Aleksandra Bensa

Liming and fertilization impact on nutrient status in acid soil

Maize (Zea mays L.) genotypes wit It improved nitrogen utilization efficiency (NUE) are of interest to growers. Field experiments were conducted to evaluate the total N uptake in the aboveground biomass and NUE (kg grain per kg of N absorbed in the aboveground biomass). Four commercial hybrids of similar maturity ranking were grown under the high-N (200 kg N ha(-1)) and low-N (1100 kg N ha(-1)) fertilization rates over three years. Growing conditions significantly affected hybrid performance for NUE, which ranged from 42 kg grain kg N-1 in the low-yielding (dry) environment to 55 kg grain kg N-1 under higher yielding environment, When compared to the low-N rate, the average N uptake was by 32% higher at the high-N rate, whereas smaller differences occurred for the aboveground biomass (12%), grain yields (14%), stover N (28%) and grain N (13%) concentrations. Significant differences existed among tested hybrids for grain yield, aboveground biomass, grain and stover N concentration, N uptake and consequently NUE.Hairy vetch (Vicia villosa Roth) and crimson clover (Trifolium incarnatum L.) were evaluated as cover crops during two vegetation seasons in the Mediterranean and Continental area of Croatia. Better tolerance to low winter temperatures was observed for crimson clover. Higher plants (10 to 3 1 cm) before winter and in spring (67 to 117 cm) were measured for hairy vetch, while crimson clover had higher yields of fresh biomass (33.7 to 113.1 t ha(-1)). Concentrations of N (1.53 to 3.34%), P2O5 (0.55 to 1.04%) and K2O (2.02 to 5.32%) in plant tissue were higher for hairy vetch. However, due to higher yields of dry matter, crimson clover accumulated more N (105 to 239 kg ha(-1)), P2O5 (28 to 83 kg ha(-1)), and K2O (105 to 440 kg ha(-1)) than hairy vetch. According to our results crimson clover could be recommended as a cover crop in Mediterranean and Continental area of Croatia.

Herbicides in the soil and waters of river Drava catchment area

The objective of this paper is to present the results of the 15 years long research into the influence of agriculture on soil and water contamination by herbicide residues in a part of the Drava catchment area. The status of triazine herbicides - atrazine, simazine, prometrine and ametrine, and chlortoluron, isoproturon, dicamba, metolachlor, metamintron, terbuthylazine, MCPA and 2, 4-D was monitored in agricultural soil and water of this area in the conditions with or without regular application of herbicides. Amont the 206 plough layer samples analyzed, herbicides were detected in 50 samples (24%) with concentrations varying from 3-119 ng/g. The most frequently detected herbicides were triazine herbicides (atrazine and simazine) owing to their persistence as well as application frequency. The results indicate that, as a rule, alkaline or potentially alkaline herbicides persist longer in soil ; atrazine residues were found as late as 10 months after its application. Acid or potentially acid herbicides were not detected in soil even within one month of their application. Among the total number of analyzed samples of surface and ground watwers, the recorded herbicide concentrations exceeded the maximum allowable concentration, MAC, for single herbicides in drinking water (100 ng/l) in 42% of samples for atrazine, 23% for simazine, 9% for prometrine, 13% for ametrine, 24% for chlortoluron, 25% for isoproturon, 17% for dicamba, 60% for metolachlor, 20% for metamitron, while terbuthylazine, MCPA and 2, 4-D were not detected.

Influences of pipe drainage and fertilization on nitrate leaching

Introduction Leaching of nitrates from soil depends on the amount, frequency and intensity of precipitation, soil properties, crop and crop development stage, evapotranspiration, and nitrogen fertilization, Vidacek et.al. (1996,1999); Nadasy and Nadasy (2006); Nemeth T. (2006) and Josipovic et al. (2006). The problem of nitrate leaching is even more expressed in agroecosystems of hydroameliorated, especially drained, soils because of changed infiltration and filtration capabilities of these soils. Total hydroameliorated areas cover 600,054 ha in Croatia, including 117,856 ha of pipe drainage system area, Vidacek (2006). The objective of this study was to assess the influence of pipe drainage and increasing application of nitrogen fertilizers on leaching of nitrates from soil in winter barley and maize production.

LIMING AND FERTILIZATION IMPACT ON NUTRIENT REMOVAL BY MAIZE AND WINTER WHEAT

Heavy application of mineral fertilizers, base cations leaching and removal with harvested crops lead to soils acidification what could be a limiting factor of the field crops yield. The aim of this study was to provide data for sustainable cropping by evaluating the impacts of liming and fertilization on maize and wheat yield and calcium, potassium and magnesium concentration in plant tissue and removal by above ground mass. The field trials were conducted during two years in a randomized block design in three replicate on two sites in the eastern Croatia. Mineral fertilization had stronger impact on maize and wheat yield than liming. Liming increased calcium concentration in grain and above ground mass, while potassium concentration was influenced by mineral fertilization. Overall, the higher concentrations of base cations were found in vegetative mass of the both crops, with exception of magnesium whose concentration was higher in the wheat grain. Concerning particular nutrient removal significant differences were found, as well as among treatments. Generally, mineral fertilization or its combinations with liming influenced more on the nutrients removal, than liming apart.

Comparison of Chemical Extraction Methods for Determination of Soil Potassium in Different Soil Types

Determining potassium supply of soil plays an important role in intensive crop production, since it is the basis for balancing nutrients and issuing fertilizer recommendations for achieving high and stable yields within economic feasibility. The aim of this study was to compare the different extraction methods of soil potassium from arable horizon of different types of soils with ammonium lactate method (KAL), which is frequently used as analytical method for determining the accessibility of nutrients and it is a common method used for issuing fertilizer recommendations in many Europe countries. In addition to the ammonium lactate method (KAL, pH 3.75), potassium was extracted with ammonium acetate (KAA, pH 7), ammonium acetate ethylenediaminetetraacetic acid (KAAEDTA, pH 4.6), Bray (KBRAY, pH 2.6) and with barium chloride (

SPECTROSCOPIC CHARACTERIZATION OF HUMIC SUBSTANCES OF ANTHROPOGENIC SOILS DERIVED FROM TERRA ROSSA

K_{BaCl_2 }

MINERALNI DUŠIK U TLU I PROCJEDNOJ VODI U UVJETIMA INTENZIVNE RATARSKE PROIZVODNJE NA LOKACIJI VINOKOVŠČAK

KBaCl2, pH 8.1). The analyzed soils were extremely heterogeneous with a wide range of determined values. Soil pH reaction