松嫩平原玉米带土壤碳氮比的时空变异特征

土壤碳氮比(C/N)是土壤质量的敏感指标,是衡量土壤C、N营养平衡状况的指标,它的演变趋势对土壤碳、氮循环有重要影响.通过野外调查、采样和分析,运用地统计学方法和GIS技术,探讨1980～2005年松嫩平原玉米带土壤C/N的时空变化规律.结果表明,1980年和2005年土壤C/N的平均值分别为10.56和12.30.2...

Spatial and Temporal Variability of Soil C/N Ratio in Songnen Plain Maize Belt

The C/N ratio of soils is a sensitive indicator of soil quality,and an indicator for assessing carbon and nitrogen nutrition balance of soils. Its variation is significant in reflecting the carbon and nitrogen cycling of soils. Based on field investigation,sample collection and analysis,and application of geostatistics and GIS technology,spatial and temporal variation of C/N ratio was analyzed and studied from 1980 to 2005 in Songnen Plain maize belt. The results indicated that the mean value of C/N ratio is 10.56 and 12.30 in 1980 and 2005,respectively. Spatial correlation distance of soil C/N ratio in two periods is 196.3 km and 51.1 km,showing a decreasing trend,which indicated that farming management factors were enhancing. In the past 25 years,84.88% of soil C/N ratio was on rise with the highest value in the west of the study area,but parts of Dehui County and Jiutai County decreased. As for different land use types,soil C/N ratios in the upland,paddy land,forest and woodland and grassland showed upward trends,with the highest increase from 10.03±1.12 in 1980 to 12.61±0.87 in 2005 in grassland and higher in upland and paddy land than the national average. The increasing soil C/N ratio illustrated that soil carbon increased faster than nitrogen. To maintain the steady growth of soil C/N ratio,it is suggested that the return of carbon be paid more attention when the input of nitrogen,such as incorporating crop residues into soil and inputting more organic fertilizers into soils for future farming practices.