Search Results (19)

While integrated practices are used in organic vegetable production for soil fertility management, their impacts on short- and long-term soil health across diverse cropping systems and environments need to be better understood, especially in sandy soils. In this two-year study (2022–2023 and 2023–2024) conducted on certified organic land, a suite of soil physical, chemical, and biological properties at the end of each organic celery (Apium graveolens L. var. dulce) production season were analyzed, with one set of field experiments assessing the influence of preplant organic fertilizers and the other set examining the effects of composts and sunn hemp (Crotalaria juncea L.) as a rotational cover crop before celery planting. Compared to feather meal-based organic fertilizer, the poultry litter-based organic fertilizer enhanced soil K and Mg base saturation, promoted micronutrient availability, and increased the overall soil fertility score. Sunn hemp cover cropping impacted soil N dynamics, and both yard waste compost and vermicompost increased the overall soil health score by over 4.0% compared to the no compost control, with yard waste compost resulting in the highest level of soil active C (10.8% higher than the control). Seasonal variations were observed in many soil parameters measured, along with marked interactions among nutrient management practices and production seasons. This study highlights the complexity of soil health assessments and improvement for sandy soils with low water and nutrient retention, and the importance of long-term, systematic studies under organic crop production. Full article

The use of crop residues is increasing across farming systems as part of climate change mitigation efforts and agricultural management practices to improve soil health. Hemp residues offer valuable potential in these efforts due to their rich nutrient composition. However, the complex chemical composition of hemp residue could pose a significant challenge by slowing the decomposition rate if not adequately managed. The aim of this study is to evaluate the influence of different timings of hemp residue incorporation, soil tillage practices, and mode of application on the rate of mineralization and soil chemical parameters. A complete randomized design field trial was conducted on hemp (Cannabis sativa L.) residue incorporation across different seasonal periods and modes of application. The results showed that the fastest mineralization occurred when hemp residue was incorporated in autumn, while the slowest mineralization was observed when the residue was left on the surface of the soil as mulch. The application of hemp residues over three years led to a slight increase in soil pH from an initial value of 4.9; however, this change was not statistically significant. Similarly, nitrogen content did not change significantly between the different periods after applying hemp residues. In contrast, hemp residues contributed to an increase in soil carbon content. Overall, this study emphasizes the need to optimize hemp residue management to maximize its benefits for enhancing soil chemical properties and promoting sustainable agriculture. Full article

Regenerative agriculture increasingly relies on organic soil amendments to improve soil fertility and crop productivity. This study evaluates the effects of dried algae (DA), vermicompost (VC), liquid hydrolyzed fish and seaweed fertilizer (LA), and a control (S0, untreated soil without amendments) on the soil fertility, growth, nutrient uptake, and physiology of sunn hemp (Crotalaria juncea L.), a key cover crop for soil improvement. Treatments were applied at 1 ton/ha (DA), 3 ton/ha (VC), and 8 mL/L (LA). Plants were grown for 10 weeks, during which plant growth, chlorophyll content, and biomass were measured. Soil and plant samples were analyzed for macro- and micronutrients. S0 and DA treatments produced the highest biomass, with S0 showing the highest total carbon and organic matter content. LA-treated soils exhibited elevated phosphorus, potassium, and sodium levels, while DA and S0 shoots had significantly higher sulfur and zinc concentrations. LA treatment notably increased chlorophyll content by the study’s end. Overall, DA demonstrated strong potential as a nutrient-rich organic amendment, while S0 provided a robust baseline for biomass production. VC enriched phosphorus and potassium but resulted in the lowest total biomass. LA promoted shoot growth and chlorophyll content but required root development and sodium management optimization. These findings highlight the need to align the amendment choice with soil characteristics and environmental conditions to optimize crop productivity and soil health in sustainable farming systems. Full article

The predominant cropping scheme for dryland wheat production in the Pacific Northwest (PNW) region of the United States includes winter wheat–summer fallow. Lack of crop diversification can deplete the soil organic matter and nutrients, while favoring the build-up of soilborne diseases. Cover crops are becoming more common within a standard rotation, primarily to provide protection against soil erosion, incorporate nutrients, and break soilborne diseases’ cycles. In this study, we investigated the potential of using hemp as a cover crop in a dryland wheat rotation to reduce soilborne diseases, and thus increase farmers’ profitability. While the benefits of barley and yellow mustard cover crops are well understood, the benefits of a hemp cover crop have not been examined in the PNW. We observed Fusarium spp. disease suppression on winter wheat following a hemp cover crop in the greenhouse studies. However, under field conditions, we did not observe a difference in pathogen abundance on winter wheat following hemp cover crop and hemp amendments in the field. Any potential to limit soilborne disease is a profitability opportunity for farmers. Our findings indicate that incorporating a hemp rotation into the PNW dryland wheat production system holds promise as a strategy to reduce soilborne diseases and improve soil health, though further research is necessary to confirm its effectiveness and underlying mechanism. Full article

The increasing environmental pollution resulting from plastic waste and the need to reuse agro-industrial wastes as a source of discarding has led to the development of innovative biobased products. In the frame of this context, the use of neat polylactic acid (PLA) and its blend with polybutylene succinate (PBS) with or without cellulose nanocrystals (CNCs) extracted from hemp fibers is explored here. This study aimed to assess the biogas production of different biopolymeric films. In parallel, life cycle assessment (LCA) analysis was performed on the same films, focusing on their production phase and potential end-of-life scenarios, regardless of film durability (i.e., single-use packaging) and barrier performance, to counteract possible soil health threats. Specifically, this study considered three specific systems: PLA, PLA_PBS (PLA/PBS blend 80:20 w/w), and PLA_PBS_3CNC (PLA/PBS blend + 3% CNCs) films. The assessment involved a batch anaerobic digestion (AD) process at 52 °C, using digestate obtained from the anaerobic treatment of municipal waste as the inoculum and cellulose as a reference material. The AD process was monitored over about 30 days, revealing that reactors containing cellulose showed inherent biodegradability and enhanced biogas production. On the other hand, biopolymeric films based on PLA and its blends with PBS and CNCs exhibited an inhibitory effect, likely due to their recalcitrant nature, which can limit or delay microbial activity toward biomass degradation and methanogenesis. LCA analysis was performed taking into consideration the complex environmental implications of both including biopolymers in the production of renewable energy and the use of post-composting digestate as an organic fertilizer. Remarkably, the PLA_PBS_3CNC formulation revealed slightly superior performance in terms of biodegradability and biogas production, mainly correlated to the presence of CNCs in the blend. The observed enhanced biodegradability and biogas yield, coupled with the reduced environmental impact, confirm the key role of optimized biopolymeric formulations in mitigating inhibitory effects on AD processes while maximizing, at the same time, the utilization of naturally derived energy sources. Full article

Heavy metal pollution is one of the most devastating abiotic factors, significantly damaging crops and human health. One of the serious problems it causes is a rise in cadmium (Cd) toxicity. Cd is a highly toxic metal with a negative biological role, and it enters plants via the soil–plant system. Cd stress induces a series of disorders in plants’ morphological, physiological, and biochemical processes and initiates the inhibition of seed germination, ultimately resulting in reduced growth. Fiber crops such as kenaf, jute, hemp, cotton, and flax have high industrial importance and often face the issue of Cd toxicity. Various techniques have been introduced to counter the rising threats of Cd toxicity, including reducing Cd content in the soil, mitigating the effects of Cd stress, and genetic improvements in plant tolerance against this stress. For decades, plant breeders have been trying to develop Cd-tolerant fiber crops through the identification and transformation of novel genes. Still, the complex mechanism of Cd tolerance has hindered the progress of genetic breeding. These crops are ideal candidates for the phytoremediation of heavy metals in contaminated soils. Hence, increased Cd uptake, accumulation, and translocation in below-ground parts (roots) and above-ground parts (shoots, leaves, and stems) can help clean agricultural lands for safe use for food crops. Earlier studies indicated that reducing Cd uptake, detoxification, reducing the effects of Cd stress, and developing plant tolerance to these stresses through the identification of novel genes are fruitful approaches. This review aims to highlight the role of some conventional and molecular techniques in reducing the threats of Cd stress in some key fiber crops. Molecular techniques mainly involve QTL mapping and GWAS. However, more focus has been given to the use of transcriptome and TFs analysis to explore the potential genomic regions involved in Cd tolerance in these crops. This review will serve as a source of valuable genetic information on key fiber crops, allowing for further in-depth analyses of Cd tolerance to identify the critical genes for molecular breeding, like genetic engineering and CRISPR/Cas9. Full article

The utilization of hemp residues, obtained after the harvest of hemp flowers, is a potential soil amendment in crop cultivation that might enhance soil health, nutrient availability, and crop productivity. However, more research is required to choose the best agricultural practice for optimizing hemp residue degradations. This study aimed to determine the integrated effects of hemp residues in different soil tillage systems on spring wheat yield. The results of the two-year experiment show that under favorable climatic conditions and soil moisture contents, the highest spring wheat grain yield (6.0 t ha⁻¹) is achieved in plots where hemp residues are plowed in autumn. Similar results are obtained in dry weather conditions, but the yield is lower by more than half—2.3 t ha⁻¹. The influence of residues increases the C content in the soil. The findings advance our understanding of integrated agricultural practices through the utilization of hemp residues for promoting resilient and sustainable crop production systems. Full article

Organic producers have few certified organic options to meet crop nitrogen (N) demand. Poultry-based amendments, including manures and processed fertilizers from livestock waste (e.g., feather meal), are commonly used in these systems, but synchronizing nutrient release with plant demand is challenging. Cover crop residues are also used in organic systems and interact with amendments to affect soil health and nutrient cycling. We conducted a greenhouse study to quantify the effects of four cover crop residues (millet, sorghum sudangrass, cowpea, sunn hemp) and three amendments (heat-treated poultry manure, poultry manure biochar, organic fertilizer) on spinach. We measured spinach yield and nutrient uptake; soil inorganic N; total soil carbon (C) and N; and two soil health indicators: permanganate oxidizable C (POXC) and autoclaved citrate-extractable (ACE) protein. Legume residues released the greatest inorganic N, whereas all cover crop residues exhibited a higher soil ACE protein concentration compared to the control without residues. The organic fertilizer released more inorganic N but had a lower ACE protein concentration than manure-based amendments. Grass residues increased POXC relative to sunn hemp, but cover crop residues had no effect on total C. In contrast, manure-based amendments increased soil’s total C but did not affect its POXC. Spinach yield and nutrient uptake were highest with biochar, with no consistent effect of cover crop residues observed on nutrient uptake. Overall, cover crops had the greatest effect on soil health indicators (POXC and ACE protein), whereas manure-based amendments had a greater impact on crop productivity and nutrition (spinach nutrient uptake and yield). Full article

Recently, there has been growing interest in the use of summer cover crops that can be grown during summer fallow periods of crop rotation. This study evaluates the potential of sunn hemp (Crotalaria juncea L.), velvetbean [Mucuna pruriens (L.) DC.] and cowpea [Vigna unguiculata (L.) Walp.]. as three annual legumes summer cover crops. The main objective of this review was to conduct global research comparing these summer cover crops to investigate the benefits, challenges, and trade-offs among ecosystems services when implementing these summer cover crops. In European agriculture, there are three main windows in crop rotation when these summer legumes can be grown: Around mid-spring after winter fallow, early summer after harvest of a winter crop, and mid- to late summer after harvest of an early-season crop. All three legumes can suppress weeds while they are actively growing. After termination, their mulch can create unfavorable conditions for weed emergence. Sunn hemp and velvetbean cover crops can cause a reduction in weed biomass of more than 50%. In addition to their ability to suppress weeds, sunn hemp, velvetbean, and cowpea provide a variety of ecosystem services, such as improving soil health, quality, and fertility, controlling pests, and sequestering carbon. The review highlights their promising role in weed suppression and their contribution to sustainable agricultural practices. However, further research is needed to evaluate their performance in weed management and their environmental impact in field trials under different soil-climatic conditions, as cover cropping is an effective practice but highly context-specific. Full article

Numerous research showed that mulching with conventional agro foils elevates soil temperature and promotes plant growth, but negatively influences soil health and brings environmental concerns. Most of the published research on nonwoven mulches for plant cultivation includes nonwoven fabrics produced by extrusion processes providing nonwoven fabric structures similar to films. A limited number of studies investigate the impact of nonwoven mulches produced by a mechanical process on the cards and bonded by needling on plant cultivation. For this study, nonwoven mulches of mass per unit area of 400 g m⁻² made from jute, hemp, viscose (CV), and polylactide (PLA) fibers were produced on the card bonded by needle punching. The field experiment was conducted two consecutive years in a row, in spring 2022 and 2023, by planting lettuce seedlings. The nonwoven mulches maintain lower temperatures and higher soil moisture levels compared to agro foil and the control field. The fibrous structure and their water absorption properties allow natural ventilation, regulating temperatures and retaining moisture of soil, consequently improving soil quality, lettuce yield, and quality. The fiber type from which the mulches were produced, influenced soil temperature and humidity, soil quality, and lettuce cultivation. The nonwoven mulches were successful in weed control concerning the weediness of the control field. Based on the obtained results, the newly produced mulches are likely to yield better results when used for the cultivation of vegetables with longer growing periods. Newly produced biodegradable nonwoven mulches could be an eco-friendly alternative to traditional agro foil, minimizing environmental harm during decomposition. The obtained results suggest that the newly produced mulches would be even more suitable for growing vegetables with longer growing seasons. Full article

Improving soil health across agroecosystems has continued to receive attention around the globe, with an emphasis on sustainable organic inputs from agricultural practice. It is well known that different organic materials, such as composts, manure and cereal straws, positively affect soil carbon. The changing agricultural practices have continuously led to new and improved plants in farming. One of these innovative plants is industrial hemp. With the increasing cultivation of industrial hemp globally, the problem of the disposal of hemp residues has been encountered. However, the rich carbon content found in hemp residues in soil is anticipated to enhance the soil quality and address the challenge of effectively utilizing hemp straw. In this study, we conducted a two-way experimental trial to evaluate the decomposition of hemp residues using placement methods (residues incorporated into the soil or left on the soil surface) and nitrogen sources as additives. Different nitrogen additives (nitrogen fertilizer pellets, liquid nitrogen, organic fertilizers, and the preparation “Bioversio”) were selected to accelerate the decomposition of hemp residues. The results showed that the mineralization rates were faster in the residues incorporated in the soil, with a mass loss of over 54% compared to the treatments left on the soil. The influence of additives on the decomposition rates was statistically significant. Additionally, there was a significant increase in the N content in the soil, while the change in carbon content in the soil was not statistically significant. These research results reinforce nitrogen fertilizers’ positive role in accelerating hemp residue decomposition in soil. Furthermore, our findings will help contribute to the effective and sustainable utilization of hemp residues as a bioresource material to improve soil health. Full article

Among inorganic contaminants, arsenic (As) is known for its toxicity and the risks to the environment and human health that could derive from its presence. Phytoremediation represents an effective strategy for the removal of arsenic from contaminated soil, provided that suitable plant species and adequate operational plans are exploited. With reference to a disused area located in Southern Italy which was the subject of a previous study, in this work, new strategies were investigated to further improve the effectiveness of a phytoremediation plan for the removal of arsenic. The usefulness of Cannabis sativa (hemp) and Zea mays (corn) was evaluated in this work by microcosm (300 g of mixed soil per test) and mesocosm (4 kg of mixed soil + 1 kg of inert gravel per test) experiments. The addition of arsenic-tolerant bacteria isolated from the rhizosphere of native herbaceous species grown in the contaminated soil was employed to promote plant growth, while different mixtures of mobilizing agents were tested to improve arsenic bioavailability. After the combined treatment, the arsenic content in the aerial parts of the plants increased by about 10 times in the case of corn (from 1.23 to 10.41 mg kg⁻¹) and by about 8 times in the case of hemp (from 1.05 to 8.12 mg kg⁻¹). Full article

Arsenic (As) is one of the most common inorganic pollutants; unfortunately, it is also one of the most toxic and is therefore a cause of great concern for the health risks that could result from it. Removing arsenic from the soil using phytoremediation approaches is an effective strategy, and several studies demonstrate the ability of Cannabis sativa (TSN 19109, hemp) to tolerate this harmful contaminant. The aim of this work was to identify the best experimental conditions for a phytoremediation plan to be applied in a disused area located in Sicily (Italy) and contaminated by As, comparing Cannabis sativa with Brassica juncea (TSN 23059) and Zea mays (TSN 42269, corn). To assist the process, several chelating agents were tested to improve arsenic mobility, and two different sets of arsenic-tolerant bacteria were isolated from the rhizospheric soil of indigenous herbaceous species and used to promote plant growth, leading to a significant improvement in terms of biomass produced and phytoextraction. After the combined treatment, the arsenic content in the aerial part of the plants increased by more than two orders of magnitude (e.g., from 0.05 to 6.57 mg kg⁻¹, from 0.04 to 6.69 mg kg⁻¹, and from 0.03 to 5.57 mg kg⁻¹ for brassica, corn, and hemp, respectively), confirming the marked increase in the total absorption of As by plants. Full article

South Florida’s agricultural soils are traditionally low in organic matter (OM) and high in carbonate rock fragments. These calcareous soils are inherently nutrient-poor and require management for successful crop production. Sunn hemp (SH, Crotalaria juncea) and velvet bean (VB, Mucuna pruriens) are highly productive leguminous cover crops (CCs) that have shown potential to add large quantities of dry biomass to nutrient- and organic-matter-limited systems. This study focuses on intercropping these two CCs with young carambola (Averrhoa carambola) trees. The objective was to test the effectiveness of green manure crops in providing nutrients and supplementing traditional fertilizer regimes with a sustainable soil-building option. Typically, poultry manure (PM) is the standard fertilizer used in organic or sustainable production in the study area. As such, PM treatments and fallow were included for comparison. The treatments were fallow control (F), fallow with PM (FM), sunn hemp (SH), SH with PM (SHM), velvet bean (VB), and VB with PM (VBM). Sunn hemp and VB were grown for two summer growing seasons. At the end of each 90-day growing period, the CCs were terminated and left on the soil surface to decompose in a no-till fashion. The results suggest that SH treatments produced the greatest amount of dry biomass material ranging from 48 to 71% higher than VB over two growing seasons. As a result, SH CCs also accumulated significantly higher amounts of total carbon (TC) and total nitrogen (TN) within their dry biomass that was added to the soil. Sunn hemp, SHM, and FM treatments showed the greatest accumulation of soil OM, TC, and TN. Soil inorganic N (NH₄⁺ + NO₃⁻ + NO₂) fluctuated throughout the experiment. Our results indicate that generally, VB-treated soils had their highest available N around 2 months post termination, while SH-treated soils exhibited significantly higher N values at CC termination time. Sunn hemp + PM (SHM)treatments had highest soil N availability around 4 months after CC termination. Soil enzyme activity results indicate that at CC termination, SHM exhibited the highest levels of β-1-4- glucosidase and β-N-acetylglucosaminidase among all treatments. Overall, SH, SHM, and FM treatments showed the greatest potential for supplementing soil nutrients and organic matter in a no-till fruit production setting. Full article

The accumulation of anthropogenic heavy metals in soil is a major form of pollution. Such potentially toxic elements are nonbiodegradable and persist for many years as threats to human and environmental health. Traditional forms of remediation are costly and potentially damaging to the land. An alternative strategy is phytoremediation, where plants are used to capture metals from the environment. Industrial hemp (Cannabis sativa) is a promising candidate for phytoremediation. Hemp has deep roots and is tolerant to the accumulation of different metals. In addition, the crop biomass has many potential commercial uses after harvesting is completed. Furthermore, the recent availability of an annotated genome sequence provides a powerful tool for the bioengineering of C. sativa for better phytoremediation. Full article