不同施氮量及施氮比例对橡胶园土壤无机氮运移特征的影响

Effects of Different Nitrogen Application and Ratios on the Transportion Characteristics of Soil Inorganic Nitrogen in Rubber Plantations

橡胶树是重要的经济树种,为探究橡胶园合理的施肥量,设置不同氮肥用量的田间试验,明确中期和后期施肥后橡胶园的氮素运移特征。设置4个处理:①空白对照(CK),不施肥;②常规施肥(C,施肥总量2 kg/株,前期∶中期∶后期=5∶3∶2);③减量施肥(J,施肥总量1.6 kg/株,前期∶中期∶后期=5∶3∶2),减量施肥相当于常规施肥减量20%;④同步施肥(T,施肥总量1.6 kg/株,前期∶中期∶后期=3∶3∶2)。结果表明:不同施肥处理的橡胶园土壤氮素运移特征不同,以垂直运移为主,水平运移在5 cm内波动明显,随着水平距离的增加,不再有明显变化。中期施肥铵态氮主要迁移至40-60 cm,而后期施肥铵态氮主要停留在0-20 cm。无机氮的变化趋势与铵态氮一致,无机氮主要以铵态氮的形式赋存。在后期施肥,铵态氮和硝态氮的迁移能力均有所减弱,向深层土壤的迁移减少。因此,调整施肥量和施肥时间,有利于提高橡胶园氮肥利用率,减少氮素损失。

Rubber tree is an important economic tree species.In order to explore the reasonable amount of fertilization in rubber plantations,field experiments with different nitrogen fertilizer dosages were set up to clarify the nitrogen trans-portion characteristics of rubber plantations after mid-and late-stage fertilization.Four treatments were set up:blank①control(CK),no fertilization;conventional fertilization(C,total fertilization 2 kg/plant,early②stage∶middle stage∶late stage=5∶3∶2);reduced fertilization(J,total fertilization 1.③6 kg/plant,early stage:mid dle stage∶late stage=5∶3∶2),and the reduction of fertilization is equivalent to a 20%reduction in conventional fertilization;simult④a-neous fertilization(T,total fertilization 1.6 kg/plant,early stage:middle stage:late stage=3∶3∶2).The results showed that the characteristics of soil nitrogen transportion in rubber plantations with different fer tilization treatments were different,mainly vertical transportion,and horizontal transportion fluctuated significantly within 5 cm,and there was no obvious change with the increase of horizontal distance.The ammonium nitrogen in the mid-term fer-tilization mainly transported to 40-60 cm,while the ammonium nitrogen in the later fertilization mainly stayed at 0-20 cm.The trend of inorganic nitrogen was consistent with that of ammonium nitrogen,the main form of soil inorganic nitrogen under different fertilization treatments was ammonium nitrogen.The transportation ability of both ammonium and nitrate nitrogen was reduced and the transportation to deep soil was reduced in the late fertilization.Therefore,ad-justing the amount and time of fertilization is beneficial to improving the utilization rate of nitrogen fertilizer in rubber plantations and reduce nitrogen loss.