亚洲一区欧美在线,日韩欧美视频免费观看,色戒的三场床戏分别是在几段,欧美日韩国产在线人成

The ecostoichiometry of soil nutrients has been successfully used in indicating soil quality and revealing the circulation and balance mechanism, and the information about ecostoichiometry of soil carbon, nitrogen and phosphorus can help to conduct soil nutrient management. However, the soil stoichiometry characteristics in dry farming region are poorly documented. To explore the spatial distributions of soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP) and ecological stoichiometric characteristics of soil C, N and P in dry farming region of Northeast China,totally 132 topsoil samples (0~20cm) were collected in 2017, and SOC, TN, TP and other properties were analyzed in all samples. The spatial variability of ecostoichiometry of soil C, N and P and its influencing factors were analyzed by geostatistics and redundant analysis. The results showed that the mean content of SOC, TN and TP in the study area was 16.79g/kg, 1.43g/kg and 0.77g/kg, respectively; and soil C/N, C/P, N/P ratios were 11.45, 22.82 and 2.03, respectively. Correlation analysis of soil C, N and P showed that significant correlations were existed among C, N, and P (P<0.05). Soil C/N, C/P, N/P ratios were lower than their average value on a national scale. The distribution of soil SOC, TN and TP were increasing from southwest to northeast, with the high value areas mainly distributed in the northern part of the dry farming region of Heilongjiang Province, and the low value areas were in the dry farming region of Jilin and Liaoning Provinces. The high value areas of soil C/N and C/P were mainly distributed in the dry farming region of Heilongjiang Province, the low value region was located in the dry farming area of Jilin and Liaoning Provinces, and the spatial variation of N/P was small in the study area. The ecostoichiometric characteristics of soil C, N and P in the study area were affected by tillage and fertilization, environmental factors and soil properties. Intensity of chemical fertilizers application and land use was an important human factor affecting the ecostoichiometric of soil C, N and P. RDA indicated that soil bulk density and water content were the main soil physical and chemical factors affecting the ecostoichiometric characteristics of soil C, N and P in dry farming region of Northeast China.