添加有机物料对豫中烟田土壤呼吸的影响

Effect of Organic Material Amendments on Soil Respiration in Tobacco Fields of Central Henan

采用田间试验,设置不施肥(NF)、单施化肥(NPK)、化肥+黑麦草(NPKG)、化肥+小麦秸秆(NPKS)和化肥+烟秆生物炭(NPKB)这5个处理,通过测定烤烟生育期土壤总呼吸速率(R_(s))及其组分以及环境因子的动态变化,探讨了添加不同有机物料对烟田土壤呼吸的影响.结果表明:(1)与NPK相比,NPKG和NPKS降低了土壤总呼吸和异养呼吸温度敏感性(Q_(10)),NPKB提高了异养呼吸Q_(10);土壤呼吸与土壤水热因子的双因素拟合模型能解释土壤呼吸变化50%~80%.(2)添加有机物料显著提高了土壤可溶性有机碳(DOC)含量和根系干物质量,土壤异养呼吸(R_(h))与DOC含量呈显著线性回归关系,土壤自养呼吸(R_(a))与根系生物量呈显著抛物线型关系,R^(2)为0.327~0.634.(3)烤烟生育期土壤呼吸呈先增加后降低趋势.与NF相比,NPK处理显著增加了土壤呼吸及其组分;与NPK相比,NPKG、NPKS和NPKB处理R_(s)速率分别显著提高20.08%、10.32%和9.88%,R_(h)速率分别显著提高24.21%、16.51%和11.68%,且NPKG处理R_(a)速率显著提高15.12%.综上所述,秸秆还田和添加生物炭主要通过提高土壤DOC促进R_(h)和R_(s);翻压黑麦草既提高了R_(h),同时也通过促进根系生长发育而提高R_(a),进而提高R_(s).

A field experiment was conducted to study the effects of different organic material amendments on soil respiration in a flue-cured tobacco field.Five treatments were set up:no fertilizer(NF),chemical fertilizer(NPK),chemical fertilizer+ryegrass(NPKG),chemical fertilizer+wheat straw(NPKS),and chemical fertilizer+tobacco straw biochar(NPKB).The results showed that:(1)Compared with that under NPK,NPKG and NPKS decreased the temperature sensitivity(Q10)of total soil respiration and heterotrophic respiration,whereas NPKB increased the Q10 of heterotrophic respiration.The two-factor fitting model of soil respiration and soil hydrothermal factors accounted for 50%-80%of the variation in soil respiration.(2)The addition of organic materials significantly increased the content of soil soluble organic carbon(DOC)and root dry matter.Soil heterotrophic respiration(Rh)was significantly positively correlated with DOC content,and soil autotrophic respiration(Ra)was significantly parabolically correlated with root biomass,with an R^(2) of 0.327-0.634.(3)Soil respiration increased first and then decreased during the tobacco growth period.Compared with that under the NF treatment,the NPK treatment significantly promoted soil respiration and its components.Compared with those of the NPK treatment,Rsrates were significantly increased by 20.08%,10.32%,and 9.88%under the NPKG,NPKS,and NPKB treatments,respectively;Rh rate increased by 24.21%,16.51%,and 11.68%respectively,and Ra rate was increased by 15.12%in the NPKG treatment.In summary,straw returning and biochar addition significantly increased Rh by increasing soil DOC,thereby promoting Rs.Incorporation of ryegrass not only increased the Rh but also increased Ra by promoting the growth and development of roots and therefore the Rs.