西南“旱三熟”区不同作物和秸秆覆盖对土壤团聚体及固碳潜力的影响  

Effects of different crops and straw mulching on soil aggregate and carbon sequestration potential in the dryland,triple cropping systems of Southwest China

作　　者：张赛[1] 王龙昌[1] 杜娟[1] 赵琳璐 陈娇[1] 石超[1] 黄召存 熊瑛[1] 贾会娟[1] 

机构地区：[1]西南大学农学与生物科技学院三峡库区生态环境教育部重点实验室南方山地农业教育部工程研究中心,重庆400716

出　　处：《草业学报》2016年第1期98-107,共10页Acta Prataculturae Sinica

基　　金：国家自然科学基金(31271673);公益性行业(农业)科研专项(201503127)资助

摘　　要：为了探讨西南“旱三熟”（小麦/玉米/大豆）套作种植模式下农田土壤团聚体的分布特征及有机碳含量变化情况,进而估算该模式下的土壤固碳潜力,在重庆北碚西南大学试验农场对传统耕作（traditional tillage,T）和传统耕作＋秸秆覆盖（traditional tillage＋straw mulching,TS）2种处理下的土壤团聚体进行筛分和测定.结果表明,3种作物种植下的〉2 mm 粒径与2～0.25 mm 粒径团聚体含量此消彼长,存在显著的负相关关系（狉= -0.985,P〈0.05）.土壤团聚体结构对不同作物的响应不同,水稳性大团聚体（〉0.25 mm 粒径）含量在小麦和大豆种植后高达90%左右,玉米种植后约为80%,说明种植玉米有利于土壤水稳性微团聚体的形成.2～0.25 mm 粒径团聚体的有机碳含量最高,而水稳性微团聚体的两个粒径团聚体有机碳含量相差不大,有机碳含量在团聚体中的分布规律不受种植作物和耕作方式的影响.秸秆覆盖显著提高了0～5cm 和5～10cm 土层的本土及各个粒径中的有机碳含量,且5～10cm 土层团聚体有机碳受秸秆覆盖的影响较大.通过估算固碳潜力发现,玉米条带的土壤固碳潜力显著大于小麦-大豆条带,在耕作处理保持-致的情况下,土壤团聚体有机碳含量对农作物的响应不同.因此,在西南“旱三熟”地区,农田土壤团聚体分布特征和不同粒径有机碳含量受到耕作措施和种植作物的双重影响,土壤固碳潜力主要由水稳性大团聚体的固碳能力决定,水稳性大团聚体更易受到耕作措施和种植作物的影响,在实践中通过秸秆还田提高土壤固碳外,合理安排农作物也有助于提高土壤的固碳能力.A study has been undertaken in experimental field sat Southwest University in Beibei,Chongqing,in order to explore changes in soil aggregate distribution and organic carbon content,and to estimate soil carbon sequestration potential,in southwest China farmland that uses the triple cropping system(wheat/corn/soybean).There were two treatments:traditional tillage(T)and T plus straw mulching(TS).There was a significantly negative correlation between>2mm and 2-0.25 mm aggregate contents(r=0.985,P<0.05)during the planting periods of the three crops.The responses of soil aggregates to the different crops varied.In the wheat and soybean belts,the content of water-stable aggregates(>0.25mm)was as high as 90%of total soil,while it was approximately 80%in the corn belt,indicating that corn performance was beneficial to the formation of soil water-stable micro-aggregates.Straw mulching significantly increased soil organic carbon content and particle size at the 0-5cm and 5-10 cm soil layers.Increases in organic carbon content at the 5-10 cm soil layer were especially notable.Soil carbon sequestration potential was greater in the corn than in the wheat and soybean belts.The study shows that the distribution of soil aggregates and of organic carbon content in soil particles with different sizes were influenced by both tillage measures and crops.In conclusion,the selection of crops and straw mulching will play important roles in promoting soil carbon sequestration in the dryland,triple cropping systems of southwest China.

关 键 词：“旱三熟” 秸秆覆盖 土壤团聚体 土壤有机碳 固碳潜力 

分 类 号：S152[农业科学—土壤学]