The effects of different amounts of carbon and nitrogen sources on the soil microbial biomass carbon,dissolved organic carbon and related enzyme activities were studied by the simulation experiment of rice straw retur...The effects of different amounts of carbon and nitrogen sources on the soil microbial biomass carbon,dissolved organic carbon and related enzyme activities were studied by the simulation experiment of rice straw returning to the field,and the mechanism of the decomposition of rice straw returning to the field was discussed.Completely randomized experiment of the two factors of the three levels was designed,and a total of nine treatments of indoor soil incubation tests were conducted.Full amount of rice straw was applied to the soil in this simulation experiment and different amounts of brown sugar and urea were added in the three levels of 0(no carbon source and nitrogen source),1(low levels of carbon and nitrogen sources)and 2(high levels of carbon and nitrogen sources),respectively.The results showed that the addition of different amounts of carbon and nitrogen sources to the rice straw could increase the soil carbon content.Compared with T0N0,the microbial biomass carbon of T2N2 was increased significantly by 170.48%;the dissolved organic carbon content of T1N2 was significantly increased by 58.14%and the free humic acid carbon contents of T0N2,T1N1 and T2N0 were significantly increased by 56.16%and 45.55%and 47.80%,respectively;however,there were no significant differences among those of treatments at later incubation periods.The addition of different carbon and nitrogen sources could promote the soil enzyme activities.During the incubation period,all of the soil enzyme activities of adding sugar and urea were higher than those of T0N0 treatment.Therefore,the addition of different amounts of carbon and nitrogen sources to rice straw returning could improve soil microbial biomass carbon content,dissolved organic carbon and soil enzyme activities.展开更多
After the sewage treatment, putting the wet sludge in which the heavy metal content is extremely low, corrupt and broken straw, bentonite, urea in proportioning according to the certain ratio, mixing well-distributed,...After the sewage treatment, putting the wet sludge in which the heavy metal content is extremely low, corrupt and broken straw, bentonite, urea in proportioning according to the certain ratio, mixing well-distributed, taking the shape of Nitrogen slow-release fertilizers, doing the dynamic bioleaching test by the method of Artificial rainfall simulation, researching the slow-release characteristic, water retention. When the mass ratio of the wet sludge whose water content is 82.5%: bentonite: corrupt and broken straw: urea is 62.5: 12.5: 12.5: 12.5, drip washing the 10g Nitrogen slow-release fertilizers by the 80ml distilled water after 48h, the residue rate of urea is 29.63%; Under the room temperature of 25 ℃, 77%RH, moisture evaporate 46.32% after 60 h. The results demonstrate that the slow-release fertilizer has a good release-effect of nitrogen and water conservation effect. It provides the basic for the development and application of the sewage in the aspect of Nitrogen slow-release fertilizers.展开更多
基金Supported by the National Key Research and Development Plan Project(2016YFD0300909-04)。
文摘The effects of different amounts of carbon and nitrogen sources on the soil microbial biomass carbon,dissolved organic carbon and related enzyme activities were studied by the simulation experiment of rice straw returning to the field,and the mechanism of the decomposition of rice straw returning to the field was discussed.Completely randomized experiment of the two factors of the three levels was designed,and a total of nine treatments of indoor soil incubation tests were conducted.Full amount of rice straw was applied to the soil in this simulation experiment and different amounts of brown sugar and urea were added in the three levels of 0(no carbon source and nitrogen source),1(low levels of carbon and nitrogen sources)and 2(high levels of carbon and nitrogen sources),respectively.The results showed that the addition of different amounts of carbon and nitrogen sources to the rice straw could increase the soil carbon content.Compared with T0N0,the microbial biomass carbon of T2N2 was increased significantly by 170.48%;the dissolved organic carbon content of T1N2 was significantly increased by 58.14%and the free humic acid carbon contents of T0N2,T1N1 and T2N0 were significantly increased by 56.16%and 45.55%and 47.80%,respectively;however,there were no significant differences among those of treatments at later incubation periods.The addition of different carbon and nitrogen sources could promote the soil enzyme activities.During the incubation period,all of the soil enzyme activities of adding sugar and urea were higher than those of T0N0 treatment.Therefore,the addition of different amounts of carbon and nitrogen sources to rice straw returning could improve soil microbial biomass carbon content,dissolved organic carbon and soil enzyme activities.
文摘After the sewage treatment, putting the wet sludge in which the heavy metal content is extremely low, corrupt and broken straw, bentonite, urea in proportioning according to the certain ratio, mixing well-distributed, taking the shape of Nitrogen slow-release fertilizers, doing the dynamic bioleaching test by the method of Artificial rainfall simulation, researching the slow-release characteristic, water retention. When the mass ratio of the wet sludge whose water content is 82.5%: bentonite: corrupt and broken straw: urea is 62.5: 12.5: 12.5: 12.5, drip washing the 10g Nitrogen slow-release fertilizers by the 80ml distilled water after 48h, the residue rate of urea is 29.63%; Under the room temperature of 25 ℃, 77%RH, moisture evaporate 46.32% after 60 h. The results demonstrate that the slow-release fertilizer has a good release-effect of nitrogen and water conservation effect. It provides the basic for the development and application of the sewage in the aspect of Nitrogen slow-release fertilizers.
