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2019, Vol. 17, No. 2

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  • Kirje
    RGB vegetation indices applied to grass monitoring: a qualitative analysis
    (2019) Barbosa, B.D.S.; Ferraz, G.A.S.; Gonçalves, L.M.; Marin, D.B.; Maciel, D.T.; Ferraz, P.F.P.; Rossi, G.
    In developing countries such as Brazil, research on low-cost remote sensing and computational techniques become essential for the development of precision agriculture (PA), and improving the quality of the agricultural products. Faced with the scenario of increasing production of emerald grass (Zoysia Japônica) in Brazil, and the value added the quality of this agricultural product. The objective of this work was to evaluate the performance of RGB (IV) vegetation indices in the identification of exposed soil and vegetation. The study was developed in an irrigated area of 58 ha cultivated with emerald grass at Bom Sucesso, Minas Gerais, Brazil. The images were obtained by a RGB digital camera coupled to an remotely piloted aircraft. The flight plan was setup to take overlapping images of 70% and the aircraft speed was 10 m s -1 . Six RGB Vegetation index (MGVRI, GLI, RGBVI, MPRI, VEG, ExG) were evaluated in a mosaic resulting from the images of the study area. All of the VIs evaluated were affected by the variability of lighting conditions in the area but MPRI and MGVRI were the ones that presented the best results in a qualitative evaluation regarding the discrimination of vegetation and soil.
  • Kirje
    An experimental investigation of performance levels in a new root crown cleaner
    (2019) Bulgakov, V.; Pascuzzi, S.; Arak, Margus; Santoro, F.; Anifantis, A.S.; Ihnatiev, Y.; Olt, Jüri; Estonian University of Life Sciences. Institute of Technology
    For the purposes of carrying out field experiments using the vertical-type cleaner with its elastic cleaning blades to remove haulm residues from the crowns of standing roots, the programme for this process and the technique behind it have both been developed by basing the process on the measurement of the volume of haulm residues that are left on the root crowns after they have been cleaned by a cleaning tool that operates at pre-set values in terms of its translational velocity, its height above the soil surface, and its rate of revolution. In addition, the cleaner’s energy-and-force performance has also been determined. In this process, the new laboratory and the field experimental unit have been put together. The unit comprises a rearmounted root crown cleaner of the rotary type with a vertical axis of rotation. During the field experiments, the general-purpose tractor which carries it moves at a pre-set velocity as registered by the track measuring wheel; the general height of the cleaning tool’s position is set within the specified range by the use of two pneumatic feeler wheels that are equipped with adjustment mechanisms. The results of the completed investigations have been statistically processed with the use of the regression analysis and correlation analysis methods. On the basis of the developed multiple-factor experiment technique, empirical mathematical models have been generated in the form of regression equations for the process of cleaning the crown’s of sugar beet roots. In accordance with the results of the calculations, it has been established that the translational velocity of the implement has the greatest level of impact on the volume of haulm residue that remains on the spherical surfaces of root crowns after cleaning. The rate of rotation for the vertical cleaning rotor and its height above the soil surface which are controlled by the two pneumatic feeler wheels have a lesser effect on the process under consideration.
  • Kirje
    Thermal comfort of pigs housed in different installations
    (2019) Cecchin, D.; Ferraz, P.F.P.; Campos, A.T.; Sousa, F.A.; Amaral, P.I.S.; Castro, J.O.; Conti, L.; Cruz, V.M.F.
    In an intensive production system, the environment directly influences the comfort and welfare of pigs. Animals under heat stress may exhibit behavioural changes and changes in physiological parameters, such as increased body temperature, respiratory and cardiac movements. The aim of this study was to evaluate the thermal comfort of growing and finishing pigs housed in facilities with different construction typologies. The evaluated pens were: pen with water depth (WDP) and pen with partially slatted floor (SLF). Data on the ambient thermal environment in the pens and in the outside were collected automatically using Hobo dataloggers, model U12-013. This equipment recorded the air temperature, relative humidity of the air and black globe temperature in intervals of five minutes. Subsequently the variables were used in the calculation of the temperature index of the globe and humidity. The physiological responses of the animals were collected: Surface Temperature (ST) and Respiratory Rate (RF). When analyzing the parameters: ST and RF, it was observed that the WDP pen presented a significant difference in all the observed hours, with an increase observed throughout the day, and the SLF pen presented a difference at 9:00 a.m. presenting a lower value than the other schedules evaluated. The BGHI inside the pens showed average values in the hottest period of the day slightly above what is recommended for adult pigs. Both facilities during the hottest time of the day demonstrated a similar trend in relation to the evaluated variables, so it was concluded that both pens provided the same conditions of thermal comfort for the animals.
  • Kirje
    Formation of photosynthetic and grain yield of spring barley (Hordeum vulgare L.) depend on varietal characteristics and plant growth regulators
    (2019) Panfilova, A.; Korkhova, M.; Gamayunova, V.; Fedorchuk, M.; Drobitko, A.; Nikonchuk, N.; Kovalenko, O.
    The aim of the study was to determine the efficiency of the barley treatment crops with modern retrograde preparations on the background of the mineral fertilizers introduction into the photosynthetic activity of crops and grain yield. The experiments were carried out in 2013 -2017 on the southern black soil in the conditions of the Ukrainian Steppe. On the basis of the study results, it was determined that the introduction of irrigated fertilizer barley in a dose of N30P30 (background) under pre-sowing cultivation and the application of extra-root crop supplements at the phases beginning of the barley outflow straw into the tube and the organoleptic fermentation of Organic D2 and natural microbial complex Escort - Bio creates favorable conditions for the formation at the optimal levels of photosynthetic parameters and grain yield. Thus, on average, over the years of research and by factor variety, grain yield on these experimental variants was 3.37–3.41 t ha-1 , which exceeded its level on uncontrolled control by 0.71–0.75 t ha-1 or 26.7–28.2%. Based on the study results, the use of modern regenerating agents against the background of mineral fertilizers can be recommended as an expedient and effective measure of spring barley raising the productivity.
  • Kirje
    Spatial distribution of thermal variables, acoustics and lighting in compost dairy barn with climate control system
    (2019) Damasceno, F.A.; Oliveira, C.E.A.; Ferraz, G.A.S.; Nascimento, J.A.C.; Barbari, M.; Ferraz, P.F.P.
    The main objective of this research was to evaluate the spatial distribution of the thermal variables, acoustics and lighting in climate controlled compost dairy barn. The experiment was conducted in October 2017, in a farm located in the west of Minas Gerais state, Brazil. For the study, the interior of the animal facility was divided into 120 meshes equidistant points, in which air temperature (tdb), relative humidity (RH), noise, illuminance, and air speed (Vair) were manually collected. The technique of geostatistics was used to evaluate the distribution and spatial dependence of variables. Spatial distribution maps showed the occurrence of high variability of attributes and content within the animal facility. Thermal environment variables showed alert situations throughout practically the entire facility. The noise and luminance levels were within the recommended values.
  • Kirje
    Comparison of lycopene and β-carotene content in tomatoes determined with chemical and non-destructive methods
    (2019) Alsina, I.; Dubova, L.; Duma, M.; Erdberga, I.; Avotiņš, A.; Rakutko, S.
    Tomatoes are one of the most popular vegetables due of their wide use as food. Tomatoes are not only tasty fruit, but one of its benefits - high carotenoids content is well-known. Non-destructive analyses methods are used more and more in different industries. It is cheaper, faster and environmentally friendly way of analyse than traditional chemical methods. But these methods need references to the traditional ones. The aim of this study was to find the correlation between lycopene and β-carotene content in tomatoes determined with reflectance spectrometer and extraction of pigments. Content of two carotenoids (lycopene and β-carotene) was determined in 27 varieties of tomatoes. Red, pink, orange, yellow and brown fruits were included in experiment. Reflectance spectrums of tomatoes fruits were obtained with remote sensing portable spectroradiometer RS-3500 (Ltd.Spectral Evolution). Tetrahydrofuran was used for extraction of pigments. Absorption spectra of extract were obtained by spectrophotometer UV-Vis -1800 (Ltd. Shimadzu). Linear regression analyses were performed to correlate spectral data with lycopene and β-carotene concentrations measured by pigment extraction. The best reflectance region for lycopene spectral detection was 570 ± 5 nm, but for β-carotene 487 ± 5 nm. Reflectance indexes for both pigments were worked out. High linear correlation (R2 > 0.9) between spectral parameters and lycopene concentration was detected. Correlation between results obtained with methods used for β-carotene determination was lower and depended of colour of tomatoes fruits.
  • Kirje
    Assessment of applied microwave power of intermittent microwave-dried carrot powders from Colour and NIRS
    (2019) Keskin, M.; Soysal, Y.; Sekerli, Y.E.; Arslan, A.; Celiktas, N.
    Applied microwave (MW) power level is an essential factor on the quality of the dried agricultural products. Even if higher MW powers result in shorter drying times, they lead to quality degradations. It is almost impossible to know the applied MW power of a dried and powdered product by human vision. Thus, the aim of this study was to predict the applied MW power of carrot powders by using two different instruments, a chromameter and FT-NIRS. The experiments were carried out at nine different power levels (100–500 W) with three replications (N = 27). The colour and NIR reflectance was measured using a chromameter and NIRS system. The data was analysed using PLS regression. The drying time of intermittent MW drying at the highest applied power of 500 W was 1.12–5.47 times shorter than those of other lower applied powers. Applied MW power was a crucial factor on all colour parameters of the powdered carrots. Brightness (L*) decreased significantly with the increase of applied MW power resulting in darker product colours. Data analysis results showed that the NIRS system (R2 = 0.99; SEP = 16.1 W) can predict the microwave power of powdered carrots with significantly better performance than a chromameter (R2 = 0.95; SEP = 29.9 W). But, the chromamater is far more inexpensive when compared with the NIRS system and hence, it can also be used to predict the applied MW power from the colour data relatively well. Also, a mathematical model was developed to predict applied MW power from the colour parameters.
  • Kirje
    Principal components in the study of soil and plant properties in precision coffee farming
    (2019) Ferraz, G.A.S.; Ferraz, P.F.P.; Martins, F.B.; Silva, F.M.; Damasceno, F.A.; Barbari, M.
    In this work, a principal component analysis was performed to evaluate the possibility of discarding obsolete soil and plant variables in a coffee field to eliminate redundant and difficult-to-measure information in precision coffee farming. This work was conducted at Brejão Farm in Três Pontas, Minas Gerais, Brazil, in a coffee field planted with 22 ha of Topázio cultivar. The evaluated variables were the yield, plant height, crown diameter, fruit maturation index, degree of fruit maturation, leafing, soil pH, available phosphorus (P), remaining phosphorus (Prem), available potassium (K), exchangeable calcium (Ca2+), exchangeable magnesium (Mg2+), exchangeable acidity (Al3+), potential acidity (H + Al), aluminium saturation (N(Al)), potential CEC (CECp), actual CEC (CECa), sum of bases (SB), base saturation (BS) and organic matter (OM). The data were evaluated by a principal component analysis, which generated 20 components. Of these, 7 representing 88.98% of the data variation were chosen. The variables were discarded based on the preservation of the variables with the greatest coefficients in absolute values corresponding to the first component, followed by the variable with the second highest absolute value corresponding to the second principal component. Based on the results, the variables V, OM, fruit maturity index, plant height, yield, leafing and P were selected. The other variables were discarded.
  • Kirje
    Model for ammonia emissions’ assessment and comparison of various dairy cattle farming systems and technologies
    (2019) Aboltins, A.; Melece, L.; Priekulis, J.
    A dairy cattle farming is an important source of ammonia emissions, particularly in Latvia. Models using a wide range in level of detail have been developed to represent or predict these emissions. Besides, models are useful for improving the understanding of various farm processes and their interacting effects on ammonia emissions. The model for ammonia emissions’ assessing or representing, predicting and comparing for manure management chain of dairy cattle was created. The model provides a tool for evaluating mitigation and management strategies, abatement measures and techniques to reduce of ammonia emissions and improve the sustainability of dairy production systems both on the dairy farm and at the national level. It could be used as a supplement tool for officials and experts. The model estimates those ammonia abatement measures and techniques that have the highest emission reduction potential and opportunities for implementation on Latvia’s dairy farms. The simulation model assesses the ammonia emissions into each stage of the farming: animal housing, manure management - manure handling and storage, and manure application. An important stage in reducing ammonia emissions is manure storage. It should be noted that the main task of the model was to compare the impact of the ammonia emission reduction options. When entering the number of animals, the average nitrogen quantity per animal, the percentage distribution of manure quantities, the first three levels of the program can be used to estimate the amount of nitrogen to be incorporated into the soil and, as the difference; and the amount of ammonia emissions.
  • Kirje
    Spatial variability of litter temperature, relative air humidity and skin temperature of chicks in a commercial broiler house
    (2019) Ferraz, P.F.P.; Ferraz, G.A.S.; Schiassi, L.; Nogueira, V.H.B.; Barbari, M.; Damasceno, F.A.
    The thermal environment inside a broiler house has a great influence on animal welfare and productivity during the production phase. Among the importance of the chicken litter is the function of absorbing moisture, provide thermal insulation and provide a soft surface for broilers. The skin temperature is an important physiological parameter to quantify the thermal comfort of animals, its variations may occur as a function of thermal variables. So, the aim of this work was to analyse the magnitude and spatial variability of chicken litter temperature and relative humidity of the air and to correlate them with the spatial distribution of chicks’ skin surface temperature throughout the broiler house during the 7th, 14th and 21st days of the chicks’ life, using geostatistical techniques. The experiment was performed in a commercial broiler house located in the western mesoregion of Minas Gerais, Brazil, where 28,000 male Cobb chicks were housed. The heating system consisted of an industrial indirect-fired biomass furnace. The heated air was inflated by an AC motor, 2,206 W of power, 1,725 RPM. Geostatistical techniques were used through semivariogram analysis and isochore maps were generated through data interpolation by kriging. The semivariogram was fitted by the restricted maximum likelihood method. The used mathematical model was the spherical one. After fitting the semivariograms, the data were interpolated by ordinary kriging. The semivariograms along with the isochore maps allowed identifying the non-uniformity of spatial distribution of the broiler litter temperature throughout the broiler house for 3 days of chicks’ life. It was observed that skin surface presented a positive correlation with the litter temperature and a negative correlation with the air humidity. The semivariograms along with the isochore maps allowed identifying the non-uniformity of spatial distribution of the litter temperature, air humidity and skin temperature of chicks throughout the broiler aviary for the three days. In addition, the use of geostatistics and distribution maps made possible to identify different environmental conditions in regions inside the broiler house that may harm the development of chicks.
  • Kirje
    Variety, seeding rate and disease control affect faba bean yield components
    (2019) Plūduma-Pauniņa, I.; Gaile, Z.; Bankina, B.; Balodis, R.
    Faba beans (Vicia faba L.) have been grown since 8000 years B.C. in the Middle East. Despite their long growing history in the world, there are only few researches carried out in Baltic region in last decades about variety, seeding rate and disease control effect on faba beans’ growth, development and yield formation. Research was carried out at the Latvia University of Life Sciences and Technologies during 2015–2017. Three factors were researched: A – variety (‘Laura’, ‘Boxer’, ‘Isabell’), B – seeding rate (30, 40 and 50 germinate able seeds m-2 ), C – treatment with fungicide (with and without application of fungicide Signum (1 kg ha-1 )). Meteorological conditions were diverse and sometimes caused stress for crop, but in general they favoured faba beans’ growth and development. High average yield of the field beans was obtained during all three trial years, however, yield differed significantly among them. Sowing time was constantly quite early, germination took longer time as expected due to the low air temperature, but later, temperature and humidity level improved and conditions were suitable for plant growth and development with some exceptions during flowering and pod filling. Number of productive stems per 1 m2 was significantly affected only by seeding rate. Plant height in trial site was affected by variety (p < 0.001), fungicide application (p = 0.008) and meteorological conditions (p < 0.001) of the year. Number of pods per plant differed depending on trial year (p < 0.001). Number of seeds per plant had a close positive correlation with number of pods per plant. Whereas number of seeds per pod was a relatively stable and typical characteristic for variety. We can observe correlation between faba bean yield and number of productive stems per 1 m2 at harvest, plant height, number of pods and seeds per plant.
  • Kirje
    Effect of two housing systems on performance and longevity of dairy cows in Northern Italy
    (2019) Leso, L.; Pellegrini, P.; Barbari, M.
    The objective of the current study was to evaluate and compare performance of dairy cows housed in compost-bedded pack barns (CBP) and free stall barns, with a focus on longevityrelated parameters. Study included 30 commercial dairy farms located in the Po Valley, Italy. Twenty farms had free stall barns, among which 10 used rubber mattresses (FSM) and 10 used deep straw bedding (FSS). The remaining 10 farms had CBP. Monthly dairy herd records were obtained from the Italian DHI association for each farm included in the study over a period of one year. All farms were visited to measure characteristics and dimensions of housing facilities. Linear mixed models were used to evaluate the association between housing system and the outcome variables. In CBP total available area was larger than both in FSM and FSS. However, space per cow over the bedded pack area in CBP (6.8 ± 2.4 m2 cow-1 ) was relatively low for this housing system. Milk production was similar among housing systems but somatic cell count and mastitis infection prevalence resulted to be higher in CBP than in FSM and FSS. Calving interval was lower in FSS compared with both FSM and CBP while no differences were found in number of services per pregnancy. Cows housed in CBP were older and had higher parities than those in FSM and FSS while no significant differences in herd turnover rate were detected among housing systems. Results confirm that CBP housing system may improve longevity of dairy cows, which is reported to be one of the most important motivations for building this kind of housing. Nevertheless, CBP housing can pose some challenges in achieving adequate udder health and high milk quality, especially with low space per cow.
  • Kirje
    Effect of environmental temperature during the of brooding period on growing period of pullets viscera and tibia
    (2019) Cândido, M.G.L.; Tinôco, I.F.F.; Barbari, M.; Freitas, L.C.S.R.; Dos Santos, T.C.; Andrade, R.R.; Gates, R.S.; Conti, L.; Rossi, G.
    Poultry production in subtropical and tropical regions faces many problems, one of which is the high air temperature causing thermal stress, particularly dangerous in high-producing birds. Thus, the negative effects caused by heat stress (HS) must be managed. The objective of this study was to evaluate the effects of four different levels of HS in viscera and tibia of pullets. A total of 648 chicks (Lohmann LSL Lite) were used in this study in two different phases. The pre-experimental phase (PEP) was from day 1 through 6 weeks of age. The birds were reared with three different environmental temperatures: thermal comfort, hot and cold. The experimental phase (EP) was conducted from the 7th to the 17th week. Pullets from each thermal environment of the PEP were submitted to: 20 °C, 25 °C, 30 °C, 35 °C. At the end of the 17th week of age 120 pullets were euthanatized and the organs, heart, liver, spleen and gizzard were weighed, as also their tibias. Effects of PEP, and its interaction with EP, were not significant (P < 0.05) for viscera and tibia weight. However, a significant increase (P < 0.05) in heart weight with the decrease of the environmental temperature was observed, being the pullets subject to 20ºC and 25 °C with the heaviest weights. For the liver, pullets subject to the 35 °C had the lowest weight and were different (P < 0.05) from the other three treatments. For gizzard, the difference (P < 0.05) was between the treatments 20ºC and 35 °C. These results indicate that brooding temperatures tested during the first 6 weeks of life did not affect the viscera and bone weight during the growing phase.
  • Kirje
    Special tractor driving wheels with two modification of spikes inclination angle
    (2019) Abrahám, R.; Majdan, R.; Drlička, R.
    The paper presents a research on an improvement of tractor drawbar properties using special driving wheels. Two modifications of the special driving wheels were designed and tested under field conditions. The results were compared with standard tyres. The special driving wheels consists of the tyres with a modified tyre-tread pattern and equips with the spike segments. The special driving wheels allow to activate or deactivate the spike segments to improve a drawbar pull at worse adhesive conditions of the ground or transport on roads with standard tyres. The first modification activates all 8 spike segments at spike inclination angle 90° and the second one 4 at angle 90°and 4 at 30°. The measurements were realised in October 2017 in an area of the Slovak Agricultural Museum in Nitra. The drawbar properties of the special driving wheels were evaluated based on drawbar pull of the test tractor Mini 070 type connected with a load tractor MT8-065 type. Using the test tractor in 1st and 2nd gear, the measurements were realized at 100% wheels slip and repeated 4 times. The results show the statistically significant differences in the drawbar pull of the test tractor with different driving wheels on a grass plot. The highest increase in drawbar pull reached the value 25.56% (2nd gear) and 19.98% (1st gear) in case of the special driving wheels with 4 spike segments at 90° and 4 at 30°. In case of the special driving wheels with 8 spike segments at 90°, increase in the drawbar pull reached the value 10.09% (1st gear) and 15.21% (2nd gear) in comparation with the standard tyres.
  • Kirje
    Assessment of production zones modelling accuracy based on satellite imaging and yield measurement of selected agriculture plot
    (2019) Jelínek, Z.; Starý, K.; Kumhálová, J.
    Currently, remote sensing or yield monitor equipment offer possibilities how to estimate productivity of the agriculture field. That is why the main aim of this study is to assess how the latest satellite images from vegetation season and final yield data from combine harvester can be used to predict yield and to assess site-specific zones productivity. The study is focused on the accuracy of these systems for the field productivity estimation. The 24.7 ha experimental field is located near to Vendoli village (the Czech Republic) and it is cultivated by conventional agricultural practices with emphasis on typical agricultural crops growing in the Czech Republic (winter wheat, spring barley and winter rape). The results showed that both methods of estimation can be used for yield prediction. Nevertheless, each of them need specific processing and has typical limitations.
  • Kirje
    Measurements of wireless detectors used to monitor animal movements in livestock farms
    (2019) Hart, J.; Hartová, V.
    At present, there is a great interest in monitoring and automating farm animals and livestock farming. There are many systems and methods to check the movement of animals in certain areas. One option is to use motion detectors. However, some installations are so specific that they require the use of wireless motion detectors. They not only have to fulfill their functional part but also have a sufficiently strong signal that should not interfere outside the defined ISM bands. Due to the frequent deployment of different types of these detectors, research has been carried out to monitor shortcomings in frequently used types of wireless detectors. This research defines which tested detectors are fully usable according to the standards and which need to be modified by the manufacturer. Also, based on measurements, the basic risks and recommendations for the use of individual types of tested detectors are defined.
  • Kirje
    Methodology of the stress detemination in the tool module during the work of the agriculture machine
    (2019) Kešner, A.; Chotěborský, R.; Linda, M.; Hromasová, M.
    Machine construction is designed using by mathematical models. The frame is a fundamental part of an agricultural soil cultivation machine so that forces were transfered during transport and machine work to frame. The stress in the machine frame is important to know for the best frame design of the machine. The mathematical model included measued strain can able to design or detect deficiencies on the machine frame. Due to the transfer of forces from the tools, stress is created in the machine frame. High requirements are placed on the determination of boundary conditions for mathematical models in agricultural machinery. Various types, sizes and equipment of agricultural tools significantly affect the transfer of draught force to the machine. The direction and magnitude of the forces, that are caused by agricultural tools, it is important to find out. Ansys mechanical solver have been used to determination strain like response of frame from chisel module. The results can be used as a boundary condition for mathematical models.
  • Kirje
    Modeling the functional role of the microorganisms in the daily exchanges of carbon and nitrogen in intercropping system under Mediterranean conditions
    (2019) Latati, M.; Rebouh, N.Y.; Aouiche, A.; Laouar, M.
    Carbon (C) and nitrogen (N) sequestration in plants and soil micro-organisms is considered as a major phenomenon against global warming. The modeling of this phenomenon aims at highlighting the role that the legumes-cereals mixed crop can play in the reduction of greenhouse gases. It is based on field experiments in maize (Zea mays L.)-common bean (Phaseolus vulgaris L.) intercropped system of the cereal agroecosystem in Setif region of Algeria. For this purpose, the MOMOS model was selected and validated in a calcareous soil and low phosphorus (P) conditions. It revealed some mechanisms that control the C and N sequestration in the compartments of the complex soil-plant-atmosphere-microorganism system. CN modeling results show that the daily growth of intercropped maize with common beans is positively correlated with the microbial CN transformation during the cropping cycle, under limited P and N conditions. Thus, this approach revealed the functional role of rhizobial symbiosis in maintaining the balance between the different C and N exchanges from soil to atmosphere and from atmosphere to soil.
  • Kirje
    The effect of Minituber Weight on their Field Performance under a Northern European environment
    (2019) Dimante, I.; Mežaka, I.; Gaile, Z.
    Weight of potato minitubers as well cultivar affects field performance of minitubers. The aim of this study was to compare minitubers of four weight classes (MtC) (3 to 4.99 g, 5 to 9.99 g, 10 to 19.99 g, and > 20 g) with respect to their field performance. Three year experiments were conducted at AREI, Latvia (57°19′ N, 25°20′ E) between 2014 and 2016. Cultivars ‘Monta’, ‘Prelma’ and ‘Mandaga’ were used. A significant relationship between the number of stems and the number of progeny tubers per plant was detected and the number of stems explained 74% of variation in progeny tuber number. Multiplication rate, expressed as the number of progeny tubers > 25 mm per planted minituber, was in range from 4.2 to 13.1 tubers and was significantly affected by the cultivar and MtC. Cultivar and MtC had significant effect on the number of tubers and tuber yield per m2 . The number of progeny tubers and yield increased with increases for MtC. The highest number of progeny tubers (size > 25 mm) per m2 were obtained from minitubers > 20 g of ‘Prelma’ (93.4), but the highest yield was from minitubers > 20 g of ‘Mandaga’ (4.92 kg m-2 ). The effect of MtC was more pronounced on number of tubers than on tuber yield. Cultivar and MtC determined mean size (diameter (μ)) of progeny tubers. Mean size increased as MtC decreased. MtC had a significant effect on standard deviation (σ) only for ‘Prelma’. When σ was recalculated to coefficient of variation (CV), no significant effect of MtC remained.
  • Kirje
    Evaluating the effects of application modes and soil types on the herbicide efficacy and crop yield of pendimethalin and clomazone on transplanted pepper (Capsicum annuum L.)
    (2019) Glatkova, G.; Pacanoski, Z.
    Field experiment was carried out in 2014 and 2015 in two locations Kochani and Drachevo in Republic of Macedonia to evaluate the efficacy and crop safety of pendimethalin and clomazone on transplanted pepper according to mode of application, (pretransplant -PRE-T and pretransplant incorporated -PTI) and soil types (alluvial soil and vertisol). The weed population in both years and locations mainly consisted annual spring and summer grasses and broadleaf weeds. Weed competition significantly reduced pepper yield. There was no recorded difference between the efficacy of pendimethalin PRE-T and pendimethalin PTI. However, the efficacy of clomazone PTI was higher than that of clomazone PRE-T in both experimental years and locations, indicating incorporation into soil if critical for clamazone. Both pendimethalin and clomazone had low efficacy on Solanum nigrum L. Pepper plants were not visibly injured by any herbicides treatments. In summary, locations and soil types did not affect herbicide efficacy and pepper selectivity. Pepper yield was markedly affected by herbicide efficacy in both years and locations.