[Research on the characteristics of Ulva prolifera in Shandong Peninsula during 2008-2012 based on MODIS data].

In the present study, the MODIS data were used to monitor the situation of Ulva prolifera in the Shandong Peninsula waters during the period of 2008-2012. Those studies mainly calculate the area of NDVI, and get the information of the time, area , scope , floating path of Ulva prolifera by using threshold segmentation method. The feasibility of monitoring Ulva prolifera information based on MODIS data and the macroscopic regularity of the outburst of Ulva prolifera was elementally studied. The results showed that Ulva prolifera first generated in the middle of May or early June, the time, area, scope of Ulva prolifera reached a maximum, but the relative crowding density was earlier or later when Ulva prolifera developed into a outburst. Finally, Ulva prolifera died away after existing for 71 days in the late July or the early August. Wholly, the floating path moved to the northwest from off the coast to offshore. Based on those aspects above, the outburst of Ulva prolifera in 2008 and 2009 was more serious than others.

[Dynamic change of soil organic matter under different cropping systems in the oasis of Tianshan Mountain northern slope].

Taking the oasis of lower Sangong River watershed in the Tianshan Mountain northern slope as study area, six kinds of cropping systems, including those of saline-alkaline tolerance crop, food crop, melon and vegetables, economic plants-cotton, economic plants-grape, and economic plants-hop, were selected based on the investigation of local cropping systems, and the dynamic change of soil organic matter under effects of these cropping systems was analyzed by using the laboratory data in 1982, 1999 and 2003. The results showed that land policy and market price had a direct effect on the transformation from annuals cropping system to perennials cropping system, while soil organic matter (OM) content experienced a decline in 1982-1999 owing to the transformation from planting other crops to planting cotton, and a rise in 1999-2003 resulting from the conversion from planting food crops and cotton to planting perennial crops. On the whole, the soils in the oasis presented as a carbon sink, suggesting that the change of artificial vegetation in the oasis was helpful to the accumulation of soil OM, and beneficial to the sustainable use of farmland.