Milan Mesić

NITROGEN USE EFFICIENCY IN WINTER WHEAT

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

Marginal abatement costs for reducing leaching of nitrates in Croatian agriculture

The aim of this paper is to estimate marginal abatement costs (MAC) of N-fertiliser tax policies which aim to prevent NO3 levels from rising. Estimates of MAC provide information on how large reductions in Nfertilisation rates should be before other measures are considered. Based on N-response experiments from Croatian field trials with maize, N-response curves were estimated and profit maximising N-doses were derived. Values of NO3-N concentration in lysimeter water from the same treatments were used to estimate an NO3-leaching function. A sample of 20 Croatian family farms was used to obtain records of producer and input prices as well as actual N-doses. Abatement costs and MAC for an N-tax, a product tax and an Nquota were estimated. The MAC for all the instruments are non-constant and increase at an accelerating rate. The MAC for N-taxes are positive for N-taxes lower than 60%, indicating a net return to society. Reduction rates in fertilisation up to this level should be achieved before considering governmental support for other measures. The N-tax has the lowest abatement cost and the lowest MAC for a particular level of reduction while the N-quota has a lower MAC than the product tax when total reduction levels are below 20 mg NO3 l -1

NITRATE CONCENTRATION IN DRINKING WATER FROM WELLS AT THREE DIFFERENT LOCATIONS IN NORTHWEST CROATIA

The findings confirm that nitrate concentrations in water samples from wells in 3 different locations in Northwest Croatia are significantly different. The highest average nitrate concentration of 28.7 mg L−1 NO3− is related to location Koprivnica, which is the area of intensive agricultural production. At location Krizevci wells are located at suburban area and average nitrate concentration is 26.5 mg L−1 NO3−. Compared to this two values significantly lower average concentration of 4.6 mg L−1 NO3− is determined at location Kalnik in water samples without any influence of agriculture and urbanisation.

Soil type influence on drainage discharge and yield of soybean

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

Influence of mineral nitrogen fertilization on corn grain yield and nitrogen leaching

In a stationary field trial with 10 treatments in 4 replications corn was grown as test crop. Trial treatments are: 1. Check, 2. N0 PK, 3. N100 PK, 4. N150 PK, 5. N200 PK, 6. N250 PK, 7. N250 PK + Phosphogypsum, 8. N250 PK+Zeolite tuff+CaCO3, 9. N300PK, and 10. Black fallow. Nitrogen content has been determined in samples of soil, lysimeter water and plant material. Mineral nitrogen utilization is shown in terms of corn grain yields and the amount of mineral nitrogen applied, together with the results of chemical analyses for nitrogen content in soil and in lysimeter water. According to the results it is possible to conclude that sustainable mineral fertilizer rate for corn in the given agroecological conditions ranges between 150 and 200 kg /ha of mineral nitrogen. Additional amounts of nitrogen can cause increase in yield and in grain nitrogen content, but with stronger adverse effects on water quality.

Changes in soil and crop yield caused by oil incidents

Eksploataciju nafte u svim dionicama, o pocetnih radova rudarskog busenja do izgradnje sustava za otpremu - podzemne mreže naftovoda, prate zahvati i postupci rizicni za okolis. Premda suvremena tehnicka rjesenja i suvremeni materijali koje koristi INA - Naftaplin u svim dionicama pružaju visok stupanj jamstva sigurnosti, mogucnost razlicitih incidenata ipak nije nažalost potpuno iskljucena. Incidenti dovode u opasnost prirodne resurse, ponajprije tlo i vodu, a ovisno o težini, mogu, na krace ili dulje vrijeme dovesti u pitanje namjenu zemljista na kojemu se incident zbio, odnosno iskljuciti mogucnost koristenja zemljista za uzgoj bilja i stoke. U posljednjem desetljecu djelatnici Agronomskoga fakulteta sudjelovali su u izradi mnogih studija koje su se odnosile na procjenu oneciscenosti tla u kome je doslo do naftnoga incidenta, odnosno izradili su studije i elaborate mjera popravke tih tala uslijed nekih nepredviđenih incidenata u rudarskim radovima. U ovom radu izloženi su rezultati jednogodisnjih istraživanja uzgoja ozime psenice u vegetacijskim posudama pri razlicitom stupnju oneciscenja tla naftom. U istraživanjima su pracene promjene u kemijskom kompleksu tla (pH, promjene biljci pristupacnoga fosfora i kalija, sadržaj organske tvari, ukupnih i mineralnih ulja, teskih kovina, policiklickih aromatskih ugljikovodika), sadržaj ukupnih i mineralnih ulja u procjednoj vodi, a isto tako i ostvarene prinose uzgajanoga usjeva - ozime psenice sa istraživanim parametrima (kemijske promjene u biljnom materijalu uzrokovane razlicitim stupnjem oneciscenja tla), kao i promjene sklopa biljaka sto se i izlaže u ovom radu.

Rearrangement of bicyclo[3.2.0]heptyl precursors to the 7-norbornyl cation in the cryogenic SbF5 matrix

The first direct observation by IR spectroscopy in the cryogenic SbF5 matrix was made of the rearrangement of 2- and 3-chlorobicyclo[3.2.0]heptanes (3) and (4), respectively, to the 7-norbornyl cation 1 and its subsequent transformation into the 2-norbornyl cation 5.

Influence of drainpipe spacing on nitrate leaching and maize yield

The objectives of the study were to determine the extent of nitrate leaching and maize yields in four drainpipe spacing variants (15 m, 20 m, 25 m and 30 m). The study was carried out at an experimental reclamation field during a period of five years (growing seasons). Maize was grown as the trial crop and the same agricultural practices were applied in all drainpipe spacing variants in all trial years. Nitrogen fertilization rates varied in different trial years (from 145 kg/ha/year to 175 kg/ha/year). The results indicate that nitrate concentrations in drainage water exceeded the allowable values in a larger part of the year (four to seven months) in all drainpipe spacing variants and maximum values were from 18.15 mg.dm−3 (drainpipe spacing of 15 m in 1999/00) up to 34.71 mg.dm−3 (drainpipe spacing of 25 m in 2002/03). Quantity of nitrogen leached differed from year to year and corresponded to the total nitrogen added with fertilization and annual precipitation. Statistically significant higher maize yields were achieved in most years with the drainpipe spacing of 15 m compared to other drainpipe spacing variants.

Reducing sampling intensity in order to investigate spatial variability of soil pH, organic matter and available phosphorus using co-kriging techniques. A case study of acid soils in Eastern Croatia

ABSTRACT Soil pH, hydrolytic acidity (HA), organic matter (OM) and plant available phosphorus (AP) are factors controlling the environmental-friendly soil management in agroecosystems. These parameters are highly variable in space. The objective of this work is to study spatial variability of pH, HA, OM and AP using several interpolation methods in Eastern Croatia. A total of 1004 (0–30 cm) soil samples were collected, and several univariate and multivariate interpolation performances were tested. The results showed that soils of the study area had high HA and AP, while pH and OM were low. The variogram analysis revealed different spatial structures among studied soil properties and demonstrate a need for variable-rate management. Soil pH and OM had lower spatial variability compared to AP and HA. Ordinary kriging was the most accurate method to estimate the studied variables. The incorporation of auxiliary variables increased the precision of the estimations for HA. Soil AP and OM showed different results for spatial prediction obtained by co-kriging. Overall, the incorporation of pH as auxiliary variable increased the prediction of the models. However, more co-variates should be incorporated in further models, in order to identify with more precision areas that need to be restored.

Sulphur cycling between terrestrial agroecosystem and atmosphere

Central gas station of the natural gas borehole system Podravina is located near the village Molve. It delivers more than a quarter of total energy used in Croatia to its consumers. Over the years, adapting technology to increasingly demanding and rigorous standards in environmental protection has become paramount. Yet, despite all the industry has undertaken to address the risk of harmful substances entering the food chain, a multidisciplinary research team of independent scientists monitors the content of specifi c substances in all components of the ecosystem. This paper presents measurements of total sulphur contents in soil surface [(0 to 3) cm] and subsurface [(3 to 8) cm] layers (study period: autumn 2006 - spring 2010) and in plants (study period: spring 2000 - spring 2010), and the concentration of gaseous sulphur compounds in the air. Concentrations of hydrogen sulphide (H2S) and mercaptans (RSH) were measured from the summer of 2002 until the autumn of 2010, while concentrations of sulphur dioxide (SO2) were measured from the spring of 2008 until the autumn of 2010. The paper also shows total annual atmospheric sulphur (S-SO4) deposition at Bilogora measuring station (study period: 2001 - 2010). Average monthly concentrations of H2S in air varied between 0.2 μg m-3 and 2.0 μg m-3, RSH between 0.1 μg m-3 and 24.5 μg m-3, and SO2 between 0.4 μg m-3 and 2.8 μg m-3 depending on the location and the season of sampling. Mean values of total sulphur in soil and in Plantago lanceolata plant ranged between 610 mg kg-1 and 1,599 mg kg-1 and between 3,614 mg kg-1 and 4,342 mg kg-1, respectively, depending on the soil type, location, and sampling depth. Average values of total sulphur mass ratio for all examined single soil samples (n=80) were 1,080 mg kg-1 for both studied layers, and 4,108 mg kg-1 for all analysed plant samples (n=85). Average total annual atmospheric sulphur deposition at Bilogora measuring station was 6.3 kg of S-SO4 per hectar.