Effect Of Swine Manure And Chicken Manure On P Accumulation Characteristics Of Pilea Sinofasciata

The inappropriate application of swine manure and chicken manures in farmland caused phosphorus?P?accumulation in soil.Excess P in soil entered into waterbody through rain or drainage,raising risk of eutrophication.Phytorextraction is an efficient way to extract excess P from soil.Pot experiments were conducted to investigate the effect of swine manure and chicken manure on P accumulation characteristics in a mining ecotype?ME?of Pilea sinofasciata screened as P accumulator,with a non-mining ecotype?NME?as contrast.The following is a summary of the results:1.Biomass and P accumulation in shoots of P.sinofasciata grown in soils amended with swine manure were 1.14¹.33 and 1.19¹.49 times higher than seedlings grown in chicken manure treatments.P.sinofasciata was more capable of accumulating P from soils mixed with swine manure.Maximum values of biomass and P accumulation in shoots of both ecotypes were noticed in soils mixed with 50 g kg^-1 swine manure or chicken manure.The ME demonstrated 1.10¹.39 times higher values of P accumulation in shoots than the NME.Under swine manure and chicken manure treatments,both ecotypes accumulated more P in shoots,and the total ratio of P distribution in stems and leaves of the ME was over 83%,and that of the NME exceeded80%.Under swine manure and chicken manure treatments,inorganic P and nucleic P dominated in tissues of both the ME and the NME.The ME showed higher concentrations of ester P and nucleic P in tissues under swine manure treatments than under chicken manure treatments,showing 1.08¹.16 and 1.18¹.50 times higher values,respectively.Meanwhile,higher concentrations of ester P in leaves and inorganic P in roots were noticed in the ME compared to that in the NME.The values of ester P,nucleic P and residual P in roots of the ME were also significantly higher than that of the NME when grown in soils with chicken manure.The ME was capable of maintaining higher metabolic activity,ultimately contributing to higher P accumulation.2.After 11 weeks growth,biomass and P accumulation of both ecotypes were significantly higher under swine manure treatments than those under chicken manure treatments.Under suitable swine manure and chicken manure application rates,biomass and P accumulation of P.sinofasciata increased with growth period prolonged.Maximum values of P accumulation in shoot of the ME were 283.07 mg plant^-1 under swine manure treatment and 243.20 mg plant^-1 under chicken manure treatment,which were 1.16 and 1.33 times higher than that of the NME.The highest value of periodic P accumulation of P.sinofasciata was observed at 7th-9th week,followed by 9th-11th week.Periodic P accumulation at 7th-11th week accounted for 72%⁹2%in the ME and 77%⁸6%in the NME.Maximum shoot P accumulation rate of the ME was observed at the 11th week,and was higher than that of the NME.Shoot P extraction rate and P removal of both ecotypes increased with growth period prolonged,while the plant effective numbers?PEN?decreased.Compared with the chicken manure treatments,the P extraction rate and the P removal of P.sinofasciata increased and the PEN decreased under the application of swine manure,indicating that P.sinofasciata was more efficient in P extracting from swine manure impacted soil.Besides,the P extraction rate and the P removal of the ME were higher than those of the NME,while the PEN was lower.These results demonstrated that the ME was more capable of removing excess P from soil.3.Under suitable application rates of swine manure and chicken manure,with growth period prolonged,concentrations of chlorophyll a,chlorophyll b and carotenoid of both ecotypes decreased by 6%⁴7%,7%³9%and 3%³6%,respectively,and the ME showed higher values than the NME.No statistical difference in photosynthetic pigment concentrations and gas exchange parameters was observed between swine manure treatments and chicken manure treatments,which suggested that photosynthesis of P.sinofasciata was less affected by manure types.The Pn,Gs,Tr of P.sinofasciata decreased by 9%⁴3%,34%⁷4%and 10%⁷0%,respectively,while the Ci maximized at the 9th week,then significantly decreased,indicating that the synthesis of dry matter was reduced.The ME demonstrated higher Pn,Gs and Tr than the NME,while the Ci was lower than the NME,indicating that the ME was more efficient in photosynthesis.4.The concentrations of all P fractions in soil were greatly enhanced by swine manure and chicken manure application.Under swine manure treatments,concentrations of NaHCO₃-P and HCl-P in rhizosphere and bulk of P.sinofasciata were significantly higher than those under chicken manure treatment,showing 1.11¹.96 and 1.47⁴.80times higher values,respectively.Concentrations of H₂O-Pi and NaHCO₃-P in rhizosphere of both ecotypes were higher than that in bulk soils,while H₂O-Po and NaOH-Pi in rhizosphere showed lower values than bulk soils.Depletions of H₂O-Pi,NaHCO₃-P,NaOH-Pi in rhizosphere of the ME were observed compared to the NME,indicating that the ME was more capable of P uptake.Activities of acid phosphatase?ACP?,alkaline phosphatase?ALP?and phytase in rhizosphere and bulk of the ME were higher in swine manure treatments than those in chicken manure.pH and activities of ACP,ALP and phytase of both ecotypes were higher in rhizosphere than in bulk.Under swine manure treatments,higher phytase activity of the ME was observed compared with that of the NME.Meanwhile,activity of ACP was also higher in the ME than that in the NME when grown in soil amended with chicken manure.The greater rhizosphere phosphatase activity in the ME contributed to the availability of soil P,thus promoting P accumulation in P.sinofasciata.