Abstract: Based on the 2000〖KG-*2〗-〖KG-*7〗2006 MODIS 8-day composite NDVI and day -by-day meteorological data, the seasonal and inter-annual variations o f Horqin meadow NDVI as well as the relationships between the NDVI and r elevant meteorological factors were studied. The results showed that as for the seasonal variation, Horqin meadow NDVI was more related to water vapor press ure than to precipitation. Cumulated temperature and cumulated precipitation tog ether affected the inter-annual turning-green period significantly, and the pr ecipitation in growth season (June and July), compared with that in whole year, had more obvious effects on the annual maximal NDVI. The analysis of time lag effect indicated that water vapor pressure had a persistent (about 12 days) prominent effect on the NDVI. The time lag effect of mean air temperature was 11-15 days, and the cumulated dual effect of the temperature a nd precipitation was 36-52 days.

Key words: inhibitor, paddy soil, pig manure, soil nitrogen pool., ¹⁵N