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Distribution Pattern Of The Stoichiometry Characteristics In Main Plantations Of Sichuan Basin,China

Posted on:2020-11-17Degree:MasterType:Thesis
Country:ChinaCandidate:S M SongFull Text:PDF
GTID:2393330590998025Subject:Forest cultivation
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Ecological stoichiometry is a critical path to understand the relative proportion of plant chemical elements and it’s common change law with the biological factor or abiotic environment in the ecological process.It can provide data basis for formulating nutrient management strategy of resource demand-supply situation at different levels in plantation management and cultivation.In order to understand the distribution pattern of C,N,P and ratios of plantations in Sichuan basin,we chose four main species(Eucalyptus grandis,Cupressus funebris,Pinus massoniana and Cunninghamia lanceolata)as our survey samplings from 288 standard plots from the main cultivation.The content of C,N and P in the leaves of different species in different age groups and site types were determined,and their C:N,C:P and N:P ratios were calculated.The results showed that:1)The C,N and P contents in the leaves of four plantations(Eucalyptus grandis,Cupressus funebris,Pinus massoniana and Cunninghamia lanceolata)were(529.30±21.52)g kg-1,(10.05±0.77)g kg-1 and(1.08±0.21)g kg-1,and the C:N ratio,C:P ratio and N:P ratio of which were 53.31±5.81,509.29±106.92,9.51±1.58,respectively.From the perspective of large-scale geographical pattern,as a whole,four plantations in the study area presented a nutrient pattern of―scarce N,P relatively‖,N may become a limited nutrient element in their growth and development.The four plantations in the middle hilly of Sichuan basin(N:P was 9.73±2.22),the southern middle-low mountains of Sichuan basin(N:P was 9.09±1.27),the northern middle-low mountains of Sichuan basin(N:P was9.88±0.42),and the western middle-low mountains of Sichuan basin(N:P was 9.54±1.79)were all restricted by N and the southern middle-low mountains of Sichuan basin was the most serious.The four plantations in the plain(N:P was 7.75±0.25)and the hilly(N:P was9.53±0.54)were both restricted by N and the plain was the most serious,while the mountainous(N:P was 10.01±0.83)was retricted by both N and P or unrestricted restrictions of them.The four plantations in the purple soil(N:P was 9.37±1.42)and the yellow soil(N:P was 9.15±1.66)were both restricted by N.2)The C,N,P contents and their ratios of the four plantations were significantly affected by the species,site type,age group and their interactions(p<0.05),the characteristics of plant nutrient distribution were different in species,site type and age group.Compared with the four different species,the Eucalyptus grandis and Cunninghamia lanceolata were mainly restricted by N in each site type(N:P were 7.88±0.34 and 9.23±0.35);the Cupressus funebris in the northern middle-low mountains of Sichuan basin(N:P was 10.04±0.26)and the mountainous(N:P was 10.04±0.24)were retricted by both N and P or unrestricted restrictions of them;whlie the other site types were restricted by N severely(N:P was 9.65±0.46),the other site types were retricted by both N and P or unrestricted restrictions of them in the Pinus massoniana(N:P was 10.92±1.30),except N restriction in the northern middle-low mountains of Sichuan basin(N:P was 9.77±0.12).3)Site type significantly affected the C,N and P characteristics of the main plantations in different age groups.In the same age group,N and P were insufficient relatively in all site types of Eucalyptus grandis.N and P were insufficient relatively in the best site types of Cupressus funebris(Cf-Ⅱ1.11、Cf-Ⅱ21 and Cf-Ⅰ1.12),and the growth was retricted by both N and P or unrestricted restrictions of them;N and P were scarced relatively in the general site types,and partial growth was limited by N,the other partial growth was retricted by both N and P or unrestricted restrictions of them;N was scarced relatively in the poor site types(Cf-Ⅰ2.21、Cf-Ⅰ1.31 and Cf-Ⅰ2.31),and the growth was retricted by N severely.N and P were insufficient relatively in the best site types of Pinus massoniana(Pm-Ⅰ11、Pm-Ⅰ12、Pm-Ⅰ13、Pm-Ⅰ21、Pm-Ⅱ1.11、Pm-Ⅱ1.21 and Pm-Ⅱ1.22)and the general site types,the growth was retricted by N or P;N was scarced relatively in the poor site types(Pm-Ⅱ1.42、Pm-Ⅱ2.11 and Pm-Ⅱ2.21),and the growth was retricted by N severely.N and P were insufficient relatively in the best site types of Cunninghamia lanceolata(Cl-Ⅱ1.12、Cl-Ⅱ1.21、Cl-Ⅱ1.22 and Cl-Ⅱ1.23)and the general site types;N was scarced relatively in the poor site types(Cl-Ⅰ11、Cl-Ⅰ12、Cl-Ⅰ13、Cl-Ⅰ21、Cl-Ⅰ22、Cl-Ⅰ23、Cl-Ⅱ2.11 and Cl-Ⅱ2.13),and the growth in all the site types was retricted by N severely.4)Age group significantly affected the C,N and P characteristics of the main plantations in different site types.In the same site type,with the age group increased,the C content,C:N ratio,C:P ratio and N:P ratio of Eucalyptus grandis,Pinus massoniana and Cunninghamia lanceolata decreased first and then rose,the N content and the P content of them rose first and then fell,the change trend of Cupressus funebris plantation was opposite.The growth process of the four main plantations in Sichuan was restricted by N severely(N:P was 8.91±1.23),which was alleviated in the later growth stage,while the mature stand stage of growth stage of Pinus massoniana was restricted by P(N:P was16.45±0.56).Combined with the basic data above,an efficient,concise and reasonable nutrient diagnostic index system can be established from the perspective of stoichiometry.The aim was to find out the supply of restricted nutrient elements in different age groups and site types,balance and adjust the distribution pattern of plant C,N and P.At the same time,N fertilizer(at the young stage of four plantations)or P fertilizer(at the mature stage of Pinus massoniana plantation)can be applied,or introduced nitrogen-fixing irrigation plants.The research results were of great significance to understand the C,N and P nutrient distribution pattern of the main plantations in our province,guide their production practice and sustainable management,and construct a stable and healthy plantation ecosystem.
Keywords/Search Tags:site type, age group, ecological stoichiometry, nutrient utilization efficiency, Eucalyptus grandis, Cupressus funebris, Pinus massoniana, Cunninghamia lanceolata
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