摘要
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 2 232.3-2 524.2 kg·hm-2。与处理N0相比,处理N152(N 152kg·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 228kg·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 6 829.1-8 950.2 kg·hm-2和C 4 898.2-6 766.8 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%。
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）. Temper
出处
《生态环境学报》
CSCD
北大核心
2013年第1期18-24,共7页
Ecology and Environmental Sciences
基金
中央级公益性科研所基本科研业务费专项基金项目(BSRF201003)
国家重点基础研究发展计划项目(2012CB955904)
国家自然科学基金项目(30871447
71103186)
国际科技合作项目(2010DFB30550)
中央级基本科研业务费项目(1610122012003)
关键词
氮水平
夏玉米
土壤呼吸
碳平衡
nitrogen addition
summer-maize
soil respiration
carbon balance
