Overall changes in farmland to some extent mark the developing rules of regional social economy, human activities and urban changes, of significance to research urban developing process. This paper, in terms of Xi'ning's land use survey data 2009 to 2016, uses spatial vector data of dry land and watering land by processed by Arcgis to analyze its farmland dynamics, changes and core shift, and discusses the actual land overall changes and spatial distribution of three counties and four districts in Xi'ning in recent years, revealing an inner relation between urban development and farmland changes. SAS, SPSS and EXCEL are used to forecast the future farmland overall changes in Xi'ning city and to study its impact on future urban development moderation, offering a theoretical basis for Xi'ning to balance the relation between farmland protection and urban development amid the future natural resource planning.

The results of the magnetic susceptibility of the Qidingshan loess varies in a range of 5.21×10^-8m³ kg^-1 to 42.42×10^-8m³ kg^-1, which is much lower than in other localities. The vertical changes of magnetic susceptibility and grain have a positive relation. The magnetic minerals are mainly focused on over 8ф in grain size. A comparison in Oxide isotope indicates that Qds20—Qds28 is consistent with the 3rd section of Guliya ice core and with abyssal 3a, 3b and 3c sub-section in fluctuation, and that Qds28—Qds31 is analogous with the 2nd section of Guliya ice core and with abyssal 2nd section. The study reveals during 60 to 22 ka BP the Malan loess sedimentation period is generally dry and cold with an interim warm and wet climate.

A high solution analysis was carried out on loess particle at Qidingshan through screen method via SA-CP3 (a granularity analysis instrument made in Japan) and TL chronology, with the results that the loess granularity is dominantly coarse, coarse silt 4~6φ about 26.39~48.33%, a less clay (0.05~2.44%). At Malan, the loess granularity concentrates on two grades, 2~4φand 4~6φ, with coarse silt slightly more than fine sand. At Lishi, the loess granularity is dominantly 4~6φ. This paper, based on a comprehensive statistical analysis on sediment granularity parameters, indicates that there has been a big difference with inland winding loess since the middle Pleistocene. The loess sediment in Qidingshan is derived primary from a nearby source and secondarily from far source.