基于吴起县耕地分等成果，利用修正法，对吴起县耕地进行了级别评定。吴起县耕地共分为五个级别，质量高的一级地相对较少，只占6．79％，二、三、四、五级地分别占总耕地面积15．65％、20．42％、29．84％和27．3％。吴起县耕地质量总体不高，以四、五级地为主。质量高的地集中在中心城镇周围、川道以及道路附近，表明区位因素对土地级别的影响。

Based on farmland classification result of Wuqi, we graded the farmland of Wuqi to five grades. The area of grade one is little,be of 6.79% of total farmland. The areas of grade 2~(nd) , 3~(rd) ,4~(th) and 5~(th) occupied 15. 65% , 20.42% ,29. 84% and 27. 3% of total farmland respectively. The farmland quality of Wuqi is not high, grade 4~(th) and 5~(th) are the most. The high quality farmland is located around the central town, near the river and near the road, showing the location affecting on farmland grade.

黄土高原地区不同立地条件的坡面其土壤水分状况有很大差异,利用这种差异来提高植被成活率已经成为黄土高原生态恢复建设的重要方向。采用探针式TDR对陕西省吴起县合家沟流域内不同立地类型的土壤含水量进行测定,然后用SPSS进行聚类分析,将17种立地类型聚为5类,并按照植被恢复的难易程度进行排序。建议对不同立地类型组配置与其相应的植被模式从而更加因地制宜的进行植被恢复建设。

The slope soil moisture of different site conditions have very great differences in the loess plateau.Using the difference of soil moisture content to improve the survival rate of vegetation has become an important method for the ecological restoration construction in this area.We used probe-type TDR to measure the soil water content of different site types in He valley of Wu Qi County,Shannxi Province,then clustered 17 kinds of site type to 5 categories by cluster analysis of SPSS and sorted it according to the difficulty level of vegetation restoration.We should configure corresponding vegetation patterns for different site types,thereby carry on the construction of vegetation restoration more suitable.

为了研究QuickBird影像提取切沟形态参数的精度，该文选取陕北黄土区吴起县合沟与绥德县桥沟小流域，分别利用同时相的三维激光扫描全站仪和 QuickBird 影像数据源提取切沟形态参数，分析 QuickBird 影像提取切沟形态参数的精度，探究误差产生原因。研究结果表明：与三维激光扫描全站仪相比，QuickBird 影像目视解译合沟和桥沟小流域切沟面积、周长的平均相对误差都在5%左右；沟缘线边界偏差大于0.6 m（相当于QuickBird影像的一个像元值）的面积百分比的均值都能控制在4%以内；2个小流域中沟长的平均相对误差分别在2%和5%左右，沟长的平均绝对误差分别在0.5和0.75 m左右；目视解译面积、沟长的平均相对误差、最大相对误差、不同解译人员的最大误差与参数值之间都具有显著地负相关，即切沟越大，误差越小；沟缘线附近的植被类型影响目视解译精度，与灌草植被覆盖的小流域相比，草本覆盖的小流域中切沟参数的解译精度更高。总体上来看， QuickBird影像为小流域尺度上监测切沟发育提供了便捷、可靠地数据源。

High-resolution satellite images such as those from Ikonos and QuickBird are increasingly available and are considered a valuable tool for extracting the consequences of gully erosion, and QuickBird imagery has been used to map gully features. To evaluate the accuracy of extracting morphological parameters of bank gullies including area, perimeter, and length from QuickBird imagery bymanual visual interpretation, and to analyze the causes of errors, 20 bank gullies were selected in Hegou catchment and Qiaogou catchment located in the Loess Plateau of northern Shaanxi province, respectively. 3D laser scanner was used to measure the topography of bank gullies within two weeks after the QuickBird images were taken. The interval among measurement points of 3D laser scanner was set as 0.15 m. 3D laser scanner had been increasingly used to measure the topography as it can provide a high accuracy, non-contacted, penetrating and rapid method that enables the rapid production of accur

河北杨 Populus hopeiensis 和沙棘 Hippophae rhamnoides 为黄土丘陵区主要的造林树种，其对生态恢复和保护具有重要作用。为比较两种树种的光合生理生态适应性，分别以吴起县人工栽培林内的河北杨和沙棘为研究对象，测定了两树种的叶片光响应曲线、蒸腾速率 Tr、水分利用效率 RWUE 和叶绿素荧光参数等光合生理指标季节动态变化。结果表明：除5月下旬外，沙棘的最大光化学效率 Fv/Fm 在不同生育期均显著高于河北杨（P ＜0.05）；沙棘在5月下旬、8月上旬和9月中旬的光合电子传递量子效率ΦPSII 均显著高于河北杨（P ＜0.05）；且不同生育期下沙棘的光化学猝灭 qP 和非光化学猝灭 qNPQ 均显著高于河北杨(P ＜0.05)，表明沙棘具有相对较高的 PSII 光化学效率和较强的光保护能力。河北杨和沙棘在整个生育期均具有较高的 LSP，且不同生育期下河北杨的 RAQE，Pmax，Tr 和 Rd 均显著高于沙棘，但 LCP 与之相反（P ＜0.05），表明两者均属典型阳性植物且能较适应当地的强光环境，而河北杨相对于沙棘具有较高的叶片光合能力。

In loess hilly-gully region, Populus hopeiensis and Hippophae rhamnoide are the main afforestation tree species which played important roles in ecological restoration and protection. To compare the photosynthesis and physiological adaptability P. hopeiensis and H. rhamnoide, by taking the two tree species grew in the artificial forest in Wuqi County, Shaanxi Province as the tested materials, the seasonal changes of photosynthetic physiological indexes of the two tree sppecies, such as the leaf light response curves, transpiration efficiency Tr, water use efficiency RWUE and chlorophyll fluorescence characteristics etc., were investigated. The results indicate that the maximum photochemical efficiency Fv/Fm of H. rhamnoide were significantly higher than P. hopeiensis in different growth periods except in late May (P < 0.05), the photosynthetic electron transport quantum efficiency ΦPSI of H. rhamnoide in late May, early August and mid September were significantly higher than

吴仓堡油区三叠系油层有长6、长8、及长9等开采层系，均具有低孔、低渗透、低压、低产等特征，一般不经压裂无自然产能，但是常规水力压裂改造后，单井产量低、产量下降快、油田稳产形势严峻，严重制约了三叠系油藏的有效开发。本文针对三叠系主力油层长6、长8和长9为主要研究对象，结合吴起油田勘探开发过程中的水力压裂改造实践经验，借鉴国内外低渗透、低压致密油层改造先进技术理念，以储层研究为基础，分析了体积压裂的增产机理及在吴仓堡油区开展体积压裂的可行性，探索了吴仓堡油区三叠系油层体积压裂的工艺设计模式，为吴起油田低渗透、低压致密油层开展体积压裂提供了有益的参考。

Chang 6, Chang 8 and Chang 9 oil formations which are being mined in Wucangbu area are characterized by low prosity, low permeability,low pressure, low production etc. In general, the well without fracturing always has no natural productivity. However, fracturing has been completed, there still exist some problems that hamper the oil efficient recovery such as lower single well production, rapidly declined production and unexpected situation for stable production. The paper takes examples of Chang 6, Chang 8 and Chang 9 formations that are mainly produce layers. We have drawn lessons from the advanced technical idea deals with the lower permeability and lower pressure tight reservoirs at home and abroad , combining with the practical experience of hydraulic fracturing during the process of exploration and development of WuQi Oilfield,based on the reservoir research, we make an analysis on the enhance mechanism of volume fracturing and investigate the feasibility of volume fracturing de