Phosphorus(P) bioavailability is an important factor in alpine meadows and plays an important role in the response to climate change and the maintenance of ecosystem functioning.However,little is known about how envir...Phosphorus(P) bioavailability is an important factor in alpine meadows and plays an important role in the response to climate change and the maintenance of ecosystem functioning.However,little is known about how environmental factors,such as elevation and slope aspect,affect soil P bioavailability.We explored the effects of elevational gradient and slope aspect on different forms of P and P availability in the alpine meadows on the southern slope of the Tian Shan Mountain range.Total P was found to be 851.9-1556.7 mg·kg^(-1) at different elevational gradients and 437.5-1547.0 mg·kg^(-1) at different slope aspects,and highest at 3337 and 3652 m.a.s.l.,but little differences between slope aspects.Olsen P and Labile P linearly increased with the elevational gradient.The valley and the base of the shady slope had higher contents of H_2O-Po.NaHCO_3-Pi,and NaHCO_3-Po,and high-active organic P(NaHCO_3-Po,NaOH-Po,and H_2O-Po) was positively correlated with soil total carbon(TC),total nitrogen(TN),soil organic carbon(SOC),and aboveground biomass(AGB),but was negatively correlated with pH,aluminum(Al),and calcium(Ca) at different elevational gradients.High-active bioavailable P(H_2OPi,H_2O-Po,NaHCO_3-Pi,and NaHCO_3-Po) was positively correlated with soil SOC and AGB and was negatively correlated with pH at different slope aspects.Our results suggest that soil P availability in alpine meadows is significantly controlled by topographical factors and the valleys and base of shady slopes are reservoirs of high-active bioavailable P.展开更多
The primary productivity of terrestrial ecosystems is influenced by soil phosphorus bioavailability, which depends largely on chemical fractions of phosphorus. The sequential fractionation technique developed by Hedle...The primary productivity of terrestrial ecosystems is influenced by soil phosphorus bioavailability, which depends largely on chemical fractions of phosphorus. The sequential fractionation technique developed by Hedley et al. or its subsequent modification is a well-known method to determine soil phosphorus forms. Hedley sequential fractionation technique separates the phosphorus into fractions based on their different chemical solubilities in extractants with certain chemical properties. Recently, synchrotron-based X-ray absorption near edge structure(XANES) spectroscopy has been employed to measure soil phosphorus species directly and non-invasively. The XANES method provides information concerning local structure and chemical information of target elements at a molecular level. Thus, it can distinguish phosphorus fractions bound by metal oxides or hydroxides(such as Fe, Al, and Ca). In this present work, the phosphorus speciation of topsoil along a glacial foreland chronosequence in Gongga Mountain is determined using these two methods. The changes in soil phosphorus bioavailability along the 120-year-old chronosequence are assessed based on comparisons of the results obtained by these two methods. The results indicate that Hedley sequential fractionation technique shows a greater ability to determine soil bioavailable phosphorus(Resin-P and NaCHO3-P), while XANES is effective in distinguishing phosphorus bound by metal compounds. In the chronosequence, Ca- and Al-bound phosphorus were derived mainly from primary minerals, whose phosphorus contents decreased within 120 years of moraine weathering and soil development. The content of soil bioavailable phosphorus increased rapidly after 30 years since deglaciation. The increasing phosphorus bioavailability promoted the colonizing and primary succession vegetation.展开更多
基金grants from the National Natural Science Foundation of China(U1703244)
文摘Phosphorus(P) bioavailability is an important factor in alpine meadows and plays an important role in the response to climate change and the maintenance of ecosystem functioning.However,little is known about how environmental factors,such as elevation and slope aspect,affect soil P bioavailability.We explored the effects of elevational gradient and slope aspect on different forms of P and P availability in the alpine meadows on the southern slope of the Tian Shan Mountain range.Total P was found to be 851.9-1556.7 mg·kg^(-1) at different elevational gradients and 437.5-1547.0 mg·kg^(-1) at different slope aspects,and highest at 3337 and 3652 m.a.s.l.,but little differences between slope aspects.Olsen P and Labile P linearly increased with the elevational gradient.The valley and the base of the shady slope had higher contents of H_2O-Po.NaHCO_3-Pi,and NaHCO_3-Po,and high-active organic P(NaHCO_3-Po,NaOH-Po,and H_2O-Po) was positively correlated with soil total carbon(TC),total nitrogen(TN),soil organic carbon(SOC),and aboveground biomass(AGB),but was negatively correlated with pH,aluminum(Al),and calcium(Ca) at different elevational gradients.High-active bioavailable P(H_2OPi,H_2O-Po,NaHCO_3-Pi,and NaHCO_3-Po) was positively correlated with soil SOC and AGB and was negatively correlated with pH at different slope aspects.Our results suggest that soil P availability in alpine meadows is significantly controlled by topographical factors and the valleys and base of shady slopes are reservoirs of high-active bioavailable P.
基金supported by the National Natural Science Foundation of China(Grant No.41272220)the Chinese Academy of Sciences(Grant Nos.KZCX2-YW-BR-21 and KZZD-EW-TZ-06)
文摘The primary productivity of terrestrial ecosystems is influenced by soil phosphorus bioavailability, which depends largely on chemical fractions of phosphorus. The sequential fractionation technique developed by Hedley et al. or its subsequent modification is a well-known method to determine soil phosphorus forms. Hedley sequential fractionation technique separates the phosphorus into fractions based on their different chemical solubilities in extractants with certain chemical properties. Recently, synchrotron-based X-ray absorption near edge structure(XANES) spectroscopy has been employed to measure soil phosphorus species directly and non-invasively. The XANES method provides information concerning local structure and chemical information of target elements at a molecular level. Thus, it can distinguish phosphorus fractions bound by metal oxides or hydroxides(such as Fe, Al, and Ca). In this present work, the phosphorus speciation of topsoil along a glacial foreland chronosequence in Gongga Mountain is determined using these two methods. The changes in soil phosphorus bioavailability along the 120-year-old chronosequence are assessed based on comparisons of the results obtained by these two methods. The results indicate that Hedley sequential fractionation technique shows a greater ability to determine soil bioavailable phosphorus(Resin-P and NaCHO3-P), while XANES is effective in distinguishing phosphorus bound by metal compounds. In the chronosequence, Ca- and Al-bound phosphorus were derived mainly from primary minerals, whose phosphorus contents decreased within 120 years of moraine weathering and soil development. The content of soil bioavailable phosphorus increased rapidly after 30 years since deglaciation. The increasing phosphorus bioavailability promoted the colonizing and primary succession vegetation.
