Effects Of Fertilizer, Pesticide And Heavy Metal On Characteristic Of Microbes In Purple Paddy Soil

Soil microbe is the primary participator of soil ecosystem matter cycle and energy flow. And it has important function in the processes of soil organic matter decomposition, nutrient cycling, soil structural improvement, greenhouse gas release, environmental contamination cleansing and et al. The quantities and activity change of microbial communities can reflect sensitively whether soil quality is in condition and are the most sensitive indices about evaluating change of soil quality. Many studies were in soil physical and chemical indices in soil quality evaluation. The study of soil microbiology indices is ignored. Microbe indices of soil quality health are not established. The use of fertilizer, pesticide and other agrochemical is the most profound agriculture measure, which affecting soil quality and its continuable utilization, and the important factor in affecting quantities and activity of microbial communities. Many studies developed in the effect of fertilizer, pesticide and heavy metal pollutionto soil microbe. But these studies focused on the dry land and few studies were in the system of paddy soil amount and activity of anaerobe communities in the world. Paddy soil has unique anaerobic microbial environment. The effect of man-made activity to microbes is different to dry land farmland ecosystem. Anaerobe (methanogen, ANFB, DNB, ACDB, et al) of paddy soil has important function in organic C decomposing, N cycle and greenhouse gas letting and et al. The system study was few about the long-term fertilization, pesticide and heavy metal pollution affecting quantity and activity of anaerobe in purple paddy soil.The effects, of long-term fertilizer, pesticide and heavy metal pollution on quantity and activity of microbial communities in purple paddy soil, were studied using methods of long-term fixed experiment, indoor cultivation and math analysis in the National Monitoring Base of Purple Soil Fertility and Fertilizer Benefit. The relation, between soil microbial characteristic and soil nutrient fertility in purple paddy soil, was discussed. Indices were analyzed on species and activity of microbes, which were sensitive to pesticide and heavy metal pollution. Basic data were provided for biological evaluation of soil fertility quality and environmental quality in purple paddy soil and establishment of soil polluted alarming index system. Scientific basis was provided for pesticide and heavy metal contaminated soil remediation, constituting reasonable soil cultivated system, promoting benign cycle of paddy ecosystem. Major results showed that:The amounts of microbial communities except ANFB were increased in long-term fertilizer application. The increasing amount of soil microbe in the manure application treatment was higher than that in the chemical fertilizer application treatment. The amount of microbial community was the highest in manure and chemical combination application treatment and was the lowest in no fertilizer application treatment (CK) and uncultivated treatment. The amount of microbial community in chemical N, P, K fertilizer equilibrium application treatment was higher than that in non-equilibration application treatment. The species amount of anaerobic microbe in paddy soil was closely related to manure and nitrogenous fertilizer application. The amounts of methanogen, anaerobic cellulose-decomposing bacterium(ACDB), hydrogen producing bacterium and acetogen(HPAB), anaerobic fermentative bacterium(AFB), denitrifying bacterium(DNB), sulfate-reduction bacterium(SRB) were observably increased but the growth of anaerobic azotobacter(ANFB) was restrained after applied manure and nitrogenous fertilizer. In the anaerobic condition in this experiment, the amount of bacillus, which was more than 2 magnitudes as fungi and actinomycete, was the highest in paddy soil. The bacterial amount in chemical fertilizer and barnyard manure treatment, which was 3 times comparing with CK, was the highest in all fertilizer application treatments; the amount of fungi and actinomycete were the highest in chemical fertilizer and straw combination application treatment, which were higher 5.48 and 1.96 times as those in CK, respectively. Manure and chemical combination application could harmonize the C/N in soil, it was propitious to growth and multiply of soil microbe. It was an important measure to keep amount diversity and stability of soil microbial species.Manure improved observably breath intension, methanogen activity, sucrose enzyme and catalase related with soil C cycle, and activities of SRB and DNB related with S and N cycles. Long-term using N fertilizer reduced ANFB activity and increased urease activity. Neutral phosphate enzyme activity distinctly improved in P fertilizer treatment. All enzymatic activity and biological activity were lowest in CK and uncultivated treatments except ANFB activity. It showed that cultivation and fertilization were important measures in improving amounts and activity of microbial species.Correlation analysis, about soil nutrient content, crop yield and microbial amount of different species, biology activity, which indicated that it was preferable positive correlation between microbial amounts and activity of other species and soil organic matter, total N content, except ANFB. And it was terrible markedly positive correlation only between neutral phosphate enzyme and soil available P content. And it was bad correlation between other microbial amount, activity of different species and soil available P, K. It was indicated that magnitudes of soil microbial amount, enzymatic activity and biological activity reflect soil C, N fertility level in some degree, which was not related with soil P, K content. Anaerobic microbe and enzyme (ACDB, HPAB, DNB, methanogen enzyme activity, sucrose enzyme, catalase) related with organic matter decomposing and C, N cycle was markedly positive correlation with paddy soil organic matter and N content, which was best to token function of soil C, N fertility. Indicating function of phosphate enzyme activity was prime to soil P fertility.The effect trend, different concentration of butachlor, carbofuran was similitude. Low concentration of butachlor, carbofuran (1 mg kg^-1 dry soil) could stimulate all microbial growth and increased biological and enzyme activity, except epiphyte, which was evidently restrained epiphyte amount. They restrained all microbial growth and reduced biological and enzymatic activity when concentrations of carbofuran and butachlor increased 10 mg kg^-1 ( dry soil). Carbofuran and butachlor inhibited function was biggest at 7d. And their inhibited function decreased along with the using time of pesticide and amounts and activity of microbial species resumed gradually. Carbendazim restrained obviously all microbe and its activity whether its concentration high or not. The inhibited intensity of carbendazim to paddy soil microbe was greater than carbofuran and butachlor and it showed that soil microbe was sensitive to carbendazim.The sensitivity of different microbial species was biggish differentia to pesticide pollution. The sensitivity of anaerobic microbe (methanogen, ACDB, ANFB, DNB, SRB, HPAB, AFB) was higher than aerobic microbe (bacteria, epiphyte and actinomyces) in the same treatment. It was the strongest that carbofuran restrained epiphyte and the highest efficiency, which carbendazim restrained actinomyces in three species of aerobic microbes. ACDB, HPAB and methanogen were the most sensitive to pesticide pollution in seven kinds of anaerobic microbe. And pesticide restraining ratio reached 50% to those three kinds of anaerobic microbe in seven days when the dosage of carbofuran, carbendazim were 10 mg kg^-1, 5 mg kg^-1 (dry soil). So these kinds of anaerobic microbe could be used for indicating biology of pesticide pollution. The sensitivity of different enzymatic activity was different to pesticide pollution. The inhibiting function of pesticide pollution on neutral phosphate enzymatic was higher than urease, cane sugar reductase and catalase.The effect of the same pesticide was biggish differentia to microbial amount and activity of different species. The most sensitive microbes were HPAB, AFB, methanogen and epiphyte in 10 kinds of microbes in the experiment. And these kinds of microbes reduced 40-50% when the dosage of carbofuran was 10 mg kg^-1 (dry soil) at 7d. Methanogen, HPAB, AFB and ACDB were most sensitive to carbendazim and their inhibiting ratio reached 55-80% when the dosage of carbofuran was 5 mg kg^-1 at 7d. AFB and DNB were sensitive to butachlor and the restraining ratio reached 35-40% when using 10 mg kg^-1 butachlor at 7d.The inhibiting function, carbofuran,carbendazim,butachlor to species amount and activity of methanogen, which was strongest. And they were the most sensitive indices tokening pesticide pollution of paddy soil. The magnitude of their amount and activity could primely reflect the polluted status of carbofuran, carbendazim, butachlor in purple paddy soil. So suggested adopting methanogen and its activity as alarming indication biology.Low concentrations, Cd²⁺, As⁵⁺, Cu²⁺ treatment (concentration was 0.5, 30, 50 mg kg^-1 dry soil separately), stimulated growth of 8 kinds of microbes and improved enzymatic activity except epiphyte and SRB. Three kinds of heavy metals seriously inhibited DNB activity and inhibiting ratio reached upwards 97%. Cd²⁺ effected less epiphyte and SRB amount and its activity but As⁵⁺ obviously inhibited function. Cu²⁺ inhibited activity of epiphyte and methanogen. The treatments, middling and high concentrations of Cd²⁺, As⁵⁺, Cu²⁺, which reduced amounts and activity of all microbial species. Middling concentration (1.0 mg kg^-1) of Cd²⁺ reduced amounts and activity of all microbial species and inhibited function strongest to amounts and activity of DNB and SRB, methanogen and its activity. As⁵⁺ 60 mg kg^-1 treatment inhibited all microbes and it was the most inhibiting function to amount and activity of actinomyces, methanogen, ANFB, ACDB and HPAB. And their inhibiting ratios were 46%, 57%, 98%, 45%, 44%, Cu²⁺500 mg kg^-1 separately at 7d and all microbes were inhibited. DNB activity, SRB and methanogen were most sensitive to Cu pollution and their inhibiting ratios were 98%, 71% and 45% separately. Correlation analysis, between amount and activity of microbes and concentration of heavy metal, which showed that the relation between concentration of Cd²⁺, As⁵⁺, Cu²⁺ and amount and activity of microbes was negative correlation. Amount and activity of soil microbes could token degree of soil heavy metal pollution in a certain extent. For Cd²⁺ inhibiting microbes resulted in upheaval concentration MD50, which concluded Cd²⁺ inhibition of actinomyces, ANFB, AFB, catalase and sucrose enzyme upheaval concentration MD50 at 2.3～2.7 mg kg^-1. And it showed that their endurance was strong to Cd²⁺ pollution. Upheaval concentration MD50 of Methanogen and its activity, DNB, RSB and ACDB inhibition was around 1 mg kg^-1 (according to soil quantity standard of national third class). It was high that Cu inhibiting upheaval concentration MD50 of actinomyces, ANFB and AFB (hyper- 1000 mg kg^-1), and endurance of these microbes was strong. Upheaval concentrations MD50 of HPAB, DNB, ACDB and methanogen inhibition were at 500～700 mg kg^-1. And these kinds of microbes were sensitive to Cu pollution, which could be as indication biology for Cu pollution.Low concentration Pb²⁺(200 mg kg^-1 dry soil) obviously stimulated amount and activity of AFB and methanogen in soil and obviously inhibited activity of actinomyces, ACDB and DNB. Inhibiting ratios were 18%, 19% and 98% after 7d. Low concentration Pb²⁺ affected less on microbial amount and enzymatic activity. Middling and high concentrations Pb²⁺ inhibited amount and activity of all microbes. And epiphyte, ACDB and DNB were most sensitive to Pb²⁺. 400 mg kg^-1Pb²⁺ treatment reduced 44%, 41% and 98% respectively after 7d.Amount and activity of all microbes inhibited in soils in the treatment of Cr³⁺200 mg kg^-1 (dry soil). And amount and activity of SRB and activity of methanogen, DNB and ANFB were affected seriously. Their amount and activity reduced 60%, 34%, 66%, 98% and 65% after 7d. Microbes were inhibited seriously in 400 mg kg^-1 (dry soil) Cr³⁺ treatment and all microbes reduced upwards 50%, all biological activity reduced 99%. Activity of urease, sucrose enzyme, phosphate enzyme and catalase reduced 60%, 21%, 59% and 42%. All microbes were killed and, amount and activity of microbes only had about 1% of CK when using 1600 mg kg^-1 Cr. And all microbes were sensitive to Cr pollution.