Study On Distribution Pattern Of Soil Calcium Carbonate In Seven Provinces Of Northern China

The content and deposition depth of calcium carbonate in the soil profile is an important indicator to determine the degree of soil development and distinguish the soil type.The calcium layer is an information base of the soil development environment,which can be used to reconstruct paleoclimate and ancient precipitation.In recent years,carbonate has been given a new meaning with the global climate change.In this paper,7 provinces(cities,districts)in Heilongjiang,Jilin,Liaoning,Hebei,Inner Mongolia,Beijing and Tianjin were studied in this paper.Soil from 138 soil profiles and 627 soil levels was sampled under different climate conditions by carrying out field investigation and then its physical and chemical properties was analyzed;the data was processed by using GIS,SPSS and Microsoft.According to "China Soil System Classification Retrieval"(third edition)regarding the soil diagnosis and diagnostic characteristics of the classification criteria,soil diagnostic horizons and diagnostic characteristics of calcium and calcite was determined and Soil calcium carbonate content,the spatial distribution law of calcium deposition layer depth and thickness were discussed,to provide the theoretical basis for the classification of soil survey and the determination of soil type.The results are as follows:(1)In the 138 soil profiles surveyed,the number of samples without lime reaction was 61,and the number of samples formed by lime reaction without calcareous layer was 42,and the number of samples with calcareous layer was 35,accounting for 44.2%,30.4%and 25.4%of the total samples respectively.The average content of calcium carbonate in the calcium layer was 171.8 g/kg,the minimum value was 61.8 g/kg,and the maximum value was 304.1 g/kg.Soil calcium layer is usually formed in the depth of 1 m,the calcium layer depth of 48.57%soil profile was at the range of 21-50 cm,the average depth was 40 cm;calcium layer thickness distributed in the depth of 13-91 cm,The average thickness was 35 cm.(2)The geographical distribution characteristics of calcium carbonate content in the soil and the depth and thickness of the calcium layer were obvious.The soil profile without lime reaction(soil calcium carbonate leaching thoroughly)mainly distributed in Nenjiang,Na River,Arongqi,Longjiang,Yangyuan,Tailai,Changling,Horqin Zuoqi rear wing,Coulomb flag,Aohan flag,Luanping,Zhulu,the annual average precipitation is 380 mm-777 mm,and the annual mean temperature is 1 ?-9? in such regions;The soil profile with the lime-free and non-calcined layer mainly distributed in Nenjiang,Na River,Lyon Creek,Tailai,Tuoquan,Zha Lute flag,Aruokeqinqi,Wengniute flag,paddock,Chongli,and Lingel,Ejin Holo flag,and Jiayin,Nanchuan District,Tonghe,Shangzhi,Shulan,Huadian,Liuhe,Xinbin,Taian,Jianchang,wide city,booming,easy county,Fuping,the original level,Xing County,the annual average precipitation is 334 mm-963 mm,and the annual mean temperature is 1 ?-14 ? in such regions;the soil profile with the calcium-containing layer mainly distributed in Hailun,Wang Kui,Shuangcheng,Fuyu,Dehui,Gongzhuling,pear tree,Horqin left wing right flag,Naiman flag,Wengniute flag,is blue flag,is white flag,chemical,Chahar right wing flag,And Lingel,Deng mouth,Bayin hair Road,the annual average precipitation is 134 mm-508 mm,and the annual mean temperature is 3 ?-7 ? in such regions.(3)The statistical analysis shows that there is a significant function relationship between the calcium carbonate content,the depth of the calcium layer in the soil profile and the annual precipitation.Calcium carbonate content x(g/kg)and annual average precipitation y(mm)was linearly dependent on y =-0.4748x + 334.83,(r = 0.680,P<0.01,n = 35).Developing depth of calcium layer x(mm)and annual mean annual precipitation y(mm)was dependent on y=138.88x~0.2893,(r = 0.680,P<0.01,n = 35).