河西绿洲农田土壤呼吸特征及其对长期施肥的响应

以河西走廊典型的荒漠绿洲新垦农田为研究对象，设置9个施肥处理（高量有机肥，M3；高量氮磷肥，NP3；低量氮磷肥+高量有机肥，NP1M3；低量氮磷钾肥，NPK1；中量氮磷钾肥，NPK2；高量氮磷钾肥，NPK3；低量氮磷钾肥+高量有机肥，NPK1M3；中量氮磷钾肥+中量有机肥，NPK2M2；高量氮磷钾肥+低量有机肥，NPK3M1），于2019—2020年7—8月采用LI-COR 8100对玉米农田土壤呼吸进行观测，分析土壤呼吸的变化、日动态及其主要影响因素。结果表明：（1）不同施肥处理，土壤呼吸速率M3>NP3>NPK1M3>NPK3M1>NPK2M2>NP1M3>NPK2>NPK3>NPK1，单施有机肥能显著提高土壤呼吸速率，较其他处理增长22.1%—41.4%。（2）不同施肥措施土壤呼吸日变化呈单峰曲线，峰值出现在13：00—16：00，土壤呼吸日变化主要受土壤温度变化的影响。（3）土壤温度和土壤湿度分别解释了土壤呼吸变化的24.2%—44.8%和7.7%—36.4%，土壤呼吸与土壤温度显著正相关，而与土壤湿度无显著相关性，不同施肥处理土壤呼吸温度敏感性系数Q₁₀值1.419—1.600。（4）土壤呼吸与有机质、总氮、总碳、碱解氮存在显著正相关关系，施用有机肥使土壤有机质、总氮、总碳、碱解氮分别提升188.9%、80.5%、79.3%、147.0%，进而促进土壤呼吸，土壤呼吸与玉米产量无显著关系。不同的施肥措施会对土壤质量和土壤呼吸产生不同影响，有机肥和氮磷钾化肥的平衡施用，能够在提升土壤质量的同时减少碳排放，可在生产实践中采用。

Characteristics of soil respiration in farmland of Hexi oasis and its response to long-term fertilization

The soil respiration rate was measured by LI-COR 8100 in the newly reclaimed farmlands in Hexi desert oasis in July and August from 2019 to 2020. We analyzed the changes of soil respiration rate and diurnal dynamic variation under 9 different fertilization treatments to determine the key factors. The results showed that： （1） The soil respiration rate was influenced by M3， NP3， NPK1M3， NPK3M1， NPK2M2， NP1M3， NPK2， NPK3， NPK1 in turn from high level to low level. This indicates that the treatment of organic fertilizers application alone significantly increased soil respiration rate by 22.1%-41.4% in comparison with combined manure with chemical fertilizers and the treatment of chemical fertilizers alone. （2） The diurnal dynamic variation of soil respiration in different fertilization presented unimodal curve， and the peak value was found in the periods of 13：00-16：00. The diurnal dynamic variation of soil respiration had a significant correlation with soil temperature （5 cm）. （3） Soil temperature （5 cm） and soil moisture （5 cm） could explain 24.2%-44.8% and 7.7%-36.4% of soil respiration， respectively. A remarkable correlation was found between soil respiration rate and soil temperature， but soil respiration rate had no significant correlation with soil moisture. The temperature sensitivity coefficient of soil respiration Q₁₀ was in the range of 1.419 to 1.600， which was lower than the world average value of 2.4， because high temperature led to decreased sensitivity of soil respiration to temperature changes. （4） Soil respiration was significantly negatively correlated with organic matter， total nitrogen， total carbon and available nitrogen. After applying organic fertilizers， soil organic matter， total nitrogen， total carbon and available nitrogen increased by 188.9%， 80.5%， 79.3% and 147.0% respectively. Thus soil respiration was promoted. There is no significant relationship between soil respiration and maize yield. In conclusion， fertilization measures have an effect on soil quality and soil respiration rate. The balanced application of organic and inorganic fertilizers can improve soil quality while reducing CO₂ emissions， which can be adopted in production practice.