Papers by Author: Xin Chen

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Authors: Ming Fen Niu, Jian Wei, Jian Ma, Xin Chen
Abstract: This paper studied the removal effect of domestic sewage nitrogen and phosphorus during the start-up period of underground infiltration system. The experiment is conducted under the conditions of influent temperature 9~10°C, hydraulic loading 0.04m3·m-2·d-1, COD concentration 112.31~143.49mg / L, NH4+-N 20.93~27.26mg / L and TP 2.12~2.86mg / L. The experimental results showed the removal rate of COD, NH4+-N and TP was 80%, 98% and 95% respectively. In the start-up period, TN removal was not obviously for 34% removal rate. After treated the effluent nitrate nitrogen concentration was high, showing during the start-up period the nitrification was better than the denitrification. Lacking of carbon source and low temperature may account for this. To improve the conditions of the start-up period, promoting denitrification was the key to improve nitrogen removal rate by underground infiltration system.
Authors: Shuai Liu, Ming Da Liu, Xu Wang, Yi Shi, Xin Chen
Abstract: Cd accumulation characteristic of 8 Chinese cabbage cultivars was evaluated to screen Chinese cabbage cultivars with low-level Cd accumulation. The results showed that significant differences (P<0.05) in Cd content, bioaccumulation factors (BFs) and translocation factors (TFs) were found among the 8 cultivars Chinese Cabbages. The levels of Cd accumulation by Beijingxin3 and Dongbao were less than 0.5 mg · kg-1, and their BFs and TFs were lower than 1. This indicated that these two cultivars had the low-level Cd accumulation potential and could be recommended for cultivation in areas mildly polluted with Cd. Although the level of Cd accumulation by Qiumei also was less than 0.5 mg · kg-1, the TF was higher than 1. So, the Qiumei cultivar could be planted in the renovation process of contaminated soils.
Authors: Cai Yan Lu, Ya Jie Zhao, Zhi Quan, Jian Ma, Xin Chen, Yi Shi
Abstract: The amount of soil total soluble N (TSN), NH4+-N, NO3--N and soluble organic N (SON) declined significantly with increasing of sampling depth (P < 0.0001). Compared with CK, application of chicken manure significantly increased the amount of soil TSN and NO3--N by 77.0% and 213.0% in the CM20 treatment, and 176.4% and 766.4% in the CM 30 treatment, respectively (P < 0.0001). The amount of soil NH4+-N was lower in CM20 treatment than CK and CM30 treatments. However, the amount of soil SON was higher in CM20 treatment than CK and CM30 treatments (P < 0.0001). Proportion of NH4+-N to TSN was lowest. Application of chicken manure remarkably increased the proportion of NO3--N to TSN, and decreased that of NH4+-N and SON to TSN (P < 0.0001). Soil SON accounted for the majority of soluble N irrespective of soil layer in CK and CM20 treatments, and followed by NO3--N. However, the trend was reversed in CM30 treatments. This result indicated that application of chicken manure significantly increased the amount of soil soluble N, especially SON and NO3--N, which may extend N leaching risk into deeper soil layer.
Authors: Zhi Yuan Liu, Xin Chen, Yi Shi, Zhen Cheng Su
Abstract: Eleven chlorpyrifos-degrading bacterium were isolated from a Chinese soil and compared by microbiological and molecular methods. The strains were significantly different in the ability of degradation efficiency, and one strain (Bacillus cereus) was selected for further analysis. The ability of Bacillus cereus to degrade chlorpyrifos was investigated under different culture conditions, such as pH, temperature, chlorpyrifos concentration and so on. Experimental results obtained in different conditions show that the optimum temperature, pH, concentration of chlorpyrifos were 30°C, 7.0, less than 100 mg L-1, respectively.
Authors: Hong Xiang Wang, Yi Shi, Jian Ma, Cai Yan Lu, Xin Chen
Abstract: A field experiment was conducted to study the characteristics of non-point source nitrogen (N) in the surface runoff from sloping croplands and the influences of rainfall and cropland slope gradient. The results showed that dissolved total N (DTN) was the major form of N in the runoff, and the proportion occupied by dissolved inorganic nitrogen (DIN) ranged from 45% to 85%. The level of NH4+-N was generally higher than the level of NO3--N, and averaged at 2.50 mg·L-1 and 1.07 mg·L-1 respectively. DIN was positively correlated with DTN (R2=0.962). Dissolved organic N (DON) presented a moderate seasonal change and averaged at 1.40 mg·L-1. Rainfall amount and rainfall intensity significantly affected the components of DTN in the runoff. With the increase of rainfall amount and rainfall intensity, the concentrations of DTN, NH4+-N and NO3--N presented a decreased trend, while the concentration of DON showed an increased trend. N loss went up with an increase in the gradient of sloping cropland, and was less when the duration was longer from the time of N fertilization.fertilization.
Authors: Jian Ma, Xin Chen, Yi Shi
Abstract: Agricultural non-point source (NPS) pollution is a growing environmental problem, contributing much to water eutrophication in China as well as in other parts of the world. NPS pollutants are heterogeneously distributed and discharged from agricultural lands and other sources, and extremely hard to control by technical measures. Hence, control of the water quality problems caused by agricultural NPS pollution becomes difficult if recommended best management practices (BMPs) can’t be well implemented. In this paper, current research progress related to distinguishing agricultural NPS pollution sources was reviewed. Three pivotal methods for identifying agricultural NPS pollution sources were introduced and the advantages and disadvantages of each approach were discussed. Finally suggestions were presented on better identifying agricultural NPS pollution sources in China.
Authors: Yi Shi, Jun Wang, Guang Yu Chi, Xin Chen
Abstract: The study was carried out at the base for the production of greenhouse vegetables located in Damintun Town of Xinmin City. A series of experiments (e.g. a field investigation and plot experiment) was conduced to clarify the origin and accumulation of the heavy metal cadmium (Cd) in greenhouse soils under different years of culitivation. The field investigation study revealed that the contents of heavy metal Cd of the sample soils exceeded Class I criteria (Cd≤0.2mg•kg-1) but no soil samples exceeded Class III. The results from the field plot experiment showed that contents of Cd in all greenhouse soils (after 1, 2 or 5 years of cultivation) were increased with the amount of manure applied. This suggested the potential risk of Cd pollution would be increased with the age of cultivation in the greenhouse soils and the accumulation of Cd in the greenhouse soils was mainly associated with the input of manures.
Authors: Ya Jie Zhao, Xin Chen, Yi Shi, Cai Yan Lu, Bin Huang, Mu Qiu Zhao
Abstract: The vegetable utilization rate of phosphorus fertilizer in greenhouse condition was low in the season of fertilizer application, resulting in phosphorus accumulation in the top soil year after year. The risk of phosphorus loss through leaching increased under the circumstance of inappropriate watering management and fertilization. In this study, leaching experiments using columns packed with a greenhouse soil with different soil phosphorus status (low, medium and high levels) were carried out under greenhouse condition to investigate the impact of fertilizer application on phosphorus leaching from greenhouse soil. The fertilization treatments included no fertilizer [CK], organic manure and chemical fertilizer [M+NPK], organic manure [M], chemical fertilizer [NPK]. The vertical migration and leaching loss of soil phosphorus were measured. Results were as follows: (1) total phosphorus (TP) content increased with the extension of leaching time. In the low-level- and medium-level-phosphorus greenhouse soils, TP concentration in the effluent increased with the application of manure; (2) In the high-level-phosphorus greenhouse soil, phosphorus in the effluent from the treatment with the use of fertilizer was the highest TP, with accumulative leaching amount of 2.85 mg in 51 days. The leaching of phosphorus became small after 36 days of leaching experiment. Our study showed that application of manure and chemical fertilizer at proper rates according to soil phosphorus status is beneficial to reduce the leaching loss of phosphorus to the environment.
Authors: Ya Jie Zhao, Xin Chen, Yi Shi, Cai Yan Lu
Abstract: In this study, columns packed of a greenhouse soil with various soil fertile levels (low, medium and high) were carried out under greenhouse condition. The leaching experiment lasted 51 days. There were four fertilization treatments including no fertilizer [CK], chemical fertilizer [NPK], organic manure [M], organic manure and chemical fertilizer [M+NPK]. Microbial biomass C and N were measured. The results were as follows: organic or inorganic fertilizer increased the contents of soil microbial biomass C and N, and combination of chemical fertilizer and organic fertilizer significantly elevated the amount of soil microbial biomass C and N compared to organic or inorganic fertilizer treatment. There were significant differences in the amount of microbial biomass C and N among different fertile level soil under different fertilization practices in 0-20 and 20-40cm soil layers. Our study showed that application of manure and chemical fertilizer at proper rates according to soil fertile status is beneficial to increase the amount of microbial biomass C and N.
Authors: Lu Fei, Xin Chen, Mu Qiu Zhao, Ya Jie Zhao, Yi Shi, Bin Huang
Abstract: Inappropriate applications of phosphorus (P) in agricultural production lead to the leaching loss of P, which subsequently contributes to the eutrophication of water bodies. A leaching experiment using unsaturated intact soil columns was conducted to study the influence of fertilizer application on leaching of phosphorus in a gley meadow soil at different fertility levels (low-, medium and high fertility levels). The soil column at each fertility level received three fertilization treatments (control [CK], manure [M] and chemical fertilizer [F]). The results indicated that the leaching loss of total P (TP) from the soil column was induced by the P input from either manure or chemical fertilizer application, and the extent of leaching loss of P was also positively related to the soil fertility level. In addition, the TP concentrations in the leachates from all fertilization treatments exceeded the critical value for water eutrophication (0.02 mg P/L). This suggests that applications of manure and chemical fertilizer at proper rates with close consideration of the soil fertility level are essential to reduce the leaching loss of TP to the environment.
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