长期施肥对东北中部春玉米农田土壤呼吸的影响

【目的】探究不同施肥措施对土壤呼吸的影响，为我国东北黑土区固碳减排研究提供科学依据。【方法】本研究基于“国家黑土肥力与肥料效益监测基地”长期定位试验，选取不施肥 (CK)、单施化肥 (NPK)、化肥配施秸秆 (NPKS)、化肥配施低量有机肥 (NPKM1)、化肥配施高量有机肥 (NPKM2)5个不同施肥处理。采用Soil-box343土壤呼吸测量系统进行野外监测，并同时观测环境条件。【结果】长期不同施肥处理下，农田土壤呼吸速率变化范围为4.12～7.23 μmol/(m2·s)，随玉米生长表现出“先升高后降低”的季节变化特征，最高值出现在播种后69天左右，NPKM2处理土壤呼吸速率的峰值显著高于其他处理 (P < 0.05)。监测期内土壤呼吸速率与土壤温度之间呈现显著的正相关关系，土壤温度可以解释土壤呼吸速率变异的41%～77%，土壤温度敏感系数Q ₁₀值的变化范围2.35～3.49。春玉米生长季内农田土壤呼吸总量变化范围为3473～5643 kg/hm2，NPKS处理显著高于CK处理34.2%，而NPKM2处理分别比NPKS、NPK和CK处理高21.0%、26.4%、62.4% (P < 0.05)，长期有机无机肥配施处理土壤有机碳含量增加趋势比其他处理明显，截止到2016年，NPKM1和NPKM2处理SOC较初始SOC分别增加了6.01 g/kg和5.55 g/kg。【结论】长期施用有机肥能够增加土壤呼吸，提高土壤有机碳含量，有利于农田生产力提高和农田可持续利用。

Effects of long-term fertilization on soil respiration in spring maize field in the central part of northeast China

【Objectives】In order to provide scientific basis for the study of carbon sequestration and emission reduction in black soil area of northeast China, the effects of long-term different fertilization measures on soil respiration were explored.【Methods】This study was based on the long-term fertilization experiment from the National Black Soil Fertility and Fertilizer Efficiency Monitoring Base. Five fertilization treatments were selected, including no fertilizer (CK), only chemical fertilizer application (NPK), combining chemical fertilizer with straw (NPKS), combining chemical fertilizer with low level of organic fertilizer (NPKM1), combining chemical fertilizer with high level of organic fertilizer (NPKM2). Field monitoring was conducted using Soil-box343 soil respiration measuring system, and environmental conditions were observed at the same time.【Results】The soil respiration rate of the treatments was in range of 4.12 to 7.23 μmol/(m2·s), showing the trend of " increasing first and then decreasing” during the growth period of corn, and the highest value appeared at about 69 days after sowing. The peak respiration rate of NPKM2 treatment was significantly higher than those of other treatments (P < 0.05). There was a significant positive correlation between soil respiration rate and soil temperature during the monitoring period. Soil temperature can explain 41%–77% of the variation of the soil respiration rate, and the range of soil temperature sensitive coefficient Q ₁₀ was from 2.35 to 3.49. The total soil respiration varied from 3473 to 5643 kg/hm2. NPKM2 treatment was respectively 21.0%, 26.4% and 62.4% higher than those in NPKS, NPK and CK treatments, and NPKS was 34.2% higher than that in the CK (P < 0.05). The increasing trend of soil organic carbon content in long-term organic and inorganic treatments is more obvious than other treatments, and the soil organic carbon contents in NPKM1 and NPKM2 treatments were increased by 6.01 g/kg and 5.55 g/kg compared with the initial soil organic carbon content, respectively.【Conclusions】Long-term application of organic fertilizer can increases soil respiration, and improve the content of soil organic carbon at the same time. Manure application plays a win-win effect for improving agricultural productivity and sustainable utilization.