Showing papers in "International Agrophysics in 2007"

Effect of mineral vs. biofertilizer on growth, yield, and essential oil content of fennel [Foeniculum vulgare Mill.]

Abstract: In field experiments during two successive seasons (2003-2004 and 2004-2005), the effects of biofertilization on growth, fruit yield, and oil composition of fennel plants were investigated. Application of biofertilizer, which was a mixture of Azotobacter chroococcum, Azospirillum liboferum, and Bacillus megatherium applied with chemical fertilizers (only 50% of the recommended dosage ofNPK) increased vegetative growth (plant height, number of branches, and herb fresh and dry weight per plant) compared to chemical fertilizer treatments only. The tallest plants, the highest number of branches per plant, and the highest fresh and dry weights of plants were obtained from the treatment of biofertilizer plus a half dose of chemical fertilizer (357 kg ammonium sulphate + 238 kg calcium super phosphate + 60 kg potassium sulphate ha -1 ). The lowest fresh and dry weights of plants occurred with the 50% NPK. Also, addition of biofertilizer with the chemical fertilizer increased these characters more than the half dose of chemical fertilizer alone. Total carbohydrates in the dry plant material were influenced by the biofertilizer. The highest values of total carbohydrates were found in the treatment with biofertilizer plus a half dose of nitrogen and phosphorus. Nitrogen, phosphorus, and potassium levels in the plant tissue increased when soil was inoculated by nitrogen-fixing bacteria, phosphate-dissolving bacteria, and a mixture of all strains, respectively. The least amount ofN, P and K in the plant tissue occurred with the half dose of chemical fertilizer. Essential oil content in the fennel fruits was increased due to inoculation compared to the half dose of chemical fertilizer. The highest oil yield per plant was observed with the treatment of biofertilizer plus a half dose of nitrogen and phosphorus. The lowest amount of essential oil yield was obtained with the half dose of chemical fertilizer. Oxygenated compounds were increased as a result of using biofertilizer. The highest anethol (trans-1-methoxy-4-(prop-1-enyl)benzeen; C 10 H 12 O)) in fennel essential oil occurred with the half dose of N, P, and K and inoculation with Bacillus megatherium.

Moisture dependent physical properties of cucurbit seeds

Abstract: Some physical properties of three common Iranian varieties of cucurbit seeds (Riz, Chiny, and Gushty), such as geometric properties (linear dimensions, sphericity, geometric and arithmetic mean diameters and surface area), gravimetric properties (true density, bulk density and porosity) and frictional properties (filling and emptying angles of repose and coefficient of static friction on five structural surfaces) were determined as a fun- ction of moisture content in the range of 5.18 to 42.76% (w.b.). The results showed that the mean values of all geometric properties increased with increasing moisture content. Among the varieties, Chiny had the highest values of gravimetric properties, in all moisture contents studied. The maximum and minimum values of bulk density were obtained for Riz (550.3 kg m -3 ) and Chiny (308.3 kg m -3 ). The filling and emptying angles of repose ranged between 24.29-43.94 and 13.01-44.98, respectively. At all moisture contents, the coefficient of static friction was the greatest against rubber (0.52-1.05), followed by plywood (0.42-1), glass sheet (0.31-0.99), galvanized iron sheet (0.39-0.94), and the least for fiberglass sheet (0.38-0.98). Among cucurbit varieties, Riz and Gushty showed the least and the greatest static coefficients of friction in all moisture contents studied, respectively.

Electromagnetic fields and electromagnetic radiation as non-invasive external stimulants for seeds (selected methods and responses)

Abstract: Results obtained in research on the effects of EMF (electromagnetic field) and EMR (electromagnetic radia- tion) on seeds and seedlings show that it is still impossible to draw coherent conclusions. The seed is an extremely complex system, and its state cannot always be controlled. Biological processes proceed in parallel and they may react in different directions to an EMF stimulus. Therefore, the fundamental role of the researcher is selection of biological material for the investigations and also of appropriate external conditions for running them. This work fo- cuses on some essential factors that must be considered during the experiments. The knowledge of the parameters of seeds (moisture content, growth rate, storage period) and EMF (field strength, frequency, time of exposure, polarity) as well as environmental parameters (temperature, light, moisture content of soil) is necessary to understand the correlations between the physiology and cytology of the growing seedlings and the electromagnetic stimulus. The classification of parameters and quantities which are determined during the research of the influence of electromagnetic and laser treatment of seeds and some basic equations determining the dose of EMF or EMR absorbed by seeds are also presented. K e y w o r d s: pre-sowing stimulation, magnetic field, electric field, laser radiation

Starch granule porosity and its changes by means of amylolysis

Abstract: Thepresent work is a review on hydrolysis of native starch using a- and glucoamylases and its influence on starch granules porosity. Changes of specific surface area of starch granules were particularly taken into consideration as well as modifications of their surface observed by means of various microscope techniques. The most common methods for studying porosity of starch granules were briefly characterized. Scanning electron micrographs of hydrolysed granules were also presented as a part of authors' own research.

Physical properties of watermelon seed as a function of moisture content and variety

Abstract: ThephysicalpropertiesofthreecommonIranianvarieties of melon seeds have been evaluated as a function of seedmoisturecontentvaryingfrom475to476,from502to4681,andfrom 455 to 4522% (wb) for Ghermez, Kolaleh and Sarakhsi,respectively Increasing moisture content was found to increaseaxial dimensions, surface area, emptying angle of repose, bulk andtrue density, sphericity, geometric and arithmetic mean diameters,and static friction coefficient on five structural surfaces, whiledecreasing porosity and filling angle of repose Among the varie-ties, Ghermez had the highest values of geometrical properties, inall moisture contents studied An increase of surface area withmoisture content was observed The maximum values of bulkdensity and true density among the varieties were obtained forKolalehseedsGhermezmelonseedhadthehighestporositywhichdecreased with increase in moisture content The filling angle ofrepose decreased as the moisture contents increased for all threevarieties The maximum and minimum values for emptying angleof repose were obtained for Sarakhsi and Kolaleh At all moisturecontents, plywood showed the highest friction coefficient,followed by galvanized iron sheet, then fibreglass, and finallyglass The increase in friction coefficient with moisture contentwas the largest for Ghermez melon seed on fibreglass surface,followed by Sarakhsi and Kolaleh on fibreglass and galvanizediron sheet surface, respectively Ghermez variety had the highestfriction on all frictional surfaces at all moisture levelsKeywords:watermelon seed, physical properties,moisture content, varietyINTRODUCTION

Modeling of thin-layer drying kinetics of sesame seeds : mathematical and neural networks modeling

Abstract: Natural drying characteristics of sesame seeds (SS) were investigated under indoor conditions with both forced convection (FC) and natural convection (NC) of air. The drying kinetics of SS was characterized in terms of effective diffusion coefficient and resistance to diffusion. For the FC method, seeds were dried at a constant air velocity of 1.1 m s -1 and air temperature and relative humidity in the range of25-29°C and 35-40%, respectively. For the NC method, air temperature and relative humidity were in the range of 32-36 and 30-35%, respectively. Six thin-layer drying models, namely, Khazaei, Peleg, Page, Handerson and Pabis, logarithmic, and Weibull, were fitted to drying data. Modelling the correlation between moisture ratio with drying time and drying method was also carried out using artificial neural networks (ANN). SS of average initial moisture content of around 50.8% (d.b.) were dried to the final moisture content of about 3.0-3.7% (d.b.) until no further changes in their mass were observed. The drying of sesame seeds took place in the falling rate period. During the FC experiments, the time to reach the final moisture content of 3% was found to be 400 min. The same moisture content of sesame seeds was found to achieve its equilibrium moisture content (3.7%) after 900 min when seeds were dried using the NC method. Thus, the FC drying times were around 55% shorter than the NC drying times. In the FC and NC drying methods, the drying rates of sesame seeds at the very beginning times of drying were equal to 22.47 and 6.9 (g H 2 O kg -1 dry matter min -1 ), respectively. The effective water diffusion coefficients of SS under FC and NC conditions were 3.1×10 -11 and 1.1×10 -11 m 2 s -1 , respectively. Corresponding values for overall resistance to diffusion were 70.8×10 5 and 19.6× 10 6 m 2 s kg -1 , respectively. The results showed that the Khazaei model gave better fit than the other five models. The Peleg and logarithmic models also had an acceptable accuracy in predicting the drying kinetics of SS. The ANN technology was shown to be a useful tool for predicting the moisture ratio of SS as a function of drying method and drying time. The optimal ANN model was found to be a 2-6-3-1 structure with hyperbolic tangent transfer function. This optimal model was capable of predicting the moisture ratio with R 2 higher than 0.998, RMSE of less than 0.0192 and MRE about 2.63%. It was concluded that ANN represented SS drying characteristics better than the mathematical models.

Some physical properties of African nutmeg (Monodora myristica)

Abstract: Physical and some frictional properties of African nutmeg (Monodora myristica), a wild perennial edible plant, were investigated at a moisture content level of 4.93% dry basis. Measured values for sphericity, unit volume, average geometric diameter, unit mass, true density, bulk density, surface and pro- jected areas were 0.74 0.064, 1008 mm 3 169, 12.42 mm 0.70, 0.89 g 0.14, 830, 488 kg m -3 , 483 and 1216 mm 2 , respectively. The average values for coefficient of static friction on four test surfaces ranged from 0.502 (for galvanized iron sheet) to 0.702 (for rubber). Thus, the technical data obtained from this study may be useful in the design of process machines.

Some physical properties of orange [var. Tompson]

Abstract: Orange is among the popular fruits and of a high economical value. Sizing and grading of orange is needed for the fruit to be presented to local and foreign markets. A study of orange physical properties is therefore indispensable. Some physical properties of grade one (large), two (medium) and three (small) oranges were investigated. These properties included: dimensions, mass, volume, surface area, porosity and coefficient of static friction. The major, intermediate and minor diameters of the grade two orange were 84.1, 77.4 and 75.5 mm, respectively. Volume and mass of the grade two orange were 217.8 cm 3 and 215.4 g, respectively. As for grade two orange piles, the bulk density and fruit density were respectively calculated as 0.44 and 1.03 g cm -3 . Porosity of grade one, two and three oranges was 44.64, 49.39 and 51.2%, with their sphericity being 0.948, 0.931 and 0.923, respectively. The static angle of friction of grade two orange on galvanized, glass and plywood surfaces were found to be 20.2, 23.4 and 23.5, respectively. The three classes of oranges were signifi- cantly different from each other regarding their physical properties. Orange mass was determined through a polynomial function of third degree involving the average diameter of the orange. The function was evaluated with a determination coefficient of 0.991.

New nondestructive method based on spatial-temporal speckle correlation technique for evaluation of apples quality during shelf-life

Abstract: This paper presents a new spatial-temporal speckle correlation technique applied for quality evaluation of apples. Evaluations were performed using a nondestructive and noninvasive method based on the interpretation of an optical phenomenon that occurs when the fruit is illuminated with coherent light, referred as biospeckle. The temporal and spatial changes of speckle patterns created by laser light scattered in fruit have been measured through their correlation functions. The cross-correlation coefficient of biospeckle patterns decrease or increase in fruits with different speeds subject to conditions of their freshness, moisture and preservation. Significant exponential changes of the cross-correlation coefficient value difference Ct=15 were observed during apple shelf life. This shows that the method can be utilized for quality evaluation of apples.

Mass and volume modelling of tangerine (Citrus reticulate) fruit with some physical attributes

Abstract: There are instances in which it is desirable to determine relationships among fruit physical attributes. For example, fruits are often graded on the basis of size and projected area, but it may be more economical to develop a machine which would grade by mass or volume. Therefore, the relationships between mass/volume (either mass or volume) and other physical attributes of fruit are needed. In this study three Iranian varieties of tangerine were selected and the various models for predicting mass/volume of tangerine from its dimensions, projected area, and volume/mass were established. The models were divided into three classifications: 1 - single and multiple variable regressions of tangerine dimensions, 2 - single and multiple variable regressions of projected areas, 3 - estimating tangerine mass/volume based on its volume/mass. The results revealed that mass and volume modelling on the basis of intermediate diameter, on any projected area, and the measured volume are the best models. Based on the results, mass and volume modelling, respectively on the basis of the actual volume and one projected area, were identified as the best models. The highest determination coefficient in all the models was obtained for volume modelling based on projected area as R 2 = 0.97. Finally, volume modelling from economical standpoint was recommended as the most reliable modelling.

Physical properties of guna fruits relevant in bulk handling and mechanical processing

Abstract: The physical properties ofguna fruits, relevant in bulk handling and mechanical processing, were determined and the effect of variety, post harvest history and moisture content investigated. Two varieties of the crop, namely Citrullus colocynthis and Citrullus lanatus, three post harvest storage durations of eight weeks, four weeks and fresh state that gave three moisture levels in the ranges of 87.21-92.45% (w.b.) and 85.07-89.74% (w.b.) for the Citrullus colocynthis and Citrullus lanatus fruits, respectively, were used. Fruit moisture content was found to decrease with increase in storage period. In the above moisture ranges, the major and minor semi-axial dimensions varied from 5.27 to 5.71 cm and 5.18 to 5.61 cm, respectively, for the Colocynthis variety and from 4.53 to 4.96 cm and 4.25 to 4.66 cm, respectively, for the lanatus. The thickness of the epicarp and mesocarp and fruit volume, the fruit, pod and pulp masses, as well as the pod-fruit and pulp-fruit mass ratios increased with increase in moisture content for each fruit variety, while the average seed mass remained virtually constant and the seed-fruit mass ratio decreased with increase in moisture. The true and bulk densities of the fruits also increased with increase in moisture content and ranged from 0.767 to 0.803 g cm -3 and 0.664 to 0.698 g cm -3 , respectively, for the colocynthis fruit, and from 0.637 to 0.765 g cm -3 and 0.554 to 0.665 g cm -3 , respectively, for the lanatus. Regression equations that could be used to adequately express the relationship existing between the above properties and fruit moisture were established. The impact strength, bioyield, yield and rupture points and the bioyield, compressive and rupture strengths, as well as the modulus of stiffness and modulus of elasticity of the fruits were higher at the longitudinal loading orientation than at the lateral. At a similar storage condition, all the properties investigated were higher for the Citrullus colocynthis fruits than those of Citrullus lanatus.

Relationships between the De Martonne aridity index and water requirements of some representative crops: A case study from Romania**

Abstract: A b s t r a c t. In Romania, arid regions occupy a large area especially in the south-eastern and southern regions eg the Romanian Danube Plain and Dobrogea, where most of the crops need to be irrigated during summer time. The method recommended by FAO uses the Penman-Monteith reference evapotranspiration (PM-ETo) to determine irrigation water requirements (IWRs) and crop evapotranspiration (ETc). Unfortunately, there are places in this country and most probably in the neighbouring countries with similar climate, where long-term records of solar radiation, wind speed and air humidity are missing. The purpose of this paper is to document the range of an aridity index, called De Martonne's aridity index (lar-DM) as it applies across the country of Romania, and to determine its relationship with irrigation water requirements of representative crops of Romania. I ar -DM is the ratio between the mean values of precipitation (P) and temperature (T) plus 10°C, annually or monthly. The goal is to help preserve water resources through use of the index. I ar -DM was calculated and averaged for a period of about 100 years and was plotted as maps by using the kriging interpolation method. l ar -DM was correlated with both crop evapotranspiration and irrigation water requirements of the crops in this country. Inverse and strong regression equations were found between the correlated parameters. These relationships have a regional character and might help irrigation system designers and planners estimate the order of magnitude of IWRs and ETc by using l a r-DM, and evaluate environmental water resources in temperate climate regions like areas in Romania and neighbouring countries, where only measurements of temperature and precipitation exist. Because of competition for water among various consumers, this study might help hydrologists and planners make proper decisions concerning how to use scarce water resources during summertime. The procedures used in the paper might be applied in many regions in Europe, and thus have widespread application.

Stimulation of Pinus tropicalis M. seeds by magnetically treated water

Abstract: Magnetically treated water (MTW) was used to stimulate the germination process of Pinus tropicalis M. seeds. This species ofPinus is an endemic of the western part of Cuba and at present is threatened due to a visible decrease that has been detected in its populations. The main cause of this decrease is the low seedling production at nurseries, since the germination percentage of this species rarely exceeds 50%. To carry out our work, normal water (water + ions) was treated using 1200 G isotropic strontium magnets. This was done in two forms: statically and dynamically. The MTW was applied to the samples as irrigation water and as water for imbibition during 24 h. The results showed an increase in the germination percentage up to 70-81% with respect to the control samples (43%) as well as greater seedling growth after germination. The best results were obtained while the treated water was applied dynamically and statically with initial inbibition. In this last case the germination percentages reached 81%, which represents an increase of 88 % compared to the control samples (43%).

Role of water content in food and product texture

Abstract: A b s t r a c t. Water is very important component forming practically all important properties of the agricultural products, the foods and the biological objects. Among the properties, the important role is played by mechanical properties including the viscoelastic ones. These properties are influenced mainly by temperature and the strain rate but water plays the role of the main plasticizer in the controlling mechanisms. The relative simple models were developed for deformation of the soft homogeneous substances and character of the theories is discussed in this paper. Moreover, the role of water in the real agricultural products is structurally and concentration dependent. This role can be well described by sorption properties expressed by the sorption isotherms.

Effect of rapeseed and wheat kernel moisture on impact damage

Abstract: One of thecauses of the occurrence of mechanical damage to seeds during harvest and other technological processes is the effect of impact forces acting during the contact of seeds with moving elements of agricultural machinery. Seeds of winter rape cv. Californium and Bazyl and of spring rape cv. Start, and kernels of winter wheat cv. Rysa, Zawisza and of spring wheat cv. Jasna were subjected to the of impact forces. The effect of the seed and kernel moisture on the extent of impact damage was studied. The study was conducted under laboratory conditions, on a test stand designed at the IA, PAS, in Lublin. It was found that the relation between seed/kernel moisture content and impact damage was non-linear, and that there exists an optimum moisture level at which the minimum damage occurs under the effect of impact forces.

Dehydrogenase activity of technogenic soils of former sulphur mines (Yavoriv and Nemyriv, Ukraine)**

Abstract: The dehydrogenase activity (an index of the total soil biological activity), sulphur content, pH and C org were determined in technogenic soils of the former (1954-1994) sulphur mines in Ukraine (open pit and underground sulphur melting, Yavoriv and Nemyriv, respectively). The soils were neither managed nor reclaimed, and underwent natural self-restoration processes. Soils of former open pit sulphur mine showed C org of 0.07-1.29%, pH of 7-7.9 and a high SO 4 -S content (1.7-14.7 g kg -1 ). Dehydrogenase activity was 2-3 fold lower than in the control forest podzolic soil. Sulphur mining by underground melting resulted in strong soil acidification (pH of 1.5-4.5) and a drastic lost of soil dehydrogenase activity, despite the relatively low S tot content (0.02-0.2 g kg -1 ). In upper horizons dehydrogenase activity decreased up to 28 fold as compared to the forest podzolic soil. In soil located 40 m from the boring well, with a high C org of 8-9% (versus 0.07-1.11% in other soils that area) the decrease in the activity was not as heavy (11-fold) despite a low pH (1.5-1.8) and higher S tot (2.1-3.3 g kg -1 ).

Determining some physical properties of bergamot (Citrus medica)

Abstract: Physical properties are often required for designing post harvest handling/processing equipment for agricultural products. Bergamot is a species of citrus fruit. Physical properties of bergamot are necessary for equipment used in activities such as transportation, storage, grading, packing, and in food production processes like drying, jam production and so on. In this study some physical properties of bergamot were determined. Properties which were measured included fruit dimensions, mass, volume, projected area, fruit density, shell ratio, geometric mean diameter, sphericity and surface area. Bulk density, porosity and also packing coefficient were measured for three groups of small, medium and large category of bergamots. Experiments were carried out at moisture content of 84.9% w.b. for bergamot shell and 87.34% w.b. for its meat. Result showed that average mass and volume were 291.9 g and 456.83 cm 3 , respectively. Dimensions increased from 78.7 to 160 mm in length, 64.2 to 128.5 mm in width, and 64 to 125 mm in thickness. The mean projected area perpendicular to length, width, and thickness obtained 7063.61, 7933.39 and 8137.77 mm 2 , respectively. The geometric mean diameter and surface area were calculated as 97.02 mm, 30412.31 mm 2 , respectively, while sphericity and shell ratio (w.b.) were measured at 0.89 and 0.62%, respectively.

Effects of Temperature and Moisture Content on the Strength Properties of African Nutmeg (Monodora Myristica)

Abstract: BURUBAI, W., A. J. AKOR, A. H. IGONI and Y. T. PUYATE, 2007. Effects of temperature and moisture content on the strength properties of African nutmeg (Monodora myristica). Bulg. J. Agric. Sci., 13: 703-712 The effects of temperature and moisture content of African nutmeg seedcoat was studied as it affects compressive force, deformation, failure stress, strain energy and modulus of elasticity (firmness). Quasi-Static compressive tests were conducted at Sample temperatures of 60 o , 100 o , 140 o , 180 o and 220 o C. Similar tests were also performed at moisture content levels of 8.0, 11.2, 14.0, 17.4 and 28.7 percent (db) in an axial loading orientation. Investigations reveal that force needed to crack open the seedcoat decreased from 52.8N to 32.0N at temperatures of 60 o C and 220 o C respectively. A similar trend was also observed as compressive force decreased from 56.6N to 33.0N as moisture levels increased from 8.0 to 28.7 percent respectively. Deformation values were observed to increase from 0.64mm to 0.97mm for 60 o C and 220 o c respectively. These values of deformation varied from 1.07mm to 1.54mm at moisture content levels of 8.0 to 28.7 percent respectively. Failure stress, strain energy and young’s modulus all tended to decrease with an increase in temperature. Also as moisture content increases, failure stress and modulus of elasticity decreased. However, an increase in strain energy was observed from 0.0201N.mm to 0.0341N.mm for an increase in moisture from 8.0 to 28.7 percent respectively. Based on these findings important recommendations are made.

Influence of magnetic fields on the activity of enzymes: alpha- and beta-amylase and glutathione S-transferase [GST] in wheat plants

Abstract: The paper presents the impact of magnetic fields on enzyme activities in plants. Three species of wheat with different ploidy levels were used in the experiments: Triticum monococum (diploid), T. dicocum (tetraploid), and T. aestivum (hexaploid). Air-dry seed samples, made up of 100 seeds each, were treated with an alternating magnetic field of low frequency (16 Hz) for 2 h. The control samples were not tested with the magnetic field. After the 13th day of magnetic field treatment, measurements were conducted on the following enzymes: - and -amylase and glutathione S-transferase. The magnetic field caused a reduction in the activity of alpha- and beta amylases. This can be really important in breeding and seed production and in certain sections of the agricultural and food industry. Plants grown from treated seeds will be more resistant to sprouting in the future. The magnetic field caused a higher activity in the glutathione S-transferase enzyme. It caused that the plants have a higher resistan- ce to pathogen attack, oxidative stress, and heavy-metal toxicity.

Synthesis and properties of model humic substances derived from gallic acid

Abstract: A b s t r a c t. A model humic acid (HA) was synthesized from a strong natural antioxidant, 3,4,5-trihydroxybenzoic acid (gallic acid-GA), in a slow oxidative polymerization/condensation reaction catalysed by OH- at pH ca. 8. The resulting dark-brown product (HAG), acidified to pH ca. 2, did not precipitate from the reaction solution and it was isolated and purified by dialysis. Its physicochemical and spectroscopic properties, as determined by means of elemental analysis, high performance liquid chromatography (HPLC), Fourier transform infra red (FTIR), ultraviolet-visible (UV-VIS), fluorescence and electron paramagnetic resonance (EPR) spectroscopy, showed a close resemblance to natural humic substances. The antioxidative activity of HAG was assayed by quenching of chemiluminescence of lucigenin and compared to that of standard antioxidants. The similarity and differences between HAG and natural humic substances and the role of the HAG antioxidative activity are discussed.

Effect of fonofos on soil dehydrogenase activity

Abstract: Thepurpose of the present study was to provide information about the effect exerted by fonofos pesticide on dehydrogenase activity of Mollic Gleysol, Eutric Fluvisol and Eutric Histosol soil samples. The effect of fonofos on dehydro- genase activity was evaluated taking into consideration the pesticide dose and soil incubation time. It was found that soil dehydrogenase activity showed an inhibitory effect with increase of the pesticide doses. Dose on the level of 1µg g -1 of pesticide caused 5-21% inhibition of enzymatic activity, whilst ten times higher doses resulted in 17-44% drop of activity in comparison to the control. Increase of dehydrogenase activity was also connected with fall of redox potential (Eh). The results suggest a negative effect of fonofos on soil dehydrogenase activity in the first stage after application.

Effects of pre-shelling treatment on the physical properties of cashew nut (Anacardium occidentale)

Abstract: Thorough knowledge of the physical properties of cashew nuts in its present form is necessary in the design of its shelling machine. A study was carried out to determine the effects of pre-treatment by hot oil roasting and steam boiling on the phy- sical properties of cashew nut. Samples of cashew nuts obtained from five plantations in Iseyin area of Oyo State and Iwo in Osun State in the South-Western Nigeria were used in this work. About 3kg of nuts were picked from 20 randomly selected trees in each of the plantations. The cashew nuts were subjected to pre-treatment by steam boiling and hot oil roasting. The physical properties of raw and pre-treated cashew nuts were determined using standard methods. The results showed that nuts from South-Western Nigeria, which were used for the experiment, could be classified as medium large and extra large ie 22-35 mm. The pre-shelling treatment showed significant difference (P<0.05) in the means of length and width of cashew nut, and no significant difference for thickness, aspect ratio and sphericity index. The treatment showed significant difference (P<0.05) in true and bulk densities but showed no difference in the porosities of the nuts. The moisture content of raw kernel was significantly different (P<0.05) from that of roasted and steam-boiled kernels. The physical properties of cashew nuts were found to be affected by pre-treatment by hot oil roasting and steam boiling.

Preliminary study of sludge effect on soil microbial activity of a podzolic soil under willow culture

Abstract: A b s t r a c t. The study was performed on a model of a field experiment in which a podzolic soil was fertilized with various doses of municipal-industrial sewage sludge (1,2.5,5,10 and 20% of dry mass). Next, the soil was planted with willow (Salix viminalis L). After six months from the application of the sludge, determinations were made of the so-called total number of bacteria with low and high nutritional requirements, total number of fungi, number of cellulolytic and 'proteolytic' bacteria and fungi, respiratory activity, cellulose mineralization rate, intensity of ammonification, nitrification, dehydrogenases and protease activity in the soil. In the Ap horizon of the soil higher doses of the sludge caused significant stimulation of growth of most of the studied groups of bacteria and fungi (with the exception of 'proteolytic' bacteria and fungi). Also, stimulation of almost all of the biochemical parameters studied was observed, increasing with growing concentration of sludge. Only the process of ammonification was strongly inhibited in the treatment with 20% dose of sludge. In the deeper layer of the soil (20-40 cm) the effect of sewage sludge was weaker and less dependent on the dosage applied than in the Ap horizon. Only stimulation of growth of cellulolytic fungi was recorded and, in some treatments, of'proteolytic' bacteria and fungi. Moreover, a slight - though in most treatments significant -increase was observed in the rate of respiration and of cellulose mineralization. The study showed the existence of positive correlations among most of the studied microbial groups and biochemical properties of both soil horizons.

Application of image analysis for soil macropore characterization according to pore diameter

Abstract: t. Soil scientists often examine the soil structure and macroporosity by observing sections using a variety of microscopic and photographic techniques. The most frequent parameters used in the image analysis to characterize pores are: shape factors (like circularity, compactness, elongation, etc.), size parameters (surface area, Crofton perimeter, etc.) and arrangement eg MBR (minimum bounding rectangle) angle. The pores are usually classified according to equivalent pore diameter estimated from the area of pores. This paper presents a proposal of a method for separating macropores according to their real diameter. Aphelion, the image analysis system, was used to prepare a procedure for splitting soil macropores and dividing them into selected fractions according to the diameter. The procedure was tested on porous and compacted soil samples which differ in their porosity, pore shape and size. The results show that the detection of macropores according to the real pore diameter is suitable for the characterization of the actual state of soil macroporosity, especially in porous soils with continuous branching macropore system.

Effect of soil compaction on root system development and yields of tall fescue

Abstract: Soil compaction caused by tractor traffic is one of the most important factors responsible for environmental degradation and leads to plant yields reduction. It is a serious problem for perennial crops, where the soil is wheeled and compacted without ever being loosened. The aim of this study was to evaluate the effect of tractor traffic on tall fescue (Festuca arundinacea) yields and roots development. The field experiment was located in Mydlniki near Cracow, Poland, on silty loam Mollic Fluvisol. Experimental plots were established in completely randomised design with four replications. Four compaction treatments were applied using the following range of number of passes: (P0) untreated control, (P2) two passes, (P4) four passes and (P6) six passes completely covering plots surface after each harvest. The dry matter (DM) of the yield and roots (RMD) were determined. Morphometric parameters of roots were estimated using image analysis software, and root length density (RLD), specific root length (SRL) and mean diameter (MD) were calculated. Bulk density of soil under perennial grass was increased with increase in the number of tractor passes. The tractor traffic resulted in significant decrease in tall fescue annual yields. However, this effect was not observed during the first cut, when the yields were equal for all the treatments. The soil compaction caused by multiple tractor passes changed the morphology and distribution of roots. More roots were found at compacted objects (RLD above 40 cm cm -3 at P4 treatment) with respect to untreated control, P0 (26 cm cm -3 ). These roots were also significantly thicker. The MD value ranged from 0.44 mm at P4 treatment to 0.31 mm at P0.

Effect of moisture content on crackability of bambara groundnut using a centrifugal cracker

Abstract: One of the most tedious operations in processing bambara groundnut is the shelling operation. However, moisture content normally affects the handling and processing of agro-materials, such as nut shelling/cracking. This study was conducted to determine the effect of moisture content on shelling efficiency of bambara groundnut using a centrifugal cracker. A 50 kg bag of bambara groundnut obtained from Damboa Local Government Area of Borno State, Nigeria, was divided into three groups. These groups were prepared for tests by soaking them in ordinary water at room temperature for different periods of 0, 60 and 90 min to obtain different levels of moisture content. Moisture content of each sample was determined by oven drying at 130°C for 6 h. The moisture content levels were found to be 5.3,9.6, and 12.2% (d.b.) for samples A, B and C, respectively. The samples were subjected to impact energy through a centrifugal impaction device operating at an angular velocity of 1920 r.p.m., using three different types of impellers. Data obtained on the percentage of fully shelled pods and unbroken seeds, fully shelled pods with broken seeds, partially shelled pods and unshelled pods were statistically analysed. Results showed that both moisture content and impeller angulations have a significant effect on these performance indices. The most effective performance was obtained at moisture content of 5.3% (d.b.), at which the shelling efficiency, percentage of damaged seeds, percentage of partially shelled pods and percentage of unshelled pods were 96, 3.4, 0.6 and 0, 86.6, 3.6, 5.6 and 4.2, 85, 2.4, 5.4, and 7.2% for the forward facing impeller, radially positioned impeller and the backward facing impeller, respectively. The study farther showed that development of a centrifugal impact bambara groundnut sheller with winnower would eliminate the tediousness of the present manual pod cracking methods.

Analysis of the strength properties of pea stems

Abstract: A b s t r a c t. In the study the authors determined the mechanical properties of pea stems, in the dynamic test, as well as the wall thickness of hollow stem (G) and cross-section area (S). The study was conducted on narrow-leaf pea varieties with varied resistance to lodging: Komandor (susceptible to lodging) and Brutus (resistant to lodging). For purposes of result comparison, also an older lodging-resistant variety - Piast - was included in the study. The strength characteristics of pea stems were obtained through determination of cutting work (E d ) and cutting work per unit of stem cross-section area (W d ), with the help of Dynstat apparatus. The measurements were taken at five points on the stem height. It was demonstrated that the cutting work reaches the highest value in the middle of stem length, while the work per unit of stem cross-section area is the highest close to the root. The study showed that there is a differentiation of the mechanical properties of pea stems. Varieties resistant to lodging are characterized by much higher values of their mechanical parameters. On the basis of correlation coefficients a significant correlation was found between the cutting work and the stem wall thickness and cross-section surface area. Negative correlation coefficients were obtained for the correlation between the cutting work per unit of stem cross-section area and the geometrical parameters of the stems. On the basis of the cutting work and the cutting work per unit of stem cross-section area intervarietal differences were shown. At the same time, the study in which estimation was made of the absorption of X-ray radiation by stems on the basis of the parameter AOD, determined with the densitometric method, showed intervarietal differences. Complementary anatomical study, made on the basis of seven traits, showed cross-sections at the analysed heights on the stems of pea varieties, suggesting also the occurrence of intervarietal differences.

Comparison of soil amendments to decrease high strength in SE USA Coastal Plain soils using fuzzy decision-making analyses

Abstract: Cemented subsurface layers restrict root growth in many southeastern USA Coastal Plain soils. Though cementa- tion is usually reduced by tillage, soil amendments can offer a more permanent solution if they develop aggregation. To increase aggre- gation, we amended 450 g of a Norfolk soil blend of 90% E horizon (the hard layer) and 10% Ap horizon with 0 or 6.44 g kg -1 ground wheat (Triticum aestivum L.) residue and 0, 30, or 120 mg kg -1 polyacrylamide (PAM, 12 x 10 6 Da anionic, linear, and 35% charge density). During a 60-d incubation, parameters measured included water added to maintain 10% soil moisture, soil strength, bulk density, and aggregation. Data were analyzed using a cost-benefit approach with normalized fuzzy logic indicators. Analyses inclu- ded building normalized decision matrices, calculating weighting vectors, ranking alternatives, and defining the best alternatives. When only physical parameters were analyzed using fuzzy logic indicators, addition of wheat residue with 30 mg kg -1 PAM proved to be the best alternative whereas wheat residue with 120 mg kg -1 PAM had been selected as the best alternative with analysis of va- riance because it did not simultaneously analyze all variables. When both physical and economic parameters were included, the best alternative was the treatment with wheat residue and 120 mg kg -1 PAM. When using fuzzy logic, judgment of the user was

Effect of hydraulic press parameters on crude palm oil yield

Abstract: An investigation was carried out on the effect of hydraulic press parameters such as press cage diameter (D) (80, 120, and 150 mm) and wall pore diameter (H) (4,6, and 10 mm) and expression pressure (P) on crude palm oil yield. The oil yield was found to increase with increase in cage diameter from 80 to 120 mm, after which it decreased as the cage diameter was increased to 150 mm. The volumetric oil flow followed the same pattern. The oil yield and volumetric flow increased with increase in pore size from 4 to 6 mm and decreased as the pore size increases to 10 mm. Increase in pressure form 0.5 to 1.5 MPa was observed to increase oil yield. Statistical analysis of the effect of the processing factors on oil yield indicates that the effect of all the factors were significant at 99%. It was observed that oil yield can be represented by the regression equation: Y=27.76-0.07D+0.33H+5.82P. The results of this study are useful in optimising the design of presses for palm oil extraction.

Colour of paprika powders with different moisture content

Abstract: The colour characteristics of paprika powder with different moisture contents were analysed. The colour, determined by using the CIELab colour system, was measured with a Minolta CR-300 tristimulus colorimeter. We investigated several quality Hungarian paprika powders. The moisture contents of these paprika powders were increased by 1,2,3,4 and 5% relative to the initial sample. Increase of moisture content caused significant change in L*, b*, C* ab and h° ab colour values. The moisture content increase of 3-5% caused decrease of hue angle by 2-4°, decrease of lightness coordinate by 1.5-2 unit, and decrease of chroma by 1.5-2 unit. The ΔE ab colour difference calculated between the initial samples and the samples with various added moisture contents crossed over the minimum perceptible (threshold) of total colour difference 1.5, when added moisture was 3-5%.