CAJ | 학술논문

为探讨氮肥对华北平原高产农田土壤呼吸动态变化及其碳平衡的影响,试验设计了习惯施氮量(N228,228 kg·hm-2)、2/3习惯施氮量(N152,152 kg·hm-2)和不施氮(N0)3个处理,采用密闭静态箱法研究了不同施氮水平下夏玉米生长季农田的土壤呼吸速率季节变化、土壤呼吸与地温等环境因素的关系以及农田系统的碳平衡.结果表明,夏玉米农田土壤呼吸速率均值和土壤呼吸释放的总碳量分别为C 98.8~115.9 mg·m-2·h-1和C 2232.3~2524.2 kg·hm-2.与处理N0相比,处理N152(N 152 kg ·hm-2)和N225(N 225 kg ·hm-2)的土壤呼吸速率均值分别增加了10.2%和17.4%,土壤呼吸释放的总碳量分别增加了6.74%和13.1%.地温(5 cm)和土壤含水量(0-10 cm)分别与土壤呼吸速率呈指数和二次曲线关系,R2均达显著水平.其中地温(5 cm)解释了土壤呼吸季节变化的55.9%~67.0%,而土壤含水量(0-10 cm)可解释土壤呼吸季节变化的25.3%~59.3%.土壤呼吸的温度敏感系数Q10在2.05~2.23之间,且随着施氮水平的提高而增加.处理N0、N152(N 152 kg·hm-2)和N228(N 228 kg·hm-2)的土壤含水量分别是22.5%、22.7%和23.3%时,土壤呼吸速率达最高值,超过此阈值,土壤呼吸速率均呈下降的趋势.夏玉米农田系统是大气二氧化碳(CO2)重要的汇,净初级生产力(NPP)固碳量和农田系统的净碳输入(NEP)分别为C 6829.1~8950.2 kg·hm-2和C 4898.2~6766.8 kg ·hm-2.处理N152(N 152 kg·hm-2)和N228(N 228 kg·hm-2)与处理N0相比,NPP固碳量分别增加了24.8%和131.1%,NEP分别增加了31.9%和38.1%.
위탐토담비대화북평원고산농전토양호흡동태변화급기탄평형적영향,시험설계료습관시담량(N228,228 kg·hm-2)、2/3습관시담량(N152,152 kg·hm-2)화불시담(N0)3개처리,채용밀폐정태상법연구료불동시담수평하하옥미생장계농전적토양호흡속솔계절변화、토양호흡여지온등배경인소적관계이급농전계통적탄평형.결과표명,하옥미농전토양호흡속솔균치화토양호흡석방적총탄량분별위C 98.8~115.9 mg·m-2·h-1화C 2232.3~2524.2 kg·hm-2.여처리N0상비,처리N152(N 152 kg ·hm-2)화N225(N 225 kg ·hm-2)적토양호흡속솔균치분별증가료10.2%화17.4%,토양호흡석방적총탄량분별증가료6.74%화13.1%.지온(5 cm)화토양함수량(0-10 cm)분별여토양호흡속솔정지수화이차곡선관계,R2균체현저수평.기중지온(5 cm)해석료토양호흡계절변화적55.9%~67.0%,이토양함수량(0-10 cm)가해석토양호흡계절변화적25.3%~59.3%.토양호흡적온도민감계수Q10재2.05~2.23지간,차수착시담수평적제고이증가.처리N0、N152(N 152 kg·hm-2)화N228(N 228 kg·hm-2)적토양함수량분별시22.5%、22.7%화23.3%시,토양호흡속솔체최고치,초과차역치,토양호흡속솔균정하강적추세.하옥미농전계통시대기이양화탄(CO2)중요적회,정초급생산력(NPP)고탄량화농전계통적정탄수입(NEP)분별위C 6829.1~8950.2 kg·hm-2화C 4898.2~6766.8 kg ·hm-2.처리N152(N 152 kg·hm-2)화N228(N 228 kg·hm-2)여처리N0상비,NPP고탄량분별증가료24.8%화131.1%,NEP분별증가료31.9%화38.1%.
Impacts of nitrogen fertilizer on soil respiration has attracted the attentions of scientists in soil science, plant nutrition and climate change, but the conclusions varied and even contrasted in present researches. This research adopted closed static chamber method and statistical analysis to explore the impacts and hidden mechanisms of nitrogen fertilizer application on soil respiration dynamics and carbon balance in high yield farmland of North China Plain. This experiment set 3 treatments:i.e. traditional nitrogen fertilizer application rate (N228, N 228 kg·hm-2), 2/3 traditional nitrogen fertilizer application rate (N152, N 152 kg·hm-2) and the control treatment (N0, no nitrogen addition). This study analyzed the seasonal dynamic of soil respiration, revealed the relationships between soil respiration and major environmental factors, including soil temperature (5 cm) and soil water content (0-10 cm),and calculated the carbon balance of the high yield farmland during the summer-maize season to reveal the impacts of nitrogen addition on soil and farmland carbon dynamics. The results showed that the rate of mean soil respiration and the total carbon flux release from soil respiration in the high yield farmland of summer-maize in the North China Plain were C 98.8~115.9 mg·m-2·h-1 and C 2 232.3~2 524.2 kg·hm-2 respectively. When compared with N0 treatment, the rate of mean soil respiration of the N152 treatment and N228 treatment increased by 10.2%and 17.4%respectively, and the carbon flux from soil respiration increased by 6.74%and 13.1%respectively. The relationship between soil respiration rate and soil temperature (5 cm), and that between soil respiration rate and soil water content (0-10 cm) could be described by the indicial equation and quadratic function respectively with very significant determination coefficients (R2). 55.9%~67.0%and 25.3%~59.3%of the seasonal variations could be explained by soil temperature (5 cm) and soil water content (0-10 cm). Temperature sensitivity of soil respiration (Q10) ranged from 2.05 to 2.23, and there is a positive correlation between Q10 and nitrogen fertilizer application. Soil respiration rates of N0 treatment, N152 treatment and N228 treatment reached the highest values when the soil water content were 22.5%, 22.7%and 23.3%respectively., and decreased when the soil water content exceeded these thresholds. The net primary productivity carbon was C 6 829.1~8 950.2 kg·hm-2, and the net ecosystem productivity was C 4 898.2~6 766.8 kg ·hm-2, which indicated that the high yield summer-maize field in the North China Plain was an important sink of atmospheric carbon dioxide (CO2). Compared with N0 treatment, net primary productivity carbon for the treatments of N152 and N228 had increased by 24.8%and 131.1%respectively, and the net ecosystem productivity increased by 31.9%and 38.1%respectively.