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以位于西南大学的农业部紫色土生态环境重点野外科学观测试验站始于1990年的长期定位试验田为对象,研究了冬水田平作(DP)、水旱轮作(SH)、垄作免耕(LM)及垄作翻耕(LF)等4种耕作方式对紫色水稻土有机碳(SOC)和微生物生物量碳(SMBC)的影响。结果表明,4种耕作方式下SOC和SMBC均呈现出在土壤剖面垂直递减趋势,翻耕栽培下其降低较均匀,而免耕栽培下其富集在表层土壤中。同一土层不同耕作方式间SOC和SMBC的差异在表层最大,随着土壤深度的增加,各处理之间的差异逐渐减小。在0—60 cm剖面中,SOC含量依次为:LM(17.6 g/kg)>DP(13.9 g/kg)>LF(12.5 g/kg)>SH(11.3 g/kg),SOC储量也依次为:LM(158.52 Mg C/hm2)>DP(106.74 Mg C/hm2)>LF(93.11 Mg C/hm2)>SH(88.59 Mg C/hm2),而SMBC含量则依次为:LM(259 mg/kg)>SH(213 mg/kg)>LF(160 mg/kg)>DP(144 mg/kg)。与其它3种耕作方式比较,LM处理显著提高SOC含量和储量以及SMBC含量。对土壤微生物商(SMBC/SOC)进行分析发现,耕作方式对SOC和SMBC的影响程度并不一致。SMBC与SOC、全氮、全磷、全硫、碱解氮、有效磷均呈现极显著正相关(P<0.01),与有效硫呈显著正相关(P<0.05);表明SMBC可以作为表征紫色水稻土土壤肥力的敏感因子。
This study was conducted on the long-term experimental plots of field started in 1990, located at Southwest University’s Key Laboratory of Purple Soil Ecology Environment Science Experiment Station. The effects of winter paddy field flattening (DP), water and drought rotation (SH) And tillage (LF) on soil organic carbon (SOC) and microbial biomass carbon (SMBC) in purple paddy soil. The results showed that under the four tillage methods, both SOC and SMBC showed a decreasing trend vertically in the soil profile, which was more uniform under the tillage cultivation, while it was enriched in the topsoil under no tillage. The difference of SOC and SMBC between different tillage methods in the same soil layer is the largest in the surface layer. With the increase of soil depth, the differences among treatments are gradually reduced. In the 0-60 cm section, the SOC contents were: LM (17.6 g / kg)> DP (13.9 g / kg)> LF (12.5 g / kg)> SH (11.3 g / kg) : LM (158.52 Mg C / hm2)> DP (106.74 Mg C / hm2)> LF (93.11 Mg C / hm2)> SH (88.59 Mg C / hm2) )> SH (213 mg / kg)> LF (160 mg / kg)> DP (144 mg / kg). Compared with the other three tillage methods, LM treatment significantly increased SOC content and reserves and SMBC content. An analysis of soil microbial agents (SMBC / SOC) found that the impact of farming practices on SOC and SMBC was not consistent. There was a significant positive correlation between SMBC and SOC, total nitrogen, total phosphorus, total sulfur, available nitrogen and available phosphorus (P <0.01), and significant positive correlation with available sulfur (P <0.05) Sensitive factors of soil fertility in paddy soils.