Comparative Analysis of Soil Nutrient Status across Different Ecological Zones in Ningxia
To understand the soil fertility and nutrient status in Ningxia,soil samples from major soil types across three ecological zones were collected and analyzed for pH,organic carbon,total nitrogen,total phosphorus,total potassium,available phosphorus,cation exchange capacity,and exchangeable potassium,sodium,calcium,and magnesium as well as particle and mineral compositions within the 0 to 40 cm soil layer.The results indicated that the central arid zone had the lowest soil nutrient content,followed by the southern mountain area,with the best overall nutrient status found in the Yinhuang irrigation district.The pH and salt base saturation were highest in the Yinhuang irrigation district(north of Yinchuan)and lowest in the southern mountain area,with the lowest mineral ion content in the central arid zone.The southern mountain area had the best soil particle composition,predominantly consisting of medium coarse particles.The soils of the southern mountain area black loessial soil and grey-brown soil had relatively high nitrogen content,at 0.83 g/kg and 1.51 g/kg respectively,with other soils all below 0.60 g/kg,indicating a deficiency in soil nitrogen.The saline and irrigated soils in the Yinhuang irrigation area had available phosphorus contents of 19.62 mg/kg and 18.28 mg/kg,respectively,three to four times than that of the the grey desert soil and grey calcium soil in the same ecological zone.The available phosphorus content of the loess soil in the central arid zone was 15.82 mg/kg,while it was only 3.13 mg/kg in the loess soil of the southern mountain area,less than one fifth.The gray desert soil in the Yinhuang irrigation area(north of Yinchuan)and the gray and brown soil in the southern mountain area had organic carbon contents of 19.09 g/kg and 17.43 g/kg respectively,significantly higher than other ecological areas where soil organic carbon content was generally below 10.00 g/kg,placing them in the fourth tier or lower in the national soil nutrient classification,indicating that overall soil organic matter content in Ningxia is low.Humic substances were higher in the organic matter of the Yinhuang irrigation area and central arid zone,while fulvic acids were more prevalent in the black loessial soil and grey-brown soil of the southern mountain area.
国家科技期刊平台
NSTL
万方数据
