塔克拉玛干沙漠公路防护林不同咸水滴灌下土壤有机碳与无机碳垂直分布特征

干旱半干旱荒漠区是一个潜力巨大的碳汇,荒漠植被建设则进一步加速了其固碳过程。探究咸水滴灌条件下塔克拉玛干沙漠公路防护林土壤碳垂直分布特征及其影响因素,可为干旱荒漠区人工林碳储量的估算和可持续管理提供科学依据。选择沙漠公路沿线4.82~28.40g/L的4个高矿化度地下水滴灌的人工防护林,采集并分析了0~5m各层土壤有机碳(SOC)与无机碳(SIC)含量及碳密度的垂直分布特征及其与含水量、pH和土壤电导率(EC)间的相关关系。结果表明,SOC与SIC随土层深度的增加分别呈现“减-增-减”与“增-减-增”趋势,并最终分别在2m和3m以下土层趋于稳定;浅层(0~40cm)土壤有机碳密度(SOCD)和无机碳密度(SICD)分别比流沙地增加了73%~346%和1.5%~14.0%,5m深土层SOCD、SICD和总碳密度分别增加了8.3%~28%、5.4%~58%和8.3%~29.9%,其中SICD为SOCD的13.3倍;人工林SOC分布与含水量和EC呈正相关,SIC与含水量同样呈正相关,同时SOC与SIC间相关关系为正相关。总之,荒漠人工防护林建设显著提高了SOC与SIC储量,且灌溉水矿化度、土壤含水量和EC均对SOC和SIC储量及垂直分布产生不同程度的影响。

Vertical Distribution of Soil Organic and Inorganic Carbon in the Taklimakan Desert Highway Shelterbelt Drip-irrigated with Different Mineralization Water

Arid and semiarid desert is a huge potential carbon sink,and the vegetation construction can accelerate the carbon sequestration process.The exploration of the vertical distribution of soil carbon in the Taklimakan Desert Highway Shelterbelt under saline drip irrigation and the influencing factors can provide a scientific basis for estimating the carbon storage and the sustainable management of the artificial shelter-forest in arid deserts.In this paper,four sections of desert highway shelterbelt drip-irrigated with different salinities ranged from 4.82 to 28.40 g/L were selected,different layers of soil in a 0-5 m profile were sampled,soil organic carbon (SOC) and soil inorganic carbon (SIC) and carbon density were determined,and their relationships with soil water content,pH and electrical conductivity (EC) were also analyzed.The results showed that with soil depth increasing,the distribution of SOC showed as a'decrease-increase-decrease'trend and SIC showed an “increase-decrease-increase” trend,and finally tended to be stable beneath 2 m and 3 m,respectively.Compared with the shifting sand,soil organic carbon density (SOCD) and soil inorganic carbon density (SICD) of shallow soil in the shelterbelt increased by 73%-346% and 1.5%- 14.0%,SOCD,SICD and total carbon density of the 5-meter-deep soil increased by 8.3%-28%,5.4%-58% and 8.3%-29.9%,respectively,of which SICD was 13.3 times of SOCD.SOC distribution of the artificial shelterbelt was positively correlated with soil water content and EC,SIC was positively correlated with soil water content,and there was a positive correlation between SOC and SIC.In summary,the construction of artificial shelterbelt increased desert SOC and SIC storage,the storage and vertical distribution of SOC and SIC could be influenced by irrigation water salinity,soil water content and EC at different degrees.