Key Laboratory of Agricultural Resources and Environment of Chongqing

Chongqing, China

Key Laboratory of Agricultural Resources and Environment of Chongqing

Chongqing, China
SEARCH FILTERS
Time filter
Source Type

Zhang M.-H.,Southwest University | Zhang M.-H.,Key Laboratory of Agricultural Resources and Environment of Chongqing | Lu J.-W.,Chongqing Dianjiang Environmental Protection Monitoring Station | Zhao X.-L.,Southwest University | Zhao X.-L.,Key Laboratory of Agricultural Resources and Environment of Chongqing
Huanjing Kexue/Environmental Science | Year: 2016

An aerobic incubation experiment was conducted at a constant temperature to investigate the differences in nitrogen mineralization between an acid purple soil and a calcareous purple soil amended with five organic materials including biogas residues of pig manure(PM), cow manure(CW), sewage sludge compost(SC), rural waste compost(RWC1)and the compost of rural waste plus 20% of sewage sludge(RWC2). The results showed that the organic nitrogen forms in these materials followed the order of amino acid N>hydrolysable unidentified N>ammonium N>non-hydrolysable N>amino sugar N. Application of organic materials could significantly improve the contents of NH4 +-N and NO3 --N in acid purple soil, PM and SC could significantly improve the content of NH4 +-N, but CM reduced the content of NO3 --N in calcareous purple soil. Except for CM, which had no significant effect on the quantity of nitrogen mineralization in acid purple soil, but decreased the quantity of nitrogen mineralization in calcareous purple soil, applying the organic materials could significantly increase the quantity of nitrogen mineralization in both soils. Correlation analysis showed that the quantity of nitrogen mineralization was significantly and positively correlated with the contents of amino acid N and ammonium N, but were significantly and negatively correlated with the content of organic matter and the C/N of organic materials. Overall, the results illustrated that the effect of organic materials on the mineralization of nitrogen varied with soil types and the characteristics of organic materials, especially the content of organic matter, C/N and the fractions of organic nitrogen in organic materials. © 2016, Science Press. All right reserved.


Shi Q.-B.,Southwest University | Zhao X.-L.,Southwest University | Zhao X.-L.,Key Laboratory of Agricultural Resources and Environment of Chongqing | Chang T.-J.,Southwest University | Lu J.-W.,Chongqing Dianjiang Environmental Protection Monitoring Station
Huanjing Kexue/Environmental Science | Year: 2016

A long-term experiment was utilized to study the effects of tillage methods on the contents and distribution characteristics of organic matter and heavy metals (Cu, Zn, Pb, Cd, Fe and Mn)in aggregates with different sizes (including 1-2, 0.25-1, 0.05-0.25 mm and <0.05 mm)in a purple paddy soil under two tillage methods including flooded paddy field (FPF) and paddy-upland rotation (PR). The relationship between heavy metals and organic matter in soil aggregates was also analyzed. The results showed that the aggregates of two tillage methods were dominated by 0.05-0.25 mm and<0.05 mm particle size, respectively. The contents of organic matter in each aggregate decreased with the decrease of aggregate sizes, however, compared to PR, FPF could significantly increase the contents of organic matter in soils and aggregates. The tillage methods did not significantly affect the contents of heavy metals in soils, but FPF could enhance the accumulation and distribution of aggregate, organic matter and heavy metals in aggregates with diameters of 1-2 mm and 0.25-1 mm. Correlation analysis found that there was a negative correlation between the contents of heavy metals and organic matter in soil aggregates, but a positive correlation between the amounts of heavy metal and organic matter accumulated in soil aggregates. From the slope of the correlation analysis equations, we could found that the sensitivities of heavy metals to the changes of soil organic matters followed the order of Mn>Zn>Pb>Cu>Fe>Cd under the same tillage. When it came to the same heavy metal, it was more sensitive in PR than in FPF. © 2016, Science Press. All right reserved.


Wang F.,Southwest University | Wang Q.,Southwest University | Wang Q.,Key Laboratory of Agricultural Resources and Environment of Chongqing | Mu Z.-J.,Southwest University | And 3 more authors.
Huanjing Kexue/Environmental Science | Year: 2015

Phthalic acid esters (PAEs) have received increasing attention in recent years due to their widespread use and hazards to human health and fertility in the environment. In order to understand the migration and release processes of organic pollutants in huge fluctuating zone soil, Dibutyl-phthalate (DBP) was chosen as a typical substance, and its migration and release characteristics in the fluctuating zone of the Three Gorges Reservoir to overlying water and the impacts of DBP concentration in the soil, ionic strength and the concentration of organic mater in overlying water on the process were studied using static flooding method. The results showed that DBP migrated from the soil to the overlying water in the early days after flooding, and the release process of DBP was divided into two phases: one was quick release with a relatively short releasing time and a rapid releasing rate; the other was slow release with a relatively long releasing time and a slow releasing rate. The migration and release processes were well fitted by two-compartment first-order kinetics. After different concentrations DBP were added into soil, the rate of quick release increased with the increasing DBP concentrations in soil while the percent of quick release decreased with the increasing DBP concentrations. The results of rate of slow release and the percent of slow release were on the contrary. The water conditions of overlying water could impact the migration and releasing process of DBP when the soil in fluctuating zone was flooded. The amount of DBP released into the overlying water would increase when the ionic strength in the water increased. At the same time, when the ionic strength increased, in spite of the decreasing quick release rate, the percent of quick release increased. The higher concentration of organic matter in overlying water, the more the amount of DBP released into the overlying water. At the same time, all of the rates of quick release, slow release and the percent of quick release would increase with the increasing concentrations of organic matter, while there was almost no influence on the percent of slow release of DBP. ©, 2015, Science Press. All right reserved.


Chang T.-J.,Southwest University | Chang T.-J.,Key Laboratory of Agricultural Resources and Environment of Chongqing | Cui X.-Q.,Southwest University | Cui X.-Q.,Key Laboratory of Agricultural Resources and Environment of Chongqing | And 4 more authors.
Huanjing Kexue/Environmental Science | Year: 2014

A long-term experiment, conducted at Southwest University since 1990, was used to evaluate the effect of tillage methods on the total and available contents of heavy metals (Fe, Mn, Cu, Zn, Pb, Cd) in the profile of purple paddy soil and the contents of those metals in root, stem leaf and brown rice. The experiment included five tillage methods: conventional tillage, paddy-upland rotation, no-tillage and fallow in winter, ridge-no-tillage and compartments-no-tillage. The results showed that the total concentrations of Fe, Cu, Zn, Pb and Cd in the soil profile had no significant differences among five treatments, but it was found that total Mn has a significant decline in 0-20 cm under conventional tillage, paddy-upland rotation and no-tillage and fallow in winter compared with ridge-no-tillage and compartments-no-tillage. The availability of Fe, Cu, Zn, Pb and Cd decreased with the increase of soil depth in all treatments, but the availability of Mn was found to be the highest in the 20-40 cm layers except those in the paddy-upland rotation. In the ploughed layer, the contents of available Fe, Mn was the highest in paddy-upland rotation, while the contents of available Znand Pb was the highest in conventional tillage, but tillage treatments had not significant influence to the contents of available Cu. Correlation analysis showed that available Fe was significantly negatively related to the pH values and significantly negatively related to the organic matter of soils, available Mn was significantly negatively related to the pH values and organic matter of soils, whereas the available Zn was significantly positively related to total Zn. The contents of Fe, Mn in rice root, the contents of Fe, Mn, Cu and Cd in rice straw and Cu in brown rice were higher under paddy-upland rotation, ridge-no-tillage and compartments-no-tillage than those in conventional tillage and no-tillage and fallow in winter. Paddy-upland rotation can significantly lower the migration coefficient value of Cd in brown rice, and the Pb, Cd concentration in brown rice in the treatment of paddy-upland rotation was lower than the upper limit (<0.2 mg·kg-1) of the National Standard for Food Hygiene for Cd concentration. The content of Fe in root was significantly and negatively related with soil pH and significantly and positively related with soil available Fe, the content of Mn in root was significantly negatively related with soil pH and significantly positively related with soil available Mn, the content of Mn in straw was significantly negatively related with soil pH, significantly positively related with soil total Mn and significantly positively related with soil available Mn, the content of Cu in straw and brown rice was significantly negatively related with soil pH, the content of Zn was significant related with soil pH and significant related with soil CEC. The content of Fe in root, Mn in root and straw and Cd in straw was positively related with soil available Fe, Mn and Cd, respectively, but was negatively related with pH in plough layer soil, Zn in straw was also negatively related with plough layer soil pH. From the results as above, it is concluded that different tillage methods can change the values of soil pH, alter the availability of heavy metal in soils, consequently affect uptake of heavy metal by rice. Of the tillage methods, paddy-upland rotation could increase the availability of Fe and Mn, but decrease the availability of Zn, Pb and Cd in purple paddy soils. Paddy-upland rotation can also increase the contents of Fe, Mn in rice root and straw, but decrease Cd content in brown rice, and could reduce the Pb, Cd contents in brown rice in a certain extent, however, attention should be given to long-term paddy-upland rotation cause of leaching of soil surface Mn.


Chen C.,Southwest University | Chen C.,Key Laboratory of Agricultural Resources and Environment of Chongqing | Xie Q.,Southwest University | Xie Q.,Key Laboratory of Agricultural Resources and Environment of Chongqing | And 4 more authors.
Water Science and Technology | Year: 2014

Two immobilized nano-sized TiO2 catalysts, TiO 2/activated carbon (TiO2/AC) and TiO2/silica gel (SG) (TiO2/SG), were prepared by the sol-gel method, and their use in the photocatalytic degradation of organic matter in fresh garbage leachate under UV irradiation was investigated. The influences of the catalyst dosage, the initial solution pH, H2O2 addition and the reuse of the catalysts were evaluated. The degradation of organic matter was assessed based on the decrease of the chemical oxygen demand (COD) in the leachate. The results indicated that the degradation of the COD obeyed first-order kinetics in the presence of both photocatalysts. The degradation rate of COD was found to increase with increasing catalyst dosage up to 9 g/L for TiO2/AC and 6 g/L for TiO2/SG, above which the degradation began to attenuate. Furthermore, the degradation rate first increased and then decreased as the solution pH increased from 2 to 14, and the degradation rate increased as the amount of H2O2 increased to 2.93 mM, after which it remained constant. No obvious decrease in the rate of COD degradation was observed during the first four repeated uses of the photocatalysts, indicating that the catalysts could be recovered and reused. Compared with TiO2/AC, TiO2/SG exhibited higher efficiency in photocatalyzing the degradation of COD in garbage leachate. © IWA Publishing 2014.


Zhao X.L.,Southwest University | Zhao X.L.,Key Laboratory of Agricultural Resources and Environment of Chongqing | Mu Z.J.,Southwest University | Mu Z.J.,Key Laboratory of Agricultural Resources and Environment of Chongqing | And 3 more authors.
Communications in Soil Science and Plant Analysis | Year: 2012

A pot experiment was conducted to investigate the effect of sewage sludge compost (SSC) alone and applied with chemical fertilizer on growth and heavy-metal accumulations in lettuce grown on two soils, a Xanthi-Udic Ferralosol and a Typic Purpli-Udic Cambosol. The treatments included control; nitrogen-phosphorus-potassium (NPK) fertilizer; sewage sludge compost applied at the rates of 27.54 (SSC), 82.62 (3SSC), 165.24 (6SSC) t hm-2; and coapplication treatment (1/2 SSC + 1/2 NPK), where the N, P, and K inputs from NPK fertilizer, SSC, and coapplication treatments were normalized to the local recommend rates. The SSC application increased the biomass; copper, zinc, and lead contents in lettuce; and soil total and diethylenetriaminepentaacetic acid (DTPA)-extractable metals. However, SSC alone at the recommended rate caused less plant biomass than NPK fertilizer alone. Coapplication treatment obtained greater or similar biomass to NPK fertilizer alone and did not increase heavy-metal accumulation in soils and plants. The results demonstrated that SSC should be applied to soils with chemical fertilizers. © 2012 Copyright Taylor and Francis Group, LLC.


Wang S.,Southwest University | Luo S.,Southwest University | Li G.,Southwest University | Zhao X.,Southwest University | Zhao X.,Key Laboratory of Agricultural Resources and Environment of Chongqing
Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae | Year: 2011

The effect of anionic polyacrylamide (PAM) with different molecular weight (MW) and hydrolysis degree (HD) on the settleability and dewaterability of sewage sludge was evaluated by determining the particle size distribution, specific filtration resistance and cake solid content of flocculated sludge as well as the supernatant volume, and concentrations of DNA, protein and sugar in the supernatant of sewage sludge. Addition of anionic PAM increased the percentage of particles with diameter greater than 0.60 mm, while it decreased the percentage of particles with diameter less than 0.25 mm. The increase in the HD of PAM with the same MW led to a rise of the supernatant volume, but a decline in the specific filtration resistance. For PAM with the same HD, the supernatant volume increased with the MW from 6 to 8 MDa, but decreased with a further increase of MW to 12 MDa. The response of specific filtration resistance to the MW of anionic PAM was opposite to that of supernatant volume. The effective application dosage of PAM for optimal settleability and dewaterability varied with the type of PAM. The optimal settleability and dewaterability were obtained at 75 mg·L-1 for PAM with MW of 6 MDa and HD of 30%, and for the PAM with MW of 8 MDa and HD of 20%. It was also found that both the elevated HD of anionic PAM with the same MW and the elevated MW of anionic PAM with the same HD could induce an increasing concentration of protein and sugar in the supernatant of sewage sludge, implying that the release of extracellular polymeric substance (EPS) from the sludge surface was one of the main reasons for the improvement of settleability and dewaterability associated with PAM addition.


Zhu H.,Southwest University | Zhao X.,Key Laboratory of Agricultural Resources and Environment of Chongqing
Advanced Materials Research | Year: 2012

A pot experiment was performed to study effects of application of metal rich sludge cocomposted with lime on soil physicochemical properties, ryegrass biomass and heavy metal uptake by ryegrass. The results show that application of sludge compost with(LSC) and without lime(SC) could increase the soil pH, and the organic matter, available N, P and K in soils, consequently, improve the growth of ryegrass. No significant differences were found in the plant growth between sludge composted with lime and without lime. Sludge compost rich in Zn and Cd resulted in two elementals accumulation in soil and plant. The content of Zn and Cd in ryegrass from LSC-treated soil was much lower than those from SC-treated soils at the same application rate. The results illustrated that lime was very effective in stabilizing Zn and Cd in compost. However, the fact that Cd in ryegrass from LSC treated soil was close to or even exceeded the guideline for the health standard of feed and food in China(GB 13078-2001) implied the limitation of liming in stabilization heavy metals in sludge.


Wang Q.,Southwest University | Wang Q.,Key Laboratory of Agricultural Resources and Environment of Chongqing | Song J.-Y.,Southwest University | Song J.-Y.,Southwest Computer Corporation Ltd | And 4 more authors.
Huanjing Kexue/Environmental Science | Year: 2016

The typical soil-purple soil in Three Gorges Reservoir was the tested soil, the characteristics of adsorption leaching of dimethyl phthalate (DMP) in contaminated water by the soil, and the influencing factors in the process were conducted using soil column leaching experiment. The results showed that the parabolic equation was the best equation describing adsorption kinetics of DMP by soils. The concentration of DMP in the leaching solution had significant effect on the adsorption amounts of DMP. With the increasing concentration of DMP in the leaching solution, the adsorption capacities of DMP by purple soil increased linearly. The ionic strength and pH in leaching solution had significant effects on adsorption of DMP. On the whole, increasing of the ionic strength restrained the adsorption. The adsorption amounts at pH 5.0-7.0 were more than those under other pH condition. The addition of exogenous organic matter (OM) in purple soil increased the adsorption amount of DMP by purple soil. However, the adsorption amount was less than those with other addition amounts of exogenous OM when the addition of exogenous OM was too high (≥30 g·kg-1). The addition of surfactant sodium dodecylbenzene sulfonic acid (SDBS) in purple soil increased the adsorption amount of DMP by purple soil. The adsorption amount was maximal when the addition amount of SDBS was 50 mg·kg-1. However, the adsorption amounts decreased with increasing addition amounts of SDBS although the adsorption amounts were still more than that of the control group, and the adsorption amount was almost equal to that of the control group when the addition amount of SDBS was 800 mg·kg-1. Continuous leaching time affected the vertical distribution of DMP in the soil column. When the leaching time was shorter, the upper soil column adsorbed more DMP, while the DMP concentrations in upper and lower soil columns became similar with the extension of leaching time. © 2016, Science Press. All right reserved.


Li L.,Southwest University | Li L.,Key Laboratory of Agricultural Resources and Environment of Chongqing | Zhao X.,Southwest University | Zhao X.,Key Laboratory of Agricultural Resources and Environment of Chongqing | And 6 more authors.
Tobacco Science and Technology | Year: 2015

To control the fertility of tobacco planting soil effectively and conduct carbon management in field reasonably, soil samples were collected from typical tobacco planting areas (Pengshui, Fengdu and Wushan) in Chongqing. The samples were divided into different soil aggregates by particle size with dry-sieve method, then the contents of high labile organic matter (HLOM), moderate labile organic matter (MLOM) and labile organic matter (LOM) in these aggregates were determined via treating the samples with KMnO4 solution at the concentrations of 33, 167 and 333 mmol·L-1, respectively; and the distribution characteristics of organic matter and LOM in aggregates of each particle size range were analyzed. The results showed that: 1) The major aggregates were the aggregates of 1-2 mm in particle size, which accounted for 40.16%-42.02% of total aggregates from the three areas. Except that the content of 0.25-0.5 mm aggregates was significantly higher in the samples from Wushan, there was no significant difference between the three areas (P>0.05). 2) With the increase of particle size, the contents of total organic matter (TOM) and LOM decreased in all aggregates, while the contents of HLOM and MLOM decreased in the aggregates from Pengshui and Wushan, and decreased first then increased in the aggregates from Fengdu. 3) TOM, HLOM, MLOM and LOM in soil mainly distributed in 1-2 mm aggregates, their percentage reached 29.99%-31.58%, 24.29%-33.36%, 24.15%-29.09% and 18.46%-21.69%, respectively. Therefore, 1-2 mm aggregates were determined as the characteristic aggregates of organic matter for the typical tobacco planting soils in Chongqing. 4) The contents of TOM and LOM in soils extremely significantly positively correlated to those in aggregates of <0.25 mm, respectively, it indicated that TOM and LOM in the aggregates of <0.25 mm could be used as a sensitive index for the change of organic matter content in tobacco planting soils in Chongqing. © 2015, Editorial Office of Tobacco Science and Technology. All right reserved.

Loading Key Laboratory of Agricultural Resources and Environment of Chongqing collaborators
Loading Key Laboratory of Agricultural Resources and Environment of Chongqing collaborators