Analysis of shelterbelt effect on crop growth condition

shelterbelt system plays an important role in improving environment, protecting farmland and enhancing crop yield. The previous researches about effect of shelterbelt on crop were mainly focused on crop yields by field measure. These methods restricted to study the protection effect of shelterbelt on regional scale and long time series. In this paper, by comparing with the previous researches, it tried to take the crop condition instead of crop yields as index. It chose Dehui, Nong’an, Yushu and Fuyu located in the mid-west of Jilin Province, China as study area. Using the 16 days MODIS NDVI data with 250m×250m spatial resolution in the study area as data source, the NDVI curves of crop growth were extracted to indicate the crop condition. Then through comparing the crop condition in shelterbelt protected zone with unprotected zone, it analyzed the effect of shelterbelt on crop condition at different growth phase. And with the consideration of mean annual air temperature, precipitation and soil type, it divided the study area into nine sub-zones and analyzed the impact of air temperature, precipitation and soil type on the protection effect of shelterbelt. The results showed that, 1) The crop condition in the shelterbelt protected zone is better than unprotected zone as a whole, and it is the most obvious during the peak period of crop growth, where the accumulated value of NDVI in protected zone was increased by 0.05 than unprotected zone; 2) As the air temperature increase, the impact on protection effect tend to increase significantly, and as the air temperature increased by 0.5℃, the difference of accumulated value of NDVI between protected and unprotected zone was increased by 0.02; 3) With increase of precipitation, the impact on protection effect also tends to increase significantly at the beginning of crop growth, and with the precipitation increase of 100 mm, the difference of accumulated value of NDVI between protected and unprotected zones increased by 0.03 in this phase; 4) For different soil types, there was no significant impact on protection effect. In a word, the research can not only provide decision-making support for the shelterbelt management, promote the information technology level of management, but also enrich the monitoring method in shelterbelt field for remote sensing and improve the monitoring level of shelterbelt at regional scale.