豫东平原不同年限农林间作系统土壤有机碳库特征

为全面了解杨树-农作物间作系统的固碳效能,研究了沙质平原区3、9、13、17a杨农(杨树与农作物)间作系统土壤有机碳库特征。结果表明,杨农间作系统土壤有机碳含量随着土层深度增加而逐步下降,随着间作年限增加而增加;0～60cm土壤有机碳密度随着间作年限的增加而增加,间作3、9、13、17a分别达到11.25、11.19、13.71、16.17t/hm2;土壤碳密度随着土层深度增加而下降,但随着间作年限增加,40～60cm土壤碳密度所占比例逐步增加,到间作17a时,已达到28.76%,说明随着间作年限增加可以增加深层土壤固碳能力;土壤有机碳固存速率随着间作年限增加而增加,间作3～9a为0.145 0t/(hm2·a),间作9～13a为0.397 5t/(hm2·a),间作13～17a达到最高,为0.615 0t/(hm2·a),平均为0.351 4t/(hm2·a),说明豫东平原杨农间作系统要达到一定年限,才能充分发挥其土壤固碳效能。

Characteristics of Soil Organic Carbon Stock of Poplar Crop Intercropping System of Different Years in Eastern Henan Plain

Characteristics of soil organic carbon stock of 3 a,9 a,13 a,and 17 a poplar crop intercropping system(PCIS) were investigated to comprehensively understand carbon sequestration efficiency of PCIS in eastern Henan plain.The results showed that the soil organic carbon content decreased gradually with the increasing of soil depth,and it increased with the increase of intercropping years.Also the soil organic carbon density increased in 0-60 cm soil layer with the increase of intercropping years,which reached 11.25 t/hm2,11.19 t/ha,13.71 t/ha and 16.17 t/ha in 3 a,9 a,13 a,17 a,respectively.The carbon density decreased with the increase of soil depth,and the proportion of the carbon density in 40-60 cm soil layer increased with the increase of intercropping years,and it reached 28.76% in 17 a,illustrating the ability of carbon sequestration increased with the increase of intercropping years in deep soil.The soil organic carbon sequestration rate increased with the increase of intercropping years,which was 0.145 0 t/(ha·a) in 3-9 a,0.397 5 t/(ha·a) in 9-13 a,0.615 0 t/(ha·a) in 13-17 a,and the average was 0.351 4 t/(ha·a),suggesting PCIS could not give full play to its soil carbon sequestration efficiency until it reached a certain number of intercropping years in eastern Henan plain.