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本研究通过在板栗林地设置径流小区,于2013年1—10月间采集径流水样进行测试,同时结合雨季前后土壤氮素数据,分析了浙江北部赋石水库集水区板栗林土壤氮素迁移特征.结果表明:板栗林地的10次地表径流事件中,各径流小区径流水量差别较大,最大达0.51 m~3;其中氮是主要的流失元素,硝态氮(NO_3~--N)、铵态氮(NH_4~+-N)、总氮(TN)和化学需氧量(CODMn)的浓度分别为0.02~1.87、0.04~3.53、1.69~5.33和5.30~14.07 mg·L~(-1),各水质指标受径流水量影响较大,且用一元一次方程可以较好地拟合氮素流失量与径流水量之间的相关关系;雨季前后板栗林地径流场上部、中部和下部3个位置的土壤中,氮素含量差异较大;总的变化趋势是随着海拔升高氮素含量增加,随着土层深度加深氮素含量降低.比较雨季前后4种土壤氮素(NO_3~--N、NH_4~+-N、TN和水解性氮Hydro-N)的差异发现,差异较大的为Hydro-N和TN,平均差异值为20.21和307.49 mg·kg~(-1).该区氮素随径流流失风险较大,对赋石水库水体富营养化构成潜在压力,需重点关注.
In this study, runoff plots were set up in chestnut forestland to collect runoff water samples from January to October in 2013, and meanwhile the soil nitrogen data before and after the rainy season were used to analyze the soil nitrogen transport in chestnut forests in the catchments of Shifushi Reservoir in northern Zhejiang Province. The results showed that in 10 chestnut forest land runoff events, the runoff volume of each runoff plot varied greatly, reaching a maximum of 0.51 m ~ 3. Among them, nitrogen was the main drainage element, nitrate nitrogen (NO_3 ~ - N) The concentrations of NH 4 + -N, TN and CODMn were 0.02-1.87, 0.04-3.53, 1.69-5.33 and 5.30-14.07 mg · L -1, respectively ), And each water quality index is greatly affected by runoff. And the correlation between nitrogen loss and runoff can be well fitted by a univariate linear equation. Before and after the rainy season, the top, middle and lower part of the runoff field Of the soil, the content of nitrogen was quite different, and the general trend was that with the increase of altitude, the content of nitrogen decreased with the deepening of soil depth.Comparing the contents of NO_3 ~ N, NH_4 ~ + -N, TN and hydrolysable N-Hydroxyl-N) found that the difference is more Hydro-N and TN, Differences in values were 20.21 and 307.49 mg · kg ~ (-1). Nitrogen runoff area with a greater risk of loss of water body eutrophication Fushi reservoir pose a potential pressure, need to focus on.