Affecting factors on the concentration and amount of forest run-off waterchemicals.

1.本文研究了森林生态系统中水分化学物质的垂直分布，每月垂直采集2-4次降水、森林穿透水、枯落物层、5、10、20、30、50、70 cm土层和径流水，研究了其中的水分化学物质。将内径为19.5cm的塑料管垂直插入每个土壤层中以收集水样。降水中各矿物的浓度随穿透雨的增加而增加。在入渗过程中，NH_4-N、有机N、P、K、Cl、SO_4的浓度均呈下降趋势。NO_3-N、Ca、Mg含量在各土层均呈增加趋势，在70 cm左右达到最大值.降水和径流水化学成分的季节变化：冬季，由于西北季风携带海盐，降水中Na和Cl含量增加。Cl的增加影响了河水中Cl的浓度。从4月份开始，随着土壤生化活性的增强，河水中NO_3-N含量逐渐增加，到秋末达到最大值。在冬季减少之后，在融雪季节再次被冲洗。夏季径流量增加时，河流中SO_4、Ca、Mg含量呈下降趋势。pH、SiO_2、NH_4-N、有机氮和Na的季节变化不明显。河水中NO_3-N浓度随径流量的增加而增加，当径流量达到最大值时，NO_3-N浓度达到最大值，随径流量的减少而降低。Na、Mg、SO_4含量随水分的增加而降低。Cl的变化与洪水季节有关，Ca和K的变化与流域有关。

1. Vertical distribution of waterchemicals in a forest ecosystem.Precipitation, forest throughfall, a litter layer, 5, 10, 20, 30, 50, 70 cm soil layers, and stream run-off water were collected vertically 2-4 times per month, and the waterchemicals therein were studied. Plastic pipes with an inside diameter of 19.5cm were inserted vertically into each soil layer to collect the water samples. The concentration of each mineral in the precipitation increased in the throughfall. While infiltrating through each soil layer, the concentration of NH_4-N, organic-N, P, K, Cl, So_4 decreased. On the other hand, NO_3-N, Ca, and Mg increased in each soil layer and reached a maximum at around 70cm in depth.2. Seasonal change of waterchemicals in precipitation and stream run-off water.Na and Cl in precipitation increased in the winter due to sea salt which wascarried by the north-west monsonn. The increase of Cl affected the concentration in stream water. NO_3-N in stream water incresed from April with the increase of biochemical activity in the soil, reaching a maximum late in the autumn. After the decrease in winter, it was flushed again during the snow melting season. SO_4, Ca, Mg in stream water tended to decrease in the summer when run-off water increased. Seasonal change was not detected in pH, SiO_2, NH_4-N, org-N, or Na.3. Change of the concentration of waterchemicals in floodwater.NO_3-N concentration in stream water increased with the increase in run-off water and reached a maximum when run-off water reached a maximum, and decreased with the decrease in water. Na, Mg, and SO_4 tended to decrease with the increase in water. The change of Cl depended on the season of floods, and those of Ca and K depended on the watersheds.