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Effects of growing spring barley in organic agriculture as a result of constructed bacterial consortia and living mulch
The Response of the Mycobiome to the Biofumigation of Replanted Soil in a Fruit Tree Nursery
In a long-term monoculture with fruit trees and tree nurseries, it is necessary to regenerate the soil due to the risk of apple replant disease (ARD). The occurrence of ARD is manifested in the structure of the mycobiome. The assumption of our experiment was that the use of oil radish (Raphanus sativus var. oleifera), white mustard (Sinapis alba), and marigold (Tagetes patula L.) as phytosanitary plants for biofumigation would provide crops with nutrients, improve soil physicochemical properties, and influence the diversity of microbiota, including fungal networks, towards a beneficial mycobiome. Metagenomic analysis of fungal populations based on the hypervariable ITS1 region was used for assessing changes in the soil mycobiome. It showed that biofumigation, mainly with a forecrop of marigold (Tagetes patula L.) (R3), caused an improvement in soil physicochemical properties (bulk density and humus) and the highest increase in the abundance of operational taxonomic units (OTUs) of the Fungi kingdom, which was similar to that of agriculturally undegraded soils, and amounted to 54.37%. In this variant of the experiment, the most OTUs were identified at the phylum level, for Ascomycota (39.82%) and Mortierellomycota beneficial fungi (7.73%). There were no such dependencies in the soils replanted with forecrops of oilseed radish (Raphanus sativus var. oleifera) and white mustard (Sinapis alba). Biofumigation with marigold and oil radish contributed to a reduction in the genus Fusarium, which contains several significant plant-pathogenic species. The percentages of operational taxonomic units (OTUs) of Fusarium spp. decreased from 1.57% to 0.17% and 0.47%, respectively.
Nitrogen Hotspots on the Farm—A Practice-Oriented Approach
The proactive management of nitrogen (N) on a farm is the best way to protect the environment against N pollution. The farm is the basic business unit, where simple and low-cost methods of identifying and ameliorating weaknesses (nitrogen hotspots) in the N-flow chain can be applied. The basis for the effective use of mineral N fertilizers (Nf) is the farmer’s knowledge of the farm’s own N resources, their quantity, and the potential availability for growing crops. These resources include both primary sources of N (N2 fixed by legumes) and those that are recyclable, which include crop byproducts and manure. On the other hand, crop requirements must be accurately quantified to exploit the yield potential of the crop varieties grown on the farm. The basic challenge for the farmer is to maximize the use efficiency of the N resources. In this regard, the farmer has two diagnostic tools available to recognize nitrogen hotspots and to quantify N resources. These are (1) the N balance method (difference between the N inputs and outputs), which allows for a surplus or deficiencies in the N-flow between farm units (fields, livestock housing) to be identified, and (2) the nitrogen gap, which is based on the amount of Nf applied and the yield of a given crop. It is possible to calculate the maximum attainable yield as well as identify the fields on the farm that require a correction of N management.
Additives Improving the Efficiency of Biogas Production as an Alternative Energy Source—A Review
Additives for anaerobic digestion (AD) can play a significant role in optimising the process by increasing biogas production, stabilising the system and improving digestate quality. The role of additives largely boils down to: (i) enhancing direct interspecies electron transfer (DIET) between microbial communities, resulting in improved syntrophic interactions and methane production rates (e.g. biochar, magnetite and carbon nanotubes), (ii) adsorption of toxic substances that may inhibit microbial activity (e.g. activated carbon, zeolites), (iii) improving microbial activity and increasing process stability (e.g. cobalt, nickel, iron, selenium), (iv) maintaining optimal pH levels for microbial activity (e.g. magnesium oxide), (v) reducing inhibition (the aforementioned adsorbents and conductive substances), (vi) accelerating the decomposition of complex organic materials into simpler compounds that are more easily digested by microorganisms, thereby increasing the rate of hydrolysis (enzymes, including cellulases, proteases and lipases). Through the aforementioned action, additives can significantly affect AD performance. The function of these materials varies, from enhancing microbial activity to maintaining optimal conditions and protecting the system from inhibitors. The choice of additives should be carefully tailored to the specific needs and conditions of the digester to maximise benefits and ensure sustainability. In light of these considerations, this paper characterizes the most commonly used additives and their combinations based on a comprehensive review of recent scientific publications, including a report on the results of conducted studies. The publication features chapters that describe: carbon-based conductive materials, metal oxide nanomaterials, trace metal and biological additives, including enzymes and microorganisms. It concludes with a chapter summarising reports on various additives and discussing their indications for functional systems with determined properties. A notable advantage of this work is the updated literature data, clear summaries, and a substantive description of the performance of the additives discussed.
The Problem of Weed Infestation of Agricultural Plantations vs. the Assumptions of the European Biodiversity Strategy
Meeting the nutritional needs of a dynamically developing global society is a major challenge. Despite the modernisation of agriculture, huge losses in the quality and quantity of crops occur each year, mainly due to weed species, which are the most important biotic limitation to agricultural production. Globally, approximately 1800 weed species cause a 31.5% reduction in plant production, which translates to USD 32 billion per year in economic losses. However, when the same herbicides are frequently applied, plants develop segetal immune mechanisms. There are currently around 380 herbicide-resistant weed biotypes worldwide. Due to the negative influence of herbicides on ecosystems and the legal regulations that limit the use of chemical crop protection products, it is necessary to develop a new method of weed control. Bioherbicides, based on living organisms or their secondary metabolites, seem to be an ideal solution. The biocontrol market is worth around EUR 550 million in Europe and EUR 1.6 billion worldwide, with an estimated 15% growth expected by 2025. Despite numerous studies that have demonstrated the effectiveness of microbial bioherbicides, only 25 mould-based bioherbicides are currently available to growers. Due to the high specificity and selectivity of biological crop protection products, as well as their low production costs and non-toxicity to the environment and human health, they would appear to be a safe alternative to chemical pesticides.
Effect of plant growth-promoting bacteria and undersown crops on the total protein content of spring barley grain grown in organic agriculture
A combination of bacterial products and cover crops as an innovative method of weed control in organic spring barley
Quantitative and Qualitative Changes in the Genetic Diversity of Bacterial Communities in Anaerobic Bioreactors with the Diatomaceous Earth/Peat Cell Carrier
This paper analyses the impact of the diatomaceous earth/peat (DEP; 3:1) microbial carrier on changes in the bacterial microbiome and the development of biofilm in the anaerobic digestion (AD) of confectionery waste, combined with digested sewage sludge as inoculum. The physicochemical properties of the carrier material are presented, with particular focus on its morphological and dispersion characteristics, as well as adsorption and thermal properties. In this respect, the DEP system was found to be a suitable carrier for both mesophilic and thermophilic AD. The evaluation of quantitative and qualitative changes in the genetic diversity of bacterial communities, carried out using next-generation sequencing (NGS), showed that the material has a modifying effect on the bacterial microbiome. While Actinobacteria was the most abundant cluster in the WF-control sample (WF—waste wafers), Firmicutes was the dominant cluster in the digested samples without the carrier (WF-dig.; dig.—digested) and with the carrier (WF + DEP). The same was true for the count of Proteobacteria, which decreased twofold during biodegradation in favor of Synergistetes. The Syntrophomonas cluster was identified as the most abundant genus in the two samples, particularly in WF + DEP. This information was supplemented by observations of morphological features of microorganisms carried out using fluorescence microscopy. The biodegradation process itself had a significant impact on changes in the microbiome of samples taken from anaerobic bioreactors, reducing its biodiversity. As demonstrated by the results of this innovative method, namely the BioFlux microfluidic flow system, the decrease in the number of taxa in the digested samples and the addition of DEP contributed to the microbial adhesion in the microfluidic system and the formation of a stable biofilm.
Eco-Friendly and Effective Diatomaceous Earth/Peat (DEP) Microbial Carriers in the Anaerobic Biodegradation of Food Waste Products
This article aims to present the results of research on anaerobic digestion (AD) of waste wafers (WF-control) and co-substrate system—waste wafers and cheese (WFC-control), combined with digested sewage sludge. The aim of this study was to assess the physicochemical parameters of the diatomaceous earth/peat (DEP; 3:1) carrier material and to verify its impact on the enzymatic activity and the process performance. The experiment was conducted in a laboratory, in a periodical mode of operation of bioreactors, under mesophilic conditions. The results of analyses of morphological-dispersive, spectroscopic, adsorption, thermal, and microbiological properties confirmed that the tested carrier material can be an excellent option to implement in biotechnological processes, especially in anaerobic digestion. As part of the experiment, the substrates, feedstock, and fermenting slurry were subjected to the analysis for standard process parameters. Monitoring of the course of AD was performed by measuring the values of key parameters for the recognition of the stability of the process: pH, VFA/TA ratio (volatile fatty acids/total alkalinity), the content of NH4+, and dehydrogenase activity, as an indicator of the intensity of respiratory metabolism of microorganisms. No significant signals of destabilization of the AD process were registered. The highest dehydrogenase activity, in the course of the process, was maintained in the WFC + DEP system. The microbial carrier DEP, used for the first time in the anaerobic digestion, had a positive effect on the yield of methane production. As a result, an increase in the volume of produced biogas was obtained for samples fermented with DEP carrier material for WF + DEP by 13.18% to a cumulative methane yield of 411.04 m3 Mg−1 VS, while for WFC + DEP by 12.85% to 473.91 m3 Mg−1 VS.
Fungi of the Trichoderma Genus: Future Perspectives of Benefits in Sustainable Agriculture
The negative impact of chemical pesticides on the environment and human health has contributed to the introduction of legal regulations that ensure the reduction in the use of agrochemicals in favor of biological products. The existing review of the literature, including our research, clearly shows that the ideal biocontrol agents are Trichoderma fungi. The production of antibiotics, lytic enzymes degrading the cell walls of plant pathogens, or inducing a defense response in plants are just some of the features supporting the wide use of these microorganisms in sustainable agriculture. It is estimated that currently about 60% of biofungicides used to eliminate fungal pathogens are produced based on Trichoderma sp. strains.
Ocena jakościowych i ilościowych zmian mikrobiomu bakteryjnego w procesie beztlenowego rozkładu materii organicznej
Czy mikrobiologiczne bioherbicydy mogą być alternatywą dla chemicznych środków ochrony stosowanych w uprawie buraka cukrowego?
Phosphorus HotSpots in Crop Plants Production on the Farm - Mitigating Critical Factors
Phosphorus resources, both in phosphate rocks and in the soil, are limited. However, effective food production is not possible without the use of P fertilizers. Recognizing and eliminating or at least ameliorating factors (hot spots) that interfere with the uptake and use of phosphorus (P) by crop plants is of key importance for effective use of both P and nitrogen (N) on the farm. Plants have developed many adaptation mechanisms to their environment, i.e., soil low in available phosphorus. The most important ones include the secretion of organic compounds into the rhizosphere and the association of plant roots with microorganisms. A classic example is mycorrhiza. These mechanisms can be used by the farmer to sequentially select plants in the crop rotation. The uptake of inorganic P (Pi) by plants from the soil is reduced by environmental (temperature and water) and soil factors (low content of available phosphorus, soil acidity, soil compaction). These factors are responsible for the growth and size of the root system. Mitigating these negative effects improves the efficiency of phosphorus uptake from the soil. The second group of critical factors, limiting both root growth and availability of phosphorus, can be effectively controlled using simple measures (for example, lime). Knowing this, the farmer must first control the level of soil fertility in the plant’s effective rooting zone and not only in the topsoil. Secondly, the farmer must multiply the productivity of applied mineral fertilizers used through targeted recycling: crop rotation, crop residues, and manure.
Nośnik diatomit/torf w intensyfikacji fermentacji metanowej odpadów organicznych: efektywność i stabilność procesu oraz zmiany mikrobiomu
Innovative Spring Barley Cultivation Technology Based on the Use of Microbial Products Together with Living Mulch in Organic Farming
Field research was conducted in Poland in 2019–2021 to determine the effect of microbial products and living mulches on grain yield and grain yield structure elements as well as the biological index of soil fertility (BIF) in spring barley grown in organic agriculture. Two factors were examined: I. microbial products: control (no treatment with microbial products), inoculation with phosphorus-releasing bacteria (Bacillus megaterium var. phosphaticum, Arthrobacter agilis), and co-inoculation (simultaneous inoculation) with phosphorus-releasing bacteria (Bacillus megaterium var. phosphaticum, Arthrobacter agilis) and nitrogen-fixing bacteria (Azospirillum lipoferum Br17, Azotobacter chroococcum); II. living mulch: control (no living mulch—spring barley grown in a pure stand), red clover, red clover and Italian ryegrass, and Italian ryegrass. The study results demonstrated that the highest grain yield at 4.5 t ha−1 with superior structure was produced by spring barley following co-inoculation with phosphorus-releasing bacteria (Bacillus megaterium var. phosphaticum, Arthrobacter agilis) and nitrogen-fixing bacteria (Azospirillum lipoferum Br17, Azotobacter chroococcum). The highest value of the biological index of soil fertility (BIF II) determined at the flowering stage was obtained in plots with spring barley cultivated with the living mulch of red clover mixed with Italian ryegrass or red clover following inoculation with phosphorus-releasing bacteria and nitrogen-fixing bacteria 6.9 and 5.7, respectively.
