基于耕作半径的采矿复垦区农村居民点安置规模预测

耕作半径对农村居民点的规模具有重要影响,而地形则是耕作半径的决定因素之一。该文采用耕聚比和缓冲区分析的方法,对比采矿前后农村居民点的耕作半径变化。考虑研究区地形起伏的影响,计算耕作半径地形修正系数,确定最优耕作半径。在此基础上预测矿区复垦后可安置农村居民点的面积、数量及人口。研究结果表明:平朔复垦区农村居民点耕作半径地形修正系数为1.6836,复垦区规划农村居民点最优耕作半径为1 500 m;复垦区预测回迁安置农村居民点总规模约651.24 hm2,共67个农村居民点;预测单个农村居民点面积9.72 hm2,控制耕地面积约109.68 hm2;预测回迁安置总人口约29 521人,共7 380户,该研究结果可为露天采矿复垦区农村居民点回迁安置规模与布局提供决策支持。     

Maize (Zea mays L.) Grain Yield Response to Methods of Nitrogen Fertilization

ABSTRACT

In the developing world, fertilizer application is commonly achieved by broadcasting nutrients to the soil surface without incorporation. A commonly used nitrogen (N) source is urea and if not incorporated, can sustain N losses via ammonia volatilization and lower crop yields. This study evaluated the effect of planting, N rate and application methods on maize (Zea mays L.) grain yield. An experiment with a randomized complete block design (nine treatments and three replications) was established in 2013 and 2018 in Oklahoma. The planting methods included; farmer practice (FP), Oklahoma State University hand planter (OSU-HP), and John Deere (JD) mechanical planter. Side-dress N application methods included; dribble surface band (DSB), broadcast (BR), and OSU-HP. Nitrogen was applied at the rate of 30 and 60 kg ha^?1 as urea and UAN at V8 growth stage. On average, planting and applying N at 60 kg ha^?1 using OSU-HP resulted in the highest yield (11.4 Mg ha^?1). This exceeded check plot yield (5.59 Mg ha^?1) by 104%. Nitrogen application improved grain yield by over 57% when compared to the 0-N check (8.77 Mg ha^?1). Mid-season N placement below the soil surface using OSU-HP makes it a suitable alternative to improve grain yield.     

Response of corn to plowed‐down and disked‐in Zn as zinc sulfate

Abstract

A field investigation was conducted to compare the efficacy of plowed‐down and disked‐in Zn as ZnSO₄.H₂O in correcting Zn deficiency of corn (Zea mays L.). The soil, Buchanan fine sandy loam, was nearneutral in pH and contained 0.7 ppm of EDTA‐extractable Zn and 1.4 ppm of dilute HCl‐H₂SO₄ extractable P. Application of 6.72 kg Zn/ha as ZnSO₄.H₂O corrected Zn deficiency of corn plants on the soil. Corn grain yields and Zn concentrations in tissue samples indicated that the plowed‐down and disked‐in Zn were about equally effective in correcting Zn deficiency where the level of Zn application was 6.72 kg/ha.     

CONTROLLED-RELEASE UREA FOR RICE PRODUCTION AND ITS ENVIRONMENTAL IMPLICATIONS

Controlled-release urea (CRU) and its placement method in rice production were investigated during 2007 and 2008 seasons. Controlled-release urea was applied at 62.5, 125, and 187.5 kg nitrogen (N) ha^?1, and the urea was 187.5 kg N ha^?1. All the CRU treatments were applied to the nursery beds once, and they were brought into the paddy field during transplanting, while the urea treatment was split into three applications from the plowing to the harvest. The results showed that rice seedlings with CRUs germinated and grow well and there was no salt damage at the nursery stage. The CRU treatment with 125 kg N ha^?1 had 33% less N than urea treatment (187.50 kg N ha^?1), but it produced significantly higher grain and straw yields, higher total N uptake and total apparent N uptake efficiency. In addition, all the CRU treatments effectively decreased floodwater ammonium (NH₄ ⁺)-N and nitrate (NO₃ ^?)-N concentrations, pH, and N runoff.     

Robust Adaptive Control Based on On-line Identification to Multi-parameters

In system controlled,Sampling these parameters and with parameters for controller in time, it is an object to adaptive control. The article presents a scheme that the structure parameters on it's model and model parameters is robust identified by on line, while to optimal of algorithm on adaptive control is fulfilled. In control scheme, method of intelligent identifying to the structure parameters(levels of model) and algorithm of robust pole placement are introduced also It is advancer for already mentioned scheme. Whole scheme presents new model on adaptive control.     

南水北调中线工程水质监测站点布设研究

科学合理布设水质监测站点是加强南水北调中线工程对突发水污染事件监控,保障水质安全的重要手段.制定水质监测站点的布设方案受到监测效率与布设成本的约束,同时,监测仪器精度、污染物衰减特性的不确定性等问题也对布设方案产生影响.以中线工程京石段为研究对象,基于一维水质模型,以突发水污染事件漏报率最低、发现时间最短以及监测站点布...     

不同安放角度对污水搅拌器水力特性的影响

为深入对比污水处理池中搅拌器不同安放角度对其水力特性的影响,文中基于Fluent对搅拌器在不同安放角度下的水力特性进行数值模拟,得出适合搅拌器工作的较优工况.利用标准k-ε湍流模型及SIMPLEC算法对不同工况进行模拟,对比相应的流速分布和搅拌器中心所在平面的速度分量.结果表明:当搅拌器安放角度为-15°时,处理池内平...     

不同阶段沼液作发酵接种物对牛粪产气的影响

在牛粪厌氧发酵中,不同阶段沼液的物理、化学性质及微生物种群有较大差异,利用不同发酵阶的沼液作接种物必然会影响到系统的产气特性。实验结果表明:以发酵20天的发酵沼液作接种物可以加快反应速度,增加产气量,提高COD去除率;用60天的发酵沼液作接种物不利于产气的进行。     

Modeling and Simulation Based on Pole-zero Placement Self-adaptive Temperature Control System

Based on model parameters estimating, a kind of algorithm of pole-zero placement self-adaptive temperature control is put forward according to closed loop apices distribution of resistance furnace temperature control. The mathematic model is presented by discursion for the controlled object, at the same time, the algorithm is illustrated identification method of model parameters, compute formula and simulation result of controlled parameters. Simulations and practices of the model proved that the algorithm is of rapid constringency speed , satisfactory effect on the object with time changing especially for the controlled objects of the high current and low voltage characteristics. The algorithm has been applied in the temperature control of intelligent slag measurement equipment of a iron-steel graduate school.     

Tracking Phytophthora infestans with SSR markers within and between seasons – a field study in Sweden

The dynamics of a late blight epidemic and sexual reproduction in Phytophthora infestans were studied in an experimental field in mid‐Sweden. The field was inoculated with six isolates of P. infestans taken from another potato field where sexual reproduction of the pathogen was suspected. Three weeks after inoculation single‐lesion leaflets were sampled and the resulting isolates characterized using microsatellites (SSRs) and mating type as markers. Among the 151 isolates analysed, the inoculum genotypes constituted more than 80% of the genotypes found, with three other genotypes making up the remainder. The following year, P. infestans obtained from soil samples taken from this field were analysed, and six novel genotypes were identified. Genotypes from the previous summer’s population were not detected. Analysis of the genotypes recovered was consistent with them being recombinants, with the previous summer’s population acting as parents. These findings are consistent with the hypothesis that oospores produced during a summer epidemic in Sweden can overwinter and cause infection the next year.