The Influence Of Chinese Ifr Ecosystem Conversion On The Soil Phosphorus Forms And Its Mechanism

Phosphorus is one of the essential nutrient elements for plant’s growth and development, it isan important component composed of many compounds in plants, and plays an irreplaceable role inplant’s growth and metabolic processes. Studies have shown that phosphorus deficiency soil areaare widely distributed in China, it is estimated that China’s about1/3to1/2soil have phosphorusdeficiency, fertilization utilization is very low, the phosphate fertilizer applied to soil, and soontransformed into forms of inorganic phosphorus accumulated a direct impact on phosphorusbioavailability[1⁴].Therefore, to explore soil phosphorus forms and their conversion characteristics,and how to improve the utilization of soil phosphorus, so that a large number of invalid statephosphorus stored in the soil can be utilized for the growth of plants, has cause for wide range ofconcern of foreign soil scientists and plant nutritionists in many domestic.The chemical behavior of phosphorus in the soil and the presence of form is one of thepriorities of soil science research. From the results of the present study, the research on soilphosphorus forms in the field of the agricultural sector is relatively large, mainly concentrated inexploration and improvement of Soil Phosphorus Fractionation methods,and farming methods, croprotation, fertilization, soil type and parent material Soil phosphorus forms[5⁹], as well as measuresto increase soil phosphorus availability in the field.Research on forestry soil phosphorus forms has arelatively late start, the study is relatively small and weak. Fir is a fast-growing timber specie insouthern China, the soil fertility decline mechanism have been numerous reported, and a number ofdifferent viewpoints and hypotheses have been Put forward[10¹3], these studies focused on soilphysical properties, nutrient content, enzyme activities and microbial and other aspects relevanteven planted fir soil phosphorus forms is rarely reported. Therefore, to enhance the study of soilphosphorus forms in their transformation of fir ecosystem conversion process, have greatsignificance for revealing the scientific management of Chinese fir plantation soil fertility declinemechanism in-depth and Scientific management of forest ecosystems.In view of this, We select the Nanping celery forest teaching floor to establishe5forestecosystem models （including the mode of evergreen forest, old growth forest mode, the buddingforest mode,91plantations mode and93plantation mode） as the fir ecological series plots of theconversion mode, using the method of field orientation, focus on the composition of the soilphosphorus forms in the fir ecosystem translation process, content and its temporal variationin-depth study, while the use of artificial simulation technology, to further explore the simulatedacid rain, Add a litter and the mechanism of calcium carbonate on the soil of inorganic phosphorus.Scientific theory and practical guidance for in-depth to reveal the the fir plantition recessionmechanism, explore effective ways of the soil phosphorus and degraded Chinese fir plantationecosystem restoration and reconstruction.Specific conclusions are as follows;（1）There are significant difference of the total soil phosphorus content, the overallperformance is that the second-generation fir （bud forest,91plantations and93plantations） washigher than the law of the old growth forest and evergreen forest, as well as the seasonal variation of total soil phosphorus.（2） The available phosphorus content of various systems in soil is overall at the same level,the contentof second-generation fir is slightly lower than the old growth forest and evergreen forest,but the difference is not obvious. Analysis of variance showed that it only reach a significant levelof content in each system between July and the rest of the month the difference was not significant.（3） The soil phosphorus activation coefficient （PAC） were lower than2.0, overall, PAC of theold growth forest and evergreen forest is higher,the second-generation fir generally shows lowphosphorus availability.（4） The content of total phosphorus, available phosphorus, various forms of inorganicphosphorus, organic phosphorus forms in various systems of soil generally decreased with depth,but Al-P of the evergreen forest, O-P and stability of organic phosphorus and91plantations in theCa-P, the O-P as well as93plantations in the O-P, O-P content of the medium activity organicphosphorus and old growth forest with soil depth has increased.（5） There are some differences between various systems of Al-P content, in particular,91、93second-generation fir content are higher than other systems; various systems of Fe-P content was nosignificant difference in the seasonal changes of the various systems of Fe-P content in Aprilcompared with other months are relatively low; each system O-P content differences,second-generation fir content higher than the old growth forest and evergreen forest, especiallybudding forest of the content is much higher than other systems, there is a certain law in theseasonal changes, the system in April20-40cm soil O-P was significantly higher than other months;have some differences in the various systems of Ca-P content, evergreen content is significantlylower than other fir, and the laws change with the seasons, usually in January and October, therelative higher, lower in April and July.（6） The proportion of the total phosphorus of the inorganic phosphorus is in the range of50.58⁶9.02%; In various forms of inorganic phosphorus, the proportion of O-P in the total inorganicphosphorus is about67.82⁸1.14%, followed by Ca-P and Fe-P The proportion of8.57to15.77%and7.86to15.13%, respectively, Al-P has the lowest proportion of1.11⁴.72%.（7） The proportion of organic phosphorus forms in the total organic phosphorus and totalphosphorus is between30.28and47.97%; the organic phosphorus forms in the medium activityorganic phosphorus accounted for the highest proportion of organic phosphorus,60.01⁸1.54%,the stability of organic phosphorus, followed by6.64²9.24for the high stability of organicphosphorus,4.89to11.34%active organic phosphorus share of the lowest in the range of1.32to6.58.（8） Significant positive correlation coefficient r=0.483**,0.594**,0.437**, and O-Preached a significant negative correlation between total P and labile organic phosphorus, organicphosphorus of the medium activity of Ca-P correlation coefficient of-0.279**, significant negativecorrelation with the Fe-P, the correlation coefficient was-0.176; soil available P and Al-P, Fe-P,pHand medium activity organic phosphorus correlation coefficient r=0.220**,0.394**,0.204**,0.293**, to achieve a very significant positive correlation.（9） Principal component analysis concluded that the five forest ecosystems in general dividedinto three categories, the first category of old growth forest and evergreen forest, the two systems ofCa-P, Al-P and high-stability organic phosphorus content is low; the second type of Ca-P, Al-P, aswell as highly resistant organic phosphorus content is higher; third category91,93plantation ofCa-P, Al-P, and highly resistant organic phosphorus content highest. This can even planting but soil may be insoluble and difficult to absorb, aluminum phosphate, calcium phosphate and highlyresistant organic phosphorus increasing trend.Added（10） Soil CaCO₃incubation of Ca-P content in the soil increased trend, other forms of inorganicphosphorus decreased; as CaCO₃amount increase of Ca-P, Al-P, the OP content gradually increased,Fe-P is gradually reduced; training in January and February, compared the soil of Ca-P content afterprocessing CaCO₃0.2g than the train in January after the content was increased, and other processingthan the train in January decreased, soil Fe-P content higher than after the control, and CaCO₃0.2gCaCO₃0.8g processing train in January after the content CaCO₃0.4g processing content is lower thandeal with the content after the January of each treatment soil AL-P content the culture of the amountin January, and soil content of the O-P are lower than the January content.（11）To be cultured by joinning the litter, the soil of Ca-P content in general there is anincreasing trend of Fe-P content of the O-P have different degrees of reduction of Al-P content in theculture was increased in January, training in February then be reduced.（12） Different systems of soil inorganic phosphorus forms in response after the extraction ofsimulated acid rain of different pH values, the bud Lin and93plantations system response isrelatively sensitive to acid rain, followed by evergreen forest, while the other two systems on acidrain response is relatively insensitive.（13） The results show that the second-generation fir （including91second-generation Chinese firplantation,93second-generation Chinese fir plantation and second-generation fir sprout naturalregeneration forest）,Although the content of available phosphorus will be slightly lower than thegeneration of aging fir, both close to each other in general, the difference is not obvious; overall totalphosphorus content is also slightly higher than the generation of aging fir, active organic phosphorus andorganic phosphorus in soil of the medium activity is also higher than the generation of aging fir. It showsthat, Fir continuous planting haven’t resulted in the total phosphorus and available phosphorus content insoil decreased under the experimental conditions. This is somewhat inconsistent with the view of somescholars. This difference is whether it is the second generation of this test fir originated in the aging fir （toextend the harvesting of a rotation） through afforestation and fir bud formation stand types, forest land torecuperate, the ecological environment must recovery reasons, fir multi-generation plant connected to soilfertility decline and the existence of regional sensitivity sake, these issues still need further in-depth study.In addition, the morphological comparison of soil phosphorus, also found that the use of second-generationfir forest soil insoluble and difficult to absorb the Al-P and Fe-P, Ca-P, O-P and the stability of organicphosphorus and highly resistant organic phosphorus generally slightly higher than the generation of agingfir, especially Al-P content of soil phosphorus activation coefficient decreased. This phenomenon may becontinuously planted Chinese fir forest soil fertility decline a manifestation of the internal mechanism to bemore research data to validate.