氮磷钾肥料对茶园土壤溶液中氟含量的影响

在室内模拟条件下,设置茶园土壤单施不同水平及形态的氮肥以及配施不同水平氮、磷、钾肥料处理,根据各处理施肥后土壤中的肥料浓度向土壤中添加相应肥料溶液,测定不同时间段后土壤溶液的pH值和氟含量,分析氮肥水平和形态,氮、磷、钾配施对茶园土壤溶液中氟含量的影响。结果表明:(1)单施氮肥条件下,施用铵态氮和硝态氮增加了土壤溶液中氟含量,酰胺态氮则降低了土壤溶液中氟含量,且三者对氟含量的增加或降低作用均随施肥时间和氮肥水平的增加而增加;施肥后48 h土壤溶液中氟含量与土壤溶液pH值呈负相关(r=-0.658~(**)),氮肥形态通过影响土壤溶液pH进而影响土壤溶液氟含量。(2)氮、磷、钾配施时,随着施肥时间的增加,土壤溶液中氟含量增加,不同处理的差异显著性则降低;相同磷、钾水平下,土壤溶液中氟含量随氮肥(硫酸铵)水平的增加而显著增加;磷肥可显著降低土壤溶液中氟含量,钾肥可以增加土壤溶液中氟含量,同样施氮条件下,土壤溶液中氟含量的大小基本为N+KN+P+KNN+P;施肥后48 h土壤溶液中氟含量与氮水平高度正相关(P0.01),与土壤溶液pH值高度负相关(P0.01),氮、磷、钾配施茶园土壤溶液中氟含量主要受氮肥水平和土壤溶液pH的影响。可见,在茶园中施用适量的酰胺态氮,或者配施磷或磷钾,在一定时间内可以提升土壤pH值,进而降低土壤溶液氟含量,为合理施肥,降低茶园土壤有效氟提供了理论依据。

Effects of N,P and K fertilizer on the concentration of fluoride in tea garden soil solution

Laboratory simulation experiment was conducted by designing different forms and levels of N fertilizer and different levels of P and K fertilizer.Fertilizer solution was added into the soil according to the fertilizer concentration in the soil after fertilization,then the pH value of soil solution and the concentration of fluoride in it was determined at different times after fertilization for analyzing the effects of N,P and K fertilizer on the concentration of fluoride in soil solution under tea garden soil.The results were as followed:(1)Under the condition of single N fertilizer,the application of ammonium nitrogen and nitrate nitrogen increased the concentration of fluoride in soil solution,while amide nitrogen reduced the concentration of fluorine in the soil solution.The effects of the three forms of N fertilizer increased with time and N level.The concentration of fluoride in soil solution was negatively significant correlated with the pH value of soil solution(r=-0.658**)at 48 hour after fertilization.Nitrogen forms influenced the concentration of fluoride in soil solution by influencing the pH value of soil solution.(2)Under the condition of the same level of P and K,the concentration of fluoride in soil solution increased with the level of N.The application of P fertilizer significantly reduced the concentration of fluoride in soil solution,while K fertilizer increased it.Under the condition of the same level of N,the order of fluoride concentration in soil solution basically was N+K>N+P+K>N >N+P.Fluoride content in soil solution was highly positive correlated with N level(P<0.01),while it was highly negative correlated with the pH value of soil solution(P<0.01)at 48 hour after fertilization.The effect of N,P and K fertilizer on the concentration of fluoride in tea garden soil solution mainly caused by N fertilizer and the pH value of soil solution.Applying moderate amide N,or with P or P and K,in the tea garden can increase soil pH in some periods,reduce the concentration of fluoride in tea garden soil solution.Thus it provides a theoretical basis for reducing the availability of fluorine in tea garden soil by rational fertilization.