科尔沁改良草场土壤全碳、全氮空间分布

以科尔沁盐碱地改良草场为研究对象,采用经典统计学与地统计学相结合的方法,研究退化草场改良5年和改良1年后土壤全碳和全氮的含量变化及空间分布特征。结果表明,改良1年退化草场土壤全碳和全氮含量高于改良5年的退化草场,其中土壤全氮含量二者差异达到极显著水平(P<0.01);与改良5年退化草场相比,改良1年土壤全碳和全氮的基台值和空间相关度较小,而变程和分数维较大,说明改良1年退化草场土壤全碳和全氮空间变异性小于改良5年退化草场。克里格制图直观地反映了不同改良年限土壤全碳和全氮的空间结构差异,这种差异可能与草地翻耕和自然植被恢复有关。为此,建议采取牧草还田或施加化肥来提高土壤肥力和保护草场改良工程的实施效果。

Spatial distribution of soil total carbon and nitrogen in meliorated grasslands of Horqin region

By using traditional statistics and geostatistics,this paper studied the contents and spatial pattern of soil total carbon (TC) and nitrogen (TN) after melioration of degraded grasslands in Horqin region.The results show that the contents of TC and TN were higher in grassland after 1-year melioration (Glym) than in grassland after 5-year melioration (G5ym),respectively,and the significant difference of TN content was found between treatments (P<0.01).Compared with G5ym,the sill value and spatial dependence of TN and TC in Glym were lower and their ranges and fractal dimensions were higher,which indicates that the spatial heterogeneity of TC and TN in Glym was lower than those in GSym.Kriging maps also reflect the difference of TC and TN between Glym and GSym,which may be influenced by ploughed grassland and nature plant restoration.Therefore,our study suggests that the pasture should be returned to field and the grassland be fertilized in order to improve soil fertility and protect the effects of engineering measures on meliorated grasslands in Horqin region.