长期不同施肥下新疆灰漠土土壤呼吸特征研究

目的]探讨长期不同施肥下新疆灰漠土的土壤呼吸变化特征,为西北干旱区灰漠土农田土壤碳通量的计算以及灰漠土固碳潜力的评估提供依据。方法]在连续定位施肥22 a灰漠土长期试验的12个处理中选择5个处理,利用英国ACE土壤碳通量测量仪,对其呼吸速率进行24 h的连续监测。同时监测试验区气温和5 cm地表温度等相关气象数据。结果]长期施用有机物料(NPKM、M、S)的土壤呼吸速率总体高于不施用有机物料(NPK、CK)的处理,以单施有机肥(M)处理对土壤呼吸速率的影响最为显著,秸秆还田处理其次。NPKM处理的土壤呼吸速率小于M和S,说明化肥配合有机肥的施肥方式能够减缓农田CO_2的释放,长期施用有机物料处理的土壤呼吸速率对环境温度的敏感性大于不施用有机物料的土壤,除NPKM处理外,其余处理与地表温度间存在线性关系。结论]从农业固碳减排和土壤肥力培育的角度,有机无机配合施用是实现新疆农田地力提升和环境友好双赢的重要培肥措施。

The Soil Respiration Characteristics of Grey Desert Soil under Different Long - term Fertilization

Objective]The objective of this study was to demonstrate soil respiration characteristics of grey desert soil under different long - term fertilization in order to provide scientific basis for estimating carbon flux and carbon capacity of grey desert soil in northwest arid region of China.Method]This long - term deferent fertilizer experiment last for 22 years.Five out of the twelve treatments were selected for this study. Soil respiration rate was 24 hours continuous observation using ACE CO₂ exchange instrument.The treatment included no fertilizer（CK）,applied nitrogen,phosphorus and potassium fertilizer（NPK）,applied livestock （M）,straws return（S） and combined application of organic manure and chemical fertilizer（NPKM）.Air temperature and 5 cm soil surface temperature were monitored as well.Result]For the five treatments,long - term application organic material（NPKM,M,S） had much higher soil respiration rate than no organic manure（CK,NPK）.Especially M has significant impact on soil respiration rate,followed by S（straw return）.Organic material was found to have smaller soil respiration rate at NPKM than M and S.This clearly exhibits that combination of manure and mineral fertilizer could mitigate CO₂ efflux from cropland.This finding is in agreement with the results of other authors.Sensitive analysis of relationship between soil respiration rate and ambient temperature showed that application of organic material,either M or S was more sensitive than no application organic material.Except for NPKM,the linear regression was shown between soil respiration rate and 5 cm surface temperature.Conclusion]The results of the present study further support the idea that appropriate fertilizer management practices need to be developed for sustainable soil fertility promotion and environmental friendliness.Therefore,the existing fertilizer recommendations require revision for the farmland carbon sequestration and CO₂ efflux.Chemical fertilizer and manure application was the optimal choice.