物联网在智慧农业中的应用

介绍了物联网及智慧农业的内涵,结合农业智能化生产的实际情况设计了智慧农业物联网架构,主要包括物联网感知层、物联网网络层和物联网应用层.同时,通过农产品疾病识别与治理系统,具体研究了物联网在智慧农业中的应用.     

基于农业无线传感器网络技术下智慧农业系统的设计

随着大数据、物联网及传感器等信息技术的快速发展，农业生产正在向集约化、大型化和智慧化方向发展，智能化农业生产系统的构建是目前的研究重点与主要发展趋势。基于智能农业系统构建关键技术，对智能农业系统的组成和设计进行分析，实现田间农业生产环境技术参数的采集和传输。研究结果可以满足现代农业智能化发展要求，具有良好的应用发展前景和推广价值。     

大数据技术在智慧林业中的应用

在科学技术的快速发展下，大数据技术在社会各个领域的应用日渐广泛，林业发展也逐渐受到影响，形成了以信息网络为支撑的智慧化林业发展体系，通过智慧林业对林业资源进行统一科学化的管理。智能林业的主要特征表现为智能化、物联化和感知化三个方面。本文通过介绍大数据技术在智慧林业中的具体应用，分析现阶段智慧林业在大数据技术应用中存在的不足，并据此提出一些可行建议，以期提高智慧林业发展质量水平。     

农业装备智能控制技术研究现状与发展趋势分析

智能控制是农业装备实现智能化的关键核心技术。从农业装备智能感知、智能控制、智能决策、自主作业、智能管控五方面阐述分析了国内外智能农机的发展现状,着重阐述了约翰迪尔、凯斯、科乐收、爱科等国际农机企业在农机智能控制方面的最新技术进展,分析了我国智能农机与国外的差距,指出了制约我国农机智能控制发展的关键问题。为实现我国从农机制造大国向农机制造强国的转变,融合大数据、云计算、物联网、人工智能等信息领域的前沿技术,提出了"智能在端、智慧在云、管控在屏"的智能农机系统发展新思路,指明现场控制智能化、云端决策智慧化、监控调度移动终端化是未来智能农机的发展方向。     

智能化农机装备发展现状与建议

"智慧农业"是农业发展的高级阶段,目前尚未有统一定义,其基本内涵是集成物联网、云计算等信息技术,实现农业生产环境的智能感知、智能预警、智能分析、专家在线指导,为农业生产提供精准化种植、可视化管理、智能化决策等。智能化农机装备(目前一些省市农机管理部门称为"智慧农机")既是智慧农业的重要组成部分,也是发展智慧农业的重要物质手段。目前国内各省市都在积极推进"智慧农业"发展,然而国内现有各种农业机械在作业功能、效率和能源消耗等方面.     

果园智能化作业装备自主导航技术研究进展

果园生产管理主要包括喷药、施肥、割草、修剪、授粉、疏花和采收分级等作业环节,需要大量的人力投入,随着我国人口老龄化程度加剧,亟需果园生产管理由机械化向智能化转型升级。自主导航技术是果园机械化装备实现智能化的关键技术。本文围绕果园智能化作业装备导航控制需求,结合国内外研究现状,分别阐述了包含导航定位信息和障碍物信息的果园作业场景感知技术,导航地图构建、导航路径提取和路径规划技术,行走底盘运动学模型构建、运动控制技术,多机协同控制、远程交互控制技术等。随着智慧农业发展,智慧果园已成为果园未来发展方向,果园智能化作业装备是智慧果园建设必不可少的关键环节,在此基础上,归纳了我国果园智能化作业装备自主导航技术发展面临的问题为：环境感知能力不足、路径提取不稳定、局部路径规划不灵活、导航系统环境适应性欠缺、多机协同和远程控制不成熟等,提出了多传感器融合的环境感知与路径提取、完整路径规划、强通用性果园导航、大型果园多作业环节的多机协同与远程操作等未来发展方向。     

基于无人机平台的智慧农业系统研究与应用

智慧农业是利用数字技术、数据分析和人工智能等先进技术手段,对农业生产进行精细化管理和智能化决策的一种新型农业生产模式。它可以通过实时监测、预测和调控土壤、气象、水文、植物生长情况等各方面信息,为农业生产提供高效、经济、环保的解决方案。无人机的应用给智慧农业发展带来了巨大推力,既可提高农业工作的效率、降低成本,同时也为智慧农业更加智能化、精细化提供了必要的技术支持。因此,课题组通过分析基于无人机平台的智慧农业发展现状,剖析无人机在智慧农业中的应用优势和应用场景,重点对数据获取端的数据感知系统功能、农业植保无人机任务载荷系统功能、农业植保无人机和农情监测无人机选型进行了详细论述。     

浅析农产品智慧供应链构建及运作模式

在新的技术时代下,信息技术与传统行业的深度融合,为传统行业的转型升级注入了新的灵魂。在智能化迅速发展的信息时代,信息产业在农业产业上发挥的作用越来越大,创建一体化和智慧化农产品供应链,创新智慧供应链的构建模式和运作模式,已经引起了全社会的高度重视。基于此,本文探讨了新技术条件下农业供应链的创新发展模式的现实意义,分析了构建农产品智慧供应链的重要性,提出了从信息平台构建、基础设施完善、智慧物流建设等多方面构建农产品智慧供应链体系的框架建议,并重点分析了智慧物流供应链中的核心板块,仅供参考。     

智慧农业视域下农业机械智能化技术的应用

农业机械智能化技术已广泛应用于农业生产领域,对提升农业生产效率、解放劳动力以及推动智慧农业持续发展具有重要意义。笔者基于智慧农业视角,阐述了农业机械智能化技术应用于农业生产的重要意义,分析了环境感知技术、自动化控制技术、农机定位技术、跟踪控制技术、电子智能技术等农业机械智能化技术的具体应用,并预测了仿真技术、逻辑思维技术等的发展趋势,以期提高农业生产质效,提升农业机械自动化、智能化、信息化水平,推动智慧农业的持续健康发展。     

泵站智慧管控一体化平台的研究

本文研究开发大型泵站机组安全、运行、调度、分析、决策统一构建的泵站智慧管控一体化平台,从而实现机组运行状态监测与诊断、泵站运行经济性分析、优化调度辅助决策及泵站信息全方位展示等功能。在南水北调东线一期工程山东段邓楼泵站自动化系统升级改造项目中应用示范,充分利用大数据、物联网、云计算对泵站各类信息进行深入挖掘分析,实现全方位数据感知、全自动安全控制、全场景智能预警、全方位安全预警预测,达到“远程控制自动化、业务管理信息化、调度决策智能化”的目标,实现了调度生产指标可视化、运行状态管理集约化、运行调度智能化和泵站智慧管控一体化。     

Application of drag reducing commercial and purified guargum for reduction of energy requirement of sprinkler irrigation and percolation rate of the soil

Drag reducing polymers reduce the drag in a turbulent flow while increase the drag in a laminar flow, due to an increase in shear viscosity. This feature of drag-reducing polymers has been utilised in reducing the energy requirements of sprinkler irrigation system and increasing the area of coverage as well as reducing the percolation loss of water added with drag reducing polymers. Two types of polymers at various concentrations were studied at the Indian Institute of Technology, Kharagpur. Two different methods of injection of polymers were also tested to determine the effect of polymer on mode of injection. The concentrations of 100, 250, 300 and 450 ppm of commercial guargum and 50, 100 and 150 ppm of purified guargum were used for homogenous injection (T₁). The concentrations of 100, 300, 600, 1000 and 1500 ppm of commercial guargum and 50, 100, 200, 350 and 500 ppm of purified guargum were used for injection at the suction side of the pump(T₂). The infiltration characteristics of the soil with polymer added water was tested for 300, 1000 ppm of commercial guargum and 100, 500 ppm of purified guargum. For T₁, the maximum power reduction of 28% was obtained in case of 300 ppm commercial guargum and approximately the same percentage was obtained in case of 100 ppm purified guargum. The maximum drag reduction was 35.5% at 300 ppm of commercial guargum and 38% at 100 ppm of purified guargum. The maximum increase in the radius of coverage at 500 ppm commercial guargum was estimated to be 33 and 37% at 150 ppm of purified guargum. For T₂, the maximum power reduction at 1000 ppm of commercial guargum and at 500 ppm of purified guargum was 31.25%. The maximum increase in radius of coverage at 1000 ppm of commercial guargum and at 500 ppm of purified guargum was 37 and 38.2%, respectively. The maximum drag reduction of 40% was obtained at both 1000 ppm of commercial guargum and 500 ppm of purified guargum. The reduction in the infiltration rate at 1000 and 300 ppm of commercial guargum was found to be 56.52 and 27%, respectively, whereas the reduction in the infiltration rate at 100 and 500 ppm purified guargum is 15 and 22.8%, respectively. The study reveals great potential of using drag reducing polymers for irrigation water management.     

Estimation of reference evapotranspiration for southern region of Saudi Arabia

The reference crop evapotranspiration (ET_r) for four areas in Saudi Arabia was estimated using five different methods: FAO-Penman, Jensen-Haise, Blaney & Criddle, pan evaporation, and calibrated FAO-Penman under local conditions (Penman_-SA). Comparison was also made between the estimated ET_r and the measured ET_r of alfalfa grown in lysimeters in the Riyadh area. Regression analysis revealed that estimated ET_r values were highly correlated with measured ET_r values. In addition, linear regression relationships between ET_r values estimated by the Penman_-SA method and other methods were determined. The results of this study indicated that the calibrated Penman_-SA method can be transferred successfully to other locations, and this method could be used for the estimation of ET_r values in all areas in the southern region of Saudi Arabia. Received: 16 January 1998     

Modelling of Discolouration of Dried Powder of Carrots

A model to represent the discolouration of dried powder of carrots as a function of temperature was developed. Two types of carrots, Asian and European, containing large amount of lycopene and β-carotene, respectively, were tested. The dried powder was stored under an atmosphere with O₂and at three different temperatures, 5,20 and 35°C. The surface colour of the powder was monitored during storage by a Hunter colour ratioa/b. In the proposed model, the rate of oxidation was assumed to be represented by the product of the fraction of concentration of oxidized pigment at arbitrary time and a specific rate of oxidation of pigment. The rate parameters in the proposed model were calculated by fitting the experimental data with smooth curves by trial and error at the end of the induction period but before discolouration took place. The frequency constant and activation energy, expressing the temperature dependence of the rate parameters, were expressed by the Arrhenius relation. The simulation results of a Hunter colour ratioa/bof dried powder at 25°C showed good agreement with the experimental data, suggesting that the proposed model was effective for the prediction of discolouration of dried powder of both types of carrot. The use of the induction period in the manner described may enable the shelf life of dried powder to be predicted.     

Evaluation of a crop water stress index for irrigation scheduling of bermudagrass

This study was conducted to assess crop water stress index (CWSI) of bermudagrass used widely on the recreational sites of the Mediterranean Region and to study the possibilities of utilization of infrared thermometry to schedule irrigation of bermudagrass. Four different irrigation treatments were examined: 100% (I₁), 75% (I₂), 50% (I₃), and 25% (I₄) of the evaporation measured in a Class A pan. In addition, a non-irrigated treatment was set up to determine CWSI values. The status of soil water content and pressure was monitored using a neutron probe and tensiometers. Meanwhile the canopy temperature of bermudagrass was measured with the infrared thermometry. The empirical method was used to compute the CWSI values. In this study, the visual quality of bermudagrass was monitored seasonally using a color scale. The best visual quality was obtained from I₁ and I₂ treatments. Average seasonal CWSI values were determined as 0.086, 0.102, 0.165, and 0.394 for I₁, I₂, I₃, and I₄ irrigation treatments, respectively, and 0.899 for non-irrigated plot. An empirical non-linear equation, Qave=1+⌊6[1+(4.853 CWSIave)^2.27]^−0.559⌋$Q_{\text{ave}}=1+⌊6{[1+{(4.853\text{CWS}{\text{I}}_{\text{ave}})}^{2.27}]}^{-0.559}⌋$, was deduced by fitting to measured data to find a relation between quality and average seasonal CWSI values. It was concluded that the CWSI could be used as a criterion for irrigation timing of bermudagrass. An acceptable color quality could be sustained seasonally if the CWSI value can be kept about 0.10.     

Economics of drip irrigation of olives in Turkey

Agricultural growers need investment and cost guidelines for drip irrigation to evaluate the economics of getting crops into production as quickly as possible and to minimise economic losses from drought during the productive life of an olive orchard. The benefits of irrigation may include; better olive survival, earlier crop production, greater yields, efficient nutrient distribution, less plant stress, reduced yield variability and improved crop quality.This research was conducted to help olive growers make decisions regarding investments in drip irrigation systems. This analysis was aimed at the farm business level to provide an economic rationale for investing in drip irrigation systems.The net present value (NPV) criterion was used to determine the discounted break-even investment results from published responses to drip irrigation systems. Growers with typical drip irrigation systems can expect investments of US$ 2244 ha⁻¹ with 1.6 ha blocks of olives. Analysis of survey findings indicate that net present value was US$ 3464 ha⁻¹ after an initial investment of US$ 2244 ha⁻¹.     

Estimation of Moisture Diffusivity Coefficient and Thermal Properties of Alfalfa Pellets

Heat and mass transfer characteristics of alfalfa pellets are needed in the optimization of coolers for freshly-made pellets and in managing storage schedules of the pellets in silos and bins. Moisture diffusivity and thermal properties are important parameters used to characterize the heat and mass transfer ability of a material. In this study, experimental thin-layer data on (a) moisture desorption, (b) moisture absorption and (c) rate of heating of alfalfa pellets were collected. By applying the inverse theory and using second order mass transfer and heat transfer equations in cylindrical coordinates, the moisture absorption and desorption data were used to estimate the moisture diffusivity as a function of moisture content of the pellets while the heating rate data were used to estimate the thermal properties (thermal conductivity and specific heat) as a function of pellet temperature.Better estimates were obtained when moisture diffusivity of the pellets was exponentially related to moisture content in comparison with a linear relation between moisture diffusivity and moisture content. Moisture diffusivity during desorption (2·40×10^-9to 4·12×10^-9 m²/s) was about three times that of the values of diffusivity during moisture absorption (7·50×10^-10to 1·26×10^-9 m²/s). A good fit to the experimental heating rate data was obtained when thermal conductivity and specific heat of the pellets were linearly related to temperature. Over a temperature range of 2 to 110°C, estimated particle thermal conductivities and specific heats of the pellets were in the range of 0·04 to 0·19 W/m K and from 962 to 2114 J/kg K respectively.     

Design of microirrigation subunit of minimum cost with proper operation

Matlab software named PRESUD (Pressurized Subunit Design) was developed to identify the optimum microirrigation subunit design using the annual water application cost per unit of irrigated area (C _T). This is defined as the cost per cubic meter of water applied to the soil for crop use, calculated as the sum of investment, maintenance, energy, and water (C _w) costs. In this study, only rectangular subunits are considered, using an iterative method for calculating the lateral and manifold pipelines. The infrastructure necessary for water delivery to the subunit inlet was taken into account in the price of water. The results indicate that C _w is the most important factor in C _T, which includes the investment and energy costs for moving water from the source to the subunit inlet. Other important factors, in order of importance, are the emission exponent (x), coefficient of variation of emitter manufacturer (CV_qmf), and emitter spacing (s _e). The minimum water application cost for a typical subunit to irrigate vegetable crops such as pepper is obtained with a subunit of 0.3–0.5 ha, with 80 m of paired lateral pipe length of 16 (13.6 mm) PE 0.25 MPa diameter, and 50 (44 mm) PE 0.4 MPa of manifold pipe diameter. The cost of a typical drip irrigation subunit design for a crop, such as grapevines on trellises, is equivalent to 25 % of the C _T of a typical subunit to irrigate vegetable crops, such as pepper.     

The effect of degradation of phalaris + white clover pasture on soil water regimes of a Brown Chromosol on the Northern Tablelands of NSW,Australia

The soil water regimes of a Brown Chromosol in response to drying and wetting are reported under three pastures types that were grazed all year long. The study was conducted at the Big Ridge 2 site near Armidale, on the Northern Tablelands of New South Wales (NSW) between 1994 and 1998. The three pasture types were degraded pasture (dominated by annual species), a phalaris dominant pasture, and an improved pasture containing phalaris + white clover. This study was conducted to assess the hydrological implications of losing perennial pasture species from the high rainfall (summer dominant) zone of south-eastern Australia. Pasture active rooting depth, water use and extraction during drying periods, and the ability of the soil profile to store water during wet periods were evaluated for each pasture type.Pasture active rooting depth, which affects water use, varied with season and water availability. During a typical autumn drying period between 1 and 22 March 1996, the phalaris + white clover pasture with an active rooting depth down to 100 cm used 46 ± 3.9 mm of water, with 16% of this extracted from the 55–130 cm zone. In the same period, the degraded and the phalaris pasture with active rooting depths of ≤60 cm used 30.7 ± 5.2 and 23.6 ± 7.9 mm of water, respectively, all from the surface 0–55 cm zone. However, under extreme drought conditions such as those in spring and early summer 1997 and autumn 1998, no differences in water use were detected between pastures.Pasture water use during dry periods affects the amount of water that can be stored in the soil profile and the potential amount of water loss during subsequent wet periods. In any wet period, the increase in soil water storage was greater in the 0–55 cm depth than in the 55–130 cm zone. For example, between 24 January and 14 February 1997 with total rainfall of 203 mm, water storage in the 0–55 cm zone was increased by 104.4 ± 6.7 mm under the phalaris + white clover pasture compared with 86.4 ± 4.3 and 84.4 ± 3.3 mm for the degraded and the phalaris pastures, respectively. The water storage increase in the 55–130 cm zone was not different between pastures (<12 mm).It was concluded that without appropriate grazing management and the presence of the legume component, the phalaris based pasture became unstable and failed to persist. The decline in the phalaris pasture caused invasion of annual species and weeds resulting in low water use, similar to that of the degraded pasture. In contrast, the combination of white clover and phalaris pasture showed a greater potential to maintain the phalaris component and a greater total biomass, and so was able to extract more water and from deeper parts of the soil profile. The vigorous phalaris + white clover pasture has greater potential to store more water than the degraded pasture and the phalaris pasture without legumes in the summer dominant rainfall area of temperate Australia. Therefore, maintaining pasture in good condition should be the main objective for sustainability of a grazing system in this region.     

Assessment of the effect of tie-ridging on smallholder maize yields in Malawi

Tie-ridging is being promoted in Malawi as an on-field rainwater harvesting technique to ensure a maize (Zea mais L.) crop during a dry or drought year. Resource-poor smallholder farmers are likely to take up tie-ridging if it increases and not decreases maize yield in most years. A numerical study was conducted to calculate the expected maize yield gain due to tie-ridging taking into account the probability of occurrence of drought, dry, normal and wet years (climatic uncertainty). Mean yields due to tie-ridging in drought, dry, normal and wet years at different N levels were derived from observed smallholder maize yield data using a linear nitrogen response model and field-observed retained rainwater amounts in tie-ridged fields. Simulation results indicate that tie-ridging will result in hybrid maize yield gain in a drought year (1050 kg ha⁻¹) and dry year (560 kg ha⁻¹). There will be a hybrid maize yield loss in a normal year (350 kg ha⁻¹) and wet year (700 kg ha⁻¹). For local maize, there will be a yield gain in a drought year (500 kg ha⁻¹), dry year (220 kg ha⁻¹) and normal year (120 kg ha⁻¹). There will be a slight yield loss in a wet year (60 kg ha⁻¹). Considering observed probability of the occurrence of drought, dry, normal and wet years in Malawi, the study reveals that there will be no hybrid maize yield gain in any coming year with tie-ridging. For local maize, the expected yield gain in any coming year was positive (133.3 kg ha⁻¹) but this gain is less than the minimum gain required considering the opportunity cost of labour (142.5 kg ha⁻¹). Thus under the smallholder conditions and climate of Malawi, the expected yield gain in any coming year due to tie-ridging is likely to be minimal and uneconomic.     

Comparison and sensitivity of measurement techniques for spatial distribution of soil salinity

In Khorezm, a district of Uzbekistan situated in the Aral Sea Basin, soil salinization is an important driver of soil degradation in irrigated agriculture. The main objective of this study was to identify techniques that enable rapid estimation of soil salinity. Therefore, bulk electrical conductivity of the soil (EC_a-meas) was measured with three different devices (2P, 4P, and CM-138) and electrical conductivity of the soil paste (EC_p-meas) was measured with the so-called 2XP device. These measurements were compared with independent estimates of EC_a-calc and EC_p-calc based on laboratory measurements of the saturated extract, EC_e, of soil samples from the same sites. Soil salinity could be assessed satisfactorily with all four devices. EC_p-meas could be well reproduced by the 2XP device (R ² = 0.76), whereas EC_a-meas estimates using 2P, 4P, and CM-138 in the field were less accurate (R ² < 0.50). The sensitivity of all devices to the main ions Cl⁻ and Ca^{2 +} suggests that the measuring principles are similar for all instruments. The devices can therefore be used interchangeably. Field assessment of soil salinity was considerably enhanced by the use of CM-138, because large areas can be quickly assessed, which may be desirable in spite of the lower accuracy.