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| Effects of different cover crops on nitrate dynamics in Shajiang black soil profile |
| Received:January 12, 2023 |
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| KeyWord:Shajiang black soil;cover crops;soil nitrate nitrogen;biomass;plant N accumulation |
| Author Name | Affiliation | E-mail | | XU Jingyi | College of Forestry/Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China | | | ZHANG Zhongbin | State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China | | | WANG Yuekai | State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
University of Chinese Academy of Sciences, Beijing 100049, China | | | ZHAO Xinya | State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
College of Tropical Crops, Hainan University, Haikou 570228, China | | | SUN Haijun | College of Forestry/Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China | hjsun@njfu.edu.cn | | GUO Zichun | State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China | | | PENG Xinhua | State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
University of Chinese Academy of Sciences, Beijing 100049, China | |
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| Abstract: |
| The objective of this study was to evaluate the effects of different cover crops on reducing nitrate(NO3--N)accumulation along the soil profile of Shajiang black soil throughout the growth period(2021.11 after sowing; 2022.03 during the nutritional growth period; and 2022.05 during the reproductive growth period). Four treatments, including winter fallow(Con), alfalfa(Alf), oilseed rape(Rap), and mixed radish and hairy vetch(Rhv), were conducted under both compacted(C)and non-compacted(NC)conditions at Longkang farm, Anhui Province. The dynamics of the soil NO3--N content and NO3--N storage were measured along the 0-120 cm soil profile by interval sampling. The aboveground and belowground crop biomasses and their nitrogen accumulation were also determined. Our results showed that the NO3--N content along the 0-120 cm soil profile continuously decreased by 43.3%, 53.9%, and 57.5% under the Alf, Rap, and Rhv treatments, respectively, throughout the growing season. During the nutritional and reproductive growth periods, the soil NO3--N storage was significantly reduced in all three cover crop treatments compared with that in the Con treatment under both compacted and non-compacted conditions(except the Rhv treatment in the non-compacted soil during the reproductive growth period, P<0.05), with a higher average reduction during the nutritional growth period(compacted:52.7% and non-compacted:60.7%)than that during the reproductive growth period(compacted:40.2% and non-compacted:35.6%). During the nutritional growth period, the soil NO3--N storage in the Alf treatment was 1.4 times higher than those in the Rap and Rhv treatments under the non-compacted condition(P<0.05). Meanwhile, during the reproductive growth period, soil NO3--N storage showed no significant difference among the three cover crop treatments under both compacted and non-compacted conditions. The aboveground biomass and N accumulation in the Alf treatment were significantly lower than those in the Rap treatment during the nutritional growth period(P<0.05), and the belowground biomass and N accumulation were significantly lower than those in the Rhv treatment(P<0.05). However, both the aboveground and belowground N accumulation in the Alf treatment were significantly higher than those in the Rap and Rhv treatments during the reproductive growth period(P<0.05). The significantly negative correlations between the soil NO3--N storage and N accumulation of cover crops indicated that nitrogen uptake by cover crops might be the main reason for the decrease in soil nitrate(P<0.05). In conclusion, the cover crops, including Alf, Rap, and Rhv, could effectively reduce NO3--N accumulation in the soil profile as compared with the Con treatment. Owing to the slow growth of Alf in the early stage, its ability to reduce soil NO3--N was lower than those of Rap and Rhv. Therefore, planting Rap and Rhv is more conducive to reducing the risk of soil nitrate nitrogen leaching in Shajiang black soil throughout the growth periods of cover crops. |
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