
Rok MihelicUniversity of Ljubljana · Biotechnical Faculty
Rok Mihelic
dr. agr.
About
53
Publications
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Introduction
Conservation (sustainable) agriculture
soil fertility; applied plant nutrition;
biogenic waste management and agriculture in circular economy
Skills and Expertise
Additional affiliations
January 2007 - present
Publications
Publications (53)
Improving soil management is crucial for mitigating climate change by increasing soil organic carbon (SOC). This study addresses the question of whether Slovenian agricultural soils can increase SOC stocks and achieve the 4per1000 initiative (4p1000.org). We calculated the SOC stocks, soil carbon sequestration (SCS) potential of the fine soil fract...
Arthospira platensis and Spirulina platensis microalgae are a rich source of pro-health metabolites (% d.m.): proteins (50.0–71.3/46.0–63.0), carbohydrates (16.0–20.0/12.0–17.0), fats (0.9–14.2/6.4–14.3), polyphenolic compounds and phenols (7.3–33.2/7.8–44.5 and 4.2/0.3 mg GAE/g), and flavonoids (1.9/0.2 QUE/g) used in pharmaceutical and cosmetic f...
Soil organic carbon (SOC) sequestration in agricultural soils is an important tool for climate change mitigation within the EU soil strategy for 2030 and can be achieved via the adoption of soil management strategies (SMS). These strategies may induce synergistic effects by simultaneously reducing greenhouse gas (GHG) emissions and/or nitrogen (N)...
Due to its fibrous structure and high water holding capacity, rock mineral wool (RMW) has boosted the development of hydroponics. Consequently, the amount of waste RMW has also increased tremendously, which has stimulated the research and development of RMW reuse options. In this study, composting and degradability of RMW from hydroponics (gRMW) we...
Soil plays a central role in most aspects of human societies, and there is a large body of literature about sustainable soil management. Nevertheless, soil is currently facing degradation arising from different threats, which undermines sustainable development globally. In order to design effective research and policy strategies, it is necessary to...
The combination of conservation tillage (non-inversion and no-till) with organic farming is rare due to weed problems. However, both practices have the potential to improve soil quality and increase soil organic C (SOC). This study investigated the changes in SOC, microbial biomass, and microbial composition during the transition from conventional...
Livestock management is recognized as the largest source of greenhouse gas (GHG) and ammonia emissions in agriculture. Despite the many available mitigation options, they are often not taken up by farmers even when they are economically beneficial for farms. Effective knowledge transfer is among the critical policy instruments to increase the adopt...
In a one-and-a-half-year study conducted in the ALS6 region in Europe (Ljubljana, Slovenia), the cultivation of microalgae in anaerobic digestate from food waste, mainly Scenedesmus dimorphus and Scenedesmus quadricauda, was investigated in three ponds (1260 L each) under a greenhouse. The effects of changing digestate quality and quantity as well...
Soils are the foundation of agricultural production, ecosystem functioning and human well‐being. Bridging soil knowledge gaps and improving the knowledge system is crucial to meet the growing EU soil policy ambitions in the face of climate change and the ongoing trend in soil degradation. The objective of this article is to assess the current state...
The European Commission has set targets for a reduction in nutrient losses by at least 50% and a reduction in fertiliser use by at least 20% by 2030 while ensuring no deterioration in soil fertility. Within the mandate of the European Joint Programme EJP Soil 'Towards climate-smart sustainable management of agricultural soils', the objective of thi...
Reduced tillage intensity is known to increase soil organic carbon (SOC) in the topsoil, but can also lead to increased microbially derived nitrous oxide (N 2 O) emissions. Although the trade-offs between C sequestration and N 2 O emissions under different agricultural practices have been extensively investigated, the reported results are conflicti...
Carbon sequestration in agricultural soils is an important strategy to mitigate climate change which gained renewed attention in the EU soil strategy for 2030. Stimulation of soil organic carbon (SOC) sequestration can be achieved via soil management strategies. However, these strategies may stimulate greenhouse gas (GHG) emissions such as nitrous...
Algae cultivation in the wastewater as bioremediation technique and production of the biomass for various products is an innovative industrial ecology model. On one hand, algae recover from the wastewater nutrients, organic carbon and minerals that would otherwise be lost. On the other hand, wastewater enables the large-scale production without usi...
A field trial of white cabbage (Brassica oleracea var. Capitata L.) was carried out under the humid temperate climate conditions in Central Slovenia to investigate the effects of calcium ammonium nitrate (0, 180 and 240 kg N ha−1) and gypsum (0 and 40 kg S ha−1) fertilisation on yield, yield quality (nitrate, glucosinolate levels and glucosinolate...
In this study, fermentation-based organic fertilizer (OF) was produced from the aboveground parts of Fallopia japonica (Houtt.) Ronse Decr. The quantity of N in OF (17.2 kg t−1 fresh lactic-fermented OF) was higher than average in cattle farmyard manure, but on a comparable level to solid poultry and rabbit manure. The OF was applied on a field to...
This work was designed to investigate the influence of artificial aeration on the sludge decomposition process in
mesocosm sludge treatment reed beds (STRBs). In addition to the typical STRB design, where ventilation is
mainly provided by a drainage pipe, passive aeration via a "chimney" and active aeration via a blower were
introduced. During the...
Maintaining good soil quality is crucial for the sustainability of agriculture. This study aimed to evaluate the effectiveness of the visual soil assessment (VSA) method by testing it on two soil types and two agricultural management practices (AMP) (organic and integrated) that are considered to protect soil quality. We selected two farms with plo...
A protocol for the continuous algal biomass production on the food-waste digestate was established based on the 2018-2020 cultivation in the sub-Alpine region (Ljubljana, Slovenia). Three identical ponds were maintained with different digestate input to design optimal procedure for the production of algal biomass for the agricultural biofertilisers...
Agro-ecosystems experience huge losses of land every year due to soil erosion induced by poor agricultural practices such as intensive tillage. Erosion can be minimized by the presence of stable soil aggregates, the formation of which can be promoted by bacteria. Some of these microorganisms have the ability to produce exopolysaccharides and lipopo...
Although there are numerous studies describing the positive influence of legumes as cereal pre-crops, little information exists on the specific crop rotation soybean–triticale. Besides that, fertilization of soybean is very complex due to its symbiosis with rhizobia where mineral nitrogen could have negative effect, therefore new soil conditioners,...
Three pilot and demo algal pond/bioreactor installations, fed with different wastewaters were designed, optimised and monitored for the wastewater treatment (WWT) efficiency and algal growth.
Algal system in Ljubljana (Koto, Slovenia) is operating continuously already since 2013 (AlgaeBioGas 2014-2106, Saltgae 2016-2019), demonstrating the algal-b...
Project Water2REturn (https://water2return.eu) is based on the circular economy approach and aims at the highest-possible recovery and recycling of nutrients from the slaughterhouse industry wastewater by utilizing a cascade system of biological, chemical and physical technology modules. The recovered nutrients will be turned into value added produ...
Algal pond systems (APS) are being tested at the demo sites in Slovenia and Spain to evaluate and optimise the resource recovery from wastewaters by algae and the subsequent valorisation of algal biomass as a secondary raw material for various products, namely material fillers, biogas substrate, agricultural biostimulants and fertilisers. When APS...
Algal pond systems (APS) are being tested at the demo sites in Slovenia and Spain to evaluate and optimise the resource recovery from wastewaters by algae and the subsequent valorisation of algal biomass as a secondary raw material for various products, namely material fillers, biogas substrate, agricultural biostimulants and fertilisers. When APS...
Agriculture can significantly contribute to climate change mitigation by storing carbon in plants and soils. Worldwide, soil contains about three times as much organic carbon as plants and twice as much as the atmosphere. However, arable soils, especially in the most intense cropping regions have lost much of their soil carbon. The knowledge on man...
Slaughterhouse waste (SW) is potentially a good source of biomethane; however, its excessive ammonia content quickly causes inhibition of microbial processes. Our aim was therefore to remove ammonia from SW before putting it into a biogas reactor. Experimental 120 L pressure container was constructed to observe NH3 removal from diluted slaughterhou...
In this paper we present effects of four paired agricultural management practices (organic matter (OM) addition versus no organic matter input, no-tillage (NT) versus conventional tillage, crop rotation versus monoculture, and organic agriculture versus conventional agriculture) on five key soil quality indicators, i.e., soil organic matter (SOM) c...
Climate change causes droughts, which in turn cause significant physiological stress for soil microorganisms. In this study, we investigated how the abundance of total bacterial, crenarchaeal and fungal communities and the abundance of N-cycling microbial guilds responded to a severe agricultural drought event in a long-term experiment of minimum t...
In this paper we present effects of four paired agricultural management practices (organic matter (OM) addition versus no organic matter input, no-tillage (NT) versus conventional tillage, crop rotation versus monoculture, and organic agriculture versus conventional agriculture) on five key soil quality indicators, i.e., soil organic matter (SOM) c...
A long-term field experiment was run for 12 years to evaluate the impact of minimum tillage (MT) compared to conventional mouldboard ploughing (CT) on soil chemical, physical and microbial properties in a shallow Cambisol formed over fluvioglacial deposits of Drava river in Slovenia. Significant differences between MT and CT were found in vertical...
Sheep's wool and leather shavings tanned without chromium (III) salts would be suitable for fertilization in organic farming, where is the lack of easily accessible fertilizer nitrogen. This hypothesis was tested in a two-year field experiment growing asparagus at Rogelj organic farm in Kranj (Slovenia). The block designed experiment with three rep...
Sheep's wool and leather shavings tanned without chromium (III) salts would be suitable for fertilization in organic farming, where is the lack of easily accessible fertilizer nitrogen. This hypothesis was tested in a two-year field experiment growing asparagus at Rogelj organic farm in Kranj (Slovenia). The block designed experiment with three rep...
Inoculation of a mixture of household organics and shredded wood with inocula from the active phase of composting enhanced mineralization of organic matter and yielded a biologically stabilized product with a more favorable C/N ratio than in a non-inoculated treatment. Analysis of phospholipid fatty acids was used to determine total viable microbia...
Long-term field experiment to follow various effects of conservation soil tillage is conducted at Biotechnical faculty in Ljubljana. The soil is Eutric Gleysol. Conventional treatment with plowing, 22 cm deep P, and conservation treatment by rotary harrow to a depth of 10 cm N, and subplots with compost amendment (-c) and without fertilization (-n)...
Long-term field experiment to follow various effects of conservation soil tillage is conducted at Biotechnical faculty in Ljubljana. The soil is Eutric Gleysol. Conventional treatment with plowing, 22 cm deep P, and conservation treatment by rotary harrow to a depth of 10 cm N, and subplots with compost amendment (-c) and without fertilization (-n)...
Intensification increases the environmental impact of livestock production systems. Efforts to recycle nutrients in livestock manure for crop production will effectively reduce several pollution problems, although general solutions are difficult to devise in view of the diversity in production systems, management strategies and legislation between...
Slovenian rules and regulation concerning fertilization are briefly presented. Current use of fertilizers, manures and compost, as well as nitrogen and humus balances in Slovene agriculture, and soil supply level with phosphorus and potassium dependent on various soils uses is given and critically stressed. Target values and fertilization norms for...
In a 3-years field trial, 6 vegetable crops (cabbage, spinach, lettuce, fennel, onion, Chinese cabbage) were grown, supplied with different fertilisers: farm yard manure (FYM), compost of hens' droppings, shredded wood and bark (COMP), and mineral fertiliser with one (NPK-2) or two applications (NPK-1) of nitrogen during the growing season of the c...
The effect of organic fertilisation on soil N dynamics was observed in two consecutive years of intensive vegetable crop rotations (early cabbage, spinach, lettuce, fennel, onion). Field trials with five treatments (0 = non-fertilised control; COMP = composted chicken manure, shredded wood and bark; FYM = well matured farmyard manure; NPK1 = minera...
The dynamics of mineral N in soil as affected by either organic or mineral N fertilisation during cabbage (from April to July 1997) and spinach (from September 1997 to May 1998) cultivation were observed in a field trial in Ljubljana. Farmyard manure (FYM) and compost from chicken deep layer manure and bark were compared to mineral fertilisation (N...
Zugl.: Giessen, University, Diss., 2003.