不同土地利用方式对岷江流域土壤团聚体稳定性及有机碳的影响
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摘要
采用湿筛法测量了岷江流域不同土地利用方式下不同土层(0—10,10—20,20—30cm)土壤大团聚体(>2mm)、中间团聚体(0.25~2mm)、微团聚体(53μm~0.25mm)以及粉+黏团聚体(<53μm)的质量分数及各粒径团聚体中的有机碳含量,并探讨了各粒径土壤团聚体的有机碳储量。结果表明,土地利用方式对土壤团聚体稳定性及其有机碳具有重要影响;土壤养分均呈现出一致性规律,大致表现为撂荒地>次生林>人工林>灌草丛>坡耕地,土壤全磷差异并不显著(p>0.05);林地的开垦行为会导致大团聚体的破碎化,灌草丛及坡耕地>0.25 mm的大团聚体含量较林地低,土壤结构趋于恶化;而坡耕地闲置为撂荒地后,则会促使粉+黏团聚体向粒径大的微团聚体及中间团聚体转化,使土壤结构趋于改善,在0—30cm土层内,灌草丛及坡耕地土壤颗粒的MWD(平均质量直径)和GMD(几何平均直径)值均显著低于林地和撂荒地(p<0.05),坡耕地撂荒后,MWD和GMD值均显著升高(p<0.05),表明林地开垦为坡耕地导致土壤团聚体的稳定性降低,而坡耕地弃耕撂荒会增强团聚体的稳定性,提高土壤抵抗外力破坏的能力。不同土地利用方式下各粒径土壤团聚体有机碳含量均随土层深度的增加而降低。在0—30cm土层深度内,不同土地利用方式下各粒径土壤团聚体有机碳储量表现为:大团聚体有机碳储量为林地>撂荒地>灌草丛>坡耕地,中间团聚体有机碳储量为撂荒地>林地>灌草丛>坡耕地,微团聚体有机碳储量为撂荒地>林地>灌草丛>坡耕地;粉+黏团聚体有机碳储量为撂荒地>林地>灌草丛>坡耕地。各粒径土壤团聚体内有机碳储量均为林地和撂荒地高于果园和坡耕地,表明将林地开垦为坡耕地后,将导致各团聚体组分内有机碳的损失,而坡耕地撂荒则有助于土壤有机碳的恢复和截存;林地和撂荒地土壤有机碳主要蓄积在中间团聚体内,而坡耕地则主要蓄积在粉+黏团聚体内,表明在土地利用变化过程中,粒径较大的团聚体有机碳不稳定,更容易发生变化。
In order to study the effect of land use type on stability and organic carbon of soil aggregates in Minjiang River Valley,we selected five land use types of soils,which are abandoned land,secondary forest,scrub-grassland,artificial forest and sloping farmland abandoned land,and then we got the proportions of large macroaggregates(>2 mm),small macroaggregates(0.25~2 mm),microaggregates(53μm~0.25 mm)and silt+clay(<53μm)by wet sieving method,and measured the content of organic carbon in each aggregate fraction in 0—30 cm soil depth and calculated the total content of organic carbon of all aggregates fraction in each soil.The results showed that the soil nutrients of these land use types had the same change rule,while the soil phosphorus had no significant difference in these land use types(p>0.05);reclamation of woodland could lead to fragmentation of macroaggregates and deterioration of soil structure,respectively;changing the sloping farmland to abandoned land could lead to the conversion of soil fraction from silt+clay to large macroaggregates and small macroaggregates,which could improve the soil structure,MWD(mean weight diameter)and GMD(geometric mean diameter)are important indicators of evaluating the stability of soil aggregates.We found that the MWD and GWD in 0—30 cm soil depth in sloping farmland were significantly lower than those in woodland(p<0.05),after changing the sloping farmland to abandoned land,the MWD and GWD increased significantly(p<0.05),which indicated that reclamation of woodland could lead to the decrease of stability of soil aggregates.However,after changing the sloping farmland to abandoned land could enhance the stability of soil aggregates,and improve the ability of soil to resist external damage.The organic carbon content in each soil aggregate of four land use types decreased with the increase of soil depth.In soil depth of 0—30 cm,the storage of organic carbon in large macroaggregates in each soil decreased in order:abandoned land>forest>scrub-grassland>sloping farmland,and abandoned land>forest>scrub-grassland>sloping farmland in small macroaggregates,and abandoned land>forest>scrubgrassland>sloping farmland in microaggregates and in silt and clay fraction.Storage of organic carbon in each aggregate in the soils of woodland and abandoned land were higher than those in the soils of sloping farmland,which indicated that reclamation of woodland could lead to a loss of organic carbon in each soil aggregate fraction,changing the sloping farmland to abandoned land could restore and sequestrate the soil organic carbon.In addition,it showed that most organic carbon accumulated in small macroaggregate in soils of woodland and abandoned land,while it was sequestrated in silt and clay in soils of sloping farmland,indicating that organic carbon in larger aggregates is unstable and is easier to convert during the land use change.
In order to study the effect of land use type on stability and organic carbon of soil aggregates in Minjiang River Valley,we selected five land use types of soils,which are abandoned land,secondary forest,scrub-grassland,artificial forest and sloping farmland abandoned land,and then we got the proportions of large macroaggregates(>2 mm),small macroaggregates(0.25~2 mm),microaggregates(53μm~0.25 mm)and silt+clay(<53μm)by wet sieving method,and measured the content of organic carbon in each aggregate fraction in 0—30 cm soil depth and calculated the total content of organic carbon of all aggregates fraction in each soil.The results showed that the soil nutrients of these land use types had the same change rule,while the soil phosphorus had no significant difference in these land use types(p>0.05);reclamation of woodland could lead to fragmentation of macroaggregates and deterioration of soil structure,respectively;changing the sloping farmland to abandoned land could lead to the conversion of soil fraction from silt+clay to large macroaggregates and small macroaggregates,which could improve the soil structure,MWD(mean weight diameter)and GMD(geometric mean diameter)are important indicators of evaluating the stability of soil aggregates.We found that the MWD and GWD in 0—30 cm soil depth in sloping farmland were significantly lower than those in woodland(p<0.05),after changing the sloping farmland to abandoned land,the MWD and GWD increased significantly(p<0.05),which indicated that reclamation of woodland could lead to the decrease of stability of soil aggregates.However,after changing the sloping farmland to abandoned land could enhance the stability of soil aggregates,and improve the ability of soil to resist external damage.The organic carbon content in each soil aggregate of four land use types decreased with the increase of soil depth.In soil depth of 0—30 cm,the storage of organic carbon in large macroaggregates in each soil decreased in order:abandoned land>forest>scrub-grassland>sloping farmland,and abandoned land>forest>scrub-grassland>sloping farmland in small macroaggregates,and abandoned land>forest>scrubgrassland>sloping farmland in microaggregates and in silt and clay fraction.Storage of organic carbon in each aggregate in the soils of woodland and abandoned land were higher than those in the soils of sloping farmland,which indicated that reclamation of woodland could lead to a loss of organic carbon in each soil aggregate fraction,changing the sloping farmland to abandoned land could restore and sequestrate the soil organic carbon.In addition,it showed that most organic carbon accumulated in small macroaggregate in soils of woodland and abandoned land,while it was sequestrated in silt and clay in soils of sloping farmland,indicating that organic carbon in larger aggregates is unstable and is easier to convert during the land use change.
引文
[1]王清奎,汪思龙.土壤团聚体形成与稳定机制及影响因素[J].土壤通报,2005,36(3):415-421.
[2]卢金伟,李占斌.土壤团聚体研究进展[J].水土保持研究,2002,9(1):81-85.
[3]史奕,陈欣,沈善敏.土壤团聚体的稳定机制及人类活动的影响[J].应用生态学报,2002,13(11):1491-1494.
[4]窦森,李凯.土壤团聚体中有机质研究进展土壤团聚体中有机质研究进展[J].土壤学报,2011,48(2):412-418.
[5]蔡立群,齐鹏,张仁陟.保护性耕作对麦—豆轮作条件下土壤团聚体组成及有机碳含量的影响[J].水土保持学报,2008,22(2):141-145.
[6]赵世伟,苏静,吴金水,等.子午岭植被恢复过程中土壤团聚体有机碳含量的变化[J].水土保持学报,2006,20(3):114-117.
[7]刘纪远,张增祥.中国近期土地利用变化的空间格局分析[J].中国科学:D辑,2002,32(12):1031-1040.
[8]王思远,刘纪远,张增祥,等.中国土地利用时空特征分析[J].地理学报,2010,56(6):631-639.
[9]王清奎,汪思龙.土壤团聚体形成与稳定机制及影响因素[J].土壤通报,2005,36(3):415-421.
[10]宇万太,沈善敏,张璐,等.黑土开垦后水稳性团聚体与土壤养分的关系[J].应用生态学报,2004,15(12):2287-2291.
[11]郑子成,何淑勤,王永东,等.不同土地利用方式下土壤团聚体中养分的分布特征[J].水土保持学报,2010,24(3):170-174.
[12]姜培坤,周国模,钱新标.侵蚀型红壤植被恢复后土壤养分含量与物理性质的变化[J].水土保持学报,2004,18(1):12-14.
[13]周虎,吕贻忠,杨志臣,等.保护性耕作对华北平原土壤团聚体特征的影响[J].中国农业科学,2007,40(9):1973-1979.
[14]邱莉萍,张兴昌,张晋爱.黄土高原长期培肥土壤团聚体中养分和酶的分布[J].生态学报,2006,26(2):364-372.
[15]苏静,赵世伟.植被恢复对土壤团聚体分布及有机碳,全氮含量的影响[J].水土保持研究,2005,12(3):44-46.
[16]杨长明,欧阳竹,董玉红.不同施肥模式对潮土有机碳组分及团聚体稳定性的影响[J].生态学杂志,2005,24(8):887-892.
[17]罗歆,代数,何丙辉,等.缙云山不同植被类型林下土壤养分含量及物理性质研究[J].水土保持学报,2011,25(1):64-69.
[18]赵世伟,苏静,吴金水,等.子午岭植被恢复过程中土壤团聚体有机碳含量的变化[J].水土保持学报,2006,20(3):114-117.
[2]卢金伟,李占斌.土壤团聚体研究进展[J].水土保持研究,2002,9(1):81-85.
[3]史奕,陈欣,沈善敏.土壤团聚体的稳定机制及人类活动的影响[J].应用生态学报,2002,13(11):1491-1494.
[4]窦森,李凯.土壤团聚体中有机质研究进展土壤团聚体中有机质研究进展[J].土壤学报,2011,48(2):412-418.
[5]蔡立群,齐鹏,张仁陟.保护性耕作对麦—豆轮作条件下土壤团聚体组成及有机碳含量的影响[J].水土保持学报,2008,22(2):141-145.
[6]赵世伟,苏静,吴金水,等.子午岭植被恢复过程中土壤团聚体有机碳含量的变化[J].水土保持学报,2006,20(3):114-117.
[7]刘纪远,张增祥.中国近期土地利用变化的空间格局分析[J].中国科学:D辑,2002,32(12):1031-1040.
[8]王思远,刘纪远,张增祥,等.中国土地利用时空特征分析[J].地理学报,2010,56(6):631-639.
[9]王清奎,汪思龙.土壤团聚体形成与稳定机制及影响因素[J].土壤通报,2005,36(3):415-421.
[10]宇万太,沈善敏,张璐,等.黑土开垦后水稳性团聚体与土壤养分的关系[J].应用生态学报,2004,15(12):2287-2291.
[11]郑子成,何淑勤,王永东,等.不同土地利用方式下土壤团聚体中养分的分布特征[J].水土保持学报,2010,24(3):170-174.
[12]姜培坤,周国模,钱新标.侵蚀型红壤植被恢复后土壤养分含量与物理性质的变化[J].水土保持学报,2004,18(1):12-14.
[13]周虎,吕贻忠,杨志臣,等.保护性耕作对华北平原土壤团聚体特征的影响[J].中国农业科学,2007,40(9):1973-1979.
[14]邱莉萍,张兴昌,张晋爱.黄土高原长期培肥土壤团聚体中养分和酶的分布[J].生态学报,2006,26(2):364-372.
[15]苏静,赵世伟.植被恢复对土壤团聚体分布及有机碳,全氮含量的影响[J].水土保持研究,2005,12(3):44-46.
[16]杨长明,欧阳竹,董玉红.不同施肥模式对潮土有机碳组分及团聚体稳定性的影响[J].生态学杂志,2005,24(8):887-892.
[17]罗歆,代数,何丙辉,等.缙云山不同植被类型林下土壤养分含量及物理性质研究[J].水土保持学报,2011,25(1):64-69.
[18]赵世伟,苏静,吴金水,等.子午岭植被恢复过程中土壤团聚体有机碳含量的变化[J].水土保持学报,2006,20(3):114-117.
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