This study was aimed to evaluate the potential effects of rest grazing on organic carbon storage in Stipa grandis steppe of Inner Mongolia, China. Using potassium dichromate heating method, we analyzed the organic car...This study was aimed to evaluate the potential effects of rest grazing on organic carbon storage in Stipa grandis steppe of Inner Mongolia, China. Using potassium dichromate heating method, we analyzed the organic carbon storage of plant and soil in Stipa grand＆ steppe after rest grazing for 3, 6, and 9 yr. The results indicated that as the rest grazing ages prolonged, the biomass of aboveground parts, litter and belowground plant parts （roots） of the plant communities all increased, meanwhile the C content of the biomass increased with the rest grazing ages prolonging. For RG0, RG3a, RG6a, and RG9a, C storage in aboveground vegetation were 60.7, 76.9, 82.8 and 122.2 g C m2, respectively; C storage of litter were 5.1, 5.8, 20.4 and 25.5 g C m^-2, respectively; C storage of belowground roots （0-100 cm） were 475.2, 663.0, 1 115.0 and 1 867.3 g C m^-2, respectively; C storage in 0-100 cm soil were 13.97, 15.76, 18.60 and 32.41 kg C m^-2, respectively. As the rest grazing ages prolonged, the organic C storage in plant communities and soil increased. The C storage ofbelowground roots and soil organic C was mainly concentrated in 0-40 cm soil body. The increased soil organic C for RG3a accounted for 89.8% of the increased carbon in vegetation-soil system, 87.2% for RG6a, and 92.6% for RG9a. From the perspective of C sequestration cost, total cost for RG3a, RG6,, and RG9a were 2 903.4, 5 806.8 and 8 710.2 CNY haq, respectively. The cost reduced with the extension of rest grazing ages, 0.15 CNY kg^-1 C for RG3a, 0.11 CNY kg-~ C for RG6a and 0.04 CNY kg℃ for RG9a. From the growth characteristics of grassland plants, the spring was one of the two avoided grazing periods, timely rest grazing could effectively restore and update grassland vegetation, and was beneficial to the sustainable use of grassland. Organic C storage for RG9a was the highest, while the cost of C sequestration was the lowest. Therefore, spring rest grazing should be encouraged because it was proved to be a very efficient grassland use pattern.展开更多
Phosphorus-modified biochar has been proven to enhance the precipitation and complexation of heavy metal ions from wastewater.However,the current modification methods require large amounts of exogenous P and have high...Phosphorus-modified biochar has been proven to enhance the precipitation and complexation of heavy metal ions from wastewater.However,the current modification methods require large amounts of exogenous P and have high energy consumption.Hence,this study proposes and analyzes a strategy integrating biochar production,phosphorus wastewater treatment,dephosphorization waste recovery,and heavy metal removal.“BC-Ca-P”was derived from Ca-modified biochar after phosphorus wastewater treatment.The adsorption of Pb(II)by BC-Ca-P followed the Langmuir isotherm and pseudo-second-order kinetic models.The maximum adsorption capability of 361.20 mg·g^(−1)at pH 5.0 for 2 h was markedly greater than that of external phosphorous-modified biochar.The adsorption mechanisms were dominated by chemical precipitation and complexation.Furthermore,density functional theory calculations indicated that oxygen-containing functional groups(P-O and C-O)contributed the most to the efficient adsorption of Pb(II)onto BC-Ca-P.To explore its practical feasibility,the adsorption performance of BC-Ca-P recovered from an actual environment was evaluated.The continuous-flow adsorption behavior was investigated and well-fitted utilizing the Thomas and Yoon-Nelson models.There was a negligible P leakage risk of BC-Ca-P during heavy metal treatment.This study describes a novel and sustainable method to utilize dephosphorization waste for heavy metal removal.展开更多
基金supported by the National Natural Science Foundation of China (31170435 and 31000242)the Key Technologies R&D Program of China during the 12th Five-Year Plan period (2012BAD13B07)
文摘This study was aimed to evaluate the potential effects of rest grazing on organic carbon storage in Stipa grandis steppe of Inner Mongolia, China. Using potassium dichromate heating method, we analyzed the organic carbon storage of plant and soil in Stipa grand＆ steppe after rest grazing for 3, 6, and 9 yr. The results indicated that as the rest grazing ages prolonged, the biomass of aboveground parts, litter and belowground plant parts （roots） of the plant communities all increased, meanwhile the C content of the biomass increased with the rest grazing ages prolonging. For RG0, RG3a, RG6a, and RG9a, C storage in aboveground vegetation were 60.7, 76.9, 82.8 and 122.2 g C m2, respectively; C storage of litter were 5.1, 5.8, 20.4 and 25.5 g C m^-2, respectively; C storage of belowground roots （0-100 cm） were 475.2, 663.0, 1 115.0 and 1 867.3 g C m^-2, respectively; C storage in 0-100 cm soil were 13.97, 15.76, 18.60 and 32.41 kg C m^-2, respectively. As the rest grazing ages prolonged, the organic C storage in plant communities and soil increased. The C storage ofbelowground roots and soil organic C was mainly concentrated in 0-40 cm soil body. The increased soil organic C for RG3a accounted for 89.8% of the increased carbon in vegetation-soil system, 87.2% for RG6a, and 92.6% for RG9a. From the perspective of C sequestration cost, total cost for RG3a, RG6,, and RG9a were 2 903.4, 5 806.8 and 8 710.2 CNY haq, respectively. The cost reduced with the extension of rest grazing ages, 0.15 CNY kg^-1 C for RG3a, 0.11 CNY kg-~ C for RG6a and 0.04 CNY kg℃ for RG9a. From the growth characteristics of grassland plants, the spring was one of the two avoided grazing periods, timely rest grazing could effectively restore and update grassland vegetation, and was beneficial to the sustainable use of grassland. Organic C storage for RG9a was the highest, while the cost of C sequestration was the lowest. Therefore, spring rest grazing should be encouraged because it was proved to be a very efficient grassland use pattern.
基金supported by the National Natural Science Foundation of China(42107081)the Fundamental Research Funds for the Central Public Research Institutes(2023-jbkyywf-dzl).
文摘Phosphorus-modified biochar has been proven to enhance the precipitation and complexation of heavy metal ions from wastewater.However,the current modification methods require large amounts of exogenous P and have high energy consumption.Hence,this study proposes and analyzes a strategy integrating biochar production,phosphorus wastewater treatment,dephosphorization waste recovery,and heavy metal removal.“BC-Ca-P”was derived from Ca-modified biochar after phosphorus wastewater treatment.The adsorption of Pb(II)by BC-Ca-P followed the Langmuir isotherm and pseudo-second-order kinetic models.The maximum adsorption capability of 361.20 mg·g^(−1)at pH 5.0 for 2 h was markedly greater than that of external phosphorous-modified biochar.The adsorption mechanisms were dominated by chemical precipitation and complexation.Furthermore,density functional theory calculations indicated that oxygen-containing functional groups(P-O and C-O)contributed the most to the efficient adsorption of Pb(II)onto BC-Ca-P.To explore its practical feasibility,the adsorption performance of BC-Ca-P recovered from an actual environment was evaluated.The continuous-flow adsorption behavior was investigated and well-fitted utilizing the Thomas and Yoon-Nelson models.There was a negligible P leakage risk of BC-Ca-P during heavy metal treatment.This study describes a novel and sustainable method to utilize dephosphorization waste for heavy metal removal.
