近40年甘肃省耕层土壤有机碳时空分异及影响因素

区域耕层土壤有机碳（Soil Organic Carbon， SOC）调查是明确全球土壤碳储量和认识土壤碳循环的重要任务。利用甘肃省1980s、2000s、2020s等3个时期的耕层土壤调查数据，通过计算耕层土壤有机碳密度（Soil Organic Carbon Density，SOCD），估算了甘肃省耕层有机碳储量。结果显示：（1）1980s、2000s、2020s甘肃省耕层SOC储量分别为97.68、109.14、123.13 Tg，近40年固碳总量约为25.45 Tg，固碳速率为0.012±0.01 kg·m^-2·a^-1，说明当前的农田管理措施有利于研究区耕地土壤长期固碳；40年间河西绿洲灌区、黄土高原区和陇南山地区耕层SOC储量呈增加趋势，甘南高原呈下降趋势。（2）从不同土壤类型来看，黄棕壤固碳速率最大，栗钙土最小。（3）近40年间甘肃省耕层SOC储量总体呈递增趋势，化肥、有机肥施用量以及秸秆还田量的持续增加，提高了作物归还量，进而增加了耕层有机物质含量，最终促进了耕层SOC的累积。

The Spatial-temporal variance characteristic of soil organic carbon in cultivited land of Gansu Province and its influencing factors in the 40 years from 1980 to 2020

Regional soil organic carbon （SOC） in the cultivated layer surveys are important in building an understanding of the global soil carbon cycle. In this paper， we estimated the organic carbon storage in Gansu Province by calculating the soil organic carbon density （SOCD） cultivated layer using soil survey data from three periods： 1980s， 2000s and 2020s in Gansu Province. The results show that： （1） the SOC storage in the cultivated layer of Gansu Province in the 1980s， 2000s and 2020s were 97.68 Tg， 109.14 Tg and 123.13 Tg， respectively， with a total carbon sequestration rate of 0.012±0.01 kg·m^-2·yr^-1 for a total of about 25.45 Tg in the last 40 years， which indicates that the current farm management measures are beneficial to the cultivated soil in the study area for long-term carbon sequestration. During the 40-year period， the SOC storage in the cultivated layer in the Hexi oasis irrigation area， Loess Plateau area and Longnan Hilly area showed an increasing trend， while the Gannan Plateau showed a decreasing trend. （2） From the perspective of different soil types， the rate of carbon sequestration of yellow-brown loam is the largest and that of chestnut-calcium soil is the smallest. （3） In the past 40 years， the SOC storage in the cultivated layer of Gansu Province has generally shown an overall increasing trend. The main influencing factor is the continuous increase in the amount of fertilizer application， the application of organic fertilizer and the return of straw to the field， which has increased the amount of crop return， which in turn increases the content of soil organic matter， and eventually promotes the accumulation of SOC in the cultivated layer.