The Experts below are selected from a list of 13788 Experts worldwide ranked by ideXlab platform
Tingping Ouyang - One of the best experts on this subject based on the ideXlab platform.
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magnetism of a Red Soil core derived from basalt northern hainan island china volcanic ash versus pedogenesis Red Soil volcanic ash versus pedogenesis
Journal of Geophysical Research, 2017Co-Authors: Zhaoxia Jiang, Xing Ding, Shasha Peng, Ti Zeng, Tingping OuyangAbstract:Similar to loess‐paleosol sequences in northwestern China, terrestrial sedimentary sequences (Red Soils) in southern China also provide sensitive Quaternary records of subtropical/tropical paleoclimate and paleoenvironment. CompaRed with Red clay sequences originated from eolian dust, Red Soils derived from bedrock have received little attention. In this study, a long core of Red Soil derived from weatheRed basalt in northern Hainan Island, China, was systematically investigated by using detailed magnetic measurements and rare earth element analyses. The results show that an extremely strong magnetic zone with a maximum magnetic susceptibility (>10 × 10−5 m3 kg−1) is interbedded in the middle of the core profile. This layer contains a significant amount of superparamagnetic magnetite/maghemite particles that primarily originated from volcanic ash, with secondary contributions from pedogenesis. The former has an average grain size of ~19 nm with a normal distribution of volume, and the latter has a much wider grain size distribution. The presence of volcanic ash within the Red Soil indicates that these Quaternary basalts were not formed by continuous volcanic eruptions. Moreover, the magnetic enhancement patterns differ between the upper and lower zones. The upper zone is more magnetically enhanced and experienced higher precipitation and temperature than the lower zone. Discrimination of superparamagnetic particles originating from pedogenic processes and volcanic ash thus provides a sound theoretical base for accurate interpretation of magnetism in Red Soils in this region.
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Environmental problems of Red Soil along the coast of South China
Soil Use and Management, 2002Co-Authors: Houyun Zhou, Yifang Xu, Tingping Ouyang, Qinglu DengAbstract:. This study employed both natural and social sciences to examine the relationship between resources and economic development in the Red Soil Zone along the coast of South China. Based on the data collected by field investigation and laboratory analysis as well as from literature sources, the authors discuss the environmental problems and the main factors influencing them by using the case of Guangdong province. The results indicate that there are three important problems of Red Soil utilization: Soil degradation and pollution, Soil erosion and geological hazards. The main reasons for these problems involve the physical and chemical characteristics and mineral composition of the Soil, climate and meteorological changes and human activities. The latter is currently the dominant factor influencing the change and deterioration of the Red Soils.
Lu Zhang - One of the best experts on this subject based on the ideXlab platform.
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intensified Soil acidification from chemical n fertilization and prevention by manure in an 18 year field experiment in the Red Soil of southern china
Journal of Soils and Sediments, 2015Co-Authors: Bo-ren Wang, Minggang Xu, Huimin Zhang, Xinhua He, Lu ZhangAbstract:Purpose Soil acidification from chemical N fertilization has worsened and is a major yield-limiting factor in the Red Soil (Ferralic Cambisol) of southern China. Assessment of the acidification process under field conditions over a long term is essential to develop strategies for maintaining Soil productivity. The objective of this study was to quantify Soil acidification rates from chemical fertilizers and determine the amount of manure needed to inhibit the acidification process.
Zhaoxia Jiang - One of the best experts on this subject based on the ideXlab platform.
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magnetism of a Red Soil core derived from basalt northern hainan island china volcanic ash versus pedogenesis Red Soil volcanic ash versus pedogenesis
Journal of Geophysical Research, 2017Co-Authors: Zhaoxia Jiang, Xing Ding, Shasha Peng, Ti Zeng, Tingping OuyangAbstract:Similar to loess‐paleosol sequences in northwestern China, terrestrial sedimentary sequences (Red Soils) in southern China also provide sensitive Quaternary records of subtropical/tropical paleoclimate and paleoenvironment. CompaRed with Red clay sequences originated from eolian dust, Red Soils derived from bedrock have received little attention. In this study, a long core of Red Soil derived from weatheRed basalt in northern Hainan Island, China, was systematically investigated by using detailed magnetic measurements and rare earth element analyses. The results show that an extremely strong magnetic zone with a maximum magnetic susceptibility (>10 × 10−5 m3 kg−1) is interbedded in the middle of the core profile. This layer contains a significant amount of superparamagnetic magnetite/maghemite particles that primarily originated from volcanic ash, with secondary contributions from pedogenesis. The former has an average grain size of ~19 nm with a normal distribution of volume, and the latter has a much wider grain size distribution. The presence of volcanic ash within the Red Soil indicates that these Quaternary basalts were not formed by continuous volcanic eruptions. Moreover, the magnetic enhancement patterns differ between the upper and lower zones. The upper zone is more magnetically enhanced and experienced higher precipitation and temperature than the lower zone. Discrimination of superparamagnetic particles originating from pedogenic processes and volcanic ash thus provides a sound theoretical base for accurate interpretation of magnetism in Red Soils in this region.
Likai He - One of the best experts on this subject based on the ideXlab platform.
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comparison of u vi adsorption onto nanoscale zero valent iron and Red Soil in the presence of u vi co3 ca u vi co3 complexes
Journal of Hazardous Materials, 2015Co-Authors: Zhibin Zhang, Xiaofeng Yu, Likai HeAbstract:The influence of U(VI)–CO3 and Ca–U(VI)–CO3 complexes on U(VI) adsorption onto Red Soil and nanoscale zero-valent iron (NZVI) was investigated using batch adsorption and fixed-bed column experiments to simulate the feasibility of NZVI as the reactive medium in permeable- reactive barriers (PRB) for in situ remediation of uranium-contaminated Red Soils. The adsorption capacity (qe) and distribution constant (Kd) of NZVI and Red Soil decreased with increasing pH, dissolved carbonate and calcium concentrations, but the qe and Kd values of NZVI were 5–10 times higher than those of Red Soil. The breakthrough pore volume (PV) values increased with the decrease of pH, dissolved carbonate and calcium concentration; however, the breakthrough PV values of the PRB column filled with 5% NZVI were 2.0–3.5 times higher than the 100% Red Soil column. The U(VI)–CO3 complexes adsorbed onto the surface of Red Soil/NZVI (SOH) to form SO–UO2CO3− or SO–UO2 (CO3)23−. XPS and XRD analysis further confirmed the Reduction of U(VI) to U(IV) and the formation of FeOOH on NZVI surfaces. The findings of this study are significant to the remediation of uranium-contaminated Red Soils and the consideration of practical U(VI) species in the natural environment.
Bo-ren Wang - One of the best experts on this subject based on the ideXlab platform.
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nitrogen mobility ammonia volatilization and estimated leaching loss from long term manure incorporation in Red Soil
Journal of Integrative Agriculture, 2017Co-Authors: Li Mei Zhai, Bo-ren Wang, Jing Huang, Yinghua Duan, X U Minggang, Xubo Zhang, Yangzhu ZhangAbstract:Abstract Nitrogen (N) loss from fertilization in agricultural fields has an unavoidable negative impact on the environment and a better understanding of the major pathways can assist in developing the best management practices. The aim of this study was to evaluate the fate of N fertilizers applied to acidic Red Soil (Ferralic Cambisol) after 19 years of mineral (synthetic) and manure fertilizer treatments under a cropping system with wheat-maize rotations. Five field treatments were examined: control (CK), chemical nitrogen and potash fertilizer (NK), chemical nitrogen and phosphorus fertilizer (NP), chemical nitrogen, phosphorus and potash fertilizer (NPK) and the NPK with manure (NPKM, 70% N from manure). Based on the Soil total N storage change in 0–100 cm depth, ammonia (NH 3 ) volatilization, nitrous oxide (N 2 O) emission, N plant uptake, and the potential N leaching loss were estimated using a mass balance approach. In contrast to the NPKM, all mineral fertilizer treatments (NK, NP and NPK) showed increased nitrate (NO 3 − ) concentration with increasing Soil depth, indicating higher leaching potential. However, total NH 3 volatilization loss was much higher in the NPKM (19.7%) than other mineral fertilizer treatments (≤4.2%). The N 2 O emissions were generally low (0.2–0.9%, the highest from the NPKM). Total gaseous loss accounted for 1.7, 3.3, 5.1, and 21.9% for NK, NP, NPK, and NPKM treatments, respectively. Estimated N leaching loss from the NPKM was only about 5% of the losses from mineral fertilizer treatments. All data demonstrated that manure incorporation improved Soil productivity, increased yield, and Reduced potential leaching, but with significantly higher NH 3 volatilization, which could be Reduced by improving the application method. This study confirms that manure incorporation is an essential strategy in N fertilization management in upland Red Soil cropping system.
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intensified Soil acidification from chemical n fertilization and prevention by manure in an 18 year field experiment in the Red Soil of southern china
Journal of Soils and Sediments, 2015Co-Authors: Bo-ren Wang, Minggang Xu, Huimin Zhang, Xinhua He, Lu ZhangAbstract:Purpose Soil acidification from chemical N fertilization has worsened and is a major yield-limiting factor in the Red Soil (Ferralic Cambisol) of southern China. Assessment of the acidification process under field conditions over a long term is essential to develop strategies for maintaining Soil productivity. The objective of this study was to quantify Soil acidification rates from chemical fertilizers and determine the amount of manure needed to inhibit the acidification process.
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Long-Term Application of Organic Manure and Mineral Fertilizer on N2O and CO2 Emissions in a Red Soil from Cultivated Maize-Wheat Rotation in China
Agricultural Sciences in China, 2011Co-Authors: Li Mei Zhai, Ji Zong Zhang, Hong Bin Liu, Jing Huang, Bo-ren WangAbstract:A long-term field experiment was established to determine the influence of mineral fertilizer and organic manure on Soil fertility. A tract of Red Soil (Ferralic Cambisol) in Qiyang Red Soil Experimental Station (Qiyang County, Hunan Province, China) was fertilized beginning in 1990 and N2O and CO2 were examined during the maize and wheat growth season of 2007-2008. The study involved five treatments: organic manure (NPKM), fertilizer NPK (NPK), fertilizer NP (NP), fertilizer NK (NK), and control (CK). ManuRed Soils had higher crop biomass, organic C, and pH than Soils receiving the various mineralized fertilizers indicating that long-term application of manures could efficiently prevent Red Soil acidification and increase crop productivity. The application of manures and fertilizers at a rate of 300 kg N ha-1 yr-1 obviously increased N2O and CO2 emissions from 0.58 kg N2O-N ha-1 yr-1 and 10 565 kg C ha-1 yr-1 in the CK treatment Soil to 3.01 kg N2O-N ha-1 yr-1 and 28 663 kg C ha-1 yr-1 in the NPKM treatment. There were also obvious different effects on N2O and CO2 emissions between applying fertilizer and manure. More N2O and CO2 released during the 184-d maize growing season than the 125-d wheat growth season in the manure fertilized Soils but not in mineral fertilizer treatments. N2O emission was significantly affected by Soil moisture only during the wheat growing season, and CO2 emission was affected by Soil temperature only in CK and NP treatment during the wheat and maize growing season. In sum, this study indicates the application of organic manure may be a preferRed strategy for maintaining Red Soil productivity, but may result in greater N2O and CO2 emissions than treatments only with mineral fertilizer. © 2011 Chinese Academy of Agricultural Sciences.
