漓江水陆交错带硝态氮淋失规律的模拟研究

Simulation Study on NO_3^--N Leaching Law in Aquatic-Terrestrial Ecotone of Lijiang River

以广西桂林市潜经村漓江水陆交错带为研究区域,按照不同淹没程度将水陆交错带分为重度淹没带(T_1)、中度淹没带(T_2)、轻度淹没带(T_3),运用室内土柱模拟试验,研究不同淹没带、不同尿素施肥量、不同价态阳离子对硝态氮(NO_3^--N)淋失的影响。结果表明:(1)在正常施肥条件下,重度淹没带NO_3^--N淋失量最大(117.5kg/hm^2),显著高于中度淹没带(108.0kg/hm^2)和轻度淹没带(102.7kg/hm^2)淋失量。(2)随着施肥量增加NO_3^--N淋失量显著增加,当施肥量分别是140kg/hm^2,180kg/hm^2,220kg/hm^2时,NO_3^--N淋失比值为1∶1.35∶1.94。(3)土壤中阳离子Na^+、Ca^(2+)的存在可显著减少11.38%~18.31%的NO_3^--N淋失量,但不同价态阳离子之间对NO_3^--N淋失量的影响差异不显著。(4)随着淹没程度减小土壤容重逐渐降低,土壤粘粒含量逐渐增加,有机质则呈先减小后增加的趋势。在低、正常施肥处理下,NO_3^--N淋失量与土壤容重呈显著正相关,与土壤粘粒含量呈显著负相关;在高施肥处理下,NO_3^--N淋失量与土壤有机质含量呈显著负相关。

This paper selected aquatic-terrestrial ecotone along Lijiang River as research area,which is located in Qianjing village,Guilin city,Guangxi province.In this study,the area was divided into severe degree inundation zone（T1）,moderate degree inundation zone（T2）and slight degree inundation zone（T3）.An indoor soil column simulation experiment was carried out to study the effects of different urea application amounts and cations of different valences on nitrate nitrogen（NO3^--N）leaching in different inundation zones.The results showed that：（1）The leaching amount of NO3^--N was the highest（117.5kg/hm^2）in severe degree inundation zone,which was significantly higher than those in moderate degree inundation zone（108.0kg/hm^2）and slight degree inundation zone（102.7kg/hm^2）.（2）With the increase of fertilization amount,the leaching amount of NO3^--N increased significantly.When the urea application amounts were140kg/hm^2,180kg/hm^2 and 220kg/hm^2,the leaching ratio of NO3^--N was 1∶1.35∶1.94.（3）The existence of cations in soil,such as Na^＋and Ca^（2＋）,could reduce the leaching amount of NO3^-- N by11.38%～18.31%.However,there was no significant difference among the effects of cations of different valences on the leaching amount of NO3^--N.（4）With the decrease of inundation degree,soil bulk density decreased,while clay content increased,and soil organic matter content increased at first and then decreased.In addition,the leaching amount of NO3^--N in low and normal fertilization amount treatments showed significant positive correlation with soil bulk density,while showed significant negative correlation with clay content,and in high fertilization amount treatment,the leaching amount of NO3^-- N had significant negative correlation with soil organic matter content.