Fulltext search in archive

The competitiveness of Bradyrhizobium japonicum inoculation strain against indigenous rhizobia was examined in a soil pot experiment. The effect of inoculation strain was evaluated under different soil conditions: with or without previously grown soybean and applied commercial inoculant. Molecular identification of inoculation strain and investigated rhizobial isolates, obtained from nodules representing inoculated treatments, was performed based on 16S rDNA and enterobacterial repetitive intergenic consensus (ERIC) sequencing. Inoculation strain showed a significant effect on the investigated parameters in both soils. Higher nodule occupancy (45% vs. 18%), nodule number (111% vs. 5%), nodule dry weight (49% vs. 9%), shoot length (15% vs. 7%), root length (31% vs. 13%), shoot dry weight (34% vs. 11%), shoot nitrogen content (27% vs. 2%), and nodule nitrogen content (9% vs. 5%) was detected in soil without previously grown soybean and applied commercial inoculant. Soil had a significant effect on the shoot, root and nodule nitrogen content, while interaction of experimental factors significantly altered dry weight and nitrogen content of shoots, roots and nodules, as well as number of nodules. Nodulation parameters were significantly related with shoot dry weight, shoot and nodule nitrogen content. Symbiotic performance of inoculation strains in the field could be improved through co-selection for their competitiveness and effectiveness.

Pot experiments were carried out to study the effects of a novel stabilizer of 2,4,6-trimercaptotriazine, trisodium salt, nonahydrate (TMT) on the bioavailability of heavy metals (Cu, Zn, As, Cd and Pb) in soils and heavy metals accumulation in tobacco. The results showed the optimal TMT dosage 200 mL/kg could effectively reduce the bioavailability of heavy metals in soils, and the bioavailability of Cu, Zn, As, Cd and Pb in soils was reduced simultaneously by up to 73.1, 63.2, 48.0, 68.9 and 57.2%, respectively. Application of TMT could significantly decrease Cu, Zn, As, Cd and Pb contents of all parts of tobacco. Furthermore, the contents of available Cu, Zn, As, Cd and Pb in soils were significantly positively correlated with Cu, Zn, As, Cd and Pb contents in upper, middle and lower leaves and stems of tobacco. There were no significant differences among plant height, number of leaves, stem girth, length and width of maximum leaves of tobacco under TMT treatments and that under control (P < 0.05), which showed that the TMT did not promote and inhibit the growth of tobacco.

Soil erosion is one of the major environmental problems in open-cut mines in tropical regions. It causes negative impacts including the removal of nutrient-rich topsoil, destroys aquatic habitat, dam and pond siltation, clogs river by deposition of sediment, and causes water pollution in the rehabilitation process. Soil texture is an important factor to affect soil erosion. In this study, artificial rainfall experiment in the laboratory scale was conducted to clarify the mechanism of soil erosion under the different soil composition and to discuss the methods for minimizing soil erosion. The obtained results showed that the soil seal generated due to the presence of fine particle under high rainfall intensity is the main contributor to accelerate the soil erosion. Additionally, the surface coverage by the cover crops is the most effective measure to reduce soil erosion because both the coarse and fine contents runoff can be minimized while arranging of the slope angle is effective for reducing the runoff of coarse contents and the soil compaction is effective to reduce that of fine contents. Soil erosion can be minimized by selecting prevention method considering the type of soil because the prevention effect on soil erosion is different depending on the type of soil.

Agronomic zinc (Zn) biofortification of crops could help to alleviate dietary Zn deficiency, which is likely to affect more than one billion people worldwide. To evaluate the efficiency of agronomic Zn biofortification of broccoli, four application treatments were tested: no Zn application (control); soil application of 5 mg/kg ZnSO₄.7 H₂O (soil); two sprays (15 mL/pot each) of 0.25% (w/v) ZnSO₄.7 H₂O (foliar); and soil + foliar combination. Soil Zn application increased Zn-DTPA (diethylenetriamine pentaacetic acid) concentration by 3.7-times but did not affect plant growth or plant Zn concentration. Foliar Zn application increased stem + leaves and floret Zn concentration by 78 and 23 mg Zn/kg, respectively, with good bioavailability based on phytic acid concentration. Boiling decreased mineral concentration by 19%, but increased bioavailability by decreasing the phytic acid concentration. The entire broccoli could constitute a good nutritional source for animals and humans. An intake of 100 g boiled florets treated with the foliar treatment will cover about 36% of recommended dietary intake (RDI) of Zn, together with 30% of Ca, 94% of K, 32% of Mg, 6% of Na, 55% of P, 60% of S, 10% of Cu, 22% of Fe, 43% of Mn, and 35% of Se RDIs.

This study was based on a long-term field experiment established in 1967 in which winter wheat is grown in two rotations consisting of: potato-winter wheat-fodder crops-winter wheat (rotation A) and oat-winter wheat-winter rye-winter wheat (rotation B). In the years 2010-2013 selected soil properties and winter wheat yields as influenced by these rotations were analysed. The soils under winter wheat grown in crop rotations A and B contained similar amounts of total organic carbon (C) (0.76% and 0.80%, respectively) and did not differ significantly with respect to biological characteristics (contents of microbial biomass C and nitrogen (N), dehydrogenase and acid phosphatase activities). Averaged for 3 years, the highest grain yields were obtained for winter wheat grown after potato in rotation A (7.94 t/ha) and the lowest (6.0 t/ha) for wheat following winter rye in rotation B. The highest take-all index and the lowest numbers of ears/m² were the main factors influencing poor performance of winter wheat following rye.

This study attempted to evaluate the efficiency of zeolite and pyrophyllite ore materials in reducing the mobility of heavy metals in soil near the lignite mining dumps, and consequently in their availability for plants. Extraction of pseudo-total and available forms of heavy metals from soil samples was performed by using aqua regia and ethylenediaminetetraacetic acid, respectively. Concentrations of heavy metals in soil and plant samples were determined by atomic absorption spectrophotometry. The results of this study illustrate that application of zeolite and pyrophyllite could be a suitable technique to reduce heavy metals availability in soils. Zeolite treatments have been shown to be significantly effective in reducing cadmium (Cd) mobility, as well as pyrophyllite treatments in reducing lead (Pb) mobility in the studied soil, regardless of applied rates. The accumulation of heavy metals in leaves of maize grown on soil plots treated by zeolite and pyrophyllite, was found to be lower compared to the untreated plots. This finding was to be expected, considering the effects of these treatments on heavy metals mobility in the studied soil.

The aim of this study carried out in 2017-2018 was to determine the effect of white cabbage (Brassica oleracea L.), which is known to have an allelopathic effect on the germination of some weed and cultural crops seeds. In addition to weeds, Amaranthus retroflexus L., Chenopodium album L. and Solanum nigrum L., cultural plants such as Zea mays L., Beta vulgaris L., were used in this study. It has been shown that the seed germination rate was decreased by the increased concentration of white cabbage post-harvest leaves extractions, which were made with different concentrations of aqueous and methanol extracts (30, 40, and 50%). The methanol extract was found to be more effective in germination. According to these results, S. nigrum and Z. mays seeds were less affected than A. retroflexus, C. album and B. vulgaris seeds. In the light of these data, it is observed that extracts obtained from white cabbage can be effective on some weeds; however, it was concluded that in order to reach more definite conclusions, studies on the subject should be increased, and similar studies should be continued under greenhouse or field conditions.

The nutritional status of winter oilseed rape (WOSR) during its vegetative period is crucial for plant growth and can be used for the seed yield prediction. This hypothesis was verified based on the data from long-term field experiments. The experiment consisted of four potassium (K) treatments based on the progressive K supply potential to plants from soil and fertilizer and two magnesium treatments (-Mg, +Mg) conducted in 2013-2015. The content of nutrients (N_tot, P, K, Mg, Ca, Fe, Mn, Zn, Cu) was determined at the rosette stage (BBCH 30) for leaves and separately for leaves and stems in the late stage of inflorescence growth (BBCH 57-59). The low K content appeared as the key limiting nutrient in WOSR plants in the rosette stage due to the insufficient soil fertility level, depended even more on weather conditions. This negative K nutritional trait persisted through the whole vegetative WOSR growth. Its detection was possible, because stems were included in the diagnostic procedure. The most reliable prognosis of WOSR yield was conducted based on the nutritional status of stems in the late stage of the inflorescence development.

Matching the planting density, fertilisation, and genotype is crucial to improve the maize yield. Here, two-year field trials, including 4 densities and 3 nitrogen (N) rates for 2 maize cultivars, were conducted to study the effects of planting density and N rate on maize growth, lodging, spike characters, and yield. Compared with 360 kg/ha, N application of 180 kg/ha decreased the plant, ear height, and stem circumference of WeiKe 702 (WK702), while increased the plant height and stem circumference, but decreased ear height of ZhongDan 909 (ZD909). Meanwhile, the N application of 180 kg/ha greatly reduced the lodging rates of maize under the high density. The maize yield increased and reached the maximum yield at 7.5 × 10⁴ plant/ha, and then decreased with increasing density. The N application of 180 kg/ha increased yield by 0.49, 0.73, 5.38, 7.81% from low to high planting densities, and reduced the bald tip length by 18.86%. WK702 was more sensitive to the planting density and N application, with greater variation of yield and spike traits than ZD909 under the densification. Therefore, the N application of 180 kg/ha and a density of 7.5 × 10⁴ plant/ha could improve maize growth and lodging, and therefore increase maize yield.

With the need to obtain new methods to protect seed material from Ditylenchus dipsaci (Kühn, 1857) nematodes, a study was conducted to evaluate the nematicidal effects of several plants' essential oils on the mortality of D. dipsaci. Tests were performed under in vitro conditions; a concentration of 2 000 ppm was tested, nematodes were added into diluted oils, and numbers of living/dead nematodes were scored after 4 and 24 h. The results show a significant effect of several plant essential oils on D. dipsaci mortality, with the highest efficacy found for oil from Cinnamomum cassia ((L.) J. Presl), with 100% mortality observed even after 4 h.

The aim of the study was to evaluate total and individual glucosinolates concentration, root weight and diameters of horseradish accessions (Cor and Mon) grown by adding nitrogen (N) and sulphur (S) and harvested at the beginning (late autumn) and towards the end (early spring) of the harvest period. The concentration of the 9 glucosinolates (GLS) quantified in roots varied greatly between accessions (6-fold higher in Cor) and with fertilization (N alone led to an increase of 64% of GLS with an additional enhancement of 65% when S was added to N). Root GLS concentration was significantly higher in early spring compared to the previous harvest in late autumn (12.5 vs 8.9 µmol/g DW (dry weight)); a drastic decline of GLS (2.7 µmol/g DW) occurred in root harvested in the following autumn from plants left ad hoc in the field. The aliphatic sinigrin was the most abundant (80% of total GLS), followed by the aromatic gluconasturtiin and the indolic glucobrassicin (5.8% and 4.7%, respectively). Root diameter and weight increased in plants treated with fertilizers (19% and 61%, respectively) and throughout the harvests with Cor showing values double with respect to Mon (925 vs 476 g/plant). Relationships between GLS concentration and root weight (R² = 0.61) and diameter (R² = 0.69) were improved by excluding the roots harvested from plants left ad hoc in the field that showed the worst performances.

The aim of the study was to evaluate the effect of nitrogen (N) and sulphur (S) fertilizer on grain yield of spring wheat and its technological quality. A field experiment (2009-2011) was conducted in south-eastern Poland on Cambisols. The experiment included 2 factors: N fertilization (0, 40, 80, 120 kg/ha) and S fertilization (0, 50 kg/ha). The experiment showed that spring wheat cv. Tybalt exhibited a positive reaction of N and S fertilization on grain yield, which was the highest at the application of 80 kg N/ha (5.40 t/ha), increasing by 1.30 t/ha (13.1%) with respect to the control. S fertilization increased grain yield by 3.58%. S application increased significantly the content of gluten by 3.2%, cysteine by 6.0% and methionine by 16.5%. The most beneficial effect on the content of N, S, total protein, gluten, cysteine and methionine was observed for N application a rate of 80 kg/ha and for S at a rate of 50 kg/ha. Positive correlation was found between the content of S in grain and grain yield (r = 0.73). Significant correlations were found also between grain yield and all other quality characteristics except for N and starch content.

Pyrolysis is a promising technology for sewage sludge (SS) treatment providing several improvements of SS properties for soil application. However, information on the influence of pyrolytic temperature on the availability of nutrients in resulting biochar (BC) is limited. In this study, anaerobically stabilised SS was pyrolysed in a laboratory fixed-bed reactor at 220, 320, 420, 520, and 620 °C for 30 min in the N₂ atmosphere. Pyrolysis resulted in a higher total content of all studied nutrients in BCs. Aromaticity and hydrophobicity of BCs increased with increasing temperatures while solubility decreased. Relative availability (% from total content) of nutrients in BCs was in order: Ca > Mg ~ K > S > P. Pyrolysis at 220 °C produced acidic BC with a higher content of acetic acid-extractable nutrients compared to non-pyrolysed control. An increment in pH and a significant drop in the content of available Ca, Mg, K and S were found at temperature 320 °C. Pyrolysis at 320 °C increased the content of available P by 28 % compared to non-pyrolysed SS. At the temperature of 420 °C and higher, available contents of all studied nutrients were lower than in non-pyrolysed SS.

The objective of this work was to investigate, before and after chemical treatment, the interrelationships of the physiological quality tests in wheat grains. Following the chemical treatments with (i) carboxin thiram; (ii) carboxin thiram + thiamethoxam; (iii) carboxin thiram + thiamethoxam + bio-stimulant; (iv) pyraclostrobin + methyl thiophanate + fipronil, and (v) pyraclostrobin + methyl thiophanate + fipronil + bio-stimulant, subsequently the grains were assessed for their physiological potential. The physiological potential of the grains could be differentiated based on the electrical conductivity, seedling growth, and emergence in sand tests. In conclusion, the use of the active ingredients changed the correlation between laboratory tests with crop emergence in the sand as well as altered the relevance of the tests for sorting the treated grains into different physiological potential. But, the seedling growth tests and the electrical conductivity were, together, the parameters most relevant for explaining the data variability.

To provide reference for scientific management of nitrogen (N) fertiliser on tartary buckwheat, the effects of the mixed application of controlled-release N fertiliser (a kind of thermoplastic polymer-coated urea types that are characterised by a semi-permeable membrane) and common urea was studied in the main tartary buckwheat production area in China. In 2018 and 2019, a two-year field experiment was conducted a randomised block design with five treatments: (1) no nitrogen fertilisation (CK); (2) 100% N from common urea (T1); (3) 15% N from controlled-released urea fertiliser (plastic coated) + 85% N from common urea (T2); (4) 30% N from controlled-released fertiliser + 70% N from urea (T3); (5) 45% N from controlled-released fertiliser + 55% N of urea (T4). The N fertilisation rate was 90 kg N/ha in all fertilisation treatments. The results showed: (1) the mixed application of controlled-release N fertiliser and common urea was conductive to enhance the yield, dry mass, N uptake and apparent N fertiliser efficiency (NFE), compared with a single application of common urea. In two seasons, NFE was 38.6% (T1), 48.6% (T2), 53.6% (T3) and 53% (T4), separately; (2) the mixed application of controlled-release N fertiliser and common urea could significantly increase the soil inorganic N content in the soil surface layer and decreased the leaching loss of N; (3) with the increasing ration of controlled-release N fertiliser, the tendency of increasing N content of crop uptake and soil residual and decreasing rate of N loss and N surplus was visible. Overall, considered the indicators of grain yield, input cost, N utilisation and N balance, the suitable N fertilisation mode for tartary buckwheat production is the mixed application of 30% controlled-release N fertiliser and 70% common urea when 90 kg N/ha is applied.

The aim of the study was to determine the glycoproteins content (total glomalin (TG), easily extractable glomalin (EEG) and soil proteins related to glomalin (GRSP)) in soil under long-term monoculture of maize. Soil microbiological and biochemical properties, including microbial biomass and enzymatic activity were also assessed. The presence of total, easily-extractable glomalin and soil proteins related to glomalin was dependent on both the growth phase of the plant and tillage system. The highest content of glomalin was detected in the soils under maize in direct sowing and reduced tillage. The glomalin content was correlated with soil biological activity. The linear regression was observed between TG and GRSP content, but no linear relationship was found between GRSP and C_org. The principal component analysis showed the strong correlations between the parameters of soil quality and biodiversity indicators. Selected indicators of soil microbial parameters explained 52.27% biological variability in soils.

The aim of the study was to evaluate the amount of nitrogen taken up from air, mineral fertilizers and soil by yellow lupine (Lupinus luteus L.) and spring triticale (Triticosecale Wittm. ex A. Camus) in their intercropping cultivation. The factor examined in the experiment was percentage of yellow lupine seeds and spring triticale grain in sown mixtures: 100/0, 75/25, 50/50, 25/75 and 0/100, respectively. Yellow lupine yield was reduced by spring triticale when intercropped. In the yield of both plants the percentage share of spring triticale grain was larger and that of yellow lupine seed was smaller than in the sown mixture. Land equivalent ratio informs that yield advantage under intercropping of lupine and triticale was minor. The total protein yield was the highest in lupine cultivation when sown pure, and decreased with increasing share of triticale in their intercropping. The mean percentage nitrogen share from N₂ fixation, fertilizer and soil reserves in yellow lupine mass was: 65.2, 8.8 and 26.0%, respectively, while in the mass of spring triticale it was 10.1, 23.5 and 68.8%, respectively.

Secondary fertilisers are becoming an important alternative to conventional mined fertilisers. For the first time, the struvite "relative" hazenite (KNaMg₂(PO₄)₂∙14 H₂O) has been artificially synthesised. A pot trial assessed whether hazenite-fertilised ryegrass had comparable potassium (K), magnesium (Mg), or phosphorus (P) uptake and shoot yields with treatments receiving conventional K (muriate of potash), Mg (kieserite) or P (triple superphosphate, TSP) fertilisers. Ryegrass shoot biomass production and K/Mg uptake in replicates receiving hazenite were as good as or superior to those amended with conventional fertilisers. Phosphorus uptake of plants whose P source was TSP was significantly higher than that of the hazenite-amended replicates without significantly higher shoot biomass, indicating luxury P uptake. Hazenite's constituent sodium (Na) makes it a potentially useful soil amendment for forage grasses or natrophilic crops such as sugar beet. Its component Mg would also be desirable in forage grasses to pre-empt ruminant hypomagnesemia or in crops with a relatively high Mg demand, for example, maize. Furthermore, hazenite represents a good alternative to KCl for chlorophobic crops such as potatoes. However, given its unusual ratio of Mg, P, and K, the ideal application of hazenite would probably be in combination with other fertilisers.

Glomalin is one of the factors with an important role at forming and stabilising soil aggregates. Long-term stationary experiments were carried out to observe the influence of various fertilisation treatments on the content of glomalin in topsoil. The content of easily extractable glomalin (EEG) and total glomalin (TG) were determined. Moreover, glomalin was also determined by using the near-infrared reflectance spectroscopy (G_NIRS). Both mineral and organic fertilisation significantly increased the content of glomalin compared to the unfertilised control. However, observed differences among individual fertilisation treatments were not significant. A significant correlation was determined between the content of EEG, TG, G_NIRS, and the content of humic substances as well as humic acids. Both methods used (EEG, TG) can equally reflect soil organic matter quality. A significant correlation was also recorded between the G_NIRS and extraction methods (EEG, TG).

Overgrazing affects typical steppe community in ways similar to grasslands in other areas. Exclusion of livestock grazing is one of the main management practices used to protect grasslands. However, it is not known if long-term exclusion of livestock grazing has positive effect on above- and belowground community properties in typical steppe of the Loess Plateau. We studied the long-term (20-year) cumulative effects of exclusion of livestock grazing on above- and belowground community properties compared with that before exclusion of livestock grazing in a typical steppe of the Loess Plateau, NW China. Our results show that twenty-year exclusion of livestock grazing significantly increased above- and belowground biomass, species richness, cover and height for five different communities. Most of belowground biomass was in the 0-20 cm horizon and grazing exclusion increased biomass especially at the depth of 0-10 cm. Our study suggests that long-term exclusion of livestock grazing can greatly improve community properties of typical steppe in the Loess Plateau.

Surface mulch is an important factor of soil protection technology in the cultivation of potatoes. Presented herein are the results of three years (2009-2011) of field trials at two sites (Leškovice and Uhříněves), where two cultivars (Finka and Katka) were grown. Three mulching treatments (grass mulch after planting, grass mulch before germination and black polypropylene mulch textile) were used in the study. The weight of marketable tubers (tuber over 40 mm) and tuber size distribution were influenced significantly by mulching. The application of grass mulch on surface of the row ensured a 20.5-24.8% increase of weight of marketable tubers and higher occurrence of tubers over 56 mm (resp. tubers 56-60 mm and over 60 mm). There was no consistent effect of grass mulch on the aboveground biomass of weeds. Higher occurrences of larvae of Colorado potato beetle was found on the plots with black polypropylene textile in warmer site Uhříněves.

Phosphorus (P) stratification in no-tillage (NT) systems has important implications for crop growth and potential P loss, but little is known about P forms and their distribution when mineral P fertilizers are placed to the depth of 5 cm in NT soil. A 10-year field experiment was used to study the effect of NT and mouldboard plough (MP) on soil P forms at three depths (0-5, 5-10 and 10-20 cm) and their relationship with Fe and Al oxides. The results indicated that stratification of organic P forms occurred under NT treatment, and Fe oxides may have a stronger capacity for adsorbing the P forms. When mineral P fertilizers were placed to the depth of 5 cm under NT treatment, there was no significant difference in P forms or crop yield between NT and MP treatment, and orthophosphate did not show any significant difference under NT treatment between 0-5 cm and 5-10 cm depth. Overall, the agricultural management practice that mineral P fertilizers are placed to the depth of 5 cm under NT treatment could result in stratification of P forms, while the changes in the distribution of P forms in soil profiles might help reduce potential P loss in surface runoff and do not make any difference to crop growth.

To develop rainfed agriculture in northern China, we conducted field experiments with three straw mulching rates (0, 6, and 12 t/ha) on two plant types (a compact type, Chaoshi1, and a flat type, Danyu86) during the summer maize-growing season in 2009 and 2010 to study soil moisture content, evapotranspiration, grain yield, and water-use efficiency (WUE). The results indicated that straw mulching could significantly (LSD, P < 0.05) improve soil moisture content at a depth of 20-80 cm below the ground surface during the anthesis-silking stage; however, at maturity, straw mulching decreased the soil moisture content at a depth of 0-60 cm below the ground surface. In 2009, straw mulching at the rate of 12 t/ha significantly (LSD, P < 0.05) increased the evapotranspiration in Chaoshi1 and Danyu86. In 2010, straw mulching at the rate of 6 t/ha significantly (LSD,P < 0.05) increased evapotranspiration in Danyu86 alone. The grain yields of Danyu86 in 2009 and Chaoshi1 in 2010 were significantly (LSD, P < 0.05) higher with straw mulching at the rate of 12 t/ha than on the application of other treatments. Irrespective of whether precipitation was concentrated during the beginning or the latter half of the summer maize growing stage, straw mulching increased the WUE of Chaoshi1, but not of Danyu86. These results indicated that under rainfed conditions in northern China, straw mulching could increase the grain yield and WUE of compact-type maize.

The impact of non-treated and primed seeds on molasses components, sugar content and technological white sugar yield of the same cultivar of sugar beet root was investigated. The study was conducted in 2012-2014 at the Experiment Field Station of Warsaw University of Life Sciences - SGGW in Skierniewice (51°97'N, 20°19'E) in the central region of Poland. The use of primed seeds resulted in a higher technological white sugar yield with higher sugar content and lower content of α-amino nitrogen in the roots. Also, seed priming increased the technological value of the roots by a lower share in the root yield fractions of the root weight less than 300 g, characterized by lower sugar content and a higher content of α-amino nitrogen.

Aiming at the problems of shallow effective soil layering and low utilization rate of precipitation in the North China Plain. The effects of different subsoiling stages on soil physical properties and water use in winter wheat/summer maize fields were studied. Three kinds of tillage treatments were studied: rotary tillage to a depth of 15 cm in October and no-tillage in June (RT), rotary tillage to a depth of 15 cm in October and subsoiling to 35 cm in June (ST-J), subsoiling to a depth of 35 cm in October and no-tillage in June (ST-O). Changes in soil bulk density and soil compaction were consistent over two seasons. Compared to RT, in the 10-50 cm soil layer, ST-J and ST-O decreased the average soil bulk density by 6.18% and 5.66%, respectively, and the soil compaction in the 10-60 cm layer was reduced by 17.89% and 20.50%. ST was improved soil structure and increased the water content of deep soil. The water use efficiency (WUE) of ST-J and ST-O increased by 4.73% and 14.83%, respectively, and the maize yields by 2.90% and 11.35%, respectively. Considering the WUE and maize yields, it was considered that ST-O is more suitable for tillage in the North China Plain.

A field experiment was established in 1972 on Luvisol. Three types of fertilizers - cattle manure (CM), cattle slurry (CS) and mineral fertilizers were used. CS was applied in the following doses: I - balanced with CM in terms of the amount of introduced total nitrogen and II - balanced with CM in terms of the amount of introduced total organic carbon (C_tot). 39 years after the experiment was established, half of each experimental plot was limed and since then the experiment was carried in two series - non-limed and limed soils. The paper presents the results of soil analyses 41 years after the experiment was started. It was found that each fertilization system increased the C_tot content in soil in relation to the unfertilized control plot. The increase of C_tot fluctuated between 0.35-6.22 g/kg of dry matter. In both series, the highest C_tot content was observed in the soil fertilized with CM and CM + PK. Limed compared to non-limed soil contained nearly 25% more carbon of humic acids than fulvic acids and nearly 20% lower content of low molecular humic bonds. Liming considerably widened the humic acids carbon:fulvic acids carbon (C_HA:C_FA) ratio of the fertilized soils, up to 1.32-1.87, while the corresponding objects of the non-limed series showed the C_HA:C_FA ratio between 0.75-0.97.

We investigated sulphate application, different statuses of soil microbial activity and their joint effects as variables associated with changes in potentially plant-available selenium (Se_ppa) and soil Se fractionation during the course of an incubation study. The time-resolved behaviour of added selenate (400 µg Se/kg as Na₂SeO₄) in two agricultural soils was elucidated by means of single extraction (50 mmol/L NH₄H₂PO₄), sequential extraction procedure (SEP) and chemical speciation analysis in phosphate extracts. The decrease in phosphate-extractable Se, a consequence of soil aging, was inhibited by sulphate (by 34% and 29% in Chernozem and Cambisol, respectively) and by gamma-irradiation (by 46% and 20% in Chernozem and Cambisol, respectively) after 72 days of incubation as compared to the control treatments. Glucose amendment dramatically decreased Se_ppa only in the Chernozem. After 1 year, the initial soil treatment with respect to inhibited or stimulated microbially-mediated processes substantially controlled the distribution pattern of exogenous Se as observed using the SEP. Application of sulphur fertilisers and sources of labile organic matter is thus an essential agronomic practice to correct unfavourable amounts of Se_ppa.

The present study was carried out in 2016-2017 to assess the effect of subsoiling depth on the soil bulk density, stability of soil structure, soil physical properties and summer maize yield based on a field experiment started in 2015. Four tillage depths were studied: conventional tillage 25 cm (CT₂₅); subsoiling tillage 30 cm (ST₃₀); subsoiling tillage 35 cm (ST₃₅) and subsoiling tillage 40 cm (ST₄₀). The results showed that at the 20-50 cm depth ST₃₀, ST₃₅ and ST₄₀ decreased the mean soil bulk by 4.59, 7.13 and 8.27%, respectively, and at the 0-40 cm depth reduced soil compactness by 17.62, 23.63 and 36.42%, respectively, as compared to CT₂₅. ST₄₀ reduced soil compactness in the 0-40 cm soil layer under conditions of relative drought (during the maize season growing season of 2016), ST₃₅ and ST₄₀ increased macroaggregates (> 0.25 mm), improved the stability of the aggregate structure (geometric mean diameter and mean weight diameter) (20-40 cm), increased soil water storage capacity at 40-60 cm and increased maize yield by 7.89% and 8.91%, respectively. Considering the improvement of soil properties and crop yield, ST₃₅ was the optimum method to increase maize yield and modulate soil physical properties in the North China Plain.

The migration and transformation of soil phosphorus (P) are essential for agricultural productivity and environmental security but have not been thoroughly elucidated to date. A 10-year field study was conducted to explore the effects of conventional tillage (CT) and no-tillage with maize residue management (NT-0, NT-33%, NT-67% and NT-100%) on P contents and phosphatase activities in soil layers (0-5, 5-10, 10-20 and 20-40 cm). The results showed that soil available P content and phosphatase activities were higher in no-tillage with maize residue than CT. Soil moisture and pH were significantly positively correlated with soil available P. Higher organic P contents and lower inorganic P contents in the 0-5 cm soil layer were found in the treatment NT-67% compared with other treatments. According to the structure equation model, the source of available P was inorganic P in NT-33%, while organic P in NT-67%. This study demonstrated that the variation of dominant mechanisms involved in soil P migration and transformation were dependent on residue input amounts, and NT-67% might play an important role in the maintenance and transformation of soil organic P.

Currently, the hybrid cultivars are predominant in the cultivation of winter oilseed rape in Europe. Cultivation of hybrid cultivars instead of the traditional line can affect the visitation of pollinators. Beekeepers and farmers claim that hybrid cultivars are not visited by pollinators as much as the line. Ten yellow and one white flowering oilseed rape cultivars were used to compare the visitation rates of pollinators (Apis mellifera L. and Bombus sp.) during flowering in the years 2015-2017. At the same time, the visitation of hybrid and line cultivars by pollinators was evaluated. Visitation of pollinators on each cultivar was calculated from observed visitations to flowering oilseed rape plants in an area 2.1 m² from the edge of single plots for 20 s. The results from this study clearly show that the individual cultivars, whether hybrids or lines, did not have a major influence on the pollinators' visitation, either by honey bees or bumble bees. It is thus proved that hybrid cultivars do not affect the pollinator visitation and there is no need to worry about the prevalence of these cultivars in the Czech fields. However, a more significant effect for both pollinator groups appears to have been the color of the flower.