马尾松改造成香榧林对地表径流及氮磷流失的影响

Impact of the Transformation of Pinus Massoniana into Torreya grandis Forest on the Surface Runoff and the Loss of Nitrogen and Phosphorus

掌握马尾松Pinus massoniana林转换为香榧Torreya grandis林对地表径流及氮磷流失的影响,可为人工林经营管理提供一定的基础。在浙江省东阳市林业总场设置马尾松林、香榧幼龄林和香榧中龄林3种处理径流小区,全面监测2023年地表径流量,分析径流水中不同形态氮、磷浓度,并计算养分流失量。结果表明:地表径流量大小为马尾松林(218.0 m^(3)·hm^(−2))>香榧幼龄林(206.0 m^(3)·hm^(−2))>香榧中龄林(157.0 m^(3)·hm^(−2));地表氮流失量大小为香榧幼龄林(806.56 g·hm^(−2))>香榧中龄林(582.80 g·hm^(−2))>马尾松林(159.89 g·hm^(−2)),磷流失量大小为香榧幼龄林(265.55 g·hm^(−2))>香榧中龄林(183.57 g·hm^(−2))>马尾松林(48.72 g·hm^(−2))。与马尾松林相比,香榧幼、中龄林地表径流量分别减少了5.5%和22.5%,而氮流失量增加了4.04倍和2.65倍,磷流失量增加了4.45倍和2.77倍。综上,马尾松林改造成香榧林后降低了地表径流,但增加氮、磷流失量,随着香榧林龄的增大,地表径流及氮、磷流失量随之降低。

Mastering the impact of converting Pinus massoniana forest to Torreya grandis forest on the surface runoff and the nitrogen and phosphorus loss could provide a certain foundation for the artificial forest management.Three types of runoff treatment plots,namely Pinus massoniana forest,young Torreya grandis forest,and middle-aged Torreya grandis forest,were set up at the Forestry General Farm in Dongyang City,Zhejiang Province.The surface runoff in 2023 was comprehensively monitored,and the concentrations of different forms of nitrogen and phosphorus in the runoff were analyzed,and the nutrient loss was calculated.The results showed that the amount of surface runoff was as follows:Pinus massoniana forest(218.0 m^(3)·hm^(−2))>young Torreya grandis forest(206.0 m^(3)·hm^(−2))>middleaged Torreya grandis forest(157.0 m^(3)·hm^(−2)).The amount of surface nitrogen loss was as follows:young Torreya grandis forest(806.56 g·hm^(−2))>middle-aged Torreya grandis forest(582.80 g·hm^(−2))>Pinus massoniana(159.89 g·hm^(−2)),while the amount of phosphorus loss was as follows:young Torreya grandis forest(265.55 g·hm^(−2))>middle-aged Torreya grandis forest(183.57 g·hm^(−2))>Pinus massoniana forest(48.72 g·hm^(−2)).Compared with the Pinus massoniana forest,the surface runoff of young and middle-aged Torreya grandis forests decreased by 5.5%and 22.5%,respectively,while the nitrogen loss increased by 4.04 and 2.65 times,and phosphorus loss increased by 4.45 and 2.77 times.In summary,the transformation of Pinus massoniana forest into Torreya grandis forest reduced the surface runoff,but increased the loss of nitrogen and phosphorus.As the age of Torreya grandis forest increased,the amount of surface runoff and nitrogen and phosphorus loss decreased.