环境温度和CO_2浓度升高对湖北早稻氮素含量及产量的影响

采用改进后的开顶式气室(OTC),大田原位模拟温度升高2℃和CO_2浓度增加60μL·L~(-1)的未来气候情景,观测其对湖北地区早稻植株全氮、土壤氮素及产量的影响。试验设置对照(CK)、增温(增2℃,IT)、增CO_2(增60μL·L~(-1),IC)以及增温+CO_2(增2℃+增60μL·L~(-1),IT+IC)4个处理,3次重复,随机区组排列,对早稻各生育期植株全氮含量、土壤NH_4~+-N和NO_3--N含量以及产量构成进行监测。结果表明:(1)温度和CO_2浓度升高以及二者同增会增加早稻生育早期(特别是分蘖期)植株体内全氮含量,分蘖期以后各处理间差异不显著,籽粒全氮含量差异亦不显著;土壤NH_4~+-N含量与植株全氮变化规律类似,在早稻生育早期,温度和CO_2浓度升高以及二者同增会增加土壤NH_4~+-N含量,分蘖期以后各处理间差异不显著;(2)温度升高使拔节期、成熟期土壤NO_3--N含量降低,抽穗期土壤NO_3--N含量增加;CO_2浓度增加会提高拔节期、成熟期,降低抽穗期土壤NO_3--N含量;(3)CO_2浓度升高,早稻增产13.4%,与CK差异极显著(P0.01),而单独增温或增温+增CO_2处理早稻产量与CK差异不显著。

Influence of Elevated Atmospheric Temperature and CO2 Concentration on Plant and Soil N Concentration and Yield of Early Rice in Hubei

Using a modified open-top chamber(OTC)method to simulate relative 60μL·L?1CO2 concentration increment and 2℃ temperature rise scenario in early rice field to study their impacts on the plant total nitrogen, soil N concentration and yield in Hubei. The experimental design consisted of four treatments arranged in randomized blocks and three replicates. Treatments were as follows: (1)the control OTC(CK, ambient CO2 concentration and temperature), (2)elevated air temperature by 2℃(IT), (3)elevated CO2 concentration by 60μL·L?1(IC), (4)air temperature increase by 2℃ plus 60μL·L?1CO2 concentration elevated(IT+IC). Surveyed the plant total nitrogen content, soil ammonium nitrogen, soil nitrate nitrogen, yield and yield components of early rice. The results showed that: (1)there was a significant increase on the plant total nitrogen content during the early growth periods (especially during tillering) when atmospheric temperature and CO2 concentration rose alone and the two of them rose synchronously, but there were no obvious differences after tillering, so did the soil ammonium nitrogen. (2)Elevated temperature had a significant decrease on nitrate nitrogen content during jointing, maturity stage, and it would increase heading stage’s, while it would have a positive effect on nitrate nitrogen during jointing, maturity stage, and have a negative impact on it when CO2concentration elevated. (3)Compared to the control, there was a significant increase on early rice grain yield by 13.4% when CO2 concentration rose, while there were no differences when only temperature rose or CO2concentration elevated alone.