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Lee W.S.,University of Florida | Alchanatis V.,Institute of Agricultural Engineering | Yang C.,U.S. Department of Agriculture | Hirafuji M.,University of Tsukuba | And 2 more authors.
Computers and Electronics in Agriculture | Year: 2010

With the advances in electronic and information technologies, various sensing systems have been developed for specialty crop production around the world. Accurate information concerning the spatial variability within fields is very important for precision farming of specialty crops. However, this variability is affected by a variety of factors, including crop yield, soil properties and nutrients, crop nutrients, crop canopy volume and biomass, water content, and pest conditions (disease, weeds, and insects). These factors can be measured using diverse types of sensors and instruments such as field-based electronic sensors, spectroradiometers, machine vision, airborne multispectral and hyperspectral remote sensing, satellite imagery, thermal imaging, RFID, and machine olfaction system, among others. Sensing techniques for crop biomass detection, weed detection, soil properties and nutrients are most advanced and can provide the data required for site specific management. On the other hand, sensing techniques for diseases detection and characterization, as well as crop water status, are based on more complex interaction between plant and sensor, making them more difficult to implement in the field scale and more complex to interpret. This paper presents a review of these sensing technologies and discusses how they are used for precision agriculture and crop management, especially for specialty crops. Some of the challenges and considerations on the use of these sensors and technologies for specialty crop production are also discussed. © 2010 Elsevier B.V.


Klein E.,Institute of Agricultural Engineering | Klein E.,Hebrew University of Jerusalem | Katan J.,Hebrew University of Jerusalem | Gamliel A.,Institute of Agricultural Engineering
Crop Protection | Year: 2012

We assessed soil suppressiveness against root-knot caused by Meloidogyne javanica, following the incorporation of crop residues (organic amendments [OA]) and soil solarization, under agricultural conditions. Two field experiments were established in tomato greenhouses and a third in a nethouse for growing Antirrhinums, all infested with M. javanica. Dried residues of wild rocket (WR) were incorporated into the soil and then it was solarized to moderate temperatures to partially effect the pathogen population. Root galling on the roots of the successive tomato crop was significantly reduced to different levels by WR, solarization or their combination, in two experiments. Solarization, alone or combined with WR amendment, significantly reduced root knot incidence in the roots of snapdragon, but suppression of root galling in the roots of snapdragon in the following crop was not evident. We further assessed the potential of various herb residues, incorporated in small plots, and solarization to induce soil suppressiveness against root-knot caused by M. javanica. Amending soil with residues of WR, tarragon, peppermint or sage induced soil suppressiveness to root knot even when M. javanica was introduced into the soil after the termination of the treatment, and reduced the galling index in subsequently grown tomato plants, compared with non-amended soil. Our findings further validate the potential role of OA and solarization in inducing soil suppressiveness, which contributes to sustainable management of soilborne pathogens. © 2012 Elsevier Ltd.


Klein E.,Institute of Agricultural Engineering | Klein E.,Hebrew University of Jerusalem | Katan J.,Hebrew University of Jerusalem | Gamliel A.,Institute of Agricultural Engineering
Crop Protection | Year: 2011

Plant residues from herb crops were examined as organic amendments for the control of soilborne pathogens with and without soil heating for a short exposure of 2 weeks. Residues of herbaceous plants of oregano, sage, rosemary, tarragon, bay, wild rocket, spearmint and thyme were incubated for 14 days in a controlled laboratory system which emulates soil solarization. Green cabbage residues were included for comparison. The tested pathogens included Fusarium oxysporum f. sp. radicis-lycopersici, Macrophomina phaseolina, Rhizoctonia solani and Meloidogyne javanica. Heating soil amended with herb residues, particularly tarragon, spearmint and wild rocket, resulted in high mortality of the tested pathogens. Volatile compounds which were generated in heated soils amended with wild rocket or tarragon showed significant toxicity to M. phaseolina and R. solani. Only oregano, thyme, bay, wild rocket and tarragon amendments were effective in pathogen control without heating. Incorporation of leaf and stem residues of thyme, sage, tarragon, rosemary or wild rocket in soil and exposure to solarization under field conditions resulted in 95-100% mortality of the tested pathogen. This study demonstrates that the residues from herb crop production can serve as organic amendments for the control of soilborne pathogens, especially when combined with heating or solarization. © 2010 Elsevier Ltd.


Klein E.,Institute of Agricultural Engineering | Klein E.,Hebrew University of Jerusalem | Katan J.,Hebrew University of Jerusalem | Gamliel A.,Institute of Agricultural Engineering
Plant Disease | Year: 2011

Soil suppressiveness to soilborne pathogens can evolve following the incorporation of plant residues in the soil and solarization. We studied its occurrence by assessing disease incidence and severity in sandy soil which was infested after the disinfestation treatment. Disease incidence and severity of crown and root rot in cucumber plants inoculated with Fusarium oxysporum f. sp. radicis-cucumerinum macroconidia were reduced by 20 to 80% when seedlings were planted in the tested soils 2 to 34 months after soil amendment. Residues of Diplotaxis tenuifolia (wild rocket [WR]), Artemisia dracunculus (tarragon), Salvia officinalis (sage), and Brassica oleracea var. italica (broccoli) were most effective for inducing soil suppressiveness. Effective soil suppressiveness continued to be evident after repeated inoculations and plantings in the same soil without additional treatment between inoculations. Moreover, residues of WR induced soil suppressiveness in two additional tested soils differing in their physical and chemical properties. Residues of Rosmarinus officinalis (rosemary), Coriandrum sativum (coriander), Mentha piperita (peppermint), and B. oleraceae var. botrytis (cauliflower) induced disease suppression at the first inoculated planting but not upon repeated inoculation and planting. The contribution of soil solarization to the evolution of soil suppressiveness, albeit evident, was inconsistent. Soil suppressiveness to Fusarium crown and root rot was also observed when cucumber seed were sown in soils which were initially amended with WR residues and later infested with F. oxysporum f. sp. radicis-cucumerinum chlamydospores. There is a potential for the use of plant residues for inducing soil suppressiveness and further contributing to the control of diseases caused by soilborne pathogens. © 2011 The American Phytopathological Society.


Hetzroni A.,Institute of Agricultural Engineering | Vana A.,Hazera Genetics | Mizrach A.,Institute of Agricultural Engineering
Postharvest Biology and Technology | Year: 2011

Mechanical properties, such as strength and elasticity, of tomato peel (exocarp) are important in fruit used both for industrial processing and for fresh consumption, and, therefore, are also of vital interest to breeders. The food industries prefer peel to be thick and stiff for easy peeling, whereas consumers of fresh produce prefer thin, soft peel, for easy eating. The various varieties of tomato fruit genetically developed by breeders might exhibit the desired quality or biomechanical characteristics, but at the same time, might produce types of peel that do not always meet the requirements of the canneries or the fresh-fruit market. The present study evaluated the morphology and mechanical characteristics of the fruit skin and its integrated cuticular membranes, and determined their suitability for industrial processing and/or human consumption. The biomechanical and anatomical properties of fruit peels of five tomato (Lycopersicon esculentum) cultivars were investigated. The mechanical properties of ripe tomato peel under axial tension were characterized by measuring strength, elastic modulus, failure stress, overall stiffness and degree of stiffening, by means of deformation and puncture testing of flat strip and circular disk samples, respectively, with a Universal Testing Machine. Data were collected by two testing methods for each peel sample from up to 15 fruit of each of five cultivars. The results were analyzed statistically to determine the instantaneous elastic strains, breaking stress (strength), and work of fracture the peels. The overall stiffness and the extent to which the stress-strain curve deviated from a straight line were calculated. The results suggested a standard measure for each tomato variety, based on its mechanical integrity and suitability for processing or fresh consumption. © 2010 Elsevier B.V.


Ignat T.,Corvinus University of Budapest | Ignat T.,Institute of Agricultural Engineering | Schmilovitch Z.,Institute of Agricultural Engineering | Fefoldi J.,Corvinus University of Budapest | And 2 more authors.
Postharvest Biology and Technology | Year: 2012

The present study created a basis for development of a fast, non-destructive method to measure ascorbic acid content during various growth stages of three bell pepper cultivars: 'Ever Green', 'No. 117' and 'Celica'. Fruit were tagged at the flowering stage and picked weekly during 9 weeks of growth, until fully ripe. Visible and near-infrared (VIS-NIR) spectra in the range 477-950nm were obtained in reflectance mode from intact peppers with a USB2000 mini-spectrometer. Short-wave infrared (SWIR) spectra in the range 850-1888nm were obtained in reflectance mode from the same sampled peppers with a Liga Spectrometer. Fruit flesh samples were cut from the area scanned for spectral measurements, and destructively analyzed for ascorbic acid content. The highest ascorbic acid content was measured in the green variety 'Ever Green' (148.1mg per 100g). Varieties 'Ever Green' and 'No. 117' accumulated significantly higher concentrations of ascorbic acid than 'Celica', and consistent and significant differences were found between the premature, green and mature stages of all three cultivars. Partial Least-Squares (PLS) regression was used in spectral model development. Comparisons were made between the PLS regression analysis of the reflectance spectra (R), its first derivative (D 1R), the log(1/R) and its first (D 1log(1/R)) and second derivative (D 2log(1/R)). VIS-NIR and SWIR spectroscopy measurements showed good correlation (r 2=0.76) with changes in ascorbic acid content. The PLS regression models were able to predict ascorbic acid content for all three cultivars, with 15.1-18.9mg per 100g cross-validation error (RPD=2-2.4). The method offers potential for non-destructive detection of changes in ascorbic acid content during growth and maturation of intact bell peppers. © 2012 Elsevier B.V.


Ecim-Djuric O.,Institute of Agricultural Engineering | Topisirovic G.,Institute of Agricultural Engineering
Energy and Buildings | Year: 2010

Good ventilation system in livestock buildings is necessary for removing excess moisture and heat and for improving building environment in general. Natural ventilation does not require energy consumption and on the other hand, animals would not be affected by electrical power failures. Because natural ventilation depends largely on temperature difference between inside and outside air and wind velocity and direction it is very important in early stages of building design to provide orientation and accurate opening areas. Numerical simulation of natural ventilation and computation of fluid dynamics in livestock buildings can be usefully integrated in whole ventilation system optimization and related energy consumption decrease. Even in mechanical system ventilation, from flow field obtained in numerical simulation it is possible to optimize these systems. CFD analysis is generally restricted to the study of buildings' environment flows and space study, and the designer must supply boundary conditions in the form of external and internal buildings' envelope/wall surface conditions. Finally, the needs for further research and engineering development are outlined. © 2009 Elsevier B.V. All rights reserved.


Gamliel A.,Institute of Agricultural Engineering
Journal of Plant Pathology | Year: 2010

Three major objectives characterize the current trend in intensive agriculture: pest control, environmentally safe measures and consumer demand for, among other things, pesticide-free products. Therefore, the main goal in pest-management research is to improve pesticide application technology for its effective action and rapid dissipation from crop tissues. Air-assisted spraying technology that makes use of fine droplet size and low volumes is an effective way of depositing the spray on both the upper and under sides of leaves. Application of pesticides with aerosol generators (foggers) and other sprayers has shown practical and effective control of insects, mites and foliar pathogens in various field and tree crops. Moreover, effective control is achieved even when pesticide rates are significantly reduced. Soil disinfestation is the most effective tool for knocking out inoculum in soil, but it has to be accompanied by additional measures in the framework of integrated pest management. Research into exploiting soil solarization by combining it with reduced doses of permitted fumigants, or other tools, is expected to produce the most promising approaches. Furthermore, a sublethal dosage of fumigant in combination with solarization, or other pest-management methods, can provide a reasonable solution to many of today's problems. Combining fumigation or solarization with biocontrol agents could also improve the control of target pests, maintain the microbial balance in soils and maintain suppressiveness against pathogen buildup in those soils. Improvement of application methods for soil disinfestation is another issue which warrants special attention.


Teitel M.,Institute of Agricultural Engineering | Atias M.,Institute of Agricultural Engineering | Barak M.,Institute of Agricultural Engineering
Biosystems Engineering | Year: 2010

Around the world in warm climates fans are used to ventilate commercial greenhouses. They are usually mounted at one end of the greenhouse and suck ambient air through openings at the opposite end. As the air moves from one end of the greenhouse to the other, gradients of temperature, humidity and CO2 develop along the structure. These gradients result in an inhomogeneous microclimate for the crop and are, therefore, undesirable for growers. Models to predict these gradients were developed for the case of constant (with respect to time) ventilation rate, and were verified by experiments in a greenhouse in which pepper was grown. The experimental results were based on measurements in which the 'open chamber' approach was applied to the whole greenhouse. The models were then used to predict changes in temperature, humidity ratio and CO2 concentration in the air along the greenhouse at different hours of the day. The model results show that the largest gradients are to be expected at around midday (11:00-12:00), when the intensity of solar radiation is greatest. © 2010 IAgrE.


Gan-Mor S.,Institute of Agricultural Engineering | Regev R.,Institute of Agricultural Engineering | Levi A.,Institute of Agricultural Engineering | Eshel D.,Israel Agricultural Research Organization
Postharvest Biology and Technology | Year: 2011

Postharvest carrots are brushed, hydro-cooled to 4-6 °C and treated with chemical fungicide before storage to prevent soft rot caused by Sclerotinia sclerotiorum (Lib.) de Bary during storage. Replacement of the fungicide with high-temperature surface heat treatment poses a dilemma: excessive heating will cause damage whereas insufficient heating will result in incomplete disinfection. This problem is further compounded by the difficulty in providing uniform surface heating. To alleviate this problem, a system for the uniform application of high-temperature short-duration steam disinfection was developed using accurate real-time temperature monitoring of individual produce segments by thermal imaging. Uniform short-duration high-temperature heat was delivered from above by steam jets combined with electric steam-drying elements and reflectors. Produce was subjected to rotational and linear motions to expose each surface segment to the same amount of heat. The novel use of thermal imaging to monitor surface temperature in steam systems was essential for determining transferred heat and heating uniformity in a treated object. The resultant, uniform application of short-duration high-temperature steam provided surface heat-disinfection with minimal internal heating and damage. Application of the steam treatment immediately after carrot hydro-cooling reduced post-storage phytotoxic color change by 60-80% and resulted in significantly reduced sensitivity to post-storage soft rots caused by S. sclerotiorum. Carrot sprouting was not increased by the steam treatment, suggesting retention of the hydro-cooling's physiological effect. These results suggest that precise heat treatment can be optimally applied after hydro-cooling to improve postharvest quality of carrots in a procedure that is harmless to man and the environment. © 2010 Elsevier B.V.

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