荒漠草原中不同密度人工柠条灌丛土壤化学计量特征

为了揭示人工灌草结合的生态系统土壤内部C,N,P平衡和循环过程,以荒漠草原为对照(CK),研究了相同林龄不同密度(高密度HD、中密度MD、低密度LD)人工柠条灌丛土壤化学计量特征。结果表明,柠条灌丛0—100cm土层平均有机碳(SOC)、全氮(TN),全磷(TP)和氮磷比(N/P)随密度的增加呈上升趋势,碳氮比(C/N),碳磷比(C/P)呈降低趋势,其中TP的空间变异性较高;垂直方向SOC,C/N和C/P随土层深度的增加呈单峰曲线,TN,TP和N/P在0—40cm土层呈锐减趋势,40cm土层以下缓慢降低并趋于稳定;0—40cm土层TN和TP含量占总含量的61.82%和55.56%,可作为密度变化对人工柠条灌丛土壤养分的敏感指标;相关分析结果发现,人工柠条灌丛土壤N和P含量呈极显著正相关(p0.01),二者均与C/N呈极显著的负相关(p0.01),说明柠条对土壤中N和P两种元素需求相一致。

Soil Stoichiometry Characteristics of Artificial Caragana Korshinskii Shrubs with Different Density in Desert Steppe

Taking the natural desert steppe as CK, soil stoichiometry characteristics of artificial Caragana korshinskii shrubs with different density(HD, MD, LD) of the same forest age were investigated to reveal soil C, N, P balance and internal circulation in artificial shrub-grass ecological system. The results showed that with the increase of the density, soil organic carbon(SOC), total nitrogen(TN), total phosphorus(TP) and ratio of nitrogen to phosphorus(N/P) in 0-100 cm presented an increase trend, while the ratio of carbon to nitrogen(C/N) and carbon to phoshorus(C/P) presented a decrease trend, and the variation coefficient of TP was higher than other soil stoichiometry; Vertical direction SOC, C/N and C/P showed unimodal curve with the increase of soil depth, while TN, TP and N/P showed a sharply decrease trend in 0-40 cm soil layer with the increase of soil depth, but in 40-100 cm soil layer showed a slow decrease and tended to be stable. In 0-40 cm soil, TN and TP accounted for 61.82% and 55.56% of total content, and the content of TN and TP soil could be used as artificial C. microphylla shrubs sensitive index of soil nutrients; Correlation analysis showed that N content was positively linearly correlated with P content(p<0.01), and both was significantly negative correlated with C/N(p<0.01), and indicates consistent demand of N and P content in soil for C. microphylla shrubs.