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Under agro-environmental conditions of Southern Serbia, the research was conducted over a three-year period to evaluate the effect of row spacing on seed yield, yield components and seed quality of alfalfa cv. 'K-23'. The average seed yield of alfalfa was highest at a row spacing of 40 cm (271.7 kg ha-1), followed by row spacing of 20 cm (249.4 kg ha-1) and 60 cm (244.0 kg ha-1). The highest and lowest number of inflorescences per stem were obtained in rows spaced 60 cm (13.37 inflorescences/stem) and 20 cm apart (8.57 inflorescences/stem), respectively. The widest row spacing of 60 cm (7.15 pods / inflorescence) resulted in the highest number of pods per inflorescence, whereas the lowest number was produced at 20 cm spacing (5.50 pods / inflorescence). Grain number per pod ranged from 3.55 (at 20 cm row spacing) to 4.05 (at 60 cm). The highest quality of alfalfa seed during the three years of the research was obtained at the widest row spacing (60 cm). Thousand-seed weight was highest at 60 cm and lowest at 20 cm (1.97 g and 2.07 g, respectively). The highest average values for seed germination rate were reported for 60 cm row spacing (88.00%) and the lowest for 20 cm row spacing (85.76 %).

Mercantile potato harvesting is an operation that requires a quality work of potato diggers, because of the possible damage to tubers caused by the working body that can affect the quality and duration of the storage of tubers. For potatoes harvesting, the best effects are expressed by single-row and double-row diggers with a conveyor belt. This paper presents the results of exploitation tests on various potato diggers used for mercantile potato harvesting in the ecological conditions of northern Kosovo and Metohia. The aim of our study was to determine the quality of the work of potato diggers, the power consumption and surface effect. On the basis of these results, it was concluded that the total loss of potato tubers was between 5.01% (565.7 kg ha-1) and 11.50% (1,291.2 kg ha-1) according to the yields in the studied plots. During the testing the digger generated effects ranged from 0.10 ha h-1 up to 0.28 ha h-1 , with an average fuel consumption of 12.60 l ha-1 up to 19.20 l ha-1 .

Operation quality of an ear-picking device for mercantile maize is defined by the grain losses, quality of harvested mass and by straw chopper cutting height. Contemporary solutions for such machines should enable quality maize harvesting in various conditions, where losses and damage of grains would not exceed tolerable values. This paper gives the results of an exploitation study on operation quality of two ear-picking device types of self-propelled combine harvesters for mercantile maize in agroecological conditions of the Toplica County. The investigation aimed to establish operation quality, operation productivity and fuel consumption. During the first phase, operating conditions were established, whilst in the second phase operating effects were established, as affected by the defined parameters. The first type of ear-picking device for mercantile maize showed better operation quality, comparing than the second one, under similarly defined parameters. Mass harvested by the first device contained over 95.24% undamaged and 8.25 % unshucked ears, with shelling degree of 1.52%. Grain losses varied from 0.52-1.10%. In the second type, there were around 93.17% of whole ears and 9.10% of unshucked ones, with grain losses of 0.73-1.65%. Shelling degree was 2.93%. Driving velocity significantly affected the increase in straw chopper cutting height, so it was 19.2-23.6 cm for the first device type, and 19.7-32.3 cm for the second one. Operation productivity was between 0.96 and 1.23 ha h-1.

This study has been aimed to determine degree of weediness, grain yield and yield components of winter barley, as affected by fertilization system and liming. For that reason, the field trial with three fertilization variants and four barley cultivars was carried out during 2009, in the Center for Agricultural and Technological Research at Zaječar. First fertilization variant included NPK nutrients (120:80:53), in the second one phosphorus amount was doubled, and in the third one were applied 5 t ha' 1 of lime fertilizer "Njival Ca" and 20 t ha' 1 of manure together with mineral fertilizers. The following four winter barley cultivars were involved in the trial: Jagodinac, Record, Premium and Crystal. The trial was set on vertisol soil type, in random complete block design with three replications. This study results show that the highest weediness degree (3.8) was observed at the control variant (without fertilization), while it was lower at the fertilized variants. The highest average grain yield (4340 kg ha'1) was reached at the variant with manure, NPK and lime fertilizers, and the lowest one (3303 kg ha'1) at the first variant. Similarly, the greatest 1000 grain mass and hectoliter mass were also observed at the variant where NPK fertilizer, lime fertilizer and manure were applied. Application of fertilizers with increased amount of phosphorus, as well as lime and manure combination, significantly decreased degree of weediness and increased grain yield of winter barley.

Intensive crop production is based on the use of various means of mechanization. Significant place in applied mechanization take sowing aggregates. Emphasizing the importance of applied sowing aggregates and their technological characteristics and quality of work (appropriate and optimal deployment of seed depth, length and width of the sowing layer) is understandable, especially if one takes into account the fact that an omission made in the technological process of sowing later practically almost can't be removed. The aim of our study was based on field-laboratory and terrain to test the mechanical seeders 634.23 IMT in sowing rye, determination quality and reliability of drill work. Based on these results it was concluded that in terms of proper adjustment of drill and well-executed presowing preparation, planter IMT 634.23 can achieve a good distribution of seeds of rye on the surface, with a spacing of 40-60 mm over 60% of seeds. Transverse distribution of seed rye was satisfactory, given that the highest content of rye seeds were grouped at a distance of 120-140 mm and amounted to over 65%. No marked significant differences in seeding depth intervals in the group which have been investigated. IMT 634.23 seeder can be used successfully for sowing rye and it belongs to a group of reliable seeder with good productivity and reliability that has been shown during operation.

In a field trial with twenty Yugoslav winter wheat cultivars genotypic variations of some utili­zation parameters of nitrogen in a plant have been studied. The aim of this study was to indicate the possibilities of discovering features and processes in different cultivars of wheat based on simpler procedures in order to use it in hybridisation and units selection. The results show that the values of indicators of nitrogen utilization (harvest index of nitrogen, reutilization of nitrogen and physiological efficiency of nitrogen) vary according to the genetic specifity as well as the environ­ment conditions. Thus in the first year of investigation the harvest index of nitrogen varied in the range from 74% at cultivar Nevesinjka to 88% at cultivar Gruza, while in the second year the values ranged from 51% at cultivars Jarebica and Renesansa to 66% at cultivar Takovčanka. .

In the study the results of macro field trial with some ZP and NS corn hybrids have been shown. The field trial was accomplished in 2001 and 2002 year in the area of Toplica. The soil on which the field trial was accomplished was smonitza. The antecedent culture was the winter barley. The insemination was performed at the beginning of May. In the macro field trial 19 ZP and NS corn hybrids of different length of vegetation were included. The results showed that the harvest lacked from 15-26% of plants in relation to the number of showed ones. The content of the damp in the harvest went from 20,7 to 28,8%. The average crop was from 4,73 (NS dunav) to 6,47 t/ha (NS zenit). .

In order to establish distribution of lead in different tissues of bean seed (seed coat, endo­sperm, embryo) depending on seed mass, treated samples (seed) by different concentration of Pb-acetate: 1O-5 M, 10-3M i 2x 10-2M. Depending on seed weight the samples derived in three groups: large (715g), middle (465g) and small (280g). Each sample contained the same number of seeds. Concentration was determined by atomic absorber (Unicam 929). At highest Pb-acetate concentration (2x10-2M) in seed with small total mass content of Pb was 1139μg/g, white in seed of 1052μg/g; in endosperm 580,6μg/g, middle 290,2μg/g and in second group 79,4μg/g. Similar pattern shows embryo but at die lower level of accumulation. On die basis of above presented results it could be concluded that concentration of Pb-acetate solution. Largest mass seed accumulate respectively less content of Pb in endosperm and embryo. Seed coat accumulated significant die larger amount of land probably embryo, in that way protects embryo. Therefore, larger bean seed are more convenient for planting in cases of potentially contamination by 1, but probably by other metals. .

On the basis of the three-year investigation it could be concluded the following: The highest intensity of dry matter increase was between 15 and 30 DABF, and its content increased incisively until 75 DABF. The highest amount of dry matter was accumulated by the earliest genotype (NSSC-375), and the lowest one by the latest genotype (NSSC-640). It was observed an intensive increase of 1000 grain mass till 75 DABF, which was slower after this date. The highest 1000 grain mass was given by NSSC-640 (344.8 g) on 93 DABF. The highest grain yield per ear had the genotype NSSC-420 (159.04 g/ear), and the lowest one had NSSC-375 (127.3 g/ear). Regarding all the three analyzed traits, it could be concluded that NSSC-420 was the best-yielding hybrid, so it can be recommended for the studied area. Growing of longer vegetation hybrids is risky because they are unable to ripen in this area. .

On the basis of the two-year study on the leaf area forming dynamism, the following conclusion can be drawn out: Leaf area increased significantly from 5-6 leaves stage to silking, and the highest value was reached in silking. Leaf area decreased after silking because of lower leaves destroying. In starting development stages, until 8-9 leaves stage, there were not differences in leaf area between the investigated genotypes, but in later stages longer vegetation hybrids had significantly greater leaf area than the earlier ones. This tendency remained till the ripening stage. Differences between sowing terms in leaf area were not apparent until the stage of 11-12 leaves. Later was observed a lower value of leaf area in the second sowing term. The largest leaf area was observed in longer vegetation genotypes in the sowing term, I.E. NSSC-420 and NSSC-640 (53.35 dm2/plant and 58.27 dm2/plant, respectively). .