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A pot experiment using root separation technique was conducted to further understand the effect of root interaction played in intercropping system under different nitrogen levels. The results showed that root interaction and increasing nitrogen application increased the green leaf area per plant and chlorophyll content of soybean, but their effects gradually decreased with increasing nitrogen fertilization level. Root interaction and increasing nitrogen application can improve photosynthetic characteristics of soybean, but root interaction only had a significant effect under low nitrogen level. The number of bacteria, fungi, actinomycetes and Azotobacteria was also obviously affected by root interaction and nitrogen fertilization, and the number of Azotobacteria presented a changing trend of first increased and then decreased with increasing nitrogen fertilization level. Root interaction and increasing nitrogen application improved soybean yield and its components, but their effects gradually decreased with increasing nitrogen fertilization level. The root activity of soybean was obviously affected by root interaction, and was significantly positively correlated with green leaf area per plant, chlorophyll content, photosynthetic rate and economic yield per plant. Our results indicate that the advantage effect of root interaction and increasing nitrogen application will be partially inhibited with an increasing nitrogen fertilization level.

Long-term field experiments are important for assessing the yield response of crops to different tillage systems and pre-crops. An experiment was established in 1996 in Raasdorf (Austria) on a chernozem with four tillage treatments (mouldboard ploughing (MP), no-till (NT), deep conservation tillage and shallow conservation tillage) and two crop rotations. Winter wheat yields were generally at similar levels with all four tillage systems in most years between 1998 and 2012. Yields increased with higher amounts of rainfall during the vegetation period (from October until June) with the smallest increase among tillage treatments in NT. This indicates that MP can be superior to NT regarding yield at higher amounts of rainfall. Pre-crops considerably influenced winter wheat with higher yields after maize, soybean and winter wheat than after sugar beet. In one year with high rainfall, a tillage × pre-crop interaction showed that yields were lower after maize in NT than in other tillage systems whereas yields after sugar beet tended to be higher with NT in years with low rainfall.

The complex interaction process of the abiotic factors (sunlight, air temperature and soil water) in regulating maize (Zea mays L.) photosynthesis has not been fully understood. Our field experiment explored the changed sensitivity (or role) of the abiotic factors in regulating maize photosynthesis under a drought development process. The experiment established a scenario with a long-term drought and an instantaneous cloud cover. The results revealed that long-term drought stress causes the sensitivity (or role) of sunlight and temperature exchanged in regulating maize photosynthesis. The maize photosynthesis was more sensitive to instantaneous sunlight rather than temperature in the absence of drought. However, a diminishing photosynthetic sensitivity to sunlight but an increasing photosynthetic sensitivity to temperature was observed with drought development process. The variable photosynthetic sensitivity indicated that the roles of temperature and sunlight in regulating maize photosynthesis were exchanged, so it is expected that higher photosynthetic rate could be achieved by adjusting temperature rather than sunlight after severe drought. Nevertheless, further studies are needed to provide more evidence and mechanism explanations.

Cereal/legume intercropping may improve resource use efficiency in agroecosystems and increase yield per unit surface area and yield stability. Two field bean (Vicia faba L.) and four barley (Hordeum vulgare L.) cultivars were mono- and intercropped (additive design) in a 2-year lysimeter experiment on a sandy loam soil. The aim was to test the effect of the cropping system on dry matter and N yield of forage, the residual effect on the subsequent ryegrass crop (Lolium multiflorum Lam. westerwoldicum), and NO₃-N leaching in the rotation. Land equivalent ratios were 1.65 for dry matter and 1.67 for N yield, indicating a clear advantage of the intercrop over sole crops. Both species suffered from competition, especially in terms of N resources, but barley was less affected. Nitrate leaching was the lowest from intercrop. Preceding crop significantly affected dry matter, N content and NO₃-N leaching of ryegrass. Field bean sole crop gave the highest benefits to ryegrass in terms of forage dry matter and N content, but also the highest NO₃-N leaching, followed by the intercrop and the barley sole crop. Barley/field bean intercropping may be an effective strategy to reduce land requirements, N leaching losses and fertilizer inputs, thereby increasing the sustainability of farming systems.

The research aimed at the assessment of the influence of mineral nitrogen (CaNPK) fertilization and lupine cropping on the N₂O emissions from agricultural soil. Observations were collected from CaNPK and Ca fertilization systems (further referred to as NIL due to the absence of nitrogen (N) fertilizers) in two consecutive years (2012 and 2013) on a long-term (since 1923) field experiment in Skierniewice in Central Poland. N₂O emissions from the soil were measured in situ by the means of infrared spectroscopy using a portable FTIR spectrometer Alpha (Bruker). N₂O fluxes from soils treated under CaNPK and NIL treatments were similar. No significant influence of the current treatment or cropping on the N₂O emissions was noted in the CaNPK treated soil. N₂O emissions in 2012 (barley, ammonium nitrate application) and 2013 (lupine, no mineral nitrogen application) were similar (0.17-23.04 g N₂O-N/ha/day, median 4.29 and 0.09-19.46 g N₂O-N/ha/day, median 4.45, respectively). During the growing period of 2012 (barley, ammonium nitrate application), the N₂O-N emissions from the CaNPK treated soil (uncorrected for NIL) represented 1.02% of the applied N dose. In the growing period of 2013 (lupine, no mineral nitrogen application), the yield-scaled N₂O-N emissions from CaNPK and NIL treatments equaled respectively to 4.4 g and 5.4 g N₂O-N per 1 kg of nitrogen accumulated by lupine.

A three-year field experiment was conducted from 2000 to 2002 in North-East Poland. Each year three sulphur fertilization rates in the form of sulphate (S-SO^2-₄) and pure (S-S⁰) sulphur were applied: 40, 80 and 120 kg/ha. In the soil horizon at the depth of 0-40 cm the triple rate of S- and S-S⁰) depressed soil reaction. Acidification of soil caused by S-SO^2-₄ became evident already in the first year of the study while that resulting from S-S⁰) application appeared as late as in the third year. The effect of sulphur on soil in the 40-80 cm horizon was irregular. As the sulphur rates increased and the duration of the experiment progressed, sulphates accumulated in soil. In the 0-40 cm soil layer, the increasing rates of sulphur tended to increase the content of N-NH⁺₄. In most objects, the NPK + S fertilization, and especially the single S-SO^2-₄ treatment, caused an increase in N-NO^-₃ in both soil layers compared with the NPK fertilized object. The dose of 120 kg/ha S-SO^2-₄ caused a significant increase in the concentration of available phosphorus in soil in the 0-40 and 40-80 cm layers.

In 2004-2009, a small-plot trial was conducted on permanent grassland dominated by Festuca arundinacea Schreb. on the mesohygrophytic site in order to evaluate effects of four levels of nutrition: F₁ = without NPK fertilization, F₂ = P₃₀ + K₆₀, F₃ = N90 + P₃₀ + K₆₀, F₄ = N₁₈₀ + P₃₀ + K₆₀ kg/ha), four levels of cutting intensity (I₁-4, I₂-3, I₃-2, early, I₄-2, late cut) and their interactive influence, i.e. a total of 16 variants on the production of forage dry matter, production of crude protein (CD) and net energy of lactation (NEL) per hectare. The dominant influence of N-nutrition is documented by significant differences in forage dry matter (DM) production between the variants (with the exception of F₁/F₂) ranging from 4.41-4.80 to 8.44-9.83 t/ha. The effect of different exploitation level on the production is subdominant and no significant differences were found either in the production of forage DM(I₁-6.41 - I₂-6.59 - I₃-6.97 - I₄-7.50 t/ha) or in the production of nutrients. Management models to be recommended for the given type of sward with respect to the interactive influence, efficacy of forage production and quality are as follows: (a) three cuts/180 kg N + PK/ha with forage suitable for dairy cows; (b) two cuts/90 kg N + PK/ha with forage suitable for cattle breeds kept for meat.

A study was conducted to investigate the influence of sodicity induced changes in soil physical properties on paddy root growth in the normal agriculture, semi-reclaimed and sodic soils. The root growth (length, length density, biomass and distribution pattern) were unfavourably affected by the soil physical properties (bulk density, soil aggregate stability, available water content, hydraulic conductivity and soil water retention potential) in the case of sodic soil. The microbial biomass carbon, bacterial, fungal population and dehydrogenase activity showed the lower values in the case of sodosol compared to the normal soil. These soil biological properties tend to sustain paddy root growth in normal and semi-reclaimed soils. Principal component analysis revealed that soil physical properties accounted for 98.2% of total variance in root growth. The study revealed that salt stress induces changes in soil physical properties limiting paddy root growth in the salt affected soils. It is important to reclaim sodosols to alleviate salt induced physical stress for optimum paddy root growth.

In the long-term field trial on an arable dystric Stagnosols, winter wheat (Triticum aestivum L.) grain yield, nitrogen use efficiency (NUE) and nitrate nitrogen (NO₃^--N) in lysimeter water were compared under treatments of 0, 100, 150, 200, 250 and 300 kg/ha of mineral nitrogen (N) during the growth years 1996/97, 1999/00, 2002/03 and 2005/06. Year properties significantly influenced N availability resulting in different responses of grain yield and NUE under variable treatments. Grain yield showed strong significant correlation with the rainfall accumulated from March to May (r = 0.77). In the case of a dry year 2003, winter wheat yield and NUE were adversely influenced by unfavourable climatic conditions. The optimal response of yield and NUE to increasing mineral N rates was found at the amount of 150-200 kg N/ha. Very strong significant correlation between the total amount of leached NO₃^--N and NUE was found for periods 1999/00 and 2005/06 where, in terms of increasing N levels, lower NUE conditioned higher NO₃^--N leaching (r = 0.91 and r = 0.94, respectively). According to the shallow depth of groundwater and installation of drainage systems, there is still a risk of freshwater contamination by nitrates if the N rates higher than 200 kg/ha were applied.

The study presents the impact of management practices on greenhouse gas emissions (GHG) and nitrogen (N) losses calculated with a denitrification-decomposition model. Two cropping systems were analysed. The first rotation (A) consisted of potato, winter wheat, spring barley and corn. The second (B) included potato, winter wheat, spring barley and clover with grasses mixture. In A1 and B1 scenarios, fluxes were estimated on the basis of mineral fertilizers input, whereas in A2 and B2 scenarios the assessment of emissions was made with regards to manure. The results indicated that the application of manure in A rotation led to the increase of nitrous oxide (N₂O) emission, N leaching, N surplus, crop yields, and the decrease of nitrogen use efficiency higher than in B rotation. Additional doses of manure in A2 scenario increased the potential of the accumulation of soil organic carbon (SOC) and global warming potential (GWP) by 157%. In B2 scenario, SOC augmented more than three-fold but GWP increased only by 10%. The N losses and GHG emissions could be minimised by controlling N application through the implementation of nutrient management plan in which N doses are defined based on the crop needs and soil quality.

It is postulated that stabilized ammonium fertilizers improve fertilizer-N utilization by crops, leading thus to higher yields with the same fertilizer rate, especially on sandy soils. However, it must be taken into consideration that in clayey soil at least a part of the NH₄⁺ ions may be fixed by 2:1 clay minerals, thus delaying the effect of the N fertilizer. Because NH₄⁺ and K⁺ have similar size and valence properties and therefore compete for the same non-exchangeable sites of 2:1 clay minerals, we investigated the influence of time and K⁺ application rate on both fixation and release of NH₄⁺. Fixation of NH₄⁺ ions was higher when K⁺ was applied after NH₄⁺, while the influence of the K⁺ application rate was less pronounced. Mobilization of non-exchangeable NH₄⁺ was retarded when K⁺ was applied at the high rate after NH₄⁺. At the first harvest yield formation of ryegrass was neither influenced by the amount as well as the application time of K⁺, because plant available N was not growth limiting, while yield of the second harvest was significantly higher with the low K⁺ application rate after NH₄⁺. After the second harvest the blocking effect of K⁺ on the release of non-exchangeable NH₄⁺ was attenuated and the highest yields of the third cut were reached in the treatments with the high K⁺ application rate after NH₄⁺. Total dry matter yield was highest when K⁺ was applied at the low rate after NH₄⁺. Our results show that K⁺ governs fixation and release of non-exchangeable NH₄⁺, which should be taken into consideration when applying ammonium containing N fertilizers like ammonium sulfate, ammonium sulfate nitrate and ENTEC. Thus K⁺ can affect N availability when N is applied as NH₄⁺ in both the short and long term.

The contents of nitrogen (N), potassium, phosphorus, calcium, magnesium and sodium were estimated in tubers of Jerusalem artichoke Helianthus tuberosus coming from the field experiment conducted over 2010-2012. The experimental factors were the cultivars of Jerusalem artichoke cvs. Albik and Rubik and different nitrogen fertilization levels, against phosphorus and potassium fertilization and the full dose of manure. Determination of elements in the soil and the dry weight of the aerial parts are performed by standard methods. When using a fixed level of phosphorous-potassium fertilizer, the highest sodium content was obtained at a level of 50 kg N/ha, magnesium and sulphur at a dose of 100 kg of N, nitrogen - 150 kg N/ha, potassium and calcium - in the objects of fertilizer phosphorus-potassium, and phosphorus - in the building control without fertilization. Cv. Albik proved to be more abundant in mineral elements than cv. Rubik. The latter was characterized by a higher stability of characteristics.

The study was based on soil samples taken after the long-term fertilizer experiment (1974-2014) where different doses of nitrogen and potassium were applied. The experiment was located at the Research Station of the UTP University of Science and Technology in Bydgoszcz (Poland). The long-term application of nitrogen and potassium fertilizers leads to changes in the concentration of mercury, soil acidification, reduction in total organic carbon, total nitrogen as well as affluence of available nutrients (P, K, Mg) and increased mobility of copper and zinc. The significant positive correlation between total mercury content in the soil and the content of N-NO₃, Zn, N-NH₄ and the hydrolytic acidity value were stated.

A three-year field experiment was conducted from 2000 to 2002 in North-East Poland. Each year three sulphur fertilization rates in the form of sulphate (S- SO₄^2-) and pure sulphur (S-S⁰) were applied: 40, 80 and 120 kg/ha. The most beneficial effect on the yields of cabbage, onion and barley was produced by the rates of 40 and 80 kg S/ha, while the dose of 120 kg S/ha (especially when applied as S-SO₄^2-) reduced the yields of these crops. Increasing rates of sulphur used as a fertilizer caused increased concentration of sulphates in plants up to their luxury accumulation. Irrespective of the test crop species or form of sulphur applied, once the crops terminated their vegetative season, the plants fertilized with sulphur typically contained more total N than those fertilized only with NPK. The S-SO₄^2- fertilization tended to raise the accumulation of N-NO₃^- in the crops, especially during the juvenile phase. The application of 120 kg S-SO₄^2-) /kg caused depressed amounts of potassium in cabbage, onion and in barley during the heading phase.

Based on a long-term fertilization experiment on a light soil, a study was conducted on the impact of varied fertilization on the levels of silicon forms available in the soil. It was shown that the exchangeable silicon content in the tested soil was very low, which can have a limiting effect on crop yields. Soil pH is a factor that significantly affects the exchangeable silicon content of the soil. Therefore, under the conditions of acidic soils, liming is a treatment that increases the level of silicon forms available to plants in the soil.

In the present study, the effects of fungicide Aliette WG 800 [80% fosetyl-Al (aluminium tris-o-ethyl phosphonate)], widely used against Phytophtora infestans on tomatoes grown in greenhouse in Turkey, were studied on the morphology and viability of tomato (Lycopersicon esculentum Mill.) pollens. The fungicide was applied to tomatoes grown in greenhouse at recommended dosage (200 g/100 l water) and at double the recommended dosage (400 g/100 l water). The fungicide caused changes in the morphological structures of tomato pollens. Some pollen morphological structures that are not observed in the control group were encountered in the pollens in equatorial view and in polar view at 200 g/100 l treated groups. On the other hand, pollen viability level decreased as the dosage increased. Especially, non-viable pollen types such as wrinkled pollen or pollen with abnormal shape were encountered in the fungicide groups. It was expected that the pollen fertility as well as yield would decrease in future.

This study investigated the combined effects of drip irrigation and mulches on yield, water-use efficiency and economic return of tomato. The treatments of the study comprised different combinations of three drip irrigation levels (100, 75 and 50% of crop water requirement, ETc) and two mulches (black polyethylene sheet and paddy straw). The yield and yield-contributing characters in the mulched treatments for all levels of irrigation were significantly higher compared to those in the unmulched treatments. The yield of tomato increased with the increasing amount of irrigation water in unmulched treatment. The trend was reversed when drip irrigation was coupled with mulches. The highest yield for each mulch (81.12 t/ha for polyethylene and 79.49 t/ha for straw) was obtained when 50% of water requirement was applied. With 100% water application, polyethylene-mulched treatment produced lower yield than the straw-mulched treatment. The highest water use efficiency of 592 kg/ha/mm was obtained with 50% water application under polyethylene mulch. The highest net return (US$ 7098/ha), incremental net return (US$ 1556/ha), and incremental benefit-cost ratio (7.03) were found for 50% water application with straw mulch. The study thus reveals that drip irrigation with mulch has an explicit role in increasing the land and water productivity of tomato.

The availability of risk elements in soil can be possibly reduced by various soil additives. Among them, the attention has been recently focused on the research of unconventional soil additive - biochar. The aim of this study was (i) to observe the effect of biochar application on risk elements transport through the soil profile and (ii) to assess the availability of risk elements in biochar amended soil to willow growth. The experiment was established at greenhouse conditions and extremely contaminated soil, reaching 43 mg/kg cadmium (Cd) and 4340 mg/kg zinc (Zn), was used. To observe risk element content in leachate, the lysimeter cylinders were tested. The rates of biochar were 0 (control); 5, 10, and 15% per mass of soil. The results showed that biochar significantly increased biomass production whereas the plant Cd and Zn contents remained unchanged in most cases. In leachate, Cd and Zn content decreased by 99% at all the biochar treatments. We can summarize that biochar appears to be a very effective regulator of availability of observed risk elements and improver agent for biomass production of plants and remediation efficiency.

A field trial with four potato cultivars (Faluka, Manitou, Madeleine and Stirling) was conducted in two consecutive years (2012 and 2013) at a laboratory field of Biotechnical Faculty in Ljubljana. The aim of the study was to evaluate different requirements of the selected cultivars in regard to the ridge and tuber cluster. The following parameters were defined and monitored: area of the form surrounding the tubers (ellipse), cross-sectional area of the ridge, vertical and horizontal tuber span in the ridge, the length of semi-axes (a) and (b) of the ellipse, minimum distance of tubers and ellipse from the outer ridge side. The results of 2012 trial indicated that the minimal ellipse method defining the ellipse was not satisfactory as statistical significance was limited due to a large volume of vacant space in the ridge not occupied by potato tubers. Therefore, the mathematical model was upgraded in 2013 and a physical parameter (tuber mass) was incorporated in the equation to better depict the tuber cluster. The trials were designed as a randomized block with five repetitions. The largest ellipse, horizontal tuber span in the ridge and the longest semi-axis (a) were recorded for the cv. Manitou resulting in the highest yield. However, no statistical differences were recorded in the horizontal tuber span, the length of the semi-axis (a) or cross-sectional area of the ridge among cultivars analysed. It was determined that different cultivars require specific growth space in the potato ridge. Moreover, the newly developed method proved efficient for determining growth requirements of potato tubers in the ridge.

Miscanthus × giganteus (Greef et Deu) is an agro-energy crop of the second generation cultivated in purpose to obtain annually renewable bio-fuel produced from the aboveground biomass. Cultivation is preferred on marginal lands to avoid occupation of arable lands. Influence of fertilization and soil type Gleysol, Planosol and Technosol (open pit coal mine overburden) on yield and biomass traits of miscanthus were investigated during five years' field experiment. Among biometric characteristics: stem height, length and width of leaves, the number of leaves (dry and green) per stem and number of stems per rhizome, only the last one has a strong positive correlation with yield. Fertilization increased yield during fourth and fifth year of development on Gleysol and Technosol. The highest yield on Gleysol was 23.12 t/ha in 2014, on Planosol 10.16 t/ha, and 4.77 t/ha in 2015 on Technosol. The yield of miscanthus, beside fertilization, depends on weather conditions and weeds. Cultivation of miscanthus is possible on marginal soils with minimum application of agricultural measures only in the year of establishment. Gleysol is a type of soil that can be recommended for miscanthus cultivation.

The field experiment with different soil tillage treatments has been carried out in Prague-Ruzyně locality (Czech Republic) since 1995. Data of two growing cycles in the years 2007-2010 and 2011-2014 were evaluated. Tillage technique was decisive for changes in soil characteristics and crop yields. Bulk density, organic carbon (C_org) and microbial biomass C (C_mic) were more equilibrated throughout all tested soil layers (0-0.1; 0.1-0.2 and 0.2-0.3 m) in conventional tillage (CT). In reduced tillage (RT) and no-tillage (NT) treatments significant accumulation of C_org and increase of C_mic in the surface layer were found, compared to CT. No significant differences in C_org and C_mic between two growing cycles were determined; however, mostly higher values were obtained in the top layer of NT during the second growing period. Higher bulk density under conservation tillage techniques did not negatively affect soil characteristics and should be taken in consideration for data evaluation as it can alter interpretation of their changes in the soil profile. Crop yields were comparable in CT and RT. Yield decrease in NT was mostly observed for winter wheat and pea. Beneficial effects of RT and NT conserving soil moisture on crop yield were not observed in dry years.

Potato yield is affected by an interaction between nitrogen (N) and potassium (K) supply. This hypothesis was verified in a series of field experiments conducted during 2010-2013 in Albania (AL), Czech Republic (CZ) and Poland (PL). The two-factorial experiment was founded on relative scales of K (0, 50, 100, and 150%), and N application rates (75% and 100%) of the recommended doses, which were country-specific. The average tuber yield was doubled for AL, increased by 50% for PL, and by 15% for the CZ in response to K and N interaction. These differences are caused by an increase in the apparent nitrogen efficiency (ANE), which rose significantly by the progressive Krates. Maximum average ANE of 90 kg tubers/kg N was recorded in AL; it was 2-fold lower in CZ. Top average apparent potassium efficiency (AKE) of 65 kg tubers/kg K was recorded in PL; it was 4-times lower in CZ. The relationships between AKE and ANE clearly demonstrate the tight interaction between the N and K, and its effects on potato yield. However, a sound K application management should be adjusted to the local edaphic and climatic conditions.

The aim of this study was to compare the incidence of pathogens and pesticide residues in rapeseed samples depending on integrated and organic cultivation systems and cultivars. No pesticide residue was detected in seeds coming from the organic production system. However, trace amounts of pesticide residues admissible in rapeseed protection were detected for samples from integrated pest management. Seeds from both cultivation systems were most frequently infested by fungi Alternaria brassicicola and A. alternata. The greatest number of Leptosphaeria spp. cultures was obtained from seeds from organic cultivation.

This study evaluated the effects of biochar application on some properties of an alkaline soil and on lentil (Lens culinaris Medik) growth. Lentils were grown in the soil amended with the rates of 0.4, 0.8, 1.6, 2.4, and 3.3 weight percent of two biochars (B₁ and B₂), produced from rice husk under different pyrolysis conditions. Lentils were harvested after 70 days. Soil samples were also analysed for changes in physico-chemical properties. The results indicated that biochar application significantly increased soil organic carbon, cation exchange capacity, available potassium and below ground biomass of lentil, while it decreased soil bulk density. The results suggested that biochar application to alkaline soils has benefits to both soil quality and plant growth.

Soil management is aimed at the maintenance of optimal soil physical quality for crop production. In order to explore the effects of tillage practices on soil physical properties, a study was conducted to compare the effects of no tillage (NT), moldboard plow (MP) and ridge tillage (RT) on soil bulk density (BD), soil penetration resistance (SPR), soil water content (SWC), soil macroporosity (MAC) and soil air-filled porosity (AFP) in Northeast China. Results showed that both NT and RT led to significant BD increment than MP at 0-20 cm (P < 0.05). Compared with MP, NT and RT increased SPR at the depths of 2.5-17.5 cm (P < 0.05). SWC of 0-10 cm layer was significantly higher in NT and RT than MP soils (P < 0.05). NT showed a significantly lower MAC than MP and RT at 0-20 cm soil depths (P < 0.05). All AFP values were above the limit of 0.10 cm³/cm³ under all tillage treatments. RT improved the soil physical quality as evidenced by decreased BD and SPR, and increased SWC, MAC and AFP relative to NT.

Members of Brassicaceae have been frequently cited as allelopathic crop. The toxic effect of Brassica spp. may be caused by hydrolysis products of glucosinolates that occur in substantial amounts in the vegetative parts of Brassica spp. This study investigated the allelopathic potential of Brassica napus, B. rapa and B. juncea on the sunflower seed germination and seedling growth. Aqueous extracts of three species from two stages (full flowering and straw) of sampling were separately made with 0 (distilled water), 10, 20, 30 and 40% concentrations. This experiment was conducted in 2 × 3 × 5 factorial arrangement based on completely randomized design with five replications. There was a highly significant difference among different concentrations of extracts and also between two stages of extraction. All aqueous extracts significantly affected sunflower germination, germination rate, seedling root and hypocotyl length, fresh and dry matter weight when compared with distilled water control. The greatest concentration showed a stronger inhibitory effect. Root length was more sensitive to extracts than hypocotyl length.

A 2-year field experiment was conducted under light enrichment and shading conditions to examine the responses of seed yield and yield components distribution across main axis in soybean. The results showed that the maximum increase in seed yield per plant by light enrichment occurred at 27 plants/m², while the most significant reduction in seed yield per plant by shading occurred at 54 plants/m². Light enrichment beginning at early flowering stage decreased seed size on average by 7% while shading increased seed size on average by 9% over densities and cultivars, resulting in a fewer extent compensation in seed yield decrement. Responses to light enrichment and shading occurred proportionately across the main axis node positions despite the differences in the time (15-20 days) of development of yield components between the high and low node positions. Variation intensity of seed size of three soybeans was dissimilar as a result of changes in the environment during the reproductive period. The small-seed cultivar had the greatest stability in single seed size across the main axis, followed by moderate-seed cultivar, while large-seed cultivar was the least stable. Although maximum seed size may be determined by genetic potential in soybean plants, our results suggested that seed size can still be modified by environmental conditions, and the impact can be expressed through some internal control moderating the final size of most seeds in main stem and in all pods. It indicates that, through redistributing the available resources across main stem to components, soybean plants showed the mechanism, in an attempt to maintain or improve yield in a constantly changing environment.

This study is aimed at investigating the effect of different vineyard soil management systems on soil erosion and earthworm (Lumbricidae) population. Three soil management systems were investigated: permanent green cover (control), straw-cover and periodic soil tillage. Inter-row periodic soil tillage was applied in 2002 and 2003 (May and August), and straw-cover in May 2002. Periodic soil tillage resulted in increased erosion, i.e. 1746 kg/ha of soil/per year, on average. The greater portion of erosive events occurred after tillage in summer (August 2002), which was accompanied by heavy rainfall and slow renewal of grass cover (slower than in spring). The lowest average amount of soil erosion was observed in the treatment with straw-cover (56 kg/ha per year). This management system provided better environment for earthworm populations, most of which were found close to the soil surface, especially in the dry year 2003. In periodical soil tillage, the majority of earthworms were found in the soil horizon not disturbed by the tillage, i.e. at the depth of 10-20 cm. The lowest number of earthworms (only 2 per m²) was recorded in the herbicide intra-row strip.

Effects of insecticidal sprays on poppy root weevils (Stenocarus ruficornis, Stephens 1831) were assessed in small plot trials at three localities in the Czech Republic during two years (2011-2012). In addition, the effects of seed dressing were included into the assessment in one of the localities (Červený Újezd). The levels of root damage caused by the insect pest larvae (expressed as number of bore holes per root) and yield got from individual treatments were compared. Sprays applied for 18 days after the first record of poppy root weevils in trials showed the highest effects on a decrease of the levels of root damage (40% of untreated control). In general, sprays applied at the date when SATF₁₄ value exceeded 20°C showed significant effects on decreasing the levels of root damage. The highest effects were usually recorded in sprays which were applied when SATF₁₄ value exceeded 100°C.