| A large amount of solid waste was produced in the process of human production and life.If not handled in time,it will cause secondary pollution to the environment.In order to expand the way of solid waste resource utilization,this paper uses the solid waste domestic sludge,straw,vermicompost,fly ash and coal cinder which have large output and easy to obtain in daily life as raw materials,mixed and temperature-constant incubation in different proportions to formulate Technosols.Measured the physical and chemical characteristic,to study whether it reached the range of natural soil and used it for acid soil improvement.The experimental results are as follows:(1)The basic physical and chemical properties of the five raw materials were tested,and it was found that the organic raw material had sufficient nitrogen,phosphorus and potassium,and the heavy metal content of each raw material was lower than the agricultural standard stipulated by the state,which could be used for the preparation of Technosols.The formula was determined by the pre-cultivation experiment of pH change:the organic raw material was mixed by domestic sludge and vermicompost/straw in a mass ratio of 3:2 and 4:1,and the inorganic raw material was composed of fly ash and cinder in a mass ratio of 4:1.Next mixed the organic and inorganic raw materials according to the mass ratio of 4:6,6:6,and 9:6,and then 12 kinds of Technosols were prepared by culturing.(2)The total amount of water-stable aggregates in the Technosols was between 49.83%?86.44%,all reaching the level of normal soil in our country.The total amount of water-stable agglomerates was relatively higher in the straw treatments,and the percentage of aggregate destruction(PAD)was lower,the mean weight diameter(MWD)and geometric mean diameter(GMD)were higher,it means that the soil aggregates were more stable.The contribution rate of organic carbon and nitrogen to the aggregates with different particle sizes was the highest in 0.25?1 mm aggregates,the next one is 1?2 mm aggregates,and the contribution rates of organic carbon and nitrogen increased with the increase of the proportion of organic raw materials.Under the same conditions,the contribution rate of organic carbon and nitrogen in small and micro aggregates treated with vermicompost was higher than that treated with straw,which was beneficial to the sequestration and long-term supply of carbon and nitrogen in the Technosols.(3)The pH of the Technosols was ranged from 7.08?7.69,which basically meets the needs of most plant growth.Compared with the straw treatments,the pH of the vermicompost treatments was lower;after culturing for 90 days,the TOC was ranged from 5.26%?8.74%,higher than most soils,it can provide a large amount of carbon source for plant growth.The available nutrients changed in different degrees before and after culture.The final content of alkaline hydrolyzable nitrogen was ranged from 0.64 g·kg-1?1.01 g·kg-1,decreased by 11.03%-38.08%compared with that before culture;the content of available phosphorus was ranged from 122.30 mg·kg-1?227.51 mg·kg-1,decreased by 5.79%?25.05%;available potassium was relatively stable,the final content was ranged from 0.88 g·kg-1?3.56 g·kg-1,referring to the nutrient classification standard of the second national soil census,the nutrient content of each treatment reached the higher level specified by the standard.(4)The final Zn content of the Technosols was relatively high,it should be used to grow non-edible crops for safety reasons.The biological toxicity test shows that the ratio of domestic sludge and vermicompost/straw by 3:2,the ratio of organic and inorganic raw materials by 3:2(treatment 5 and treatment 6),the ratio of domestic sludge to straw by 4:1,and the ratio of organic and inorganic raw materials by 1:1(treatment 10)was most favorable for plant growth.Treatment 1,treatment 3 and treatment 11 have moderate toxic effects on plants and were not suitable for directly growing plants.The other treatments with germination index between 70%-85%have only low toxicity to plant growth,which basically meet the growth requirements.This proves that Most of the Technosols can meet the most basic soil function of allowing plants to grow normally.(5)Potted experiments showed that adding 20 wt.%Technosols to acid soil can significantly improve pH and nutrient conditions,which is beneficial to the germination and growth of ryegrass,and can significantly improve the germination rate,plant height and above-ground organisms.Among them,20%T12 treatment had the best effect,increasing the biomass by 156.72%,and at the same time,it could balance the absorption of trace elements(Fe?Mn?Cu?Zn)by ryegrass. |
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