The Impact of Agricultural Use of Retisols on the Molecular Structure of Humic Substances

Agricultural soil use does not only affect the amount of soil organic matter, but also the molecular composition of humic (HAs) and fulvic acids (FAs). Changed hydrothermal conditions and composition of the incoming plant residues are reflected in the rate of humification and its products. The objective of this study was to compare the molecular composition of HAs and FAs isolated from Eutric Albic Stagnic Histic Retisol (Loamic), two Eutric Albic Retisols (Loamic)—mature and arable. Plots of mature Retisols are located at a middle taiga (Komi Republic, Russia) in a bilberry-green-moss birch-spruce forest. The plot of Retisols arable is located in the fields of the Syktyvkar state farm, which is 3.3 km northeast of mature Retisol plots. The development period is about 40 years, it is sowed with a pea-oat mixture. The results obtained indicate that soil reclamation essentially increases the proportion of aromatic components and decreases the content of carboxyl and ester groups in the humic substance (HS) structure. An increased extent of hydromorphism of Retisols leads to the enrichment of HS with aliphatic fragments.

Control of Apple Replant Disease Using Mixed Cropping with Brassica juncea or Allium fistulosum

Evidence indicates that Allium and Brassica species which release bioactive compounds are widely used in bio-fumigation to suppress soil-borne diseases. However, the active molecules of such plant residues are easily volatilized. In this study, we conducted mixed cropping of the apple tree with Allium fistulosum or Brassica juncea; the results demonstrated that such mixed cropping significantly improved the growth of the grafted apple seedlings and alleviated apple replant disease (ARD) for two years. The terminal-restriction fragment length polymorphism profile results showed that the soil fungal community demonstrated distinct variation and diversity in terms of composition. A. fistulosum and B. juncea significantly improved the Margalef, Pielou, and Shannon indices. In addition, the analyses of clone libraries showed that A. fistulosum and B. juncea promoted the proliferation of antagonistic fungi such as Mortierella, Trichoderma, and Penicillium, and inhibited the proliferation of pathogens such as Fusarium. Fusarium. Proliferatum (F. proliferatum) was abundant in replanted soil and proved to be an aggressive pathogen of apple seedlings. Our findings thus indicate that apple tree mixed cropping with A. fistulosum and B. juncea was an effective long-term method for modifying the resident fungal community and alleviating ARD.

System development for production of black soldier fly larvae (Hermetia illucens) in small scale, using wild flies

Technological innovation in rural areas guarantees the maintenance and subsistence of rural producers. Additionally, it is mandatory to use strategies aimed at reducing costs in animal production and reducing the environmental impact involved, making it challenging in the current global scenario. Thus, it is necessary to develop new alternative methods of production aimed at small scales, which can be implemented in small properties with reduced capital investment. In this sense, the objective was to describe the development of a system capable of inducing the production of black soldier fly larvae-BSFL (Hermetia illucens) through the attractiveness of egg laying of wild adults. To make the larvae production system, the following were needed: a plastic drum, with a capacity of 200 liters, 10 meters of 8mm silk rope, 1.5 m2 of wire mesh with 25mm x 20mm mesh, 1 m2 3mm x 2mm nylon mesh, plastic faucet for draining the slurry, one meter of 20mm diameter hose, two plastic containers with capacity of 20 liters for collecting the slurry and pre-pupae; besides equipment for cutting and finishing the drum. The System was supplied with organic plant material from daily household disposal, and other plant residues produced on the property. The development of this System can provide great social and economic viability, as it can be implemented in small rural properties for the treatment of organic waste. The mechanism presented good performance for the recycling of organic waste, and also for the production of BSFL, with satisfactory quantity collected daily.

Feeding selectivity of Aphelenchoides besseyi and A. pseudogoodeyi on fungi associated with Florida strawberry

Aphelenchoides besseyi and A. pseudogoodeyi are foliar nematodes associated with commercial strawberry production in Florida, USA. The reproductive and feeding habits of these two nematode species were assessed on Florida isolates of the fungi Botrytis cinerea, Colletotrichum gloeosporioides, Macrophomina phaseolina, and Neopestalotiopsis spp. pathogenic to strawberry, and the non-pathogenic isolates of Fusarium oxysporum and Monilinia fructicola grown on PDA in petri dishes. Each culture was inoculated with six specimens with mix life stages of either A. besseyi and A. pseudogoodeyi and incubated at 24°C under axenic and non-axenic conditions 23 and 31 days after inoculation, respectively. Aphelenchoides besseyi reproduction rates were significantly higher on strawberry pathogenic isolates of B. cinerea, C. gloeosporioides, and Neopestalotiopsis rosae than on the non-pathogenic isolates of F. oxysporum and M. fructicola. In contrast, reproductive rates of A. pseudogoodeyi did not significantly vary across the fungi cultures. For both nematode species, Macrophomina phaseolina was a poor host because it did not produce mycelium on the media used. Our findings indicate that A. besseyi is more selective in its fungal-feeding preference than A. pseudogoodeyi. Additionally, A. pseudogoodeyi eggs and juveniles were significantly higher than adults. Yet, for A. besseyi, adult stages were more common. Fungi aid in the maintenance of soil-dwelling populations of these two nematode species. Removing fungi-infected strawberry plant residues is both a desirable and effective management practice to limit A. besseyi in central Florida commercial strawberry fields.

Livestock integration in conservation agriculture.

Grazing livestock have been presented as an unsurmountable obstacle for Conservation Agriculture (CA) in Africa, because they consume organic cover. But grazing livestock can also make positive contributions to CA, while, if properly managed, sufficient organic cover can be left for soil erosion control and soil health improvement. Urine and manure improve soil fertility and soil health, and increase the agronomic efficiency of fertilizer nutrients. Grazing livestock increase options for crop diversity, such as crop rotations with perennial forages, increased use of cover crops and tree-crop associations. Further, as crop yields improve through application of sustainable intensification methods, greater amounts of above-ground residue become available for livestock nutrition, while greater quantities of below- and above-ground plant residues can be left to improve soil health than are currently returned to the soil. At the same time, in areas where extensive systems are still common, greater amounts of crop residue can be left for soil function because alternative feed sources are available. More research and education on proper integration of livestock in CA in the African context, and successful models of pastoralist-crop farmer collaboration are needed, so both livestock and soil needs can be met.

Morphological and molecular identification of Cladosporium sphaerospermum isolates collected from tomato plant residues

This study was conducted at the Agriculture College University of Karbala, Iraq to isolate and morphologically and molecularly diagnose thirteen Cladosporium isolates collected from tomato plant residues present in desert regions of Najaf and Karbala provinces, Iraq. We diagnosed the obtained isolates by PCR amplification using the ITS1 and ITS4 universal primer pair followed by sequencing. PCR amplification and analysis of nucleotide sequences using the BLAST program showed that all isolated fungi belong to Cladosporium sphaerospermum. Analysis of the nucleotide sequences of the identified C. sphaerospermum isolates 2, 6, 9, and 10 showed a genetic similarity reached 99%, 98%, 99%, and 99%, respectively, with those previously registered at the National Center for Biotechnology Information (NCBl). By comparing the nucleotide sequences of the identified C. sphaerospermum isolates with the sequences belong to the same fungi and available at NCBI, it was revealed that the identified C. sphaerospermum isolates 2, 6, 9, and 10 have a genetic variation with those previously recorded at the National Center for Biotechnology Information (NCBl); therefore, the identified sequences of C. sphaerospermum isolates have been registered in GenBank database (NCBI) under the accession numbers MN896004, MN896107, MN896963, and MN896971, respectively.

Design of a roll crusher for sunflower stems and substantiation of the rational modes of its operation

This paper reports a study of the technological process of grinding plant residues of sunflower and the causal relationships of factors that form the system of quality indicators. The necessary prerequisites for determining rational modes and parameters of the roll crusher have been devised. A prototype of the roll crusher was designed and fabricated, in which the cutting knives are arranged along the entire width of the grip in a staggered manner, with the possibility to change the angle of inclination to the axis of drum rotation in the range of 5...20°. It was established that in the case of the right-side arrangement of the cutting edge of knives, the highest total level of the percentage of crushed stems in the range of 101‒150 mm with an additional load weighing 800 kg exceeded by 1.58 times the corresponding indicators of the roll with an additional load of 600 kg. The largest overall value of the percentage of crushed stems in the range of 0‒200 mm when additionally loading the roll with 800 kg was 1.13 times higher than the corresponding indicators of the roll with an additional load of 600 kg. In the range of 0‒200 mm, with an additional load on the roll of 600 kg, at the left-side arrangement of the cutting edge of the knives of the roll, higher total percentage of crushed stems was observed compared to the right-side arrangement. At a speed of 7.45 km/h, 13.6 km/h, the cumulative value of the percentage of crushed stems exceeded the corresponding indicators at the right-side arrangement of knives by 1.09 times, at the speed of 18.6 km/h – by 1.04 times, at the speed of 22 km/h – by 1.04 times, respectively. It has been noted that at the left-side arrangement of the cutting edge of the knives of the roll, the percentage of crushed stems in the range of 51‒100 mm, with an additional load of 600 kg, exceeded the corresponding indicators with an additional load of 800 kg. At the speed of 10.08 km/h, it was exceeded by 1.9 times; at the speed of 13.6 km/h – by 1.44 times; at the speed of 18.6 km/h – by 1.96 times; at the speed of 22 km/h – by 1.99 times, respectively

Evaluation of Particleboards Made from Giant Reed (Arundo donax L.) Bonded with Cement and Potato Starch

There is a general concern about the rationalization of resources and the management of waste. Plant residues can contribute to the development of new non-polluting construction materials. The objective of this study was to valorize a plant residue such as the giant reed and obtain a particleboard with cement using potato starch as a plasticizer in a manufacturing process involving compression and heat. The influence of cement and starch in different proportions and its stability over time were analyzed. Finally, their physical and mechanical properties were evaluated and compared to European Standards. High-quality sustainable particleboards (boards with high structural performance) were obtained and can be classified as P6 according to European Standards. Mechanical properties were improved by increasing the starch content and pressing time, whereas greater resistance to water was obtained by increasing the cement content. Giant reed particles seem to tolerate the alkalinity of the cement since there was no sign of degradation of its fibers. The use of these residues in the manufacture of construction materials offers a very attractive alternative in terms of price, technology and sustainability.

Protection of spring wheat with biopreparations and fungicides in the forest steppe of Priobye: I. First results in extreme weather conditions

The paper presents data on a comparative test of the efficacy of chemical, fungal and bacterial fungicides in limiting the harmfulness of main diseases of spring wheat. The research was carried out on leached chernozem of the forest-steppe of Priobye of the Novosibirsk region. It was shown that Sternifag, SP reduces the development of root rot at the end of the growing season by 48 %, which is comparable to the effect of a chemical dressing agent Scarlet, ME (imazalil+tebuconazole) and is slightly inferior to the action of combined application of fungal preparation Trichocin, SP with the bacterial preparation Vitaplan, SP (55 %). Preplanting seed treatment effectively reduced the development of leaf infections: Scarlet, ME suppressed the development of Septoria blotch by 54 %, Scarlet, ME + Vitaplan, SP – of powdery mildew by 69 %, Trichotsin,SP + Vitaplan, SP – of brown rust by 74 %. Fungicide Titul 390, KKR reduced the development of these diseases by 60, 81 and 85 %, respectively. Alirin-B, W with Trichocin, SP suppressed brown rust by 64 %. Cellulolytic activity increased 1.3–1.9 times compared to the control as a result of the action of biological products and Sternifag, SP. The amount of plant residues decreased 2.4 and 1.9 times 15 and 30 days after application. The greatest increase in yield was provided by chemical fungicides – 0.7 t / ha, they were not inferior to the use of Alirin-B, W with Vitaplan, SP against the background of etching with Scarlet, ME fungicide.

Allelopathy of Knotweeds as Invasive Plants

Perennial herbaceous Fallopia is native to East Asia, and was introduced to Europe and North America in the 19th century as an ornamental plant. Fallopia has been spreading quickly and has naturalized in many countries. It is listed in the world’s 100 worst alien species. Fallopia often forms dense monospecies stands through the interruption of the regeneration process of indigenous plant species. Allelopathy of Japanese knotweed (Fallopia japonica), giant knotweed (Fallopia sachalinensis), and Bohemian knotweed (Fallopia x bohemica) has been reported to play an essential role in its invasion. The exudate from their roots and/or rhizomes, and their plant residues inhibited the germination and growth of some other plant species. These knotweeds, which are non-mycorrhizal plants, also suppressed the abundance and species richness of arbuscular mycorrhizal fungi (AMF) in the rhizosphere soil. Such suppression was critical for most territorial plants to form the mutualism with AMF, which enhances the nutrient and water uptake, and the tolerance against pathogens and stress conditions. Several allelochemicals such as flavanols, stilbenes, and quinones were identified in the extracts, residues, and rhizosphere soil of the knotweeds. The accumulated evidence suggests that some of those allelochemicals in knotweeds may be released into the rhizosphere soil through the decomposition process of their plant parts, and the exudation from their rhizomes and roots. Those allelochemicals may inhibit the germination and growth of native plants, and suppress the mycorrhizal colonization of native plants, which provides the knotweeds with a competitive advantage, and interrupts the regeneration processes of native plants. Therefore, allelopathy of knotweeds may contribute to establishing their new habitats in the introduced ranges as invasive plant species. It is the first review article focusing on the allelopathy of knotweeds.