Study On Growth Characteristics Of Algae In Overlying Water,Leachate And Leaching Solutions Of Different Purple Soils

Soil is an important nutrient source for pond waters and has a large impact on algae growth.In order to investigate the difference in algae growth with different parent rocks purple soil waters,the topsoil(S_1-1)and parent soil(S_1-2)of the Jiaguan group,the topsoil(S_2-1)and parent material(S_2-2)of the Shaximiao group,the topsoil(S_3-1)and the parent soil(S_3-2)of the Suining group were used as test soils.The soil primary algae germination and the soil-water mixtures were inoculated with algae（Cyclotella sp.,Scenedesmus dimorphus and Euglena gracilis）culture test.Then,algae（Cyclotella sp.,S.dimorphus and E.gracilis）culture experiments were carried out with overlying water,leachate and leachate of three kinds of topsoil S_1-1,S_2-1 and S_3-1.The results are as follows:1.Germination characteristics of primary algae in three topsoil and parent soil（1）The content of nutrients in different purple soils is quite different.The constant nutrients of S_1-1 are relatively insufficient,but the micronutrients are abundant,while S_2-1 and S_3-1-1 are opposite.Although S_1-2-2 has higher TK and micronutrients,The contents of TP,Ca and S are low,and S_2-2 and S_3-2 are rich in nutrients,but the micronutrients are relatively insufficient.（2）50 kinds of Cyanophyta,Bacillariophyta,Cryptophyta,Euglenophyta,Chlorophyta algae were found in topsoil and parent soil overlying water.The species of Chlorophyta algae was the most,with 25 species,followed by Bacillariophyta.There are 15 species of algae.The species of algae,maximum algae density and maximum biomass of S_1-1-1 germinated were lower than those of S_2-1 and S_3-1,while the number of Cyanophyta species was higher than that of S_2-1 and S_3-1;the parent material also showed the same pattern.2.Effects of three soil-water mixtures of topsoils and parent materials on algae growth（1）The pH and EC of the overlying water of the three topsoil soil-water mixtures are S_3-1>S_2-1>S_1-1,and the overall performance of the parent materials are S_3-2>S_2-2>S_1-2.（2）For different topsoil,the suitability of S_3-1 to three kinds of algae was stronger,followed by S_2-1,and S_1-1 inhibited the growth of S.dimorphus and E.gracilis,and the suitability of algae was poor.For different parent materials,the adaptability of Cyclotella sp.and S.dimorphus of S_2-2 and S_3-2 is stronger than that of S_1-2,while E.gracilis adaptability of S_3-2 soil is slightly stronger than S_2-2 and S_1-2.3.Differences in nutrients of overlying water,leachate and leaching solution on three topsoils and their effects on algae growth（1）The pH,TN cumulative dissolution,total hardness,Ca²⁺and EC of the three purple soils overlying water,leachate and leaching solution were all S_3-1>S_2-1>S_1-1,and the cumulative dissolution rate of TN was S_1-1>S_2-1>S_3-1.The cumulative dissolved amount of TP in the overlying water is S_3-1>S_2-1>S_1-1,and the cumulative dissolved amount of TP in the leachate and leaching solution is S_2-1>S_3-1>S_1-1;the cumulative dissolution rate of TP is S_1-1>S_2-1>S_3-1.The difference of TN between overlying water and leachate is small,both of them are lower than that of leachate,while the difference of TP between leachate and leachate is small,both of them are higher than that of overlying water.NO₃^--N content,total hardness and Ca²⁺content are generally expressed as leaching solution>leachate>overlying water.（2）The maximum density of Cyclotella sp.and S.dimorphus in the overlying water,leachate and leaching solution of S_2-1 and S_3-1 is generally higher than that on S_1-1.The maximum density of E.gracilis in overlying water,leachate and leaching solution of S_2-1 and S_1-1 were generally higher than S_3-1.The maximum density difference between the leachate and the leaching solution of Cyclotella sp.and S.dimorphus was smaller than overlying water,while the difference between E.gracilis in the overlying water,leachate and leaching solution was small.（3）The maximum density of Cyclotella sp.was significantly positively correlated with TP,total hardness,Ca²⁺,pH and EC in soil solution（p<0.01）,and positively correlated with TN and SRP（p<0.05）.The maximum density of S.dimorphus was significantly positively correlated with TN,TP,SRP,total hardness,Ca²⁺and EC in water（p<0.01）,and was significantly positively correlated with pH（p<0.05）.The maximum density of E.gracilis was significantly positively correlated with TP（p<0.05）,and was significantly negatively correlated with NO₃^--N（p<0.05）.In summary,the algae in the purple soil of the Suining group are better in adaptability,and the suitability for aquaculture is better.The Shaximiao group is second,and the Jiaguan group is relatively poor.