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In this research cyanobacteria (Blue-Green Algae, BGA) were isolated, identified, multiplied and used as an inoculum in pot rice experiment. The pH, moisture and algal population were measured in four seasons. The highest and lowest pH (6.7, 6.2), moisture of soil (43%, 34%) and algal population (12, 20 Colony-Forming Units/50 ml on A and B medium and 4, 5 Colony-Forming Units/50 ml on A and B medium) were recorded in spring and winter, respectively. The only heterocystous cyanobacteria were found in soil samples identified as Anabaena with four species (A. spiroides, A. variabilis, A. torulosa and A. osillarioides). The germination of rice seeds treated with cyanobacteria was faster than control. The result of pot experiment were: increase of 53% in plant height; 66% in roots length; 58% in fresh leaf and stem weight; 80% in fresh root weight; 125% in dry leaf and stem weight; 150% in dry root weight; 20% in soil moisture; 28% in soil porosity and a decrease of 9.8% in soil bulk density and 4.8% in soil particle density. There were significant differences (P < 0.05) in pot treated with BGA as compared with control.

The article describes the use of the recently commercially available technique of microwave induced plasma optical emission spectrometry with plasma gas (nitrogen) generation for the determination of calcium, magnesium, phosphorus and potassium in Mehlich 3 extracts. The specifics of the analysis of the agricultural samples for soil fertility assessment mean there are often a great number of samples to analyse in laboratory (the daily throughput of 500 or more samples). The analytical procedures were adapted to special requirements by the use of the new multielemental instrumental techniques. The detection limits were 0.43; 0.86; 0.20 and 0.06 mg/L; the precision for real sample analysis: 4.6; 1.0; 1.8 and 1.0%; the mean accuracy 97; 92; 107 and 100% for P, Ca, Mg and K, respectively, the real throughput reached 100 samples per hour.

Festuca ovina L. is an important ornamental species used in urban landscapes and pastures reclamation. However, low resistance of this species to salt stress has hindered its extended application in low-water and salty regions. To study the effects of calcium on reducing salt stress injuries in seed germination and early growth of this species, a factorial experiment based on completely randomized design with three replications was conducted. The salt levels included NaCl solutions (5, 10, 15 and 20 dS/m). Calcium source was CaCl₂ with concentrations of 0, 10, 20 and 30 mmol₊/L. Germination percentage and mean germination time were significantly affected by interaction of salinity and calcium. As salinity increased, mean germination time increased. However, germination percentage, shootlet length, rootlet length, shootlet fresh and dry weight, rootlet fresh and dry weight and seed vigour index decreased following the increasing salinity. Concentrations of 10 and 20 mmol₊/L CaCl₂ had significant effects on reducing salt injuries on seed germination of Festuca ovina. This finding was even prominent in higher salinity levels of 15 and 20 dS/m. Therefore, to facilitate using this species in urban landscapes or in pastures, pre-treatment of the seeds using 10 and 20 mmol₊/L CaCl₂ is recommended.

The study aimed at comparing the yield of dry biomass and energy efficiency of 22 willow cultivars depending on the harvesting frequency and variable plant density. The field experiment was established in 2010. The willow cultivars were planted in two densities; 13 300 and 32 500 plants per ha. Among the compared cultivars in the second year (2013) of full production, high yield of dry matter was obtained from cvs. Tordis (33.1 t/ha/year), Inger (30.4 t/ha/year) and Klara (29.0 t/ha/year). After six years of cultivation, the highest aboveground dry matter was given by cvs. Tora (27.4 t/ha/year) and Tordis (27.0 t/ha/year). The gross calorific value of willow biomass ranged from 15.2-20.1 GJ/t dry weight. Greater energy efficiency (329.3 GJ/ha/year) occurred in willow cultivars collected in a two-year cycle than in the one-year cycle (286.4 GJ/ha/year). In the two-year cycle collected in the third year after planting, energy efficiency was greater (379.5 GJ/ha/year) than in the two-year cycle harvested in the sixth year after planting (279.15 GJ/ha/year). The initial slower growth of biomass does not determine plant yielding.

Biosolids are organic fertilisers derived from treated and stabilised sewage sludge that increase soil fertility and supply nitrogen to crops over a long period, but can also increase the risk of nitrogen (N) leaching. In this work, spring barley was grown in lysimeters filled with soil amended with biosolids, and with and without mineral N fertilisation. Biomass and the N concentration and content of shoots and roots were determined at flowering and maturity, and the N remobilization was calculated during grain filling. Drainage water was collected and analysed for N leaching. Biosolids increased soil porosity and soil nitrate, and positively affected the growth and N uptake of barley. Compared to mineral fertilisers, biosolids produced 18% higher vegetative biomass and 40% higher grain yield. During grain filling, both N uptake and N remobilization were higher with biosolids, which increased the grain N content by 32%. Nitrogen loss in leachates was 1.2% of plant uptake with mineral fertilisers and 1.7% with biosolids. Thus, soil fertilisation with biosolids greatly benefits spring barley, only slightly increasing N leaching.

Based on a long-term fertilization experiment on sandy soil, research concerning the effect of variable fertilization on the soil content of silicon extracted by CaCl₂ solution was performed. The content of plant available silicon was evidenced to depend on the applied fertilization and soil properties. Plant silicon supply coefficient varied depending on the fertiliser combination. In the case of potatoes this coefficient was smaller then 1 but for oat was usually higher then one. It suggesting that the amount of available silicon in soil is sufficient to cover the nutritional needs of potatoes but not sufficient for oat.

The water demand for cover crops (CC) should be considered to achieve competitive crop stands for weed control also under unfavorable conditions. This study aims to estimate the weed suppressive ability of winter CC, as Sinapis alba L., Phacelia tanacetifolia Benth., Vicia sativa L. and Avena strigosa Schreb., under a water-limited regime. The water deficit tolerance of different CC was determined in a greenhouse experiment by measuring the maximum quantum efficiency of photosystem II. Moreover, soil moisture, CC, and weed establishment were measured in field experiments in Southwest-Germany during two contrasting growing seasons in 2016 and 2017. A. strigosa showed a higher water deficit tolerance than S. alba in the greenhouse. In the field, A. strigosa showed the highest weed cover reduction (98%) in the field, along with an increasing effect on the soil moisture compared to the untreated control. S. alba performed most sensitive to water deficit in the greenhouse but reached the significantly highest weed control efficacy (94%) during the dry field season in 2016. Even though the selected CC showed differing sensitivities to water deficit in the greenhouse, their weed suppression ability was independent of the water supply under field conditions.

Conservation tillage harmonizes soil protection with demands of the crop, soil and climate. The continuous conservation tillage improves soil properties and modifies impact of weather extremes. The aim of the paper was to investigate the changes in four soil physical states affected by soil conservation tillage and to evaluate soil water content in a critical period. The study was carried out on Chernozems applying six tillage treatments, that are loosening, ploughing, tine tillage (a deeper, and a shallower), disk tillage and direct drilling. The investigation suggested that soil conservation was the major solution resulting in the balanced water content (SWC) and penetration resistance values in both treatments under peculiar weather conditions. However, the crumb ratio and the crusted area resulted in significant differences between the treatments, presumably due to the level of surface preservation. Soil water content differed significantly between months, with higher contents in spring and lower values in the end of summer. The higher SWC expected at the beginning of the growing season was reliably fulfilled, but the SWC level for workabilty differed from the optimum.

A reliable tuber yield prognosis requires a complex statistical analysis of potato nutritional status in the fully developed 4^th leaf at the onset of tuberisation. This hypothesis was validated in the series of field experiments conducted in 2006-2008 in Poland. The experimental design was composed of two nitrogen (N) rates (60, 120 kg/ha), two N fertilisers (Urea and Agrotain), two rates of sulfur (0, 50 kg/ha). The marketable tuber yield of cv. Zeus ranged from 31.3 to 59.3 t/ha in 2008 and 2006, respectively. Despite annual variability, the potato presented a good nutritional status. In 2008, the contents of N, Mg, Cu and Zn were about 33% lower as compared to 2006. The stepwise and path analyses indicated N, Mg and Cu as the key yield-limiting nutrients. The diagnosis and recommendation integrated system (DRIS) showed that a slight imbalance of N and Mg did not disturb tuber yield, provided a positive balance of K was maintained. The Mg index, as a result of the DRIS procedure, emerged as the best single predictor of potato yield.

Recycling of phosphorus (P) from municipal waste for the use as a fertiliser can be an alternative to the non-renewable resources of this element as well as a method in the management of civilisation by-products that are a burden to the environment. An innovative phosphorus suspension fertiliser, produced on the basis of ash from incineration of sewage sludge and phosphorus solubilising bacteria Bacillus megaterium was compared in field trials with spring wheat conducted in 2014 and 2015 with superphosphate and phosphorite. The new fertiliser was not inferior to the commercial fertilisers in terms of the effect on wheat yield volumes, the uptake of P by wheat and the sanitary condition of the wheat field, especially when grown protected from weeds, pathogens and pests. It is expected that such a fertiliser can be an alternative to fertilisers produced from non-renewable resources, provided it does not deteriorate the quality of agricultural production and will be safe for the environment.

To estimate the long-term performance and the optimal ratio of feldspathic sandstone with sandy soil, experiments with different ratios of feldspathic sandstone to sandy soil (0:1, 1:1, 1:2 and 1:5 v/v) was conducted. The physical properties as soil texture, water-stable aggregate (WR0.25) content, and the organic carbon content of the composited soil for 6 years, and corn yield for 9 years were determined. Our results showed that after the addition of feldspathic sandstone: (1) soil texture was notably improved, changing from sand loamy soil (1:2 and 1:5) to sand loam soil (1:1) and silt sand soil (1:1) over planting time; (2) content of water-stable aggregate (WR0.25) significantly increased: WR0.25 of treatments 1:1, 1:2 and 1:5 all increased (by 29.26, 31.47 and 11.56%, respectively) compared with that of treatment 0:1; (3) the organic carbon content of the composited soils increased with time in all treatments. After six years of planting, average organic carbon content in treatments 1:1, 1:2 and 1:5 were 1.64, 1.51 and 1.77 g/kg, respectively, which were higher than that of 0:1 treatment; and (4) among the three ratios, treatment 1:2 (12 984 kg/ha) had the highest corn yield, followed by treatment 1:1 (12 040 kg/ha) and 1:5 (11 301 kg/ha). In conclusion, with a good performance, 1:2 was the best ratio of feldspathic sandstone to sand in improving the sandy soil structure of the Mu Us Desert, China.

The effect of agrotechnical elements (crop rotation, fertilisation, irrigation) on maize yield and various chemical characteristics of the soil (pHH2O, pHKCl, hydrolytic acidity (y1)) were examined in a long-term experiment (established in 1983) on calcareous Chernozem in the Hajdúság region of Hungary. The yield obtained in 2019 showed the favourable water supply of the crop year and outstanding nutrient utilisation of maize. In the control (non-fertilised) treatments, maize yield was 8 t/ha in monoculture, 11 t/ha in biculture and 12 t/ha in triculture, while the highest yield obtained with the optimum fertiliser treatment increased to 13, 13.5 and 14 t/ha, respectively. In the long-term experiment established 35 years ago, the pH values of the soil greatly decreased in comparison to the initial value. The following ranges were observed in monoculture: 5.57-6.49 (pHH2O), 4.69-5.34 (pHKCl), in biculture: 5.22-6.62 (pHH2O) and 4.36-5.68 (pHKCl), and in triculture: 5.46-6.29 (pHH2O), and 4.56-5.24 (pHKCl). Hydrolytic acidity values (mono y1 = 7.75-14.75, bi y1 = 11.50-23.00, tri y1 = 10.13-18.38) showed strong soil acidity. In the long-term experiment, a moderate (0.512xx, LSD0.01=xx) correlation between fertilisation and yield and a moderate (0.397xx) correlation between crop rotation and yield could be established on Chernozem. A moderately negative (pHH2O = -0.594xx, pHKCl = -0.543xx) correlation was found between the yield and pH values, while a moderately positive (y1 = 0.409xx) correlation was found between the hydrolytic acidity and yield.

Hydrocarbon contaminants have become a global concern due to their long-term adverse effects on soil ecosystems and human health. Successful implementation of phytoremediation to clean up hydrocarbon contaminants requires the identification of the most effective remediation plant species. Twelve native plant species of the Sudd Wetland in South Sudan were evaluated for their potential application as phytoremediators. The treatments included six total petroleum hydrocarbon (TPH) concentrations of 0, 25, 50, 75, 100 and 125 g/kg soil. The twelve native plant species tested were: Sorghum arundinaceum Desv., Oryza longistaminata A. Chev. & Roehrich, Hyparrhenia rufa Nees, Abelmoschus ficulneus L., Gossypium barbadense L., Nicotiana tabacum L., Sorghum bicolour L. Moench, Eleusine coracana Gaertn., Capsicum frutescens L., Zea mays L., Tithonia diversifolia Hemsl. and Medicago sativa L. Significant differences in phytoremediation rates were observed amongst the treatments with exception of the 125 g/kg soil concentration of hydrocarbon that was lethal to all the plant species. Over 50% TPH reduction in the 75 g/kg soil concentration was observed in contaminated soil phytoremediation in H. rufa, G. barbadense, O. longistaminata, T. diversifolia and S. arundinaceum, making them potential phytoremediators of hydrocarbon-contaminated soil in the Sudd-Wetland of South-Sudan.

The aim of this research is to estimate the influence of a bioeffector (BE) application on dry matter yield and nutrient content (P, K, Ca, Mg, S) in maize (Zea mays L.). Between 2014 and 2016, a field experiment with silage maize as a testing plant was realized on sandy loam Cambisol. The application of Pseudomonas sp. in combination with phosphorus (rock phosphate (RP) or triple superphosphate (TSP)) and nitrogen fertilizers (ammonium nitrate with urea, ammonium nitrate with limestone, calcium nitrate or ammonium sulfate with a nitrification inhibitor) and with different application strategies was studied. The effects of a bioeffector application on the increase of dry matter yields were not confirmed. An important influence on the BE application and its activity was probably those of soil and site conditions and competition of the researched microorganisms with other present microorganisms. Higher yields of dry matter were shown in treatments where P fertilizers were applied. There was almost no difference between the application of RP and TSP. This could be caused by the fact that the soil had a slightly acidic pH value. In this case, the RP showed similar results to the TSP. The application of bioeffector significantly increased Mg, K and S contents in maize above-ground biomass. An increase of the Ca content was almost significant and a tendency towards a higher average content of phosphorus was also recorded.

In a two-year pot experiment, the effect of five growing media on the growth, flowering, decorative value of Pelargonium peltatum cv. Maxime as well as on their uptake of the nutrients and heavy metals were studied. The media were prepared from four composts (made from: sewage sludge 70% or 35%, potato pulp 35%, straw 30% or sawdust 30%) and peat in 1:1, V:V ratio. In the 1^st year of research 7-month-old composts and in the 2^nd year 18-month-old composts were used. Plants cultivated in 7-month-old composts showed better growth-related parameters, created more inflorescences and were more decorative than those cultivated in 18-month-old ones. The medium with compost consisting of 70% sewage sludge and 30% straw gave the best results. Composts application increased nutrients and heavy metals content in pelargonium leaves. Heavy metals content was definitely lower than the value considered toxic to plants.

Optimal soil nitrogen management is vital to crop production and environment protection. Little knowledge is available on crop yield, nitrogen uptake, use efficiency and balance in paddy rice-upland wheat cropping system of China. A thirty-five-year long-term field experiment was designed with nine treatments, including an unfertilized treatment (control), nitrogen (N), phosphorus (P), potassium (K) fertilizer, manure (M), and manure combined with mineral fertilizer treatments. Crop yield, N uptake, use efficiency, and N surplus or deficit amount were determined. The results indicated that rice, wheat yield and N uptake amount in the manure combined with mineral fertilizer treatments were higher than that in the manure alone or mineral fertilizer alone treatments. N use efficiency was the highest in the treatment with manure alone. Soil N input indicated a surplus in the mineral fertilizer in combination with manure treatment, but soil N input indicated a deficit in the control, NPK and M treatments. Considering crop yields, N use efficiency and N balance, recommended N application amount is almost 220 kg N/ha/year in the paddy rice-upland wheat cropping system. Taking into account labour and fertilizer sources, half mineral N and half organic N applications were recommended.

The experiment was carried out to observe the influence of the CULTAN method (controlled uptake long term ammonium nutrition) on grain yield and yield formation of spring barley cultivar Jersey. In four-year small-plot experiment under conditions of the Czech Republic, two methods of nitrogen fertilization were used: conventional surface fertilization and local fertilizer injection rich in ammonium into soil during vegetation at BBCH 29-30 stages. Furthermore, the impact of sulphur amendment in fertilizer and increased dose of fertilizer were observed. Basic dose of nitrogen was 80 kg N/ha, increased dose 130 kg N/ha. At CULTAN treatment, same or significantly higher grain yields were obtained compared to conventional nitrogen fertilization. Grain yield at CULTAN fertilization is formed mainly on the main stem because of reduced tillering; it has the impact on significantly higher percentage of grain retained on 2.5 mm sieve. A tendency to lower protein content in grain was recorded at local injection of fertilizer compared to conventional fertilization. CULTAN-treated plants showed a lesser dependency of qualitative parameters on fertilizer dose and sulphur amendment in fertilizer. A positive influence of the CULTAN method on yield and quality of grain was observed mainly at the less fertile site.

This study was undertaken in order to test whether the development of nodule density over the vegetation period is different in lucerne stands grown for 1, 2 or 3 years continuously. For rapidly assessing nodule density in the field, a modified profile wall method was applied. Nodules were counted on a vertical profile wall, after spraying away a 2 cm layer of soil. For validating this method nodule density was determined on roots washed from monolith samples. Field data indicate that there is a shift of nodulation towards deeper soil layers with increasing maturity of lucerne stands. In 1-year lucerne nodulation was limited virtually to the top 15 cm of soil. In the 15-30 cm soil layer and in the subsoil (30-80 cm), nodule density increased with the cropping duration (1 year < 2 years < 3 years). Temporal decreases in nodule density during the vegetation period associated with dry spells were more pronounced for 2-years as compared with 3-years lucerne.

The aim of the study was to determine the interaction of herbicides and herbicides with biostimulants on the accumulation of dry matter and starch in potato tubers. In a three-year field experiment based on the method of randomised sub-blocks, two factors were taken into account. The first factor were potato cultivars: Bartek, Gawin, Honorata. The second factor were five methods of herbicides and biostimulants application: (1) the control object without chemical protection (CO); (2) herbicide linuron + clomazone (Harrier 295 ZC) (H); (3) herbicide linuron + clomazone (Harrier 295 ZC) and biostimulant Ecklonia maxima (Kelpak SL) - (H + K); (4) herbicide metribuzin (Sencor 70 WG) - (S); (5) herbicide metribuzin (Sencor 70 WG) and biostimulant sodium para-nitrophenol, sodium ortho-nitrophenol, sodium 5-nitroguaiacol (Asahi SL) - (S + A). The cultivars and weather conditions significantly affected the content and yields of dry matter and starch. The herbicides and biostimulants used determined the starch accumulation as well as dry matter and starch yields. Most starch in tubers (more by 3.7 g/kg) and the highest dry matter and starch yields (more by 2.87 and 1.79 t/ha, respectively), compared to the control object, were obtained after the application of the herbicide Sencor 70 WG and biostimulant Asahi SL.

In order to understand and clarify the impacts of straw return on maize production and field CO₂ emission in Northeast China, the most important agricultural base of the nation, a field experiment was conducted in 2012-2015, including no straw return (CK), straw amendment at 4000 kg/ha (S₄), and at 8000 kg/ha (S₈). The average grain yield was found significantly promoted by the two straw treatments, with comparably increased magnitudes of 11.0% and 12.8% for S₄ and S₈, respectively, and the benefits were gradually enlarged with increasing experimental duration. Although straw return tends to reduce slightly the harvest index, it was detected that it exerted significantly positive impacts on nitrogen harvest index. These results implied that added straw could lead to raising grain yield and enhancing nitrogen use efficiency simultaneously. In 2015, our monitoring showed that CO₂ emission was elevated with intensified use of straw, and S₄ and S₈ decreased carbon emission efficiency by 7.3% and 13.6%, respectively. However, there was no statistical difference between S₄ and CK. Overall, straw addition at the rate of 4000 kg/ha accompanied with inorganic fertilizer was recommended to be adopted in Northeast China, which was considered as a sustainable and relatively environment-friendly agricultural technique during maize production.

A field experiment was carried out in the years 2012-2018 in Poland in a split-plot design. The aim of the study was to determine the long-term effect of legumes as forecrops on the productivity of rotation with nitrogen fertilization. The rotation included: legumes + spring barley (SB), winter rape (WR), winter wheat (WW) and winter wheat. The study was conducted as a two-factorial field experiment with four replications. The present study showed that legumes as forecrops increased the yield of all after-harvest crops in rotation. Yielding of these crops also depended on nitrogen fertilization and position in the rotation. After comparison of the influence of nitrogen fertilization on yield of cereals, it was observed that the effect of this factor was greater for WW cultivated in the fourth year of rotation than for WW cultivated in the third year of rotation. In relation with control, each dose of nitrogen fertilization caused a significant increase of WR and cereals yield, but the dose of 180 kg N/ha did not increase yield significantly in comparison to the dose of 120 kg N/ha. There was also negative agronomic N-efficiency observed between doses of 120-180 kg N/ha, which means that it is not necessary to use 180 kg N/ha, especially if there are legumes in crop rotation.

The efficacy of using maize (Zea mays L.) as a suitable substitute for other crops with high arsenic (As) accumulation in As-contaminated farmlands remains debated. Here, the As uptake capacity and the stability of accumulated As of different maize cultivars were studied using pot and field experiments, outdoor investigations and literature data analysis. When the total and available soil As levels were 238.8 and 8.1 mg/kg, respectively, grain As ranged from 0.03 to 0.07 mg/kg, significantly lower than the acceptable As limit (0.5 mg/kg) for maize in China. The results of field investigations and literature data analysis also supported this observation. Maize is a crop with low grain As, thus, making it suitable for substitution planting in As-contaminated farmlands. Further, grain As concentration varied among different maize cultivars. The planting of normal and waxy maize is prioritized over the sweet maize as the first one has lower available bio-concentration factor (aBCF) of 0.007 for grain and higher accumulated As stability among its cultivars (CV < 10%) than those for sweet maize (aBCF = 0.01 and CV = 35.5%). Arsenic compartmentalization in the roots and low As upward migration into the grain were responsible for the low grain As of maize.

Selenium (Se) is a significant trace element for human and livestock animals because of its physiological functions. Se in plants, especially in the crop plants, is treated as a critical dietary source. The effects of foliar spray together with soil application of Se on Se uptake, distribution in common buckwheat (Fagopyrum esculentum M.) plants were discussed in this study. The results showed that both foliar spray and soil application of Se increased Se uptake in common buckwheat significantly (P < 0.05). The highest Se content was observed in leaves (113.37-690.75 μg/kg), followed by roots (28.98-283.78 μg/kg), grains (26.49-135.89 μg/kg) and stems (23.19-86.80 μg/kg). Se content in grains had the highest correlation coefficient (0.827 and 0.845) with soil Se application treatments. Grain yield of F1 (5 g Se/ha for foliar spray) was 3.65% and 10.25% higher than that of F0 (0 g Se/ha for foliar spray) in two study years, respectively. Under soil Se application conditions, mean grain yields fluctuated from 2890.5-3058.6 kg/ha, 2966.4-3352.8 kg/ha in 2012/2013, respectively. These results indicated a significant interaction effect of foliar spray Se and soil Se application on Se accumulation in common buckwheat. Appropriate Se application might improve common buckwheat grain yield.

Dung deposited by grazing animals is a key driver affecting sward structure and nutrient cycling in pastures. We tested herbage and soil properties in three types of tall sward-height patches (> 10 cm): (i) patches with dung under intensive grazing; (ii) patches with dung under extensive grazing; and (iii) patches with no dung under extensive grazing. These patches were compared with grazed swards under intensive and extensive grazing. Analyses indicated no significant effect of different types of patches on plant available nutrients. Herbage nutrient concentrations from the different types of patches differed significantly. The highest concentrations of nitrogen (30.65 g/kg), phosphorus (4.51 g/kg) and potassium (22.06 g/kg) in the herbage dry matter were in the tall patches with dung presence under intensive grazing regime because of nutrients from dung utilized for sward regrowth. Regardless of dung presence, similar herbage nutrient concentrations were revealed in non-grazed tall sward-height patches in extensive grazing regime. The presence of dung did not have any effect on the plant available nutrients in any type of patches, therefore we suppose that non-utilized nutrients were probably leached, volatilised or transformed into unavailable forms and thus soil nutrient enrichment was low.

Physicochemical properties of the tuber as a commercial product differ according to environmental conditions of the area and the growing season. The knowledge about how weather affects these characteristics, allows estimating the correct selection of the cultivars in order to obtain the highest yields or desired physicochemical qualities. In this sense, the effect of the main meteorological factors on the physicochemical characteristics (size, texture, dry matter, soluble solids, phenols, flavonoids, carotenoids and inhibitor concentration (IC₅₀)) of 8 potato cultivars growing in A Limia (North-West Spain) was analysed. The study was conducted during three consecutive years (2014-2016) and the results presented significant differences in the analyzed parameters between years (P < 0.05). Spearman's correlations and principal component analysis showed that the tubers of 2014 (with colder weather conditions) had the highest phenol content and the lowest flavonoids and carotenoids content. Therefore, the temperature positively favoured the flavonoid content and carotenoid content (samples from 2016), although the size of potato tubers was considerably smaller.

Crop growth is a key factor that effects nitrous oxide (N₂O) emission in farmland soil. Clarification and quantification of the impact of maize growth on N₂O emission are important to guide maize planting and patterns, which is also useful for building model to simulate N₂O emission in an agroecosystem. In this study, we carried out a three-year (2013-2015) field experiment to evaluate the contribution of maize growth on N₂O emission using a split-plot design. The factors included planting versus not planting maize, and four rates of nitrogen (N) application (0, 150, 300, 450 kg N/ha). Our results showed the impacts of maize growth on N₂O emission decreased linearly with the growth of maize from the 43^rd day after sowing (y = -1.07x + 26.85, R² = 0.95). Nitrogen fertilizer application can reduce the impacts of maize growth on N₂O emission. The impact of maize growth on soil NH₄⁺-N and NO₃^--N are similar to N₂O emission, and they have a strong correlation. We concluded that maize growth reduces soil N₂O emission but N application can exert an antagonistic effect, and the impact of maize growth on soil NH₄⁺-N and NO₃^--N largely determines the impacts of maize growth on N₂O emission.

Relatively little is known about potassium leaching losses following harvest of silage maize. While direct negative impacts on the environment are unlikely, losses of K with leaching need to be known for accurate balancing, especially on coarse textured soils, where K can be a critical element. In a four-year field experiment the effects of fertilizer forms (inorganic, cattle slurry and pig slurry) and four levels of N input (0, 80, 160, 240 kg N/ha) with corresponding amounts of K on the nutrient balances and leaching of K from silage maize grown on a sandy soil were investigated using suction cups. After four years, surplus of K from cattle slurry led to higher lactate-soluble K in the topsoil. Potassium leaching differed between years with different amounts of rainfall during winter. Annual leaching losses of K increased with N and K input and amounted to 38 kg K/ha, while fertilizer form had no significant effect. Losses of K increased with increasing N leaching (R² = 0.69). We conclude that in maize production on coarse textured soils and under conditions of high N leaching (86-152 kg N/ha), K leaching can be large (6-84 kg K/ha) and constitutes a relevant part of K balances (-84 to +127 kg K/ha).

The effect of mineral fertilizer (F) and mineral combined with organic fertilizer (MF) on N₂O flux in grassland and cornfield was investigated for one year in Southern Hokkaido, Japan. Annual N₂O flux was higher in grassland than in cornfield, and it was higher in MF plot (14.9 kg N/ha/period) than in F plot (11.1 kg N/ha/period) in grassland. However, in cornfield, the annual N₂O flux was equal between both plots (5.6 kg N/ha/period). These results clarified that high nitrogen application was not always responsible for the high soil N₂O flux. N₂O flux was significantly correlated with air, soil temperature and water-filled pore space. More than 80% of the annual N₂O flux occurred before freezing and less than 4% during melting period. Denitrification was the main process of N₂O flux during study, it was evidenced by the distribution of N₂O and NO ratio which is from 1 to 1000. The denitrification activity (DEA) potentially increased in grassland soil in the beginning and the end of winter season when NO₃-N was abundant; on the other hand the abundance of carbon potentially increased DEA in cornfield soil.

Soil erosion by water has become an issue in the cultivation of maize (Zea mays L.) on sloping lands in recent years. The following three technologies of tillage have been assessed: disc cultivator, strip-till and no-till (raw land). Seeding machine Kinze 3500 was used for sowing maize cultivar Silvinio FAO 210. The experiments were conducted within the years 2013, 2014 and 2016. Erosion was evaluated under simulated rain in three stages of maize growth. The following parameters of each tested tillage treatment were measured: water infiltration (mm), soil loss (converted to t/ha), dry matter yield of the aboveground biomass and grain yield. The results confirmed that no-till technology reduced water erosion to the value of 0.40 t/ha. This technology along with the row spacing of 0.75 m tended to bring higher yields of aboveground biomass (13.40 t/ha). Tillage and phacelia as a catch crop increased water infiltration in the soil.

The effect of sugar beet seed (primed and non-primed) on field emergence and root yield of sugar beet was examined. The experiment was realized in the years 2012-2014 at an Experiment Field Station of Warsaw University of Life Sciences - SGGW Faculty of Agriculture and Biology in Skierniewice (51°97'N, 20°19'E) in Poland. The experimental factor was diversified seed material of the same cultivar of sugar beet - typical seeds, traditionally prepared for sowing (non-primed seeds) and seeds before sowing, subjected to the process of priming. On average for the three years of the study, no significant effect of seed priming on the field emergence was found. On the other hand, the sugar beet emergence on plots with primed seeds was faster, more even and uniform. Seed priming, on average for the three years of the study, significantly increased the mean root mass during harvest. In contrast, priming the seeds did not cause an increase in the final plant density. No significant effect of seed priming on root yield was found, both on average for the studied period and in particular years of the study.