Vermicomposting is an economical and environmentally friendly process. However, related knowledge of vermicomposting aquatic plant residues (APRs), earthworm quality, and mechanisms for metal removal ...from water is still lacking. Nelumbo and Oenanthe javanica residues and their mixture were treated with Eisenia foetida and cattle manure for 45 days. Compared with the control comprising only cattle manure, addition of the APR mixture improved earthworm quality, mainly for low crude ash, high alkaloid compounds and different fat compositions in the Nelumbo residue and the balanced protein proportion of the APR mixture. All the vermicompost especial O. javanica residue added (VO) played efficient roles in removing metals from water initially containing 2.0 mg Cu L−1 and 8.0 mg Zn L−1. There were higher removal efficiencies (Ers) at the dosage of 4 g L−1 with a small microbial contribution. VO significantly increased Ers, which could be from the decrease of phylum Firmicutes (especial Bacteroides) abundance, stronger CH2, C = O, and CH, the addition of COOH groups, and higher organic matter and total phosphorus contents. The combination of VO and Hippuris vulgaris was optimized as an ecological and economical method for treating complex-metal polluted water. Moreover, our study widened the route for APR reuse.
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•Aquatic-plant-residue vermicompost (VAPR) improved earthworm quality.•VNO improved earthworm quality and VO was better for metal removal.•Metal removal from water was increased by 6.4–13.5 % for the VAPRs addition.•VO removed metal mainly by cation-π, precipitate, and ion exchange actions.•The combination of VO and H. vulgaris was optimized for Cu-Zn polluted water.
Organic soil amendments are increasingly being examined for their potential for soil restoration. In this paper, different composted plant residues consisting of leguminous (red clover,
Trifolium ...pratense L.) (TP) and non-leguminous (rapeseed,
Brassica napus L.) (BN) plants and the combination of both plant residues (red clover
+
rapeseed,
Trifolium pratense L.
+
Brassica napus L. at a ratio 1:1) (TP
+
BN) were applied during a period of 4 years for restoring a Xelloric Calciorthid soil located near Seville (Guadalquivir Valley, Andalusia, Spain). The effect of the organic soil amendments on plant cover, soil physical (structural stability, bulk density), chemical (C/N ratio), and biological properties (microbial biomass, soil respiration and enzymatic activities (dehydrogenase, urease, β-glucosidase, phosphatase and arylsulfatase activities)) were determined. Organic amendments were applied at rate of 7.2 and 14.4
t organic matter
ha
−1. All composted plant residues had a positive effect on soil physical properties. At the end of the experimental period and at the high rate, soil structural stability was highest in the BN (28.3%) treatment, followed by the TP
+
BN (22.4%) and the TP (14.5%) treatments and then the control. Soil bulk density was higher in the BN (30.9%), followed by TP
+
BN (26.2%) and TP (16.1%) treatments with respect to the control. However, soil biological properties (biomass C and the enzymatic activities) were particularly improved by the TP
+
BN treatment, followed by TP, BN and the control. After 4 years, the percentage of plant cover increased 87.2% in the TP
+
BN amended soil with respect to the control, followed by TP (84.1%) and BN (83.8%). These differences were attributed to the different chemical composition of the composts applied to the soils and their mineralization, controlled by the soil C/N ratio. The application of TP
+
BN compost with a C/N ratio of 18, resulted a more favourable soil biological properties and plant cover than the application of TP (C/N ratio
=
8.8) and BN (C/N ratio
=
47.7) composts.
The decomposition of aquatic plant residues changes by the invasive algal organic matter in eutrophic lakes, however, the driving mechanisms of these biogeochemistry processes are still far from ...clear. In this study, a series of microcosms was constructed to simulate the mixed decomposition processes of aquatic plant residues with invasive algae as long as 205 days. Three aquatic plants (Potamogeton malaianus, Nymphoides peltatum, and Phragmites australis) and algae were collected from a typical eutrophic lake. The addition of algae promoted the decomposition of three plant residues based on the mass loss, and the positive co-metabolism effect was produced. The co-metabolism intensity was 8%–25% on the water surface and 19%–45% on the water-sediment interface, respectively. In addition, the response of three aquatic plant residues to the algal organic matter was different with their co-metabolism intensities in the order of P. australis > P. malaianus > N. peltatum on both the water surface and water-sediment interface. The phylum number of bacteria attached to the surface of plant residues increased from 27 to 52. The abundance of Bacteroidetes, which had the function of decomposing refractory organic matter, increased most significantly at the final incubation. At present, shallow lakes are under the double pressure of eutrophication and global warming, and the intensity and duration of algal blooms are increasing. Therefore, the co-metabolism effect of the residue decomposition process described here may change the carbon cycle strength and increase the greenhouse gas emissions of lakes and need to be taken into account in future lake management.
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•Decomposition of aquatic plants mediated by algal organic matter was studied.•The invasive algal organic matter was associated with the mass loss of aquatic plant.•The water surface was more favorable for the decomposition of aquatic plant.•Co-metabolism effect was closely related to the bacterial action of Bacteroidetes.•Co-metabolism effect in plant decomposition of eutrophic lakes should not be ignored.
Waste biomass from aromatic and medicinal plants (AMPs) encloses multifunctional compounds that could offer a poly-diverse pool of applications in sectors of food/feed, cosmetics, pharmaceuticals and ...agriculture. The production of essential oils (EOs) constitutes the main process that generates huge amounts of waste and/or by-product streams, since >95% of the AMPs is left as residual biomass after distillation.
This review presents the current situation of AMPs’ waste production within the Mediterranean basin and their potential valorization. A thorough mapping of the enclosed bioactive compounds is performed, focusing on sustainable and high-performing methods for their recovery. The integration of bioactives into novel-food-related systems via emerging techniques is highlighted. An insight to a holistic approach of these residues in the framework of advanced biorefineries is proposed, including biomass fractionation and bioconversion into value-added compounds.
AMPs constitute a new avenue of value-added components with multi-faceted applications. Following the extraction of EOs, the residues are rich in natural antioxidants which can be recovered employing novel and “green” methods. Innovative encapsulation techniques have been developed, enabling the incorporation of these compounds into food-related systems. Besides phenolic compounds, plant biomass could be further fractionated and bioconverted into chemicals, biofuels and polymers, encompassing the principles of bioeconomy and sustainability. Such integrated approaches comprising the complete exploitation of waste biomass pave the way towards modern and sustainable food systems.
•The residues from aromatic and medicinal plants (AMPs) are rich in bioactive compounds.•Novel extraction and encapsulation methods could boost the valorization of AMPs into foodstuffs.•Modern biorefinery schemes based on AMPs could be developed.•Sensorial and regulatory issues still hamper the wide AMPs applications.
The purpose of the research is to study the influence of different types of field crop rotation, fertilizers, drainage and hydrothermal conditions on the dynamics of humus in reclaimed soil. The ...studies were carried out on the experimental fields of the All-Russian Research Institute of Reclaimed Lands (reclamation sites “Kuzminskoye Boloto 2”, “Semenovskoye” and “Gubino” in the Tver region). Waterlogged soils were drained using closed drainage (inter-drain distance is 18–20 m, drain depth is 0.9–1.2 m). The soils of the experimental plots are soddy-podzolic, light loamy, gleyic, formed on a moraine or thin binomial. Observations of the dynamics of humus were carried out in the grain-grass-row, grain-grass, grain and grain-row types of crop rotation. The influence of crop rotation on the content of humus in the soil was determined, first of all, by the composition, the structure of the crops grown and agricultural technology of their cultivation. Due to plant residues, 56.6–76.5 % of the volume of mineralized humus were restored in grain-grass-row crop rotation, 51.8 % in grain, 26.4 % in grain-row crop rotation. The most significant qualitative changes in the composition of humus were observed in grain-grass-row crop rotation: with a positive humus balance, the ratio of humic and fulvic acids increased from 0.63 to 0.74. The use of organic and mineral fertilizers significantly changes the balance of humus in the arable layer of the soil. With an organic-mineral fertilizer system, the annual loss of humus (in kg/ha) on the drained plot was 6.8–11.4 times less, on the non-drained plot – 2.1–2.6 times less than in the variant without fertilizers. Drainage of waterlogged soils increases the role of fertilizers in the accumulation of humus, reduces its losses and improves the quality parameters of humus – the ratio of humic and fulvic acids in the composition of humus under the influence of drainage increased from 0.61 to 0.88. The impact on the dynamics of humus of hydrothermal conditions has been established. In years with a dry first half of the growing season, an increase in humus content is observed; in excessively wet years, on the contrary, a decrease is observed. The correlation coefficients of humus content with hydrothermal conditions in May-June were – 0.84 (in 1985–1993) and 0.95 (in 2014–2022).
Purpose: The present research aims to evaluate the biomass production and nutrient uptake by different cover crops, as well as to verify the effects of straw on bean productivity. Method: The ...experimental design was completely randomized, consisting of sowing beans on straw four cover crops (Crotalaria ochroleuca, Pigeon pea, Mucuna gray and Lab-lab) + control, with five replications. Results and conclusion: The Pigeon pea species has great potential for dry matter production and ability to absorb and accumulate phosphorus in the leaves in full bloom. The straw of the species Crotalaria ochroleuca, Pigeon pea and Mucuna cinza contributed significantly to the productivity of common bean cultivated in succession, as well as represent an alternative to reduce the dependence on synthetic fertilizers and increase the sustainability of agricultural systems. Implications of the research: The search for maintaining or increasing crop production through the adoption of conservation practices with emphasis on the cultivation of cover crop species is emphasized as an efficient strategy for nutrient cycling, improving soil health and increasing productivity with sustainability assumptions. Originality/value: The results obtained in this study are relevant to the scientific community, contributing to the training of educators and development of students, especially in the area of agricultural and environmental sciences, serving as a scientific basis for the regional technological process.
•Generally, soil CO2 and N2O emission were numerically lowest in slopes.•Soil CO2 production responded differentially to cover crop addition.•Cover crops did not affect soil N2O emission.•Reduced ...plant fragment size potentially decreased soil CO2 and N2O emission.•Soil temperature, moisture, and plant biomass were associated with GHG emission.
Agriculture represents about 10 % of total greenhouse gases (GHG) emission in the US, in which carbon dioxide (CO2) and nitrous oxide (N2O) can greatly contribute to global warming and climate change. Organic farming has been increasingly popular as it provides long-term environmental benefits including GHG mitigation. Judicious use of cover crops in crop rotation systems has been considered an effective approach to sustain crop productivity during organic transition period. Here, we examined effects of cover crops on soil CO2 and N2O fluxes after the first year of organic transition in corn-soybean-wheat rotation across three contrasting topographies, particularly depression, slope, and summit at Kellogg Biological Station located in Southwest Michigan, USA. Three cover cropping systems used in this study were (1) cereal rye; (2) a mixture of cold susceptible species, namely, oat, winter pea, and radish, frost-killed in winter (WK); and (3) a winter hardy mixture of cold tolerant species, namely annual ryegrass, Dwarf Essex rapeseed, and crimson clover (WH). We also examined the effect of the size of incorporated plant residue fragments on soil CO2 and N2O emissions. Soil GHG emissions were the lowest on slopes as compared to depressions and summits. Cover crop mixtures including WH and WK increased soil CO2 fluxes emitted from the soil while cereal rye decreased it. Cutting plant residues prior to incorporation tended to decrease CO2 emission, suggesting that reducing fragment size of incorporated residue has a potential to mitigate GHG emissions from agricultural soils. In contrast, differences in N2O emissions for any of the studied effects were not statistically significant, likely due to very high variability of N2O fluxes. Soil temperature, moisture and total aboveground biomass were strongly associated with soil CO2 and N2O fluxes from soil.
•Corn residue improved soil aggregate stability compared to soybean residue.•No-till, compared to chisel tillage, improve soil cohesion in the surface layer.•Soil organic C is a good predictor of ...both soil aggregate stability and cohesion.•Chisel-tilled fields yielded 20 times more sediment loss than no-till fields.
The establishment of long-term tillage and crop rotations studies helps to investigate the cumulative effect and the long-term effect of management practices on soil properties, including those affecting soil health and water quality. In this study, a suite of techniques was used to evaluate the impact of a 28-year long-term tillage and crop rotations on soil structural stability parameters including soil cohesion, aggregate stability, and sediment loss. Fluidized bed experiments to estimate soil cohesion and aggregate stability tests were performed on samples collected from plots managed under chisel tillage (CT) and no-till practice (NT) and four rotations (continuous corn Zea mays, CC; continuous soybean Glycine max, BB; corn-soybean, CB; and soybean-corn, BC). At the same site, rainfall simulation experiments were conducted and sediment loss was correlated to fluidized bed and aggregate stability measurements. No-till practice had a positive effect on soil cohesion in the 0–15 cm soil layer; average pressure drop at fluidization (ΔPf) values were 30.8 Pa for NT and 17.0 Pa for CT and a higher proportion of stable macroaggregates was present under NT practice (51.4% vs. 28.9%). In the 15–30 cm soil layer, aggregate stability measurements mimicked those of the surface layer for each tillage practice and crop rotation. In this study, we found no correlation between fluidized bed results and aggregate stability tests. The soil organic carbon content correlated to macroaggregates (R2 = 0.56) and magnitude of cohesion (R2 = 0.51). Corn residues were associated with improved aggregation in both surface and lower soil layers with respectively 18% and 13% more aggregates than soybean residues. Rainfall simulation experiments conducted on the sample sites revealed tillage effect on sediment loss patterns consistent with aggregate stability and fluidized bed measurement results. Chisel-tilled fields yielded 20 times more sediment loss than no-till fields. The effect of corn residue on aggregate stability resulted in 380 and 6.7 kg ha−1 less sediment loss under conventional and no-till practices, respectively.
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