抚仙湖流域坡耕地施肥对土壤水中氮磷质量浓度的影响

Effects of fertilizer application on N and P concentrations of soil water in slope land in Fuxian Lake Watersheds

在滇中地区抚仙湖尖山河小流域坡耕地布设9个不同施肥水平的微型小区,在微型小区及不同坡位的不同深度埋设多孔杯采样器,采集土壤水样,分析其中总氮和总磷的质量浓度变化特征。结果表明:1)施肥量增大,土壤水中总氮、总磷平均质量浓度增大1,.5和2.0倍施肥处理条件下,0～100 cm土层土壤水总磷质量浓度分别是标准施肥量的1.26和1.63倍;2)同一施肥处理条件下,坡下部土壤水总氮、总磷质量浓度基本高于坡中部0,～50 cm坡下部总氮平均质量浓度约为坡中部的1.30倍,0～100 cm坡下部土壤水总磷平均质量浓度约为坡中部的2.0倍;3)同一施肥处理条件下,随着土层深度的加深,土壤水总氮质量浓度逐渐减小0,～50、50～100、100 cm以下土壤水总氮平均质量浓度分别为4.58、3.93和3.17 mg/L;土壤水总磷质量浓度在50 cm以下呈波浪状减小,在0～100 cm变化较大(0.010～0.021 mg/L),在100 cm以下差异较小(0.010～0.014 mg/L);4)在坡耕地种植烤烟时应将施氮量控制在270.0 kg/hm2以下,施磷量要控制在61.2 kg/hm2以下。

To study the effects of fertilization and slope position on the variation of total nitrogen and total phosphorus concentrations,a field experiment was conducted in Fuxian Lake Watersheds in central Yunnan Province,Nine micro plots were arranged.Soil solution samplers of different depth were installed at different slope positions in the plots.Variation characteristics of total nitrogen and total phosphorus concentrations were studied.Results showed that： 1） With fertilizer amount increasing,average concentrations of total nitrogen and total phosphorus in soil water increased.At 1.5 times and 2 times of constant fertilization treatments,total phosphorus concentration of soil water at 0-100 cm depth were 1.26 times and 1.63 times of constant fertilization.2） Under the same fertilization treatment,total nitrogen and total phosphorus concentrations of soil water at bottom were larger than those at middle slope.Total nitrogen concentration of soil water at 0-50 cm depth at slope bottom was 1.30 times of that at middle slope.Total phosphorus concentration of 0-100 cm soil water at slope bottom was 2 times of that at middle slope.3） Under the same fertilization treatment,total nitrogen concentration of soil water had a decline trend with depth deepening.Average total nitrogen concentration of soil water at 0-50,50-100 cm,beneath 100 cm were respectively 4.58,3.93,3.17 mg/L.Total phosphorus concentration of soil water had a wavy decline trend over depth.Variation range of total phosphorus concentration was larger（0.010-0.021 mg/L） at 0-100 cm,smaller beneath 100 cm（0.010-0.014 mg/L）.4）Total nitrogen concentration should be controlled in 270.0 kg/hm2,and total phosphorus concentration should be controlled in 61.2 kg/hm2.