中文摘要：

用6%NaOCl氧化不同粒级的黄棕壤,得到稳定性有机碳和氮的样品.用选择性溶提技术提取铁铝氧化物的含量,与稳定性有机碳和氮的关系表明：在2～250μm粒级上,游离铁、无定形铁和络合态铁含量的变化范围分别为6～60.8g/kg、0.13～4.8g·kg-1和0.03～0.47g·kg-1,在〈2μm粒级上分别为43.1～170g·kg-1、5.9～14.0g·kg-1和0.28～0.78g·kg-1.在〉2μm粒级上,无定形铝和络合态铝含量变化范围分别为0.08～1.34g/kg和0.11～0.47g/kg,在〈2μm粒级上分别为2.96～6.20g·kg-1和0.38～0.78g·kg-1.水稻土黄棕壤的选择性溶提铁的含量一般高于旱地黄棕壤,而选择性溶提铝的含量低于旱地黄棕壤.在2～250μm粒级上,土壤稳定性有机碳和有机氮含量变幅分别为0.93～6.0g·kg-1和0.05～0.36g·kg-1,在〈2μm粒级上分别为6.05～19.3g·kg-1和0.61～2.1g·kg-1,水稻土的稳定性有机碳和氮的含量高于旱地黄棕壤.在2～250μm粒级上,稳定性有机碳与有机氮比值（C稳/N稳）的变幅为9.50～22.0,在〈2μm粒级上分别为7.43～11.54.在2～250μm粒级上,土壤有机碳（氮）的稳定性指数SIC和SIN的变化分别为14.3～50.0和11.9～55.6,在〈2μm粒级上分别为53.72～88.80和40.64～70.0;旱地黄棕壤的SIC和SIN一般低于水稻土的,水稻土黄棕壤有利于有机碳和氮的保存.各种形态的铁铝氧化物含量与稳定性有机碳（氮）含量呈极显著正相关,且氧化物铁铝含量和稳定性有机碳（氮）含量在黏粒部分最高,即细粒级能保护土壤有机碳（氮）.

英文摘要：

The stable organic carbon and nitrogen of the different particles were gained by oxidation of 6% NaOCl in the yellow-brown soils.The relationships between the contents of selective extractable Fe /Al and the stable organic carbon /nitrogen were investigated.It shown that amounts of dithionite-citrate-（Fed） and oxalate-（Feo） and pyrophosphate extractable（Fep） were 6-60.8 g·kg-1 and 0.134.8 g·kg-1 and 0.03-0.47 g·kg-1 in 2-250 μm particles,respectively;43.1-170 g·kg-1 and 5.9-14.0 g·kg-1 and 0.28-0.78 g·kg-1 in 2 μm particles,respectively.The contents of oxalate-（Alo） and pyrophosphate extractable（Alp） were 0.08-1.34 g·kg-1 and 0.11-0.47 g·kg-1 in 2-250 μm particles,respectively;2.96-6.20 g·kg-1 and 0.38-0.78 g·kg-1 in 2 μm particles,respectively.And amounts of selective extractable Fe are generally higher in paddy yellow-brown soils than in arid yellow-brown soils,and that of selective extractable Al are lower in the former than in the latter.Amounts of the stable organic carbon and nitrogen,higher in paddy yellow-brown soils than in arid yellow-brown soils,were 0.93-6.0 g·kg-1 and 0.05-0.36 g·kg-1 in 2-250 μm particles,respectively;6.05-19.3 g·kg-1 and 0.61-2.1 g·kg-1 in 2 μm particles,respectively.The ratio of the stable organic carbon and nitrogen（Cstable /Nstable）were 9.50-22.0 in 2-250 μm particles and 7.43-11.54 in 2 μm particles,respectively.The stabilization index（SIC and SIN） of the organic carbon and nitrogen were 14.3-50.0 and 11.9-55.6 in 2-250 μm particles,respectively;53.7288.80 and 40.64-70.0 in 2 μm particles,respectively.According to SI,it is lower in arid yellow-brown soils than in paddy yellowbrown soils.The organic carbon and nitrogen are advantageously conserved in paddy yellow-brown soil.An extremely significant positive correlation of the stable organic carbon and nitrogen with selective extractable Fe /Al is observed.The most amounts between the stable organic carbon and nitrogen and selective extractable Fe /Al appear in clay particles,na