宁夏中部压砂区表层土壤离子分布及盐分类型预测

Soil ions distribution and salinity types prediction of surface layer of gravel mulched region of middle of Ningxia

为探明宁夏环香山压砂区盐碱地表层土壤离子分布主要影响因素及盐分类型,研究选取覆盖状况、地面倾角和海拔3个因素,对0~20 cm表层土壤离子分布、盐分存在形式及钠吸附比(SAR)进行研究。结果表明:(1)覆盖状况对土壤表层离子含量有显著影响,地面倾角对HCO_(3)^(-)影响显著,海拔对Mg^(2+)有显著影响,裸地Ca^(2+)、Mg^(2+)、K^(+)、Na^(+)、Cl^(-)和SO_(4)^(2-)含量依次比压砂地高0%~284.21%、100%~130.53%、33.33%~48.94%、18.01%~182.26%、111.94%~468.72%和102.74%~118.82%,而CO_(3)^(2-)、HCO_(3)^(-)含量压砂覆盖比裸地分别高77.08%~400%和24.52%~48.09%;(2)阳离子之间除K^(+)与Ca^(2+)、Mg^(2+)具有显著正相关外其余都极显著正相关,阴离子Cl^(-)和SO_(4)^(2-),CO_(3)^(2-)和HCO_(3)^(-)呈极显著正相关,其余都呈负相关或不显著正相关,阳离子与Cl^(-)均呈极显著正相关,与SO_(4)^(2-)除K^(+)外其余均呈极显著正相关,阳离子与CO_(3)^(2-)和HCO_(3)^(-)呈负相关或不显著正相关;(3)该区域表层土壤盐分主要以NaCl、KCl、CaCl_(2)、MgCl_(2)、CaSO_(4)、MgSO_(4)和Na_(2)SO_(4)的形式存在,按照摩尔量计,盐分含量排序为:Na^(+)盐>Mg^(2+)盐>Ca^(2+)盐>K^(+)盐;(4)覆盖状况对土壤表层SAR影响显著,地面倾角随海拔变化对土壤SAR没有显著影响,压砂地SAR为3.99(mol/kg)0.5,裸地为10.73(mol/kg)0.5。宁夏环香山压砂区0~20 cm埋深土壤离子分布主要受到覆盖状况和地面倾角的影响,除K^(+)外,其他离子受海拔的影响不明显,盐分主要是Na^(+)盐,其次是Mg^(2+)盐,K^(+)盐含量最少。

The object was to explore the main effect factors and salinity type of topsoil of gravel-mulched region saline and alkaline land,in the middle region of Ningxia province,China.The soil ions distribution,salinity existence form and sodium absorption ratio(SAR)of 0~20 cm depth soil affected by coverage conditions(gravel-mulched,bare land),ground tilt angle(<2°,>2°)and altitude(1567.4~1582.7 m)were analyzed.Main conclusions were as follows:(1)Coverage conditions were significant(P<0.05)to soil ions of surface layer,and the ground tilt angle was significant(P<0.05)to HCO_(3)^(-),altitude was obvious significant(P<0.05)to Mg^(2+);Ca^(2+),Mg^(2+),K^(+),Na^(+),Cl^(-)and SO_(4)^(2-)’s contents of bare land were higher than those of gravel-mulched field by 0%~284.21%,100%~130.53%,33.33%~48.94%,18.01%~182.26%,111.94%~468.72%and 102.74%~118.82%,respectively;CO_(3)^(2-)and HCO_(3)^(-)’s contents of gravel-mulched field were higher than those of bare land by 77.08%~400%and 24.52%~48.09%,respectively.(2)The relationships among different salt cations were extremely significant,and it was significantly positive correlation each other except K^(+)with Ca^(2+)and Mg^(2+);Cl^(-)and SO_(4)^(2-),CO_(3)^(2-)and HCO_(3)^(-)were extremely significantly positive correlated,and the relationships of other anions were negative correlation or non-significant correlation.All cations had extremely significantly positive correlation with Cl^(-),and had extremely significantly positive correlation with SO_(4)^(2-)except K^(+),and all cations were negative correlated or non-significantly correlated with CO_(3)^(2-)and HCO_(3)^(-).(3)The main salinity of soil surface layer of Huanxiangshan gravel-mulched area in Ningxia was NaCl,KCl,CaCl_(2),MgCl_(2),CaSO_(4),MgSO_(4)and Na_(2)SO_(4),and the rank of salt contents was Na^(+)>Mg^(2+)>Ca^(2+)>K^(+).(4)Coverage conditions was obviously significant to SAR of soil surface layer,SAR of gravel-mulched field was 3.99(mol/kg)0.5 and bare land was 10.73(mol/kg)^(0.5).It can be concluded that the main effect factors of soil ions distribution and SAR is human activity in Huanxiangshan gravel-mulched area of Ningxia and coverage conditions and ground tilt angle has evident effect on 0~20 cm depth soil ions distribution and SAR,and altitude hasn’t evident effect.The main salinity is Na^(+)salt,next is Mg^(2+)salt,and K^(+)salt is the minimum.