2018, Vol. 16, No. 2

Selle kollektsiooni püsiv URIhttp://hdl.handle.net/10492/5375

Sirvi

Nüüd näidatakse 1 - 20 30

Analysis of cost and performances of agricultural machinery: reference model for sprayers
(2018) Yezekyan, T.; Marinello, F.; Armentano, G.; Sartori, L.
Management of agricultural operations is currently rapidly changing caused by increased attention to the concepts of sustainable development and sustainable intensification. Enhancement of productivity and efficiency of agricultural machinery are the leadi ng factors in sustainable agriculture. The complete application and exploitation of engineering advances require the revision of traditional agricultural machinery management process. The definition of the farm fleet (tractors and implements), as well as m achinery planning and management, must consider different parameters, including not only the cost of the machines but also their dimensions, weight, working width, needed power, etc. All of this information related to an agricultural machine is eventually influencing the impact on productivity, on the return on the investmen t, and also on the environment. The present work is aimed at identifying the most relevant parameters which are influencing costs and performances of sprayers, including tank volume, max imum flow, needed power, weight and price. The different parameters are analysed in a correlation matrix, in order to allow identification of dependencies a nd to extract reference models. The study is based on linear and multiple linear regression analysis carried out on technical specifications of about 700 models of sprayers. Relevant correlations were highlighted between price and weight, between weight and tank capacity and in some cases between power and weight . Following such correlations , models have been proposed, which can be implemented in order to support the decision making phases.
Chemical composition of agromass ash and its influence on ash melting characteristics
(2018) Čepauskienė, D.; Pedišius, N.; Milčius, D.
The increasing demand for biofuels leads to a growing need for agromass, such as herbaceous plants and agricultural waste. However, agromass contains high quanitites of alkali metals, mainly potassium and sodium, which limits agromass usage in thermoconversion processes. Alkali metals react with other ash forming elements which leads to ash related problems such as agglomeration, fouling and slagging during agromass burning. In this study, chemical composition and melting behaviour of ashes form ed at 550 ° C are investigated. Three herbaceous plants (reed canary grass, hemp, orchard grass), four types of agricultural waste (straws of rye, wheat, buckwheat and canola) and two types of woody biomass (birch, spruce) are selected. Ash melting behaviou r, composition and bulk structure are determined using a high temperature furnace with a video camera, inductively coupled plasma atomic emission – spectrometry and X – ray diffraction technique, respectively . Ash melting behaviour of selected agromass types s hows that the hemp ash has the highest shrinkage starting temperature which reaches 1 , 079 °C. This is due to the high content of calcium and low content of potassium and sodium in hemp ash. T hree main components calcium carbonate, potassium sulfate and pot assium chloride have been identified in ashes after agromass and woody biomass are heat – treated at temperature of 550 °C.
Combustible in selected biofuels
(2018) Vitázek, I.; Tulík, J.; Klúčik, J.
The aim of the research was to determine the moisture, combustible and ash content in selected biofuels, in dependence on temperature by the means of gravimetric method. For this purpose, the furnace Nabertherm L9/11/SW/P330 was used. Analyzed samples cons isted of crushed biomass which is used in small heat sources (e.g. spruce wood, cherry wood, apple wood, black locust wood) with bark and without additives. Biomass for larger heat sources (woodchips cuttings from coniferous trees), sawdust mix (plum, cher ry, walnut, apricot, apple) and pellets (90% spruce and 10% fir) were also analyzed. The results are processed graphically and enable to characterize the tested fuels. The highest content of combustible was found in spruce wood sample without bark (99.889% ), the lowest content of combustible indicated cuttings from coniferous trees (88.402%). Gravimetric experiments were supplemented by DSC measurement of selected samples on calorimeter Toledo DSC822e. The graphic courses of reactions are provided up to 500 °C.
Comparison of two sowing systems for CTF using commercially available machinery
(2018) Macák, M.; Rataj, V.; Barát, M.; Galambošová, J.
The crop establishment belongs to crucial technology operations. The quality of sowing is the basis for obtaining efficiency of production. Controlled Traffic Farming (CTF) is a technology which prevents excessive soil compaction and minimizes compacted area to the smallest possible area of perman ent traffic lanes (PTL). There were two sowing systems compared, namely row and band sowing when growing winter barley. Sowing parameters as well as all other field operations were identical for both compared systems. Measurements were conducted at an expe rimental field on non - compacted and traffic lane areas where CTF system was introduced in 2009, with 64% of compacted and 36% of non - compacted soil. Six crop parameters were analysed. Generally, it can be concluded that the band sowing performed better in yield (by 9.3% in non - compacted area; by 3.8 % in traffic lane), ear number (by 5.2% in non - compacted area; by 10.1% in traffic lane) and grain number (by 6.3% in non - compacted area; by 8.1% in traffic lane) as well as crop height (by 6.6% in non - compacted area; and by 2.4% in traffic lane). The only parameter performing worse was TGW with decrease of 6.6% in non - compacted area and decrease 2.8% in traffic lane for band system. Differences in number of grain per ear were negligible.
Diagnosis of air quality in broilers production facilities in hot climates
(2018) Sousa, F.C.; Tinôco, I.F.F.; Barbari, M.; Baptista, F.; Souza, C.F.; Saraz, A. O.; Coelho, D.J.R.; Silva, A.L.
The objective of this study was to evaluate air quality of industrial farms of broilers production, located at Zona da Mata region, Minas Gerais , Brazil. The environmental air quality was evaluated during the last rearing week, between 35 and 42 days of life of broilers. Facilities with beds constituted by two types of substrates were evaluated: coffee husks (6 reuse cycles) and shavings (4 reuse cycles). A total of 30 facilities (3 per each of the 10 reuse cycles) were investigated. Air quality was diagnosed by determining air temperature and relative humidity and by ammonia and carbon dioxide concentrations. Air temperature and relative humidity were not affected by reuse cycles in coffee husks bed, but these variables were affected by reuse cycles in shavings bed. Ammonia and carbon dioxide concentrations increased linearly according to the reuse cycles for both types of bed. The maximum concentr ations of ammonia and carbon dioxide were 25 ppm and 1,348 ppm in facilities with bedding of coffee husks and 10 ppm and 1,075 ppm in facilities with bedding of shavings, respectively. Air quality of facilities using coffee husk bed tends to be worse when compared to facilities using shavings bed due to the higher values of ammonia and carbon dioxide concentrations, as observed in this study. In conclusion, regardless bedding type, increases in reuse cycles tend to decrease air quality inside the facility, since a linear increasing in ammonia and carbon dioxide concentrations can be observed in relation to the number of bed reuse cycles.
Differential thermal regulation of the growth of the bee colonies in the early spring period
(2018) Jehlička, T.; Sander, J.
This paper addresses the issue of the control of activity and growth of the bee colonies (brooding) in the early spring period. The bees are brooding up already in the late winter, and the intensity of brooding in this period is determined by daytime tempe ratures and sunshine hours that increase the temperature of the inner hive space. The objective is to design and verify a technology that would ensure the conditions for the optimal brooding in the early spring period and thus the numerically strong bee co lonies. The experimental part was based on the temperature regulation in the inner hive space. A preset temperature was maintained inside the hive by an electric heating system with regulation. A differential thermal regulation which enabled the optimal gr owth of the bee colonies in accordance with the phenophases was chosen for verification. To verify the proposed method, two groups of the bee colonies were assembled. One group of the bee colonies had a heating system with regulation installed inside the h ive. The second group of the bee colonies was in the hives without the heating system installed. The dependence of the brood area on time was monitored for the evaluation of both groups of the bee colonies. It was proven that the differential thermal regul ation enables the optimal growth of the bee colonies in the early spring period in accordance with the phenophases. The brood area increased evenly for the group of the bee colonies with a regulated temperature of the hive space, reaching a larger area.
Effect of I2/KI water solution to wheat seeds imbibition assessed by image analysis
(2018) Lev, J.; Blahovec, J.
Water plays key role in a seed germination due to its participation in starting of many metabolic processes that accompany the seed germination. Rate of water uptake into seeds is a usual basis for determination of the three germination phases. The water uptake into seeds during their germination was investigated by many researchers who used various methods (e.g. magnetic resonance mic ro - imaging, near - infrared hyperspectral imaging and visualization with I 2 /KI solution (Lugol's iodine)). The method of using I 2 /KI water solution for this purpose is quite popular for its relatively applicability. In this paper we compared the seed surface area projection and shape development of the seeds imbibed in the I 2 /KI solution and in the pure water via image analysis. It was found that the presence of the I 2 /KI in water changes the increase of seeds volume during germination and the effect is diffe rent during the initial imbibition and during the next germination phases. The seed shape development is similar for both variants, pure water and I 2 /KI solution.
Effect of nitrogen fertilization on winter wheat yield and yield quality
(2018) Litke, L.; Gaile, Z.; Ruža, A.
Wheat ( Triticum aestivum L.) is the most common cereal, which is grown in Latvia. Nowadays, farmers are trying to get high grain yields in line with food quality, at the same time trying to minimize production cos ts and to use environmentally friendly technologies. The objective of this experiment was to clarify the impact of nitrogen fertilization on winter wheat yield and yield quality under two soil tillage systems and after two forecrops. Trials were conducted at the Research and Study farm ‘Peterlauki’ of Latvia University of Agriculture (56 ° 30.658 ’ N and 23 ° 41.580 ’ E). Researched factors were (1) crop rotation (wheat/wheat and oilseed rape ( Brassica napus ssp. oleifera )/wheat), (2) soil tillage (traditional soil tillage with mould - board ploughing at a depth of 22 – 24 cm and reduced soil tillage with disc harrowing at a depth below 10 cm ), (3) nitrogen fertilizer rate (altogether eight rates: N0 or control, N60, N90, N120(90+30), N15 0 (90+60) , N180 (90+60+30) , N210 (90+70+50) , and N240 (120+60+60)), and (4) conditions of the growing seasons 2014/2015, 2015/2016 and 2016/2017. The results indicate that winter wheat yield has been significantly affected by soil tillage, nitrogen fertilizer rate ( p < 0.001) and forecrop ( p < 0.05). Three - year research confirmed significant yield increase until the nitrogen fertilizer rate N180. Significantly higher average grain yield was obtained under traditional soil tillage. Nitrogen fertilizer affected significantly all tested yield quality indicators ( p < 0.001) . Increase of nitrogen fertilizer rate secured significant increase of winter wheat grain quality indices, except starch content, after both forecrops and in both soil tillage variants. Values of yield quality indicators increased significantly enhancing N - rate from N150 up to N 210.
Effect of thermal environment on body temperature of early-stage laying hens
(2018) Andrade, R.R.; Tinôco, I.F.F.; Souza, C.F.; Oliveira, K.P.; Barbari, M.; Cruz, V.M.F.; Baptista, F.J.F.; Vilela, M.O.; Conti, L.; Rossi, G.
The thermal comfort condition of early - stage laying hens can be verified by means of physiological variations. The mean surface temperature and cloacal temperature are important parameters to d emonstrate the effect of the thermal environment on the birds. The objective of the present study was to correlate homeostasis and stress with physiological responses (mean surface temperature and cloacal temperature) of lightweight laying hens of the Lohm ann LSL Lite line aged from one to forty - two days when submitted to different thermal environments. A total of 864 birds with the same age, origin and uniform body weight were randomly distributed in four climatic chambers. The characterization of the dif ferent environments was as follows: thermal comfort temperature (33.0 – 19.0 °C ), two cold stress levels (28.0 – 17.0 °C and 25.0 – 17.0 °C ) and one level of heat stress (38.0 °C – 22.0 °C ). The experiment was performed in a completely randomized design in the s ubdivided plots scheme, with four treatments in the plots and the evaluations (days) in the subplots. The means were compared using the Tukey test, adopting the 5% probability level. The birds maintained the physiological responses, based on cloacal and su rface temperatures, within the normal range for all evaluated treatments during the period between 01 and 42 days of life. The surface temperature of the birds varied as a function of the air temperature of each breeding environment, with lower surface temperatures for mild cold and moderate cold treatments.
Energy potential of densified biomass from maize straw in form of pellets and briquettes
(2018) Križan, M.; Krištof, K.; Angelovič, M.; Jobbágy, J.; Urbanovičová, O.
The aim of the study was the evaluation and comparison of energy potential of briquettes and pellets produced from the maize straw and woody biomass based on various diameters of pellets. By experimental measurements a calorific value and ash content was obser ved. Calorific value was measured by laboratory calorimeter IKA C 6000 (IKA® Works, Inc., USA) and laboratory combustion chamber Lindberg/Blue M (Thermo Fisher Scientific, Inc., USA). Individual calorific values and ash content was observed and subsequentl y confronted to obtain differences with replication. The analysis showed that calorific value of pellets with diameter 6 mm ranged from 16.99 MJ kg - 1 to 17.80 MJ kg - 1 . Calorific value of pellets with 8 mm diameter ranged from 16.63 MJ kg - 1 to 17.20 MJ kg - 1 . However, compared calorific value of briquettes ranged from 14.99 MJ kg - 1 to 15.66 MJ kg - 1 . Further analysis showed that ash content of samples varied as well and it’s even affected by diameter of pellets. While ash content of pellets with diameter 6 mm was observed as 4.9% of total volume in case of pellets with 8 mm it was observed at value 5.5%. Briquettes produced from maize straw have ash content at value 5.4%. In contrary, ash content of woody biomass was significantly higher, 11% of volume, specifi cally. At the basis of observed parameters it can be concluded that maize straw densified in form of briquettes and pellets have a great energy potential which is comparable and competitive with currently used materials for production of briquettes and pel lets.
The European performance indicators of broiler chickens as influenced by stocking density and sex
(2018) Kryeziu, A. J.; Mestani, N.; Berisha, Sh.; Kamberi, M. A.
The aim of this study was to investigate the influence of different stocking densities on the growth performance of Ross 308 broiler chickens up to six weeks of age. A to tal of 216 one - day broiler chicks were randomly assigned to three treatment groups based on the stocking density: Low (LSD) = 14 chickens m - 2 , Medium (MSD) = 18 chickens per m 2 and High (HSD) = 22 chickens m - 2 , with four replications. Higher body weight gain (TWG) was observed for the low (2,043.89 g) and medium (2 , 008.03 g) compared to the high (1,901.51 g) density. The study revealed that chickens of the LSD treatment consumed significantly ( P < 0.01) more fe ed compared to the HSD chickens. High stocking density (22 m - 2 ) tended to improve feed conversion ratio compared to medium (18 m - 2 ) and low (14 m - 2 ) stocking density, but the differences were not significant ( P > 0.05). From the results of this study it can be concluded that broiler chicks can be stocked up to 22 chickens m 2 , as far as required standards are assured.
Evaluation of break-even point and gross margin economic risks in producing winter oilseed rape
(2018) Mimra, M.; Kavka, M.; Markytán, P.
The economic result of growing winter oilseed rape is influenced by a number of variables, such as natural influences, input prices and the used technology. One of the ways to improve the business’s prof itability is to use the experience and knowledge provided by consulting companies. This paper analyses two data series covering the period of 5 to 10 years regarding specific selected key parameters for companies using the counselling services of the Union of Oilseeds Growers and Processors in Prague (UOGP) and some other companies that make no use of these services (OTHERS). For the selected key parameters, the risk analysis of reaching the gross margin and the break - even point was conducted with the aid of the Monte Carlo stochastic simulation method. The results of the calculations show that the companies using UOGP consulting achieve on average, at the same level of risk, a gross margin higher by 30% and their break - even point is lower by 11%. Taking adv antage of the knowledge and services provided by a consulting company has positive economic benefits, and it increases the competitiveness of companies.
Evaluation of the mechanized harvest of grapes with regards to harvest losses and economical aspects
(2018) Jobbágy, J.; Krištof, K.; Schmidt, A.; Križan, M.; Urbanovičová, O.
The aim of the study was to evaluate the mechanized grape harvest conducted by the trailed harvester. As a criterions was introduced the performance, harvest losses of grapes and economic efficiency from the perspective of its introduction. The calculatio ns consist of total annual and partial unit costs also with regards to indirect costs which are formed by the grape losses during the harvest. Evaluation was conducted on three varieties of grapes. The losses of grapes, total annual and partial unit costs were calculated for selected varieties of grapes and also for whole production area. The mean grape losses for whole production area were determined at 470 kg ha - 1 , while the greatest portion of these losses (9.7%) was observed in case of Neronet variety. Among other analysed aspect were the efficiency of mechanized harvest introduction by definition of labour costs and the ransom price of grapes in relation with minimum required area. A substantial part of total costs for area 100 ha was formed by direct c osts up to 15.24% greater than the indirect costs. The efficiency of machinery introduction into the harvest process was observed at minimum area of 16.92 ha in case of rental mechanized harvest of grapes. In case of mechanized harvest conducted by previou sly bought trailed grape harvester the value of minimal efficiency was determined at 27.42 ha year - 1 . As a result then serves an effective utilization of mechanized grape harvest in selected company but it is not limited to it and can be applied on any oth er scenario.
The excretion of Ca, Mg, Zn and Cu via excreta of laying hens fed low phosphorus diets and phytase
(2018) Kamberi, M.A.; Muji, S.; Kryeziu, A.; Kastrati, R.; Mestani, N.
An 8 – week experiment was conducted to study the effect of adding phytase (Natuphos ® 5000 BASF) to low and normal available phosph orus diets of laying hens on the excreta content and excretion of Ca, Mg, Zn and Cu. A total of 144 Hisex Brown laying hens that were 22 weeks old at the start of the experiment were randomly assigned to four dietary treatments. Treatments included three r eplicates (12 hens each) or 36 hens per treatment in total. Four corn - soybean meal - based diets were formulated to contain two levels of available phosphorus (AP; 0.12 and 0.46%) and two phytase levels (0 and 600 FTU kg – 1 ). The results showed that there was no significant effect of added phytase on excreta Ca and Mg content ( P > 0.05), but there was a significant effect of the dietary treatment on the content of Zn ( P = 0.0075) and Cu ( P = 0.0002). In terms of the excretion of these mine rals, the dietary treatment had no effect on Ca and Zn excretion and a borderline effect ( P = 0.0522) on Mg excretion measured as the amount of the mineral excreted per egg mass produced is observed. The results however showed a very strong effect of all three factors (available phosphorus, phytase and their interaction) on Cu excretion. The r esults indicate that adding 600 FTU to the corn - soybean meal laying hen diet with 0.12% or 0.46% AP beneficially affects the content and the excretion of Ca, Mg, Zn and Cu. Therefore, we can conclude that a laying hen diet containing 0.12% available phosphorus and 600 FTU during the first production cycle may not only satisfactorily support hens’ perf ormance but will also beneficially affect the environment.
Implementation of practical solutions to improve buffalo breeding development in rural areas of South Iraq
(2018) Rossi, G.; Conti, L.; Al-Fartosi, K.; Barbari, M.
Buffalo breeding is widely spread in rural areas of southern Iraq, especially in marshlands. In the Provinces of Basr ah, Dhi Qar and Maysan the buffalo represents the main source for survival of local people in marshlands. The paper shows the situation in these areas, remarking the main critical points for buffalo breeding development. A survey in 24 buffalo farms was ca rried out by the Department of University of Firenze to verify the situation of buffalo farming in southern Iraq (years 2014 – 2016). In particular the study shows problems related to the shortage of food for animals, to the lack of suitable structures and infrastructures, to the poor herd management by farmers. In the paper the main critical points, which compromise the success of the breeding, are pointed out, with particular reference to animal welfare, animal health and labour (care of animals and risks for workers). Solutions to mitigate the scarce results are indicated. In particular some practical interventions carried out during a project funded by Italian Agency for Cooperation and Development are presented and discussed. Such interventions refer mai nly to the application of feeding racks, systems for a safe capture of the animals, plants and equipment for heat protection. As conclusion, also in difficult and poor areas like Iraqi marshes, a correct design and a right application of simple constructiv e and plant solutions, with little employment of technological resources, coupled with a good training of farmers, can give a contribution to solve problems in buffalo breeding.
Improvement of monitoring of cattle in outdoor enclosure using IQRF technology
(2018) Hartová, V.; Hart, J.
Monitoring of cattle in the outdoor enclosure is a very important issue. Currently, the increasingly stealing cows and other cattle from the pasture. For businesses that manage it, this is a very lossy business. For thieves, the electric fences, which are currently the most widespread, are easily surmountly. And the owner does not have a chance early on to learn the fact theft of catt le. For this reason, a system for monitoring cattle on outdoor enclosure using IQRF (intelligent local network topology ) technology has been developed. We have been dealing with this issue for a long time and the biggest problem was the monitoring of only the inner part of the enclosure. Previously, there was an overlap of monitoring in the area beyond grazing. This problem has been solved by using a shielded base for mounting IQRF receivers.
The indigenous arbuscular mycorrhizal fungal colonisation potential in potato roots is affected by agricultural treatments
(2018) Loit, Kaire; Soonvald, Liina; Kukk, M.; Astover, Alar; Runno-Paurson, Eve; Kaart, Tanel; Öpik, Maarja; Estonian University of Life Sciences. Chair of Plant Health; Estonian University of Life Sciences. Chair of Soil Science; Estonian University of Life Sciences. Chair of Crop Science and Plant Biology; Estonian University of Life Sciences. Chair of Animal Breeding and Biotechnology
There is an urgent need to develop novel approaches to enhance sustainable agriculture while not reducing cr op yields. Arbuscular mycorrhizal (AM) fungi establish symbiotic associations with most crop plants improving plant performance and soil health. This study investigated the extent of colonisation of potato roots by indigenous AM fungi in the arable soil under conventional and organic farming systems. Potato roots had greater AM fungal colonisation levels under organic than conventional farming, though in general, root colonisation levels were extremely low in both farming systems . Pota to root AM fungal colonisation was lower with higher soil P content and higher with higher annual C input. Trap plant root AM fungal colonisation was considerably higher than in field potato roots and showed that soil mycorrhizal inoculum potential was hig her in organic than in conventional farming. Thus, the positive impact of manure application in organic fields to the potato AM fungal colonisation can be explained by previous higher total annual C fresh organic matter input and lower soil P content under treatment. Furthermore, the natural AM fungal abundance in the soil was sufficient to colonise trap plant roots, suggesting a low mycorrhizal dependence of the studied potato cultivar.
The influence of dietary inclusion of peas, faba bean and lupin as a replacement for soybean meal on pig performance and carcass traits
(2018) Degola, L.; Jonkus, D.
The effect of peas, faba bean and lupin seed inclusion in growing and finishing pig diets was evaluated. The control diet included soybean meal at 15%, but in the trial groups diets peas were 15 or 28%, faba bean 20 or 25%, lupin seed 12 or 15%, completely replacing soybean meal. Diets formulated to be isoenergetic for ME and with the same crude protein content. The faba bean and, especially, lupin seed meal inclusion in pig diets for growing per iod significantly reduced ADG P = 0.02 and 0.01 ), and G : F was also signi fi cantly influ enced ( P = 0.02 ) for pigs in lupin seed meal groups. There were no effects on finisher pigs average daily gain, inclusion peas or faba bean, daily gain were, respectively 892 ± 19 and 915 ± 11, 867 ± 12 and 828 ± 11, except lupin seed meal ( P = 0.04 ) inclu sion. There were no significantly effects on carcass quality and to pork chemical content, but pigs fed the diets with peas 28% and faba bean 25% had less of lean meat content, greater backfat thickness and internal fat than other groups which have a simil ar results. The muscle chemical content show that inclusi o n of pulses increased the total fat content in pork. In conclusion, results from this experiment suggest that pigs fed peas and faba bean have equal or slightly lower growth performance and carcass traits than pigs fed soybean meal, except lupin seed meal.
Influence of inoculation and phosphorus regimes on symbiotic nitrogen fixation and phosphorus use efficiency of Algerian cowpea (Vigna unguiculata L. (Walp.)) landraces
(2018) Benlahrech, S.; Kac, G.; Teffahi, M.; Ounane, S.M.
To study the genotypic variation of cowpeas on plant growth and phosphorus (P) uptake which is a function of different P regimes in the soil rhizosphere , 6 landraces of cowpea commonly found in northern Algeria ( NE4, NE10, NE11, NKT5, NKT7, NKB7 ) and 4 landraces from Sahara in southern Algeria (NAG4, NAG5, NAT2 and ND3) were studied during 2013 – 2014 in greenhouse. They were inoculated with Mesorhizobium sp. (S1), Bradyrhizobium sp. (S2) and co – inoculation (S1 – S2) under three P treatments: no P supply (P0), soluble P (PP) and insoluble P (TCP). Only varieties commonly found in northern Algeria nodulated with soluble P (PP) and inoculation containing Mesorhizobium sp . (S1). As a result of the symbiosis, the use of S1 has significantly increased shoot dry weight by 22%, total P content by 20% and P use efficiency for symbiotic nitrogen fixation by 18% compared to no inoculation (T). The landraces from the northern of Algeria expressed a higher growth than those from Sahara in the south of Algeria, especially three of them (NE4, NE10 and NE11) who showed a high performance under all P regimes. We suggest that these three landraces may be useful for improving symbiotic nitrogen fixation in cowpeas when growth is limited by low – P soils and that they could contribute to sustainable farming systems through reduction of farm er’s dependence on fertilizers.
Intensification of rapeseed drying process through the use of infrared emitters
(2018) Bulgakov, V.; Bandura, V.; Arak, Margus; Olt, Jüri; Estonian University of Life Science
The theoretical basis of the agricultural material drying techniques has been formed in the world for two and a half centuries. Nevertheless, despite the multitude of studies well presented in the literature, the i ndustry still lacks universally recognized methods of design calculation for the majority of drying problems. Presumably, this is due to the fact that the dehydration of foodstuffs is one of the most energy - intensive and complicated work processes. In the process of thermal treatment during the drying, the physical state of the water in the treated item changes, the properties of the item itself are altered. Recently, the drying of foodstuffs by means of infrared (IR) radiation has been gaining ever wider a cceptance. At the same time, the technologies for dehydrating foodstuffs and materials are now far ahead of the theory of drying. Not only the classical literature on the drying problems, but even special studies on the subject cannot provide any specific recommendations for the design of installations with the electro - magnetic principle of energy input. Whereas that is exactly the type of installations that are now actively making headway, while offering serious challenges in their modelling. For that reas on, experimenting has until now been the only reliable way of their studying. Despite the available extensive scientific literature on the drying, including works on IR units, the practical issues of engineering IR driers have not been tackled. All the exi sting studies consider solely particular cases. This study discusses the process of drying the fixed bed of rapeseeds with the use of the electromagnetic infrared emitter. The energy intensity of the process and the optimum thickness of the product bed are determined. The aim of the paper is to examine the effect that the operating condition parameter s (energy input intensity, temperature, grain bed thickness) have on the drying kinetics and the energy characteristics of the process. The methods of research are based on the thermophysical analysis of the material’s structure. The experimental studies were carried out with the use of monitoring and measuring equipment, up - to - date methods and instruments, including solutions developed by the authors. The analy tical treatment was performed with the use of the software packages: MathCAD, Excel. The sample testing and examination took place in the laboratory and the methods were in compliance with the applicable standards. A comprehensive experimental investigatio n of the effect that the operating parameter s (specific load and power) have on the rape seed IR - drying kinetics had been accomplished.

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