Phosphorus Nutrition Strategies And Output Of Plant Communities Under Different Soil Phosphorus Condition In Central Yunnan

Phosphorus is an important component of the living system,and its migration and transformation in the ecosystem is one of the decisive factors in the structure and function of the ecosystem.However,the soil contains less phosphorus and is a limiting nutrient element of biological productivity on Earth.Plants and soils in the ecosystem are mutually feedback.Plants adapt to different soil phosphorus conditions to form different phosphorus nutrition strategies.In phosphorus-rich areas,plants and microorganisms convert phosphorus in rock parent material into biogeochemistry.Phosphorus cycle(acquisition strategy).In contrast,in areas where phosphorus is scarce,a tight phosphorus cycle is established to maintain plant phosphorus demand(recovery strategy).There are few studies on the relationship between soil and plant community phosphorus strategies under different phosphorus conditions.In this study,the plant communities with different phosphorus conditions were selected,and the quantitative analysis of the indexes of phosphorus harvesting and recovery was discussed to explore the high phosphorus area.Phosphorus nutrition strategies of plant communities in the middle and lower phosphorus areas,analysis of community eco-hydrological processes,study of phosphorus loss from surface runoff in different soil phosphorus conditions,and data support for non-point source pollution prevention and control in the Fuzhong phosphorus-rich area.The research conclusions are as follows:(1)There were significant differences in soil total phosphorus content in the three project areas selected in this study.The total phosphorus content in the soil was:high phosphorus area(8268.90 mg·kg-1)>medium phosphorus area(3227.78 mg·kg-1)>low phosphorus Zone(208.62 mg·kg-1).The content of soil active phosphorus(H2O-Pi,NaHCO3-Pi and NaHCO3-Po)accounted for 4.84%?1.70%of total phosphorus,and the active phosphorus content in high phosphorus area was significantly higher than that of middle phosphorus area and low phosphorus area.The proportion of phosphorus in the medium active phosphorus content(NaOH-P)is larger,and the proportion of inactive phosphorus(HC1-P + residual-P)in the low phosphorus region is higher than that in the high phosphorus zone and the middle phosphorus zone.From the high phosphorus zone to the low phosphorus zone,the ratio of total organic carbon to organic phosphorus(C:Porganic)increased f'rom 22 to 178.Correspondingly,the SOM.TN,and various forms of phosphorus content also showed a decreasing change.(2)Under different soil phosphorus conditions,the dominant factors affecting plant community and diversity are different.From the low-phosphorus zone to the high-phosphorus zone,the correlation of TP to community structure is gradually reduced,and TN and SOM in high-phosphorus zone are the decisive factors affecting community structure and diversity.The diversity index of coniferous and broad-leaved forest communities increased with the increase of soil phosphorus background value,and the desert grass slope had the highest diversity index in the middle phosphorus region.(3)In the high-phosphorus region,the phosphorus content in the leaves of plants increased with the increase of soil concentration,and the litter showed a similar trend.In the low-phosphorus region,the phosphorus content of plants from leaves to litter decreased more than that of high-phosphorus.Although there are large differences in phosphorus concentrations in different soils,the concentration of fine root phosphorus decreases with the extent of soil phosphorus.(4)The fine root biomass increased with the decrease of soil phosphorus content(except for the grassland slope),and the rhizosphere soil acid phosphorus enzyme also showed such a trend(except for the grassland slope).Microbial phosphorus increased with the increase of soil phosphorus content,but the highest value was in the middle phosphorus area.Phosphorus fixation in the low-phosphorus area accounted for 79.93%of the available phosphorus source(phosphorus mineral dissolution and organic phosphorus ore),higher than 51.01%in the high phosphorus area and 59.37%in the middle phosphorus area,indicating that the microorganisms lack phosphorus in the soil.Under the condition,the fixation rate of phosphorus is improved,which is beneficial to maintain the availability of phosphorus in soil.It also shows that the phosphorus recovery intensity in phosphorus nutrition strategy increases with the decrease of soil phosphorus.(5)Through the quantitative analysis of phosphorus strategy indicators,in addition to the wasteland slope,the phosphorus recovery index of other communities decreased with the increase of soil phosphorus content,and the phosphorus acquisition index was reversed.The coniferous forest and broad-leaved forest community conformed to phosphorus nutrition.Strategy,but the grass slope does not match.In addition to the wasteland slope,other plant communities increased the utilization efficiency of phosphorus by the plant community with the increase of the recovery index.(6)The community structure of high phosphorus area is complex and the phosphorus area is complex.The surface runoff shows:low phosphorus area>high phosphorus area.In the same area,the more complex the community structure,the less surface runoff,showing:grassland slope>Warm coniferous forest>Sub-humid evergreen broad-leaved forest.The total amount or concentration of phosphorus in surface runoff,the high phosphorus area is larger than the low phosphorus area,and inorganic phosphorus accounts for the main part in dissolved phosphorus.