| As China's domestic sewage treatment volume increases year by year,the amount of sludge produced by sewage treatment increases rapidly.The rational use of sludge has become one of the urgent environmental problems to be solved.Domestic sludge contains a large amount of nutrients required for plant growth such as organic matter,nitrogen,phosphorus,and potassium,and can be used as a source of soil organic matter.This study started from the perspective of the agricultural use of urban sludge humus soil,and applied the urban sludge humus soil in a rational treatment instead of the rice seedling soil in the seedling raising process.It explored a feasible method for the cyclic application of the urban sludge humus soil after processing,and solved rice at the same time.In the period of childbirth,practical issues such as taking homesickness are taken.In this study,dialysis rotary evaporation was used to separate crude extracts.The crude extracts were purified and identified by infrared spectroscopy combined with thin layer chromatography and column chromatography.The active substances that inhibit seed germination in urban sludge humus soil were identified.The urban sludge humus soil and the improver were rationally compounded to determine the resistance enzymes of the rice seedling leaves,the enzymatic activity of the seedbed soil,the physiochemical properties of the seedbed soil,and the quality of the rice seedlings and determine the optimal mixing ratio of sludge humus soil and improver so that the sludge humus soil can be used in rice nursery bed soil.The specific findings are as follows:(1)The concentration of crude extract of urban sludge humus soil increased,the seed germination rate of water radish?Cabbage and cole decreased,and the seed germination was inhibited for a prolonged period.The crude extract contained active substances that inhibited seed germination.(2)The application concentration of crude extract of municipal sludge humus soils increased,the activity of SOD,POD,CAT,PAL,C4H,and 4CL in corn increased.Among them,the above-mentioned anti-reverse enzyme activity in corn was highest after 200 times application of crude extract.(3)The crude extract R_f 0.65 fraction had the strongest inhibitory effect on the germination of rice seeds.The active compound structure was preliminarily identified as 3-hydroxybenzoic acid,which has a significant inhibitory effect on?-amylase activity in rice seeds.(4)Compared with the unmodified humus soil,the modified agent mixture humus soil significantly reduced the activities of SOD and POD and the contents of PRO and MDA in the cultivated rice seedlings.It is because the conditions of adversity have been improved.(5)When the ratio of modifier to humus soil was 1:9,the cellulase,urease and phosphatase activities were:26.112 mg/L,2.514 mg/L,and 2.534 mg/L,respectively;the ratio of improver to humus increased.By 3:7,the three enzyme activities were reduced to 14.888 mg/L,2.293 mg/L,and 1.171 mg/L,respectively.It shows that the activity of cellulase,urease and phosphatase decreases with the increasing proportion of modifiers.(6)The amendments had a significant effect on the contents of nitrogen,phosphorus,and potassium in the substrate of humic soil,showing as follows:with the increase of the proportion of the amendment and the humus,the contents of nitrogen,phosphorus,potassium,and pH of the substrate were significantly decreased.(7)The number of tillers per 100 plants of rice seedlings cultivated on the humus soil with compound modifier was not significantly different from that without the amendments,but the plant height,stem base width,fresh weight aboveground and root,and aboveground and root dry weight all increased significantly.When the weight ratio of improver to sludge humus soil was 3:7,plant height was 7.19cm,stem base width was 0.216cm,ground and root fresh weight were:13.44g and6.65g,and ground and root dry weight were:5.73g and 3.22g,rice seedlings grew most robustly. |
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