Meri Engler

Phosphorus fertilization and liming impact on soil properties

Liming caused a significant changes in soil properties modifying soil acidity, nutrients and heavy metal availability. The paper is based on four-year filed trials conducted on two sites near Donji Miholjac in eastern Croatia: dystric luvisol and calcaric regosol. Conducted experiments confirmed that the lowest yield of all four crops was achieved on calcaric regosol. Liming dystric luvisol with 10 and 20 t ha-1 of carbocalk resulted in yield increasing. The highest influence of liming with 20 t ha-1 was on wheat yield increase, than on soybean and the lowest impact was on cabbage and maize yields. Ammonium-lactate soil P test and plant P removal data are sufficient for soil P balancing at low levels or no applied P fertilizer, but more fertilizer indicates that correction factor should be used for calculation impact of applied P fertilizer on increasing soil AL extractable P.

Comparison of Two Soil Phosphorus Analytical Methods in Croatia

Abstract The purpose of this article was to compare soil phosphorus (P) extraction by sodium bicarbonate solution (Olsen P) and by ammonium lactate (AL P) and to create a model for prediction of Olsen P using ordinary soil‐fertility control data. The soils data used in this study included Olsen P, pHKCl, pHH2O, organic matter, AL P, and AL K. Soil pHKCl ranged from 3.5 to 8, organic matter up to 5%, AL K up to 400 mg kg−1, and AL P up to 200 mg kg−1. Olsen P and AL P were significantly correlated, and the difference between them was influenced by soil pH. Regression models included all soil data grouped by soil pH range, which significantly decreased the difference between predicted and measured Olsen P. The validation of the model was conducted on new data sets from field fertilization trials. The results show that Olsen P can be related to AL P and used for fertilizer recommendations instead of AL P.

Four‐Year Dynamic of Potassium on Two Sites Interpreted by Different Soil Tests

Three soil–potassium (K) tests were compared using soil and plant samples collected during fertilization and liming experiments in Croatia on very acid dystric luvisol and slightly alkaline calcaric regosol. Soil samples were analyzed for pHKCl, pHH2O, organic matter, and ammonium lactate (AL, pH 3.75)–extracted phosphorus (P) and K. In addition, K was extracted with ammonium acetate (AA, pH 7) and with ammonium acetate ethylenediaminetetraacetic acid (AAEDTA, pH 4.6). In spring 2003, the dystric luvisol was limed with 0, 10, or 20 t ha‐1 carbocalk (by‐product at sugar beet processing, effective neutralizing value 69.1%). During the next four seasons, four different crops were grown without fertilization, with standard fertilization, and with doubled P amounts. All three soil K tests showed highly significant correlations of fertilization impact on extractable soil K and can be efficiently used for fertilizer recommendations. Balance calculation is closer to results of extractable K on fertilized plots than on control plots and use of AAEDTA or AL than AA extraction.

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