为了确定辽宁省坡耕地在不同耕作模式下土壤养分流失的特征,采用6°坡耕地,选取大豆作为种植作物,在天然降雨条件下,采用顺垄、横垄、免耕、免耕秸秆覆盖等耕作模式进行组合试验,观测分析降雨后氮、磷养分流失的变化特征,并通过回归分析方法说明了降雨对各土壤养分流失浓度的影响.结果表明:传统耕作顺垄+平翻模式下,氮、磷流失浓度最高,总氮为24.2mg·L-1,总磷为2.013mg·L-1；免耕和免耕秸秆覆盖在顺垄布置下与传统平翻耕作相比,分别减少总氮流失30％和32％,减少总磷流失18％和30％;与顺垄耕作组合模式相比,横垄耕作组合有效地减少径流中的各种养分流失浓度,减少总氮流失35％,减少总磷流失35.4％；硝态氮在横垄+平翻模式下流失量最低,为3.0mg·L-1,铵态氮在横垄+免耕秸秆覆盖模式下流失量最低,为6.8mg·L-1；径流中磷素浓度在0.1～0.6mg·L-1,水体富营养化现象严重；回归方程结果表明,天然降雨对径流中各养分的流失浓度影响显著.%To study the characteristics of the soil nutrient losses from slope cropland in Liaoning province, different tillage patterns, including straight -plowing, cross —plowing, no -tillage and straw mulching were carried out under natural rainfall conditions. The results showed that nitrogen and phosphorus concentrations in loss runoff were the highest under the conventional cultivation model among the 4 patterns. The farming measures of cross—plowing tillage were much better than slope tillage for each nutrient loss in runoff regulation. The loss of NO-3 in runoff was the least under traditional cross-plowing plot. The loss of NH+4 in runoff was the least under cross-plowing with no-tillage and straw mulching plot. Concentration of the phosphorus in runoff was around 0.1— 0.6mg-L-1. It showed that water there had been in entropic state. The regression analysis showed that the natural rainfall affected the loss of nutrients in runoff evidently.
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