Abstract: Based on the study of humus and enzyme activity in alkaline soil treated by different meliorative methods such as shallow plowing,phosphogypsum manuring,furfural residue,organic fertilizer,setting up manual meadow of Puccinellia tenuiflora or P.tenuiflora-Leymus chinensis and so on,the result showed that comparing shallow plowing,the content of total nitrogen,alkali-hydrolyzable nitrogen,the intensity of ammonification,nitrogen fixation,protease,urease,nitrate reductase and nitrite reductase activity increase with different degree treated by different meliorative methods.All indexes of soil nitrogen and enzyme activity increase notably with the method of shallow plowing mixing with organic fertilizer,planting of P.tenuiflora and L.chinensis.There are correlations among indexes of soil nitrogen.

Key words: alkalized soil, meliorative methods, ammonification, nitrogen fixation intensity, soil enzyme activity, nitrogen nutrition