Влияние на биовъглен върху добив от царевица и микробиална активност при Алувиално- ливадна почва

A three-year field experiment with maize was carried out on fluvisol. The aim of the present study was to evaluate the impact of biochar on maize yield at different levels of water stress and its effect on the amount of soil microorganisms. The following variants were studied: control with no biochar addition, and variants with biochar. Biochar was applied in 2 t/ha in 2016, produced by pyrolysis of rice straw, then in 3 t/ha in 2017 and 10 t/ha in 2018, both obtained by pyrolysis of oak bark. These variants were divided into three more depending on the irrigation regime: i.e. non-irrigated, irrigation at dT>0 °C, and irrigation at dT0 и поливен при dT<-1. Установено е, че при неполивни условия, ефектът на биовъглена по отношение на добива от царевица не се проявява и през трите години от добавянето му в почвата. Доказано е, че при условията на поливен воден режим, когато поливките са съобразени с водния стрес на растенията, по-високи добиви от царевицата се получават през третата година, когато и внасянето на биовъглена в почвата е в най-голямо количество (10 t/ha). При това, колкото по-скоро (при по-нисък воден стрес dT<-1) са подадени поливките, толкова по-висок е добивът. Почвената влажност се изменя по-бавно при вариантите с биовъглен като най добри стойности на температурната разлика са получени при поливка при dT<-1 през 2018 година. Направената оценка показва, че влиянието на биовъглена е значително по-голямо върху почвената микрофлора. Най-силно изразен стимулиращ ефект на биовъглена е получен спрямо бактериалните популации

Ecological problems and nitrogen balance in vegetable crops growing

The purpose of this study is to focus on the nitrogen balance and losses in agricultural system. The influence of precipitation, irrigation and fertilizer application on some soil parameters, N-uptake by plant production and N-output by lysimetric water are evaluated in this paper.The study is carried out on Fluvisol, near Plovdiv in Southern Bulgaria under the conditions of field experiments with different vegetable crops (eggplant, green beans and carrots) over the period 2009-2011. The experimental design includes 3 treatments with nitrogen application –N0, N80 and N160 on the background of P80K80 kg.ha-1. The field plots are equipped with modification of Ebermayer type of lysimeters, which collect water from 100 cm depth of soil profile.According the received data it was observed that compensation between the amounts of N input and output was achieved in two variants (N80, N160) for all crops growing. Reducing the nitrogen input to the amount applied by precipitation and irrigation waters is the most ecological-friendly technological decision and very important factor for environment protection

Agricultural practice and nitrogen leaching in a field experiment: Risk analyses using the NLEAP model

vokMTT, Viestintä ja informaatiopalvelut, 31600 Jokioine

Съдържание и износ на основни макроелементи с биомасата и зърното на ечемик (Hordeum vulgare L.) отглеждан като последействие

A field study with spring barley (Hordeum vulgare L.) was conducted on the area of long-term balance experiment in Tsalapitsa village near Plovdiv (Bulgaria), on alluvial-meadow soil. Mineral fertilization was not applied to this crop in order to equalize the area regarding nutrient content. The crop grown before barley was maize with 4 variants of fertilization and one control variant: N0P0, N100Р50, N150Р100, N200Р150, and N250P200. The present study aimed to evaluate the productivity, content and uptake of macronutrients (N, P, K, Ca and Mg) with the biomass of barley, grown as aftereffect. Due to the fertilization of the previous crop, different residual amounts of nutrients in soil lead to significant variability in barley yields. The highest grain yield was obtained in variant N250P200 - 3978.8 kg/ha, approximately four times higher than the yield in the control. Nitrogen content in the grain of barley is also influenced by the variants, being the lowest in the control - 1.25%, and the highest in variants N250P200 and N200P150 - 2.13% and 2.09%, respectively. The variability of P, K, Ca and Mg contents by variants is lower. With the total biomass of barley, depending on the variants of the experiment, between 23.2 - 132.7 kg N/ha; 26.6 - 146.3 kg K/ha and 9.3 - 36.5 kg P/ha were exported from the field. A good regression relationship was found between barley grain yield and nitrogen export with the total biomass (R2 = 0.859, P≤0.001).Върху площта на многогодишен балансов опит в ОП Цалапица, Пловдивско (България), на Aлувиално-ливадна почва е проведен полски експеримент с пролетен ечемик (Hordeum vulgare L.). При този посев не се прилага минерално торене, с цел изравняване на площта по отношение на съдържанието на хранителни елементи. Предшественик на ечемика е царевица с 4 варианта на торене и един контролен вариант: N0P0, N100Р50, N150Р100, N200Р150 и N250P200. Целта на настоящото изследване е да се оценят продуктивността, съдържанието и износа на основни макроелементи (N, P, K, Ca и Mg) с биомасата на ечемик, отглеждан като последействие. Вследствие на торенето на предшественика остатъчните количества хранителни елементи в почвата водят до доказано вариране на добивите от ечемик. Най-висок добив зърно е получен при вариант N250P200 - 3978.8 kg/ha, който е приблизително 4 пъти по-висок, отколкото в контролата. Съдържанието на азот в зърното на ечемика също се повлиява доказано от вариантите в опита, като е най-ниско в контролата – 1.25%, а най-високо във варианти N250P200 и N200Р150, съответно 2.13 и 2.09%. Съдържанието на пепелни елементи - P, K, Ca и Mg, варира по-слабо по варианти. С получената обща биомаса на ечемика, в зависимост от вариантите в опита от полето се изнасят между 23.2 kg и 132.7 kg N/ha, между 26.6 и 146.3 kg K/ha и между 9.3 и 36.5 kg P/ha. Установява се много добра регресионна зависимост R2 = 0.859, P≤0.001 между добива от зърно и износа на азот с общата биомаса на ечемика

Assessing suitability of water for irrigation in Bulgaria

The drying up, the intensive usage of near future almost all water reserves of good quality in lots of regions in Bulgaria and their irregular distribution on the country area, has shown that the part of the available set up irrigated area should use water of poorer quality. Quality control on the water for irrigation is needed to avoid emerging problems as decreasing the yield of agriculture and worsening its quality at using inadequate quality water.The development of a assessing system for the suitability of the water for irrigation aims to protect cultivated crops at using lower quality irrigation water. The system use laboratory analysis information, cultivated crops data, soil and agro-climatic characteristics, irrigation technology, legal rules and some additional parameters. The paper presented the main directions for determination of applicability of irrigation water at various crops on the basis of the assessment of its quality, exactly - the construction of irrigation water quality indicators database and assessment of the irrigation water quality, focusing on the methodology for decision-making for applicability of irrigation water at various crops and on the recommendations’ elaboration for irrigation water considering qualitative parameters of the available water. The database includes permanent information about the impact of the irrigation water quality on the agricultural production, personal information about water users, data about the water sources and its water samples, water indicators from laboratory analysis.The drying up, the intensive usage of near future almost all water reserves of good quality in lots of regions in Bulgaria and their irregular distribution on the country area, has shown that the part of the available set up irrigated area should use water of poorer quality. Quality control on the water for irrigation is needed to avoid emerging problems as decreasing the yield of agriculture and worsening its quality at using inadequate quality water.The development of a assessing system for the suitability of the water for irrigation aims to protect cultivated crops at using lower quality irrigation water. The system use laboratory analysis information, cultivated crops data, soil and agro-climatic characteristics, irrigation technology, legal rules and some additional parameters. The paper presented the main directions for determination of applicability of irrigation water at various crops on the basis of the assessment of its quality, exactly - the construction of irrigation water quality indicators database and assessment of the irrigation water quality, focusing on the methodology for decision-making for applicability of irrigation water at various crops and on the recommendations’ elaboration for irrigation water considering qualitative parameters of the available water. The database includes permanent information about the impact of the irrigation water quality on the agricultural production, personal information about water users, data about the water sources and its water samples, water indicators from laboratory analysis

Effect of long-term fertilizer application in maize crop growing on chemical element leaching in Fluvisol

The study characterized the regime of nutrient leaching under different nitrogen and phosphorus supply of irrigated maize grown as monoculture on Fluvisol for the period 1999-2008 and additionally studied in the years 2009, 2010, and 2011. The aim of the study was to estimate the effect of long-term fertilizer application on the leaching of nutrients from the soil under maize grown as monoculture. The experiment design included four nitrogen fertilizer rates (B1-control, B5, B4, B3, B2) calculated to compensate 50, 75, 100, and 125% from the plant N uptake, respectively. The field plots were equipped with lysimeters (at 50 and 100 cm depth) for studying the relationship between the applied fertilizer rates and the nutrient concentrations in the lysimetric water. The greatest nitrogen concentration in lysimetric water was observed under variant (B3-N200 P150) throughout the study period and the highest N losses were registered (36 kg ha-1) in 2010 under the same treatment (B3). A very good correlation was found between the N rates, calcium, and magnesium losses. Lysimetric water component compensation shows that agricultural activities have only influenced the speed of weathering and had no significant effect on the rates

Effect of long-term fertilizer application in maize crop growing on chemical element leaching in Fluvisol

The study characterized the regime of nutrient leaching under different nitrogen and phosphorus supply of irrigated maize grown as monoculture on Fluvisol for the period 1999-2008 and additionally studied in the years 2009, 2010, and 2011. The aim of the study was to estimate the effect of long-term fertilizer application on the leaching of nutrients from the soil under maize grown as monoculture. The experiment design included four nitrogen fertilizer rates (B1-control, B5, B4, B3, B2) calculated to compensate 50, 75, 100, and 125% from the plant N uptake, respectively. The field plots were equipped with lysimeters (at 50 and 100 cm depth) for studying the relationship between the applied fertilizer rates and the nutrient concentrations in the lysimetric water. The greatest nitrogen concentration in lysimetric water was observed under variant (B3-N200 P150) throughout the study period and the highest N losses were registered (36 kg ha-1) in 2010 under the same treatment (B3). A very good correlation was found between the N rates, calcium, and magnesium losses. Lysimetric water component compensation shows that agricultural activities have only influenced the speed of weathering and had no significant effect on the rates

Comparative Corrosion Characterization of Hybrid Zinc Coatings in Cl&minus;-Containing Medium and Artificial Sea Water

The presented investigations demonstrate the corrosion behavior and protective ability of hybrid zinc coatings specially designed for combined protection of low-carbon steel from localized corrosion and biofouling. Polymer-modified copper oxide (CuO) nanoparticles as widely used classic biocide are applied for this purpose, being simultaneously electrodeposited with zinc from electrolytic bath. The corrosion behavior of the hybrid coatings is evaluated in a model corrosive medium of 5% NaCl solution and in artificial sea water (ASW). Scanning electron microscopy (SEM) and atomic force microscopy (AFM) are used to characterize the surface morphology of pure and hybrid zinc coatings. Contact angle measurements are realized with an aim to determine the hydrophobicity of the surface. X-ray photoelectron spectroscopy (XPS) is applied for evaluation of the chemical composition of the surface products appearing as a result of the corrosion treatment. Potentiodynamic polarization (PDP) curves and polarization resistance (Rp) measurements are used to estimate the protective characteristics in both model corrosive media. The results obtained for the hybrid coatings are compared with the corrosion characteristics of ordinary zinc coating with the same thickness. It was found that the hybrid coating improves the anticorrosion behavior of low-carbon steel during the time interval of 35 days and at conditions of external polarization. The tests demonstrate much larger corrosion resistance of the hybrid coating in ASW compared to 5% NaCl solution. The obtained results indicated that the proposed hybrid zinc coating has a potential for antifouling application in marine environment