Simultaneous measurement of soil water and soil hardness using a modified time domain reflectometry probe and a conventional cone penetrometer

Soil strength and water content are important indices for assessing soil resistance to root growth and soil compaction both of which affect other soil properties. Therefore, simultaneous measurement of soil penetration resistance (PR) and soil water content can aid agricultural land management. We measured PR with a conventional cone penetrometer, followed immediately by determining water content using a modified TDR probe inserted into the penetrometer hole. From the results of a field feasibility test, soil water content was measured satisfactorily and correlated well with data obtained by the gravimetric method, except for those data from near the surface owing to soil disturbance when the cone penetrometer was extracted after the PR measurements. Field results demonstrate that PR and soil water content have three‐dimensional variability, with a markedly different distribution pattern between cultivated and subsoil layers at the field scale. Overall, the variability in the PR and soil water data is similar to that reported in previous studies. We conclude that our method produces results helpful to field management of soil and water because it is based on a simple and easy technique for the simultaneous measurement of soil water content and PR.     

杨树低产林成因及对策——以宿州市踊桥区祁县镇为例

通过设立固定标准地对杨树的中幼林龄期和近熟林龄期生长情况进行调查分析，了解踊桥区祁县镇不同立地条件下杨树长势，判断林分立地条件对生长量影响的关键因子，并进行了标准地土壤剖面结构、理化性质和土壤养分含量对比，结论如下：影响杨树生长的关键因素是林地土层厚度，分析了杨树低产林形成原因是：土壤层浅、瘠薄、空隙度小、质地粘重。并提出相应对策：杨树低产林改造；加强中幼林抚育、进行土壤改良；发展林下经济改善土壤结构理化性质；营造复层林、间接改良土壤，提高林地综合利用率。     

Influence of Seed Treatment with Uniconazole Powder on Soybean Growth,Photosynthesis, Dry Matter Accumulation after Flowering and Yield in Relay Strip Intercropping System

Abstract

The relay strip intercropping system of wheat-corn-soybean is widely used in southwest China. However, it is hard to produce soybean stably with this system, since the growth of soybean plants is slower under shading by corn at the seedling stage, and it is compensated by accelerated growth after the symbiotic stage. Soybean plants show excessive vegetative growth due to more rain during the flowering stage, which results in fallen petals, fallen pods and lower yield. This study investigated whether seed treatment with uniconazole powder (0, 2, 4 and 8 mg kg^–1 seed) suppresses excessive vegetative growth of soybean plants during the flowering stage and delays senescence of photosynthetically active leaves at the pod-setting stage. If such events are correlated with changes in photosynthesis, they may affect dry matter accumulation and seed yield in the relay stripping system. Uniconazole promoted biomass accumulation from 31 (R₃) to 61 (R₅) days after flowering (DAF) and seed yield. Seed treatment with uniconazole raised the net photosynthetic rate, stomatal conductance, transpiration rate, and total chlorophyll and chlorophyll a contents. In contrast, uniconazole reduced leaf area index (LAI) from 1 DAF (R₁) to 46 DAF (R₄) with the increase in uniconazole concentration, whereas, uniconazole significantly increased LAI at 61 DAF, and the greatest promotion occurred at 2 mg kg^–1 treatment. The study clearly showed that uniconazole effectively suppressed excessive vegetative growth of soybean during flowering stage, delayed senescence of photosynthetically active leaves at pod-setting stage and induced higher yield, which were related to the changes in photosynthetic rate, chlorophyll content, dry matter accumulation and LAI in the relay strip intercropping system.     

广东省大学生运动休闲消费特征研究

为提高潜水蒸发计算精度，利用潜水蒸发强度、埋深为零时的土面蒸发强度和水面蒸发强度的实测资料对阿维里扬诺夫公式、叶水庭公式和雷志栋公式中E₀值的选取进行了探讨，同时对比分析了E₀分别为水面蒸发强度和埋深为零时土面蒸发强度两种情况下的潜水蒸发强度。结果表明，针对新疆地区粘壤土类型，对于上述三种公式，若用埋深为零的土面蒸发强度代替水面蒸发强度，计算结果会产生误差，精度偏低，应选用E₀为水面蒸发强度进行计算，获得了η与地下水埋深的指数函数关系。该研究为潜水蒸发经验模型中E₀值的选取提供参考，同时为求解雷志栋公式中参数η提供一种新方法。     

西方商业银行市场营销

西方商业银行在市场营销方面具有丰富的经验。系统介绍了西方商业银行营销的基本内容和现代特征,以求对我国商业银行的健康发展提供一些值得借鉴的经验。     

Soil saturation effects on forest dynamics: scaling across a southern boreal/northern hardwood landscape

Patch modeling can be used to scale-up processes to portray landscape-level dynamics. Via direct extrapolation, a heterogeneous landscape is divided into its constituent patches; dynamics are simulated on each representative patch and are weighted and aggregated to formulate the higher level response. Further extrapolation may be attained by coarsening the resolution of or lumping environmental data (e.g., climatic, edaphic, hydrologic, topographic) used to delimit a patch.Forest patterns at the southern boreal/northern hardwood transition zone are often defined by soil heterogeneity, determined primarily by the extent and duration of soil saturation. To determine how landscape-level dynamics predicted from direct extrapolation compare when coarsening soil parameters, we simulated forest dynamics for soil series representing a range of drainage classes from east- central Maine. Responses were aggregated according to the distribution of soil associations comprising a 600 ha area based on local- (1:12,000), county- (1:120,000) and state- (1:250,000) scale soil maps. At the patch level, simulated aboveground biomass accumulated more slowly in poorer draining soils. Different soil series yielded different communities comprised of species with various tolerances for soil saturation. When aggregated, removal of waterlogging caused a 20–60% increase in biomass accumulation during the first 50 years of simulation. However, this early successional increase and the maximum level of biomass accumulation over a 200 year period varied by as much as 40% depending on the geospatial data. This marked discrepancy suggests caution when extrapolating with forest patch models by coarsening parameters and demonstrates how rules used to rescale environmental data need to be evaluated for consistency.     

半梯形隶属函数下土壤养分流失的模糊数学模型——以皖南山区为例

研究旨在通过皖南山区土壤检测报告给定的一些数据和信息分析养分流失程度,为合理的土壤养分管理提供可靠依据,采用指导性抽样选取样本,利用半梯形隶属度函数构建模糊数学模型,结合变异系数法,计算出不同地形类别的土壤养分流失程度。研究结果表明:以MATLAB仿真软件生成土壤养分的分布情况为直观依据,构建模糊数学模型发现多坡地的丘陵区域土壤养分流失最为严重。该模型的分析结果更贴近该地区土壤养分现状。研究验证了模糊数学模型在山区耕地土壤养分流失研究中的实用性。该模型能够很好的评估出土壤养分流失程度,为科学施肥护壤提供了理论依据。     

SCARA并联机构拓扑分析与其低耦合度机型设计

根据基于方位特征(Position and orientation characteristics,POC)的并联机构拓扑结构设计理论与方法,首先,对已提出的一类7个具有较好实用价值的SCARA并联机构,进行了拓扑结构分析,揭示了其POC集、自由度(含驱动副选取)、过约束数、耦合度以及输入-输出运动解耦性等5个最主要的拓扑特征,且发现这些机构的耦合度均较大,为2,表明其运动学正解和动力学求解十分复杂;继而基于机构拓扑结构降耦原理,又对κ=2的这7个机构进行了拓扑结构降耦优化,得到了低耦合度(κ=1),而机构POC、自由度(Degree of freedom,DOF)等保持不变的实现SCARA运动的14个新机型,不仅丰富了实现SCARA运动的4-DOF三平移一转动机型库,而且降低了这些机构的运动学和动力学代数求解难度,而其数值解可用一维搜索法方便求得,从而为这一类SCARA并联机构的运动学和动力学分析、设计及应用提供了理论基础。     

“巴仙银尖”的加工工艺及品质研究报告

探讨了利用云南大叶种茶树鲜叶生产名优绿茶－“巴仙银尖”的加工工艺，证明通过合理嫩有，适度摊放，高温杀青，中温慢烘的技术措施，能生产出名优绿茶。文中同时介绍了“巴仙银尖”茶的品质，化学特征。     

矩形薄壁侧堰水力特性试验研究

侧堰作为一种量水设施,精度较高、结构简单、安装和拆卸方便,较易在灌区应用和推广,有很大的研究价值。对不同宽度和高度的矩形侧堰在缓流条件下进行了试验,分析了各工况下矩形渠道侧堰上、下游水面线、能量分布、流量系数等水力因素。结果表明,主渠道侧堰段能量基本保持不变,符合De Marchi的恒定能量假定;主渠道靠近侧堰边壁、中心线以及另一边壁三处的水面波动程度不同,说明侧堰对堰前水流产生影响;基于De Marchi假定和无量纲分析原理得到的流量公式最大相对误差均在±10%以内,满足灌区量水精度要求。