Feng-Rui Li1, Lu-Lu Liu2, Ji-Liang Liu3, Kun Yang4. 1. Linze Inland River Basin Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; Laboratory of Ecology and Agriculture, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: lifengrui@lzb.ac.cn. 2. Linze Inland River Basin Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; Laboratory of Ecology and Agriculture, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: lululiu@lzb.ac.cn. 3. Laboratory of Ecology and Agriculture, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China. 4. Laboratory of Ecology and Agriculture, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Abstract
Soil labile inorganic and organic phosphorus (L-Pi and L-Po) extracted by NaHCO3 are potentially important sources of plant-available P. Their availability is strongly affected by soil physiochemical and biological properties. Here we conducted a field study in an arid region of northwestern China to investigate how L-Pi and L-Po dynamics are affected by changes in physiochemical and biological variables caused by agricultural cultivation of calcareous soils. Topsoils were sampled at multiple sites from natural calcareous grasslands and cultivated farmlands of different ages (32-40 vs. 90-100 years) that had been converted from natural grasslands. We measured L-Pi and L-Po concentrations and a set of key physiochemical (soil pH, concentrations of base cations (K+ + Na+ + Ca2+ + Mg2+), acid anions (Cl- + NO3- + SO42-), nitrate and ammonium nitrogen (N), organic carbon, and total P) and biological (soil microbial biomass carbon (Cmic), alkaline phosphatase activity (Aalp), and abundances of soil macroinvertebrates (Amacro) and mesoinvertebrates (Ameso)) variables. The concentration of L-Pi and L-Po was 484% and 128% higher and their proportion in the total P content was 354% and 78% higher in young farmland soils, whereas L-Pi and L-Po concentrations were 583% and 423% higher and their proportions were 353% and 240% higher in old farmland soils compared to grassland soils. Increases in L-Pi and L-Po attributable to soil P release may be driven by crucial processes of soil acidification-induced phosphate dissolution and soil biota-driven Po mineralisation. Path analyses revealed that L-Pi and L-Po dynamics were shaped by the complex interactions among five key controlling factors, soil pH, nitrate-N, Ameso, Cmic, and Aalp, involved in these crucial processes. We conclude that cultivation of calcareous soils significantly increases the availability of L-Pi and L-Po, emphasizing the importance of this land-use change as a regulator of P cycling in calcareous soils.
Soil labile n class="Chemical">inorganic andpan> class="Chemical">organic phosphorus (L-Pi and L-Po) extracted by NaHCO3 are potentially important sources of plant-available P. Their availability is strongly affected by soil physiochemical and biological properties. Here we conducted a field study in an arid region of northwestern China to investigate how L-Pi and L-Po dynamics are affected by changes in physiochemical and biological variables caused by agricultural cultivation of calcareous soils. Topsoils were sampled at multiple sites from natural calcareous grasslands and cultivated farmlands of different ages (32-40 vs. 90-100 years) that had been converted from natural grasslands. We measured L-Pi and L-Po concentrations and a set of key physiochemical (soil pH, concentrations of base cations (K+ + Na+ + Ca2+ + Mg2+), acid anions (Cl- + NO3- + SO42-), nitrate and ammonium nitrogen (N), organic carbon, and total P) and biological (soil microbial biomass carbon (Cmic), alkaline phosphatase activity (Aalp), and abundances of soil macroinvertebrates (Amacro) and mesoinvertebrates (Ameso)) variables. The concentration of L-Pi and L-Po was 484% and 128% higher and their proportion in the total P content was 354% and 78% higher in young farmland soils, whereas L-Pi and L-Po concentrations were 583% and 423% higher and their proportions were 353% and 240% higher in old farmland soils compared to grassland soils. Increases in L-Pi and L-Po attributable to soil P release may be driven by crucial processes of soil acidification-induced phosphate dissolution and soil biota-driven Po mineralisation. Path analyses revealed that L-Pi and L-Po dynamics were shaped by the complex interactions among five key controlling factors, soil pH, nitrate-N, Ameso, Cmic, and Aalp, involved in these crucial processes. We conclude that cultivation of calcareous soils significantly increases the availability of L-Pi and L-Po, emphasizing the importance of this land-use change as a regulator of P cycling in calcareous soils.
Authors: Qiao Yang; Zhongqiu Zhao; Hong Hou; Zhongke Bai; Ye Yuan; Zhijie Su; Guangyao Wang Journal: Environ Sci Pollut Res Int Date: 2020-02-07 Impact factor: 4.223