3种栽培草地N_2O释放通量季节动态的研究

Research on N_2O Emission Fluxes of 3 Cultivated Grasslands in Growing Seasons

为探究栽培草地生长季N_2O释放规律与其土壤水分、温度及土壤硝态氮、铵态氮含量的关系,在黄土高原旱塬区,采用静态箱-气相色谱法,研究早熟禾(Poa pratensis)、紫花苜蓿(Medicago satziva)和红豆草(Onobrychis viciae folia)草地生长季N_2O释放通量季节动态.结果表明:3种栽培草地生长季N_2O释放通量差异显著(P<0.05)。早熟禾草地N_2O释放通量最高,红豆草草地次之,紫花苜蓿草地最小。通量变化范围分别为—0.3185~0.4943,—0.4962~0.4755,一0.3167~0.4620 mg·m^(-2)·h^(-1)。生长季内早熟禾草地N_2O累积释放通量显著高于紫花苜蓿和红豆草草地。3种栽培草地N_2O释放通量在花期出现峰值,在再生期出现吸收现象.早熟禾草地N_2O释放通量主要受土壤水分影响。2种豆科栽培草地N_2O释放通量主要与土壤硝态氮、铵态氮含量相关联.

In order to determine the relationships between the N_2O emission fluxes of cultivated grassland in growing season and soil moisture,temperature,nitrate nitrogen content or ammonium nitrogen content,the N_2O emission fluxes of Kentucky bluegrass（Poa pratensis）,lucerne（Medicago sativa） and sainfoin（Onobrychis viciaefolia） cultivated grasslands were observed during growing seasons in the Loess Plateau using a static chamber-HPLC method.The results showed that N_2O emission fluxes had significant difference in among 3 cultivated grasslands（P〈0.05）,Kentucky bluegrass grassland had the highest N_2O emission fluxes.The N_2O emission fluxes of Kentucky bluegrass,sainfoin and lucerne grassland were-0.3185～0.4943,-0.4962～0.4755,-0.3167～0.4620 mg·m～（-2）·h～（-1）,respectively.The N_2O accumulated emission fluxes of Kentucky bluegrass grasslands was obviously higher than those of lucerne and sainfoin.The N_2O emission fluxes of 3 cultivated grasslands reached the peak during florescence,while N_2O absorption was observed during regenerative phase.The N_2O emission fluxes of Kentucky bluegrass was mainly affected by soil moisture,and the N_2O emission fluxes of two legume cultivated grasslands were related with the contents of nitrate-N and ammonium-N.