磷与镉对不同类型耕型红壤有机氮矿化的影响

采用室内培养,设磷处理浓度为0、0.1、0.3和0.5 g/kg,镉处理浓度为0、0.5和1.0 mg/kg,研究磷、镉单独处理及磷、镉共同处理对湖南省4种典型母质(第四纪红土、花岗岩风化物、石灰岩风化物和板岩风化物)发育的耕型红壤有机氮矿化的影响.结果表明:培养2~8周的耕型第四纪红土红壤氮矿化量均值随磷添加量增加而先增加后减小,且在添加0.1 g/kg 磷时土壤的氮矿化量最大,其余红壤氮矿化量均随磷添加量的增加而增加;添加镉对耕型第四纪红土红壤和耕型石灰岩红壤氮矿化有抑制作用,最大降幅分别为4.98 mg/kg 和6.53 mg/kg;磷、镉共同处理,除耕型第四纪红土红壤外,对其余红壤氮矿化均表现为促进作用,且不同红壤氮矿化量存在差异;添加0.3 g/kg 和0.5 g/kg 磷对轻度镉污染红壤的有机氮矿化效果最好

Effects of P and Cd addition on mineralization of organic N in cultivated red soils

The effect of adding P and Cd respectively or together on N mineralization in cultivated red soils derived from different parents(quater-nary red soil,weathering product of granite,weathering product of limestone,weathering product of slate),in Hunan,was studied based on indoor incubation with P concentrations of 0,0.1,0.3,0.5 g/kg and with Cd concentrations of 0,0.5,1.0 mg/kg.Results showed that the average accumulation of N mineralized in quaternary red soil increased first and then decreased with the addition of P,and the maximum N mineralization was happened when the concentration of additive P was 0.1 g/kg.Average accumulation of N mineralized in other red soils increased with the increase of P addition.N mineralization was inhibited by Cd in both quaternary red soil and limestone red soil treated with Cd in a concentration range of 0-1.0 mg/kg,and the largest decline of N mineralization were 4.98 mg/kg and 6.53 mg/kg.Adding the P and Cd together promoted N mineralization in the red soils except the quaternary red soil,and N mineralization were different in red soils derived from different parent soils.Organic N in the red soil with slight Cd pollution mineralized most effectively under the P concentration of either 0.3 g/kg or 0.5 g/kg.