长期定位施肥对保护地土壤腐殖质结合形态的影响

以长期定位施肥蔬菜保护地土壤为材料，研究了不同施肥处理土壤中结合态腐殖质含量及其相关性变化.结果表明，有机肥与无机肥配施松结态腐殖质含量高于单施无机肥的相应处理，但相对含量呈现相反趋势；稳结态腐殖质相对较稳定，没有明显变化；紧结态腐殖质绝对含量及百分含量都明显高于单施无机肥处理，其中以配施有机肥与氮磷钾肥最高,为11.53 g·kg^-1；长期定位施用有机肥后保护地土壤松/紧比值呈降低趋势， 其中有机肥与氮磷钾肥配施处理的松紧比值最低，为1.10.

Effects of long-term localized fertilization on soil humus combining form in sheltered vegetable field

The study showed that on a sheltered vegetable field, a long-term application of organic plus chemical fertilizers induced a higher content of loosely combined soil humus than applying chemical fertilizers alone, while there was no significant difference in firmly combined humus content among different fertilization treatments. More tightly combined humus was observed in organic fertilizer treatments than in chemical fertilizer treatments, and the highest content (11.53 g x kg(-1)) was in the treatment of organic fertilizer plus chemical NPK. The ratio of loosely/tightly combined humus tended to decrease after a long-term application of organic fertilizer, being the lowest (1.10) in the treatment of organic fertilizer plus chemical NPK.