秸秆生物炭输入对冻融期黑土表层无机氮磷垂直迁移的影响

为研究秸秆生物炭输入对冻融期黑土表层无机氮磷垂直迁移的影响,采用室内模拟冻融循环试验,设置冻融与不冻融、冻融循环次数和生物炭施加量3个影响因素,分析冻融作用下不同秸秆生物炭输入量土壤表层无机氮磷垂直迁移特征。结果表明:(1)冻融与不冻融、冻融循环次数及生物炭施加量对黑土表层NO3-—N、NH4+—N和PO43-—P垂直迁移液总体积、迁移液总浓度及迁移总量均有极显著影响。(2)淋溶时间随冻融作用增强而缩短,随生物炭施加量增加而延长。所有处理迁移液总体积均随生物炭输入量的增加呈降低趋势。未冻融组迁移液总体积随培养期增加呈现缓慢下降趋势,冻融组处理迁移液总体积在第5次冻融循环试验出现急剧增加,而后趋于平稳。(3)分析冻融作用下秸秆生物炭施入对无机氮磷垂直迁移累积影响,同一控制时间内生物炭对冻融组无机氮磷垂直迁移量的抑制作用大于不冻融组,且随生物炭施入量增加对无机氮磷垂直迁移的抑制作用增强。由于土壤物理性质的改变,冻融组NO3-—N、NH4+—N和PO43-—P累积迁移量均在第5次冻融循环左右发生急剧变化。综上可知,生物炭在冻融期可以有效的固持养分,研究结果可为寒冷地区解冻期面源污染防治提供一定的理论支持。

Effect of Straw Biochar on Vertical Migration of Inorganic Nitrogen and Phosphate in Surface Layer of Black Soil During Freezing and Thawing Period

In order to explore the effect of straw biochar on vertical migration of inorganic nitrogen and phosphorus in surface layer of black soil during freezing-thawing period.This research adopts the indoor simulation of freezing-thawing cycle experiment, set the freezing-thawing and not-freezing-thawing, freezing-thawing cycles, biochar apply three influence factors, to analyze the vertical migration characteristics of soil surface inorganic nitrogen and phosphorus under freezing-thawing with different straw biochar apply. (1) Results show black soil surface freezing-thawing and not-freezing-thawing, freezing-thawing cycles and biochar apply have significant effect on NO₃^--N, NH₄⁺-N and PO₄^3--P inorganic nitrogen and phosphorus migration liquid total volume, total concentration and total amount of migration through freezing-thawing and not-freezing-thawing, freezing-thawing cycles and biochar apply.(2) The leaching time was shortened with the increase of freeze-thaw action and prolonged with the increase of biochar application.All treatments of inorganic nitrogen and phosphorus migration liquid volume show a decrease trend with the increase of biochar input. The total volume of migration liquid in not-freezing-thawing group show a slowly decrease trend as the incubation period increase. The total volume of the migration liquid volume in the freezing-thawing group increases sharply in the 5th freezing-thawing cycle test, and then became stable. (3) The effect of biochar on the vertical migration and accumulation of inorganic nitrogen and phosphorus under freeze-thaw action was analyzed. During the same control period, the inhibition of biochar on the vertical migration of inorganic nitrogen and phosphorus in the freeze-thaw group was greater than that in the non-freeze-thaw group.Because of changes in the physical properties of the soil,the accumulated migration of the freezing-thawing group NO₃^--N,NH₄⁺-N and PO₄^3--P changed dramatically around the fifth freezing-thawing cycle.To sum up, biochar can effectively retain nutrients during freezing-thawing period, and the research results can provide some theoretical support for the prevention and control of rural surface pollution during thawing period in cold regions.