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土壤有机碳(SOC)含量及其变化是当前土壤碳循环研究的热点,土地利用方式对SOC的累积及易氧化有机碳(ROC)的变化具有深远影响。本文通过采集甘肃省定西市安定区梁家川村高山的荒地、乔木(杏树林)、灌木(柠条林)和草地(苜蓿)不同剖面的土壤,测定其SOC、ROC和土壤容重含量,研究不同土地利用方式对SOC库的影响。结果表明:(1)4种土地利用方式的土壤ROC和SOC含量均随着土层深度的增加而减少,且均呈现草地>灌木>乔木>荒地的趋势;(2)相对于荒地,草地、灌木和乔木的耕层SOC含量分别显著增加1.29、1.05和0.52倍;土壤有机碳密度分别显著提高2.04、0.85和0.53倍(P<0.05);(3)土壤ROC与SOC含量之间存在极显著的正线性相关关系,R~2=0.74;(4)各处理土壤碳库管理指数的变化范围在1.05~2.62之间,且草地高于灌木和乔木。研究认为,草地能快速提高土壤ROC和SOC含量,从而增加土壤碳储量,提高土壤可持续生产能力;栽培乔木和灌木,能储存更多的稳定态碳,是彻底改善生态环境的有力保障。
Soil organic carbon (SOC) content and its change are the hot topics in the current research on soil carbon cycling. Land use patterns have a profound impact on the accumulation of SOC and the change of readily oxidizable organic carbon (ROC). In this paper, the SOC, ROC and bulk density of soils were measured by collecting the wasteland, arbor (Almond grove), shrub (Caragana mongolica) and grassland (Medicago sativa L.) soil in Liangjiachuan village, Impact of Land Use on SOC. The results showed that: (1) The contents of soil ROC and SOC decreased with the increase of soil depth under four land use patterns, and both showed the trend of grassland> shrub> arbor> barren land. (2) SOC of shrub layer and shrub layer increased by 1.29, 1.05 and 0.52 times respectively, and soil organic carbon density increased by 2.04, 0.85 and 0.53 times respectively (P <0.05); (3) There was significant difference between soil ROC and SOC content R 2 = 0.74; (4) The range of soil carbon inventory management index varied from 1.05 to 2.62, and the grassland was higher than the shrubs and trees. The study shows that grassland can quickly increase soil ROC and SOC content, thus increasing soil carbon storage and soil sustainable production capacity; planting trees and shrubs, can store more stable carbon, is a powerful guarantee to completely improve the ecological environment.