| The contents of organic carbon, oxidized organic carbon and humus organic carbon in soil of plough layer(0-20cm) and vertical section(0-50cm), which included gleyed paddy soil, percogenic paddy soil, submergic paddy soil and aquil soil collected from plain of Chengdu in Sichuan province, were studied by open-country-survey method, t-testing , analysis of variance (ANOVA), Regression and correlation. The effect of parent material, soil utilization and soil particle composition on the content was also studied. The research results were listed as follow:The contents of organic carbon, humus organic carbon and oxidized organic carbon were 22.29±7.2 g kg-1,20.05±7.21 g kg-1 and 5.72±1.84 g kg-1 respectively in plough layer. The relationship of organic carbon content in four soil types soil as following: gleyed paddy soil> percogenic paddy soil> aquil soil> submergic paddy soil. The analysis of variance indicated that the organic carbon content in four soil types were notable (P=0.000). The content of humus carbon in gleyed paddy soil, percogenic paddy soil, submergic paddy soil and aquil soil were 30.82 g kg-1, 18.44 g kg-1, 12.63 g kg-1 and 18.31 g kg-1 respectively in plough layer. The content of oxidized organic carbon was 8.48 g kg-1, 5.56 g kg-1, 3.90 g kg-1 and 4.93 g kg-1 respectively.The content of organic carbon, humus carbon and oxidized organic carbon decreased gradually from up to down in the vertical section(0-50cm). The extent of decreased, however, was different in 4 sub-types soil.(1)The contents of organic carbon at the layer of 0-10 cm,10-20 cm,20-30 cm,30-40 cm and 40-50 cm were extreme notable. At the layer of 20-30cm, the content of soil organic carbon liked as gleyed paddy soil> aquil soil > percogenic paddy soil > submergic paddy soil. At the other layers, it all liked as gleyed paddy soil> percogenic paddy soi > aquil soil 1 > submergic paddy soil.-1(2)The contents of humus carbon at different layers were extreme notable. At the layers of 0- 10cm and 30-40cm, the content of humus carbon liked as gleyed paddy soil> percogenic paddy soil > aquil soil > submergic paddy soil. At the other layers, the content of humus carbon liked as gleyed paddy soil> aquil soil > percogenic paddy soil > submergic paddy soil.(3)The contents of oxidized organic carbon at different layers were also extreme noteable. At the layer of 20-30cm, the content of oxidized organic carbon liked as gleyed paddy soil> aquil soil > percogenic paddy soil > submergic paddy soil. At the other layers, it all liked as gleyed paddy soil> percogenic paddy soi > aquil soil 1 > submergic paddy soil.At plough layer(0-20cm), the relationship of organic carbon content, oxidized organic carbon content and humus organic carbon content in different parent materials liked as gray-alluvium (20.73±1.13g kg-1)>beige-alluvium(23.37±5.81g kg-1). The t-test indicated that contents of organic carbon in different parent materials were not notable. Humus carbon in different parent materials liked as gray-alluvium (21.65±5.00g kg-1) > beige-alluvium (17.66±4.22g kg-1) also, and the difference between the two types of soils from the parent materials were notable. Oxidized organic carbons of the soils from the two parent materials were 5.52±1.87g kg-1 (gray-alluvium) and 4.89±2.13g kg-1 (beige-alluvium) respectively, and did not show notable.Perpendicularly, the content of organic carbon, humus carbon and oxidized carbon decreased from surface layer to underlayer in different parent materials. The content of organic carbon was the highest at 0-10cm, and diminished sharply at 20-30cm. The content of humus carbon and oxidized carbon decreased sharply, respectively, at 10-20cm and 0- 10cm.According to soil utilization mode as paddy soil, dry and paddy rotation soil and vegetable soil, the relationship of organic carbon content, oxidized organic carbon content and humus organic carbon content at plough layer liked as paddy soil > dry and paddy rotation soil > vegetable soil. The content of organic carbon in paddy soil, dry and paddy rotation soil and vegetable soil were, 26.21 g kg-1,21.67g kg-1 and 18.28 g kg-1 respectively. The content of humus carbon was 22.46 g kg-1, 19.10g kg-1 and 16.35 g kg-1 respectively. The content of oxidized organic carbon was 6.17 g kg-1, 4.91 g kg-1 and 4.56 g kg-1 respectively. The analysis of variance indicated that the content of organic carbon, oxidized organic carbon and humus carbon was extreme notable in different utilization soil.The relationship of total organic carbon content in paddy soil,dry and paddy rotation soil and vegetable soil at different layer liked as 0-10 cm > 10-20 cm >20-30 cm > 30-40 cm > 40-50 cm. The analysis of variance indicated that the content of 3 organic carbons was extreme notable at different layer soil.The content of clay and the content of all 3 organic carbon showed as extreme notable linearity positive correlation. The correlation coefficient were, 0.917** (n=24) , 0.623** (n=24) and 0.619** (n=24) respectively. The content of slit and the content of organic carbon showed as extreme notable linearity positive correlation. The correlation coefficient was 0.629** (n=24) . The content of slit and the content of humus carbon and oxidized organic carbon did not showed any notable linear positive correlation. The correlation coefficient were 0.539**(n=24) and 0.308(n=24), respectively. The content of sand and the content of all 3 organic carbons did not showed any notable linear negative correlation. The correlation coefficient were -0.211 (n=24) , -0.180 (n=24) and -0.264 (n=24) respectively. |
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