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Study On Variabilities Of Soil Carbon Pool And Landscape Patterns In Typical Agro-Forestry Ecosystem

Posted on:2020-01-07Degree:DoctorType:Dissertation
Country:ChinaCandidate:S L CaoFull Text:PDF
GTID:1483305909478124Subject:Crop Cultivation and Farming System
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There can be numerous scientific and practical significations to study the internal relations between soil carbon pool and environmental conditions under the pattern of agroforestry landscape with different land cover types,farm managements,geographical conditions and other human activities or natural factors,such as characteristics of soil carbon sink revealing,greenhouse gas emission reducing,levels of food security and soil quality improving,sustainable agriculture developing and global carbon cycling models building.Thus,a study about changes and statuses of agricultural landscape patterns,and effects of environmental conditions on spatial variabilities of soil carbon pool and their internal relations was taken in the low plain areas of Canterbury plain which is located at the middle east of south island in New Zealand,the study was based on field soil samplings,previously obtained land use data(NALUD from LCRC,2016)and land cover data(LCDB2 from MFE,2004 & LCDB4.1 from MFE,2015),Geographic Information System,Global Positioning System and Remote Sensing technologies.Main results were summarized as follows:1.Soil type,land cover type and land use type are the main factors which contributed the spatial variabilities of soil carbon pool in agro-forestry ecosystem.2.Factors influencing soil carbon pool in agro-forestry ecosystem are different when at different scales,shelterbelt species,shelterbelt age,soil pH and soil moisture are the main influencing factors at fine scale,landuse type and soil type are the main influencing factors at mesoscale.3.Shelterbelts around the farms can reduce the effects of human activities on the structural and functional characteristics of soil living things and microbial communities in agroecosystems.4.Power analysis with 95% confidence showed that it is more scientific and feasible to set 3 samples for soil pH,soil bulk density,soil carbon and soil nitrogen,15 samples for soil moisture,soil organic carbon,soil liable carbon,BLP and TBI,and 9 samples for DHA while evaluating the spatial variabilities of soil carbon pool in agroforestry ecosystem.5.Shelterbelts around the farms contributed considerable carbon storage,the total carbon storage of above and below ground within the shelterbelt is nearly 3 times than that in the farming and pasturing farmfields nearby.6.It is more feasible and practical to operate soil carbon pools by optimizing human activities those are influencing the soil carbon pool.7.Land use types and land cover types of the study region were little changed during the period from 2002 to 2014,it was mainly based on three types of land use,which were pasture,agriculture or horticulture and forestry,while forage grass,crops and forests were the main land cover types;grassland and arable land absolutely dominated the landscape types in the study region with high connectivity and obvious basement effects while other landscape elements inlaided.8.The landscape pattern was strongly influenced by human activities while the landscape fragmentation was low;substance,energy and information with high flowability among each landscape elements;road,water body and forest frame were strongly influencing the ecological flow and distribution of land use types in the whole study region.9.Soil carbon and soil organic carbon storage of the study region were estimated to be 7.14Mt~12.66Mt(MeanąSD 9.92ą1.05)and 3.66Mt~8.54Mt(MeanąSD 6.25 ą1.02)by soil type method,while 8.35Mt~12.08Mt(MeanąSD 10.52ą1.03)and 4.13Mt~9.29Mt(MeanąSD 6.89ą1.19)by land use type method,the estimated soil carbon and soil organic carbon storage were confident due to the similar results by using two estimation methods.10.Northwest and southeast regions of the study area with higher soil carbon especially at the lower reaches of Rakaia River and most regions at the middle reaches of Rakaia River with lower soil carbon.11.Soil organic carbon gradually decreases from northwest to southeast while the altitude decreases,the pasture regions at the middle reaches of Rakaia River with highest soil organic carbon and the regions at the lower reaches of Rakaia River with lowest soil organic carbon.
Keywords/Search Tags:Agro-forestry, Landscape Pattern, Soil Carbon Pool, Land Use, Land Cover, Agricultural Sustainability
PDF Full Text Request
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