不同母质发育水稻土剖面酸度特征

Acidity Characteristics of Paddy Soil Profiles Derived from Different Parent Materials

为探讨红壤性水稻土剖面酸度特征及其主要影响因素,采集了南方红壤丘陵区典型县域(余江县)4种母质(红砂岩,河流冲积物,第四纪红土和板页岩)发育的25个不同深度水稻土样品(0~20,20~40,40~60,60~80,80~100 cm),分析了土壤酸度和养分指标。结果表明:在0~20 cm土层,水稻土酸度显著高于60~100 cm土层,其中第四纪红土母质发育土壤交换性Ca^2+、Mg^2+含量显著高于板页岩母质发育土壤,红砂岩与河流冲积物母质差异不显著。与0~20 cm土层相比,水稻土pH在20~80 cm土层显著增加了0.54~1.26,交换性H+含量显著降低了0.12~0.15 cmol/kg,交换性Al^3+含量显著降低了1.06~1.38 cmol/kg,交换性Ca^2+含量显著增加了0.81~2.22 cmol/kg,交换性Mg^2+含量显著增加了0.30~1.08 cmol/kg,不同母质之间差异不显著;在80~100 cm土层,第四纪红土、红砂岩与河流冲积物母质发育水稻土pH和交换性Ca^2+含量显著高于板页岩母质,板页岩母质发育水稻土交换性Al^3+含量显著高于第四纪红土,红砂岩与河流冲积物母质则差异不显著,第四纪红土、红砂岩和板页岩母质发育水稻土交换性Mg^2+含量显著高于河流冲积物母质。水稻土pH均与交换性H^+、Al^3+、有机质和全氮呈极显著负相关,与交换性Ca^2+、Mg^2+呈极显著正相关(P<0.01)。在0~100 cm土层,水稻土酸度表现为在0~20 cm土层较大,主要受土壤理化性质(交换性H^+、Al^3+、Ca^2+、Mg^2+、有机质、全氮)的影响,在80~100 cm土层较小,主要受成土母质影响,其中红砂岩、河流冲积物和第四纪红土母质发育的水稻土酸度小于板页岩。

To investigate acidity characteristics at different depths of paddy soil derived from different parent materials,a series of soil samples at different depths were collected from 25 sites with 4 parent materials(red sandstone,river alluvium,quaternary red clay and plate shale)to be determined and analyzed.The results indicated,at 0-20 cm soil layers,paddy soil acidity was larger than that of 60-100 cm soil layers,soil exchangeable calcium(Ca^2+)and magnesium(Mg^2+)derived from contents quaternary red clay parent materials were significantly higher than that of plate shale parent material,and there were no significant difference between red sandstone and river alluvium parent materials.Compared with 0-100 cm soil layers,at 20-80 cm soil layers,paddy soil pH increased significantly by 0.54-1.26,exchangeable hydrogen(H^+)content decreased significantly by 0.12-0.15 cmol/kg,exchangeable aluminum(Al^3+)content decreased significantly by 1.06-1.38 cmol/kg,exchangeable Ca^2+content increased significantly by 0.81-2.22 cmol/kg,exchangeable Mg^2+content increased significantly by 0.30-1.08 cmol/kg,there is no significance on different parent materials;At 80-100 cm soil layers,soil pH and exchangeable Ca^2+contents derived from quaternary red clay,red sandstone and river alluvium parent materials were significantly higher than that of plate shale parent material.Soil exchangeable Al^3+content derived from plate shale parent material were significantly higher than that of quaternary red clay parent material,and there were no significant difference between red sandstone and river alluvium.Soil exchangeable Mg^2+content derived from quaternary red clay,red sandstone and plate shale parent materials were significantly higher than that of river alluvium parent material.Paddy soil pH derived from different parent materials significantly positively correlated with exchangeable H+and Al^3+,organic matter and total nitrogen,but negatively correlated with exchangeable Ca^2+and Mg^2+(P<0.01).At 80-100 cm soil layers,the acidity of paddy soil was larger at 0-20 cm soil layer,affected by exchangeable H+and Al^3+,exchangeable Ca^2+and Mg^2+,organic matter and total nitrogen,at 80-100 cm soil layers,soil acidity variability was less,affected by parent materials,showing that acidity of paddy soil derived from red sandstone,river alluvium,and quaternary red clay parent materials was less than that of plate shale.