Phosphorus status of major upland soils in northeastern part of China in relation to agricultural division and soil type
1999
Han, J.L. (Kyushu Univ., Fukuoka (Japan). Faculty of Agriculture) | Egashira, K.
Phosphorus status of major upland soils of the northeastern part of China was assessed by means of fractionation of soil phosphorus. Soil samples were collected at Jilin and Liaoning provinces, covering Meadow soil, Black-colored soil, Dark-brown forest soil, Sols lessives, and Saline soil which occupy more than 80% of the upland field. Total P content of upland soils varied with the agricultural division from which soil samples were collected. It was lower by about 200 mg P kg(-1) for soils of Liaoning province and central division of Jilin province where soils have been cultivated for about 400 years, than for soils of eastern and western divisions of Jilin province where soils were started to be cultivated before 150 and 80 years, respectively. The lower content of total P in the former divisions was involved by the lower content of P in the adsorbed-fraction and was ascribed to the disappearance of most apatite, a main P compound in the adsorbed-fraction, due to prolonged time of cultivation. Total P content of upland soils in the eastern division of Jilin province was in the order of Meadow soilBlack-colored soilSols lessivesDark-brown forest soil in the Ap horizon. Variation of total P content with soil type was related to the difference in the content of inorganic P. The content of P in the adsorbed-fraction was in the same order as described in the above and was suggested to be a measure of apatite content controlled by landform and parent material. The content of P in the non-adsorbed-fraction was affected by application of P fertilizer in addition to land form and parent material. Calcium-type P is a predominant form of the non-adsorbed-fraction and was estimated to be an index of P fertility of upland soils in the northeastern part of China
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