蔗田滴灌施肥土壤甲烷排放通量与活性有机碳含量的关系

Relationship between soil methane emission flux and active organic carbon content in sugarcane field under drip fertigation

【目的】研究蔗田滴灌施肥对土壤活性有机碳含量和甲烷排放通量的影响,探讨蔗田滴灌施肥土壤甲烷排放通量与土壤活性有机碳含量之间的关系。【方法】2018年3—12月在南宁市灌溉试验站开展不同滴灌灌水、施肥的田间试验,试验设4种施肥水平:常规施肥(F100,N 250 kg·hm^-2、P2O5150 kg·hm^-2、K2O 200 kg·hm^-2)、增量施肥1(F110,在F100基础上增加10%)、增量施肥2(F120,在F100基础上增加20%)和减量施肥(F90,在F100基础上减少10%),以及2种滴灌灌水水平:W180(180 m^3·hm^-2)和W300(300 m^3·hm^-2)。用常规法测定不同生育时期蔗田土壤甲烷排放通量和土壤活性有机碳含量,用Pearson法分析土壤甲烷排放通量与土壤活性有机碳含量的关系。【结果】在分蘖期,W300F120处理土壤可溶性有机碳(DOC)含量较W300F100提高了156%,而土壤CH4排放通量较其他处理低。在成熟期,W300F120处理土壤DOC含量较W300F110增加了114%,微生物量碳(MBC)较W300F110增加了49.6%。蔗田土壤CH4排放通量仅与土壤DOC含量呈显著正相关,相关系数为0.38。【结论】土壤DOC含量显著影响蔗田土壤甲烷排放通量。W300F120处理可以提高分蘖期和成熟期蔗田土壤可溶性有机碳含量、减少分蘖期蔗田土壤CH4排放。

【Objective】To study the effects of drip fertigation on soil active organic carbon content and methane(CH4)emission flux in sugarcane field,and investigate the relationship between soil methane emission flux and soil active organic carbon content.【Method】The field experiment with different irrigation and fertilization treatments under drip irrigation was conducted in Nanning Irrigation Experimental Station from March to December in 2018.Four fertilization levels were designed:Conventional fertilization(F100,N 250 kg·hm^-2,P2O5150 kg·hm^-2,K2O 200 kg·hm^-2),incremental fertilization 1(F110,10% increase based on F100),incremental fertilization 2(F120,20% increase on the basis of F100),and reducing fertilization(F90,10% reduction based on F100).Two drip irrigation levels were set:W180(180 m^3·hm^-2)and W300(300 m^3·hm^-2).Soil CH4 emission flux and active organic carbon contents at different growth stages of sugarcane were measured using conventional method,and the relationships between soil CH4 emission flux and active organic carbon contents in sugarcane field were analyzed by Pearson method.【Result】At tillering stage,W300F120 treatment increased soil soluble organic carbon(DOC)content by 156% compared with W300F100 but had lower CH4 emission flux in soil than the other treatments.At maturing stage,W300F120 treatment increased soil DOC content and microbial biomass carbon(MBC)by 114% and 49.6% compared with W300F100,respectively.CH4 emission flux in sugarcane field was only positively correlated with soil DOC content,with the correlation coefficient of 0.38.【Conclusion】Soil DOC content significantly affects CH4 emission flux in sugarcane field.W300F120 treatment can increase soil soluble organic carbon content in sugarcane field at tillering and maturing stages,and reduce soil CH4 emission in sugarcane field at tillering stage.