the karst mountainous areas of southwest China. However, the resulting leaching of soil nitrogen(N)has yet to be explored, and the environmental threshold of the slurry application rate has yet to be determined. To assess the resulting N leaching and plant growth and the threshold rate of slurry application, a pot experiment was performed in a greenhouse, simulating biogas slurry irrigation using materials including yellow soil, rape, and biogas slurry from a cattle farm. Six treatments were employed, including triplicated pots containing rape plants without N fertilization(CK), containing no plants with slurry application at a rate of 480 kg·hm-2(NP480), pots growing rape plants receiving urea at a rate of 480 kg·hm-2(CF), fertilized with biogas slurry at rates of 120 kg · hm-2(R120), 240 kg · hm-2(R240), and 480 kg · hm-2(R480). In each treatment, 25 mm of tap water, urea solution, or dilute slurry was applied periodically once every 12 d, for a total of 12 applications. According to our experimental results, biogas slurry irrigation enhanced soil N leaching, predominantly consisting of nitrate(NO-3-N)leaching. The NO-3-N leaching was accelerated by increasing nitrogen application rates, accounting for a total amount of N in the R480 treatment that was 2, 1.8, and 1.4 times that in the CK, R120, and R240 treatments, respectively. In addition, the slurry resulted in lower N leaching than that with urea, as demonstrated by the TN, NH + 4-N, and NO-3-N leaching in the CF treatment at 3.8, 2.3, and 2.9 times that in of the R480 treatment, respectively. Although biogas slurry application at a rate of 480 kg·hm-2(R480)triggered N leaching, 34%, 30%, and 32% of the resulting TN, NH + 4 -N, and NO-3 -N leaching was likely reduced by plant uptake, respectively. In addition, biogas slurry applied at a moderate rate (R120)promoted rape growth compared with that under chemical fertilizer application; however, too much slurry application(R480)could undermine rape growth. Applying biogas slurry through irrigation to rape plants in the karst mountainous areas of southwest China may enhance N leaching from yellow soil. Furthermore, a slurry application rate lower than 240 kg·hm-2 might improve the balance between N leaching control, plant growth enhancement, and slurry recycling. |
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