黄土丘陵区恢复草地土壤团聚体组成及全氮分布特征OACHSSCDCSCDCSTPCD
Restoration of grassland soil aggregate composition and total nitrogen distribution characteristics in Loess Hilly Area
团聚体作为土壤基本结构单元,其各粒级全氮(TN)含量对土壤TN储量的贡献各不相同,而草地恢复过程中地上植被会影响土壤团聚体组成与各粒级TN的分布,这必然会对团聚体稳定性和土壤氮素累积产生影响.因此,以恢复10a、20a、30a、40a和50a草地和对照农田(CK)为研究对象,探究草地恢复过程中土壤团聚体氮素累积规律.结果表明:1)50年恢复过程中草地群落经历了茵陈蒿(Artemisia capillaries)茵陈蒿+铁杆蒿(Artemisia stechmanniana)铁杆蒿+兴安胡枝子(Lespedeza davurica)→铁杆蒿+本氏针茅(Stipa bungeanaTrin)→铁杆蒿+白羊草(Bothriochloa ischaemum)的演替过程,且草地群落物种多样性指数随恢复年限的增加呈先升后降的趋势,地上植物、细根和凋落物的碳和氮含量呈先上升后下降趋势.2)草地恢复过程中土壤pH和容重呈下降趋势,而土壤含水量呈先降后增趋势,土壤有机碳含量在恢复过程中显著增加(P<0.05),土壤TN含量随恢复年限呈先增后降的趋势,而TN储量呈逐年增加趋势,恢复10-50a草地与CK相比增加了 8.10%-118.92%.3)不同恢复年限草地群落土壤微团聚体(0.053-0.25 mm)占比最大,但随恢复年限增加呈下降趋势,而大团聚体(>2 mm)和中团聚体(0.25-2 mm)占比以及平均重量直径(MWD)和几何平均直径(GMD)呈上升趋势.4)不同恢复年限草地群落中团聚体TN含量最高,且各粒级团聚体TN含量随恢复年限呈先下降后上升趋势;草地群落微团聚体TN储量最高,大、中团聚体TN储量随恢复年限增加呈上升趋势,微、粘粉粒团聚体(<0.053 mm)TN储量随恢复年限增加出现波动;各粒级团聚体TN储量与地上植物、细根和凋落物生物量以及碳氮含量显著相关(P<0.05).5)草地恢复过程中大团聚体对土壤TN储量的贡献率达70%,且大团聚体占比增加是大团聚体贡献率高的主要原因.总之,草地恢复有利于土壤稳定以及氮素累积.
;Aggregates,as the basic structural unit of soil,contribute differently to soil total nitrogen(TN)stocks in terms of TN content at each grain level.Above-ground vegetation in the process of grassland restoration will affect the composition of soil aggregates and the distribution of TN at each grain level,which will certainly have an impact on the stability of aggregates and soil nitrogen accumulation.Therefore,this study investigated the patterns of nitrogen accumulation in soil aggregates during the restoration of grassland by restoring 10a,20 a,30 a,40 a,and 50 a grassland and control farmland(CK).The results are as follows.1)During the 50 a restoration process,the grass community underwent the succession process of Artemisia inchiensis→ Artemisia inchiensis+Artemisia ferruginea→ Artemisia ferruginea+Lespedeza davurica→Artemisia ferruginea+Stipa bungeanaTrin→Artemisia ferruginea+Bothriochloa ischaemum.The species diversity index of the grass community showed a trend of increasing and then decreasing with the increase of restoration years and the carbon and nitrogen contents of aboveground plants,roots,and litter showed a trend of increasing and then decreasing.2)Soil pH and bulk density showed a decreasing trend during the restoration of grassland,while soil water content showed a decreasing and then increasing trend.The soil organic carbon content increased significantly during the restoration process(P<0.05).The soil TN content showed an increasing and then decreasing trend with the restoration years,while TN storage increased year by year.The restoration of 10-50 a grassland increased by 8.10%-118.92%compared with CK.3)The percentage of soil microaggregates(0.053-0.25 mm)in grassland communities with different restoration years was the largest,which showed a decreasing trend with the increase of restoration years.However,the percentage of large aggregates(>2 mm)and medium aggregates(0.25-2.00 mm),the mean weight diameter(MWD),and geometric mean diameter(GMD)showed an increasing trend.4)The TN content of medium aggregates was the highest in the grass community at different restoration years and the TN content of each grain level aggregates showed a decreasing and then increasing trend with the restoration years.The TN stocks of microaggregates were the highest in the grass community,the TN stocks of large and medium aggregates showed an increasing trend with the increase of restoration years,and the TN stocks of micro and silt+clay fractions aggregates(<0.053 mm)fluctuated with the increase of restoration years.The TN stocks of each grain level aggregates were significantly correlated with the biomass of above-ground plants,roots and litter as well as carbon and nitrogen content(P<0.05).5)The contribution of large aggregates to soil TN stocks during grassland restoration was 70%,and the increase in the percentage of large aggregates was the main reason for the high contribution of large aggregates.In conclusion,grassland restoration is beneficial to soil stability as well as nitrogen accumulation.
阿合江·赛力克;孙琳;王绒;余舟昌;刘育书;郝洪剑;田兴芳;周荣磊;张伟
西北农林科技大学草业与草原学院,杨凌 712100
黄土高原草地恢复植被演替团聚体稳定性团聚体氮
Loess Plateaugrassland restorationvegetation successionaggregate stabilityaggregate nitrogen
《生态学报》 2023 (024)
黄土高原恢复草地土壤团聚体氮转化及功能微生物对N2O排放的协调机制
10065-10080 / 16
国家自然科学基金(42007428);陕西林业科技创新专项(SKLK2022-02-14);陕西省重点研发计划(2022SF-285)
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