The incubation experiment was conducted to evaluate the influence of fulvic acid (FA) on phosphorus (P) movement and transformation in acid soil. FA at the rate of 0, 0.1, 0.2, 0.3 g and in combination with 0.19 g KH 2 PO 4 was sprinkled uniformly on the surface of the filter paper on the soil cylinder for 21 days incubation, respectively. The result showed that the pH of soil treated with FA increased from the original value of 5.83 to the highest value of 6.27 in the surface soil layer after 21 days incubation. Due to the application of FA, exchangeable Al concentration evidently decreased in comparison to the only P treatment, which in turn significantly increased available P concentration. FA also increased the movement length of P that reached 4.5, 5.5 and 6.5 cm depth for treatments reinforced with 0.1, 0.2 and 0.3 g FA per column, respectively. As FA was added into soil, microbial population, organic matter content and cation exchange capacity (CEC) all clearly elevated. It is suggested that P fertilizer and FA are fertilized together may be considered as an optimum choice for the improvement of P availability and soil physicochemical conditions.

Four commonly applied extraction techniques for organochlorine pesticides, microwave-assisted extraction (MAE), accelerated solvent extraction (ASE), quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction and ultrasonic solvent extraction, were applied on soil samples in order to evaluate their performances. The extracts were analyzed by GC-ECD and confirmed by GC-MS/MS. The MAE and QuEChERS extraction methods generally yielded higher results compared to the ultrasonication and ASE methods, while the lowest recovery (56.8 %) for o,p 0 -DDD was obtained using the QuEChERS method. The MAE method was further applied to six different soils from Beijing. In the soil samples only a-endosulfan and b-endosulfan were not detected. The ratios of a-HCH/c-HCH and a-HCH/b-HCH indicated HCH residues likely originated from historical use of HCHs, and that technical HCHs were not likely being currently applied in Beijing.