Blaženka Bertić

Relationships among Chloroplast Pigments Concentration and Chlorophyllmeter Readings in Soybean under Influence of Foliar Magnesium Application

The influence of foliar magnesium (Mg) application before flowering on chloroplast pigment indices was investigated in a 2‐year field experiment with five soybean cultivars. Acetone extraction of pigments (chlorophyll a and b, total chlorophylls, and carotenoids as well as their ratios) was compared to chlorophyll meter (SPAD‐502) readings. The untreated plants showed significant influence of cultivar on pigment concentrations, and pigment ratios were year‐dependant. Foliar fertilization with Mg influenced chlorophyll concentration mostly in the year 2004, and carotenoids were not altered by Mg treatment. Cultivar differences prevailed in the next year when Mg treatment was less effective. The interactions among year, cultivar, and Mg application were showed to be significant for a particular parameter. The SPAD‐502 readings significantly correlated with pigment concentrations only in the untreated plants in 2005. However, the foliar treatment influenced significantly SPAD readings in 2004, through the interaction with cultivar in once‐treated plants and as a single factor in twice‐treated plants. Grain yield was under significant positive influence of leaf Mg concentration in both years, and one treatment with Epsom salt was enough for significant grain yield increase.

Excessive iron and aluminum uptake and nutritional stress in corn (Zea mays L.) plants

Abstract Disorders of corn growth were observed at 6–9 leaf stage in the growing season of 1986. They were manifested as growth retardation and chlorosis. Chlorotic corn showed signs of either P, Zn or K deficiency. Excessive Fe and Al uptake in the leaves (4.7, 3.1, 1.9 and 2.2 times higher Fe concentrations than in normal plants for chlorosis induced by P, Zn and K deficiency and in the cases of atypical chlorosis, respectively). Depending on the form of chlorosis, the dry matter of chlorotic plants was 4.6 to 10 times lower than in normal plants.

Mineral composition of alfalfa ( Medicago sativa L. ) as influenced by liming and manure application

The objecive of this research was to assess the mineral composition of alfalfa grown on a pseudogley soil limed with carbocalc (byproduct of sugar factory, containing 70.5% CaCO3) and/or enriched with organic matter by cattle manure application. Nitrogen, phosphorus, potassium, magnesium, calcium, iron, manganese, zink and copper concentration were analysed in two cuts of alfalfa, grown on acid soil for three consecutive years (2002-2004).It was concluded that liming and manure application had highly significant influence on mineral composition of alfalfa, preventing possible toxic concentrations of heavy metals. Such soil amendments enable growth of this important crop on less favorable, acid soil through soil pH adjustment and regulation of plant nutrient availability, whereas plant mineral composition can differ significantly seasonally.

Comparability of Electroultrafiltration and Ammonium Acetate-Lactate Extraction Data for Phosphorus and Potassium in Pseudogley Soils

The aim of this research was to compare two standardized soil extraction methods [electroultrafiltration (EUF) and ammonium acetate–lactate (AL)] regarding potassium (K) and phosphorus (P) availability in pseudogley soils. In total, 60 pseudogley soil samples from 12 agricultural sites in eastern Croatia (each represented by five soil samples—replicates) were simultaneously analyzed by both methods. The relations of K and P with other important soil traits [pH, selective mineral clay content (SMC), humus content] were established by multiple regression analyses. Furthermore, a highly significant regression equation (P ⩽ 0.01) was established for AL–phosphorus pentoxide (P2O5), using EUF‐P‐I and EUF‐P‐II separately as well as soil pH value determined in 1 M KCl as independent variables. The actual P amount extracted by AL differed by 9% from the value predicted by the regression function. According to the highly significant multiple regression function (P ⩽ 0.01), AL‐extractable dipotassium oxide (K2O) can be approximated using EUF‐K (sum of EUF‐K‐I and EUF‐K‐II fraction), SMC, and the EUF‐K‐Q (ratio of EUF‐K‐II and EUF‐K‐I) as the independent variables. A deviation of calculated AL‐K2O value from the extracted amount of K was 4%. These results point out the possibility of the comparison of EUF and AL extraction data in the evaluation of K and P availability in pseudogley soils. The necessity of more comprehensive research regarding the comparison of the EUF and AL method, taking into account plant nutrient acquisition specificity and a great number of interrelated soil and climate factors, was suggested.

Influence of liming on soil acidity and iron availability

Abstract The influence of liming and phosphorus application (in the range to 20 t of hydrated lime and to 480 kg P2O5/ha, respectively) on the status of plant available Fe was studied in acid soil of East Croatia. Due to application of the highest rate of line, Fe content in soil decreased from 34.1 ppm (unlimed plot) to 14.1 ppm Fe. At the same time, titratable acidity decreased from 16.0 to 1.5 raequ/100 g of soil and exchangeable acidity from 3.0 to 0.1 mequ/100 g of soil, while soil pH in KCl increased from 4.03 to 5.42. Phosphorus application did not significantly affect these soil characteristics.

Liming of acid soils in Osijek-Baranja County.

The negative trend of soil degradation process increases with intensive agricultural production. Therefore, there is a need for soil conditioning like liming, humification, fertilization, etc. to improve soil quality. One of the major problems that occur on agricultural soils of Croatia is acidification. A downward trend of soil pH is mainly present in soils of poor structure with intensive agricultural production. In agricultural practice liming often needs to rely only on the pH value, without determining the hydrolytic acidity, CEC or soil texture. Due to the above mentioned facts, calculation of liming for Osijek-Baranja County was conducted with the help of ALRxp calculator, which takes CEC, soil pH in KCl, hydrolytic acidity, bulk density of soil, soil textural class and depth of the plow layer to 30 cm into account. Low soil pH values have a great influence on soil suitability for crops as well as on the deficit of calcium and magnesium. All of these lead to the degradation of soil structure, and can even lead to disturbances of plant nutrition in some production areas. On such soils, liming would be imperatively required, but with caution because an excessive intake of lime materials, especially without the necessary analysis, causes a decline in organic matter and reduces accessibility for plant uptake of microelements.

The effect of year, genetic and morphologic specificity at the kernel mass, chemical composition and vigour of the maize seed

Oil rape is a valuable fodder because in early spring and late autumn it produces green forage used for the nutrition of domestic animals. It has been replacing sunflower and soy in colder and wetter regions. It is additionally advantageous because it leaves behind more nitrogen in soil, which is beneficial to other plants in plant rotation. There are some possible ways for the fixation of nitrogen in soil and they are as follows: by the means of oil rape straw ; by relatively long roots ; by the action of nitrogen bacteria, which perform the nitrogen synthesis within their root system, which is the case in some leguminous plants. Oil seed rape is expected to be wider used in crop rotation of West and Middle Europe, Croatia included. Due to this various sorts have been introduced and potential positive impacts have been studied in order to boost the process. This paper presents information on barley and wheat yield in case when they were sown after oil seed rape and corn. The aim of the research is to determine the presence of positive impacts upon the soil with special attention paid to a potential increase of nitrogen content after oil seed rape was grown. The preceding crops had statistically significant effect. Rape yield was significantly higher compared to the one with corn as preceding crops. Very similar results were obtained in 2007.The maize hybrids seed from three different FAO groups (FAO 400, FAO 500 and FAO 600) in four fractions (KO, KP, SO and SP) produced in two climatically different years (extremely dry 2000 and extremely wet 2001) had been different in quality and chemical composition. The effects of year, genetic specifity and seed fraction at the kernel mass, chemical composition (starch, proteins, cellulose, oil and moisture content) and seed vigour have been evaluated. The influence of agroecological conditions during two production years have been exposed at seed chemical composition and vigour indicators (cold test – CT and bulk seed electrical conductivity - EC). The genetic specificity and seed fraction had significant influence at all tested indices, with the exception of the influence of the fraction at the starch content