Ecological Survey And Compost Utilization Of Potamogeton Crispus In Dongping Lake

In recent years,with the rapid economic development,the nutrient content of lakes has increased,and the process of water eutrophication has accelerated.In North China,the middle and lower reaches of the Yangtze River and other areas,Potamogeton crispus broke out on a seasonal scale,and nitrogen and phosphorus were released after potamogeton crisps decomposed in grassland,resulting in periodic decline in water quality.Potamogeton crispus became a single dominant submerged plant species,threatening water ecosystem balance.Timely harvesting of Potamogeton crispus and sediment seed entities can effectively reduce outbreak scale and improve submerged plant biodiversity.As for freshly harvested grass,it will smell bad and produce a large amount of leachate.Dried grass has no effective way to be used,causing secondary pollution.Artificial intervention should be made to harvest Potamogeton crispus and introduce submerged plants in the same ecological niche to improve the diversity of submerged plants.It is a key issue for sustainable control of submerged plant development to effectively dispose of Potamogeton crispus and explore ways of resource utilization.This paper took Potamogeton Crispus in Dongping Lake as the research object.The area around Liuhe Pier of Dongping Lake,Laoghu Town,Dongping County,which was rich in Potamogeton Crisp distribution and 0-2 m water depth,was selected as the research area.Two ecological surveys were conducted on April 21 and August 10,respectively,to evaluate water quality and biodiversity changes before and after Potamogeton crisp rotting.Collect,collect and harvest dry grass,mix and compost with livestock and poultry manure(cow manure,chicken manure,sheep manure)as auxiliary materials,and explore the influence of different factors(auxiliary materials,water content,carbon and nitrogen ratio)on aerobic composting effect of water Crisps.The main conclusions are as follows:(1)From April to August,with Potamogeton crispus passing away,the water quality of the monitoring section in the study area decreased obviously,from Class Ⅲor Ⅳ water to poor Class Ⅴ water,and serious phenomenon of exceeding TN and TP(exceeding TN multiple of 2.77-3.99 and TP multiple of 3.2)occurred.The eutrophication degree of water body increased,and the eutrophication state changed from moderate to mild eutrophication.This means that TN and TP concentrations in the water body of the study area increased,water quality decreased significantly,and eutrophication intensified before and after potamogeton crisp rot.This means that potamogeton crisp rot will bring about obvious negative effects,resulting in water deterioration of lake and reservoir.From April to August,the status of sediment ON and OM pollution changed from light pollution and relatively clean to clean and pollution-free.This means that water crisps fishing and harvesting for Potamoton crisps can reduce sediment nutrient load and sediment pollution.In the study area,the density of submerged plants was 12.5 plants /m2 in April,and the highest frequency and relative density of individual Potamogeton crispus were 87.5% and 72%,indicating high dominance and being a single dominant species.H ’,J,R and D indexes were 0.71,0.64,0.62 and 0.58,respectively.During the survey in August,it was found that Potamogeton crispus died away,a small amount of Potamogeton crispus was found,and the density of submerged plants decreased to 7 plants /m2,showing a significant decline in dominance.H ’,J,R and D indexes were 0.79,0.72,0.78 and 0.54,respectively.As Potamogeton crispus overgrew and occupied the living space of other submerged plants,it became a single dominant species,and the diversity of submerged plant community decreased.After Potamogeton crispus died off in August,the scale of other submerged plants did not change significantly,the dominance of submerged plants decreased,and the community diversity did not increase significantly.(2)Under the condition that the initial water content was 60% and C/N was 20,livestock and poultry manure had good effect with Potamogeton crisp aerobic composting.After 42 days of composting,the seed germination index of each treatment exceeded 80%,meeting the standard requirements of organic fertilizer industry.Among them,the cow manure treatment group with higher porosity reached the basic state of maturation 6 days earlier than other treatments,and the maturation process was relatively faster.Combined with the current domestic basic production conditions of livestock and poultry manure,it is feasible to produce livestock and poultry manure with Potamogeton crispus aerobic composting.(3)Three water content gradients of 55%,60% and 70% were designed for composting experiments.The results showed that when the initial water content was70%,the degradation rate and GI of organic matter were significantly lower than those of other treatments,and the composting effect was poor,and the composting effect was not complete.When the water content was 55%,GI was higher than that of 60%,but TN increased less and nitrogen loss was higher.Both are completely decomposed.(4)Composting tests were conducted by adjusting Potamogeton crisp pile C/N to15,20 and 25.The results showed that the GI of treatment with C/N at 15 was 62.5%and not completely decomposed;The GI of C/N of 20 and 25 was more than 80%,and reached the state of complete rot.When C/N is 25,GI is higher than that when C/N is20,but TN increases less and nitrogen loss is higher.Both are completely decomposed.By studying the influence of different influencing factors on Potamogeton Crispus aerobic composting,it was confirmed that Potamogeton crispus and livestock manure aerobic composting could achieve good composting results,and cattle manure with higher porosity composting process was relatively faster.The suitable initial moisture content in actual production is between 55%-60%,and the initial C/N is between 20-25,which has a good rotting effect.Aerobic composting of livestock and poultry manure has certain production basis.Coordinated aerobic composting of recovered and harvested grass crisps combined with livestock and poultry manure can effectively solve Potamogeton crisp collection and potamogeton crisp collection from water bodies,realize resource utilization,and ensure the health and stability of submerged plant community in the lake district.