摘要
【目的】探讨不同耕作措施对民勤绿洲区农田土壤的团聚体组成及有机碳稳定性的影响,以期为开展民勤绿洲区农田土壤抗蚀性研究、促进绿洲区农田土壤资源的可持续利用提供理论依据。【方法】依托民勤绿洲区的长期定位试验,以自然撂荒地为对照(CK),研究了免耕(Tn)、少耕(Tm)、深松(Ts)和秋翻(Tf)4种耕作措施对土壤团聚体组成及有机碳稳定性的影响。【结果】(1)土壤团聚体方面,4种耕作措施均显著提高了土壤大团聚体(>0.25 mm)的含量,其中Tm处理的土壤大团聚体含量最高,在0~20 cm土层较Tn、Ts、Tf和CK显著增加了9.39%、11.38%、6.09%和35.41%,在20~40 cm土层较Tn和CK显著增加了13.74%和38.65%。同时,Tm、Ts和Tf处理也显著提高了0~20 cm和20~40 cm土层土壤团聚体的平均重量直径(MWD)和几何平均直径(GMD)。(2)土壤有机碳稳定性方面,4种耕作措施均显著提高了各土层不同粒级团聚体的有机碳含量和碳累积矿化量。其中Tn处理的有机碳含量最高,在0~20 cm和20~40 cm土层分别较Ts、Tf、CK显著增加了18.58%、39.53%、58.40%和40.08%、22.84%、60.93%,且随着粒级的减小和土壤深度的加深而减少。另外,除<0.25 mm粒级团聚体外,Tn处理的有机碳累积矿化量也显著高于CK。同时,4种耕作措施显著降低了微团聚体(<0.25 mm)的有机碳贡献率,Tn、Tm、Ts和Tf处理较CK显著降低了0~20 cm土层微团聚体(<0.25 mm)的有机碳贡献率32.89%、49.37%、26.61%、38.88%。【结论】耕作措施可以促进耕层土壤团聚体的形成,增加土壤团聚体的稳定性。其中,免耕和少耕能够减少机械的破坏作用,提高各土层及表层土壤大团聚体的有机碳含量,免耕更利于有机碳的固定,少耕更利于土壤团聚体的结构稳定性。综合分析,免耕和少耕可作为民勤绿洲区农田最适宜的土壤耕作措施。
【Objective】Aggregate distribution and organic carbon stability of farmland soil at Minqin Oasis under different methods of tillage were studied for improvements on the soil erosion eradication and agriculture sustainability in the area.【Methods】Taking advantage of the ongoing fixed position monitoring program at Minqin Oasis and utilizing a virgin land in the area as control(CK),4 tilling methods including no-tilling(Tn),less-tilling(Tm),deep-loosening(Ts),and autumn turningover(Tf)were performed to determine their effects on the aggregate composition and organic carbon stability of the soil.【Results】(1)In terms of soil aggregates,the tested tillage significantly increased the proportion of aggregates containing particles larger than 0.25 mm in the soil.Among them,Tm yielded 9.39% higher proportion than Tn,11.38% higher than Ts,6.09% higher than Tf,and 35.41 higher than CK in 0-20 cm soil,and 13.74% higher than Tn and 38.65% higher than CK in 20-40 layer.At the same time,Tm,Ts,and Tf significantly increased the mean weight diameter(MWD)and geometric mean diameter(GMD).(2)In terms of soil organic carbon stability,all 4 tilling methods significantly increased the content and cumulative mineralization of organic carbon in aggregates of different sizes in the soil layers.However,Tn resulted in greatest organic carbon content among them.It significantly increased carbon content over Ts,Tf,and CK by 18.58%,39.53%,and 58.40%,respectively,in the soil at a depth of 0-20 cm,and 40.08%,22.84%,and 60.93%,respectively,in the 20-40 cm layer.And the content decreased with reducing particle size and increasing depth of soil.In addition to agglomeration smaller than 0.25 mm,the cumulative mineralization of organic carbon treated by Tn was significantly higher than CK.Meanwhile,the tillage significantly reduced the organic carbon contribution proportion in soil by microaggregates smaller than 0.25 mm,as Tn,Tm,Ts,and Tf significantly reduced it by 32.89%,49.37%,26.61%,and 38.88%,respectively,over CK in 0-20 cm layer of the soil.【Conclusion】Tillage promoted the formation and stability of aggregates and also improved the carbon stability in soil.The less-tilling Tm and the no-tilling Tn minimized mechanical damage to the soil while increased the organic carbon content of large aggregates in surface and tillered soil.Tn was especially conducive to the carbon fixation,and Tm to the stability of soil.Thus,those two methods were recommended for farming in the region.
作者
陈亮
王军强
李彦荣
栾倩倩
王翠丽
王振龙
赵旭
CHEN Liang;WANG Junqiang;LI Yanrong;LUAN Qianqian;WANG Cuili;WANG Zhenlong;ZHAO Xu(Collaborative Innovation Center for Western Ecological Safety,Lanzhou University,Lanzhou,Gansu 730000,China;Gansu Provincial Institute of Agricultural Engineering and Technology,Wuwei,Gansu 733006,China;China West Normal University,Nanchong,Sichuang 637000,China)
出处
《福建农业学报》
CAS
CSCD
北大核心
2021年第7期826-835,共10页
Fujian Journal of Agricultural Sciences
基金
甘肃省级引导科技创新发展专项资金项目(项目号2019ZX-06)
兰州大学中央高校基本科研业务费专项资金项目(项目号lzujbky-2021-kb12)
国家自然科学基金项目(41867013,31560170)。
关键词
耕作
绿洲农田
团聚体
有机碳稳定性
Tillage
oasis farmland
soil aggregates
organic carbon stability
