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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个时期土壤C/N的空间相关距离分别为196.3 km和51.1 km,呈递减趋势,说明农田管理影响因素的作用在逐渐增强.过去25 a间,有84.88%的土壤面积的C/N呈上升趋势,以西部增加最为显著,德惠和九台市部分地区有所降低.对于不同的土地利用方式,旱田、水田、林地和草地土壤的C/N均呈上升趋势,其中以草地增加最为明显,从1980年的10.03±1.12上升为2005年的12.61±0.87;旱田和水田土壤C/N均高于全国平均水平.土壤C/N的升高表明碳素的增加速度高于氮素,为保持C/N的稳定提高,今后的农业生产中在提高氮素投入水平的同时,应注重碳素的归还水平,大力推广秸秆还田和增施有机肥.
Soil C / N ratio is a sensitive indicator of soil quality and is a measure of the balance of C and N in soil, and its evolution trend has an important impact on soil carbon and nitrogen cycling. Through field investigation, sampling and analysis, Using geostatistics and GIS techniques, the temporal and spatial variation of soil C / N in maize belts in the Songnen Plain of China from 1980 to 2005 were studied.The results showed that the average values of soil C / N in 1980 and 2005 were 10.56 and 12.30.2, respectively The spatial C / N correlations of soil C and N were 196.3 km and 51.1 km, respectively, indicating a decreasing trend of the impact of farmland management factors, and C / N of 84.88% of the soil area increased in the past 25 years The trend is the most significant increase in the west, Dehui and some areas of Jiutai City decreased.For different land use patterns, the C / N of upland, paddy field, woodland and grassland showed an upward trend, of which the grassland increased most significantly From 10.03 ± 1.12 in 1980 to 12.61 ± 0.87 in 2005. The soil C / N in upland and paddy fields were all higher than the national average.The increase of C / N in soil showed that the increase rate of carbon was higher than that of nitrogen, Maintain the steady increase of C / N in future agricultural production While the high level of nitrogen input, should pay attention to the level of carbon in return, to promote straw and organic fertilizer.