The increasing demand for sustainable agricultural practices has intensified interest in soilless cultivation systems. However, hydroponics is unable to provide mechanical support for plant roots, and traditional soilless cultivation substrates mostly suffer from poor water retention capacity, rapid nutrient loss, and difficulty in precise control. Hydrogel-based soilless cultivation substrates show great potential for application due to their excellent water absorption, water retention and adjustable transparency. In this study, P(AM-co-NIPAM)/gelatin composite hydrogels with adjustable pore structures, mechanical strength and transparency were obtained by regulating the concentration of crosslinker. Soybean seedlings were grown on these substrates to evaluate the effects of hydrogel properties on root and shoot growth. The results demonstrate that hydrogels with optimized crosslink density possess superior mechanical properties, enhanced water retention capacity, and adequate transparency, facilitating both robust plant growth and high-resolution root system observation. We found that under the MBA content of 0.05 %, the hydrogel matrix could significantly promote the growth of aerial part and root system of soybean seedlings, and was conducive to the colonization of root bacteria. This work highlights the potential of controlled hydrogel matrices in soilless cultivation as a sustainable solution to improve root growth environments, enhance resource utilization, and enable dynamic root system studies. Given their adjustable structure and compatibility with plant growth, such hydrogels may also serve as promising candidates for future application in soilless crop production systems, particularly in scenarios where water and substrate optimization are critical to sustainable agricultural practices.

Heavy metal contamination in agricultural soils is a growing environmental concern, particularly due to the increasing accumulation of cadmium (Cd) and chromium (Cr) from industrial discharge, wastewater irrigation, and excessive fertilizer use. These toxic metals severely impact crop productivity by disrupting nutrient uptake, damaging root structures, and inducing oxidative stress, which collectively inhibit plant growth and development. Maize (Zea mays L.), a globally important cereal crop, is highly susceptible to heavy metal toxicity, making it essential to develop cost-effective and sustainable mitigation strategies. Spent mushroom substrate (SMS) biochar has emerged as an effective and sustainable method due to its ability to absorb heavy metals. Spent mushroom substrate biochar improves compost quality, soil fertility, and health. Its high porosity and surface area immobilize toxic metals, reducing nutrient losses and oxidative stress in plants. Pyrolysis temperature affects its surface area, nutrient composition, and adsorption abilities. This study aims to address this gap by evaluating the effectiveness of SMS biochar at varying application rates in mitigating Cd and Cr toxicity in maize. By assessing key physiological and agronomic parameters, this research provides novel insights into the potential of SMS biochar as a sustainable soil amendment for heavy metal-contaminated soils. Five treatments, i.e., 0, 50, 100, 150 and 200B were applied under Cd and Cr toxicity in 3 replications following the completely randomized design (CRD). Results exhibited that 200B caused an increase in maize plant height (26.1%), root dry weight (99.7%), grain yield (98.2%), and chlorophyll contents (50%) over control under Cd and Cr stress. In conclusion, 200B can mitigate Cd and Cr stress in maize plants. More investigations are suggested to declare 200B as a promising amendment for mitigation of Cd and Cr stress in other crops.

Spent mushroom substrate (SMS), a waste product from mushroom cultivation, in addition to being rich in essential nutrients for crop growth, contains actively growing mushroom mycelia and metabolites that suppress some plant pathogens and pests. SMS thus has potential for fostering the suppressiveness of soil-borne pathogens of farms. This study determined the potential of using the spent Pleurotus ostreatus substrate (SPoS) to suppress the plant-parasitic nematode Radopholus similis in bananas. R. similis is the most economically important nematode in bananas worldwide. The effect of SPoS on R. similis was assessed through two in vivo (potted plants) experiments between May 2023 and June 2024. Five-month-old East African highland banana (genome AAA) plantlets that are highly susceptible to R. similis were used. In the first experiment, the plantlets were established in 3 L pots containing (i) pre-sterilized soil, (ii) pre-sterilized soil inoculated with nematodes, (iii) pre-sterilized soil mixed with 30% (v/v) SPoS, (iv) pre-sterilized soil mixed with 30% (v/v) SPoS followed by nematode inoculation, (v) SPoS without soil, and (vi) SPoS without soil inoculated with nematodes. The SPoS was already decomposed; thus, it may or may not have contained active mycelia. The nematodes were introduced two weeks after the SPoS application. In the second experiment, SPoS was introduced two weeks after nematode inoculation. The SPoS treatments without soil were not evaluated in the second experiment. Both experiments were monitored over a three-month period. Each screenhouse treatment contained four plants and was replicated thrice. In the first experiment, data were collected on changes in soil nutrient content, below- and aboveground biomass, root deaths, root necrosis due to nematode damage, and R. similis population in root tissues and soil. In the second experiment, data were collected on root deaths and the number of nematodes in root tissues and the soil. The SPoS improved crop biomass yield, reduced root damage, and colonization by R. similis. The potential of SPoS to improve the management of R. similis and banana production under field conditions needs to be determined.

Substrate is the key material of soilless culture. The physical and chemical properties of the solidified cultivation medium are good and relatively stable, and there is no need to use plastic cultivation containers in the cultivation process, which has a broad application prospect in three-dimensional greening and fruit and vegetable planting. We have developed a novel substrate solidified process with high-frequency electromagnetic heating, which significantly reduces energy consumption compared to the traditional curing process with steam heating. In this study, the effects of three modification methods (alkali modification, APTES modification, and alkali + APTES combined modification) on the physicochemical properties of jute were studied, and the strengthening effects of different modified jute fibers on solidification substrate were investigated. The results showed that the addition of jute fiber could improve the mechanical properties of the solidification substrate. Compared with the control group, the modified jute fiber could increase the breaking tension by 13.1 similar to 24.2 N, the impact toughness by 0.85 similar to 2.09 KJ/m(2), and the hardness by 21.6 similar to 35.6 HA. Moreover, the addition of a small amount of jute fiber can effectively improve the mechanical properties and will not affect the growth of plant roots.

The global reserve of sand has significantly decreased, and sand washing is predominantly favored due to its simplicity and low operational costs, but this method poses significant environmental risks like landslides, making its reuse essential for sustainability. In view of this challenge, based on the composite preparation method, an innovative approach was proposed to prepare an artificial soil substrate from sand-washing slurry. The physical and vegetative feasibility performance, including strength, density, water absorption, retention, electrical conductivity (EC), and pH; and microstructural characteristics, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and nuclear magnetic resonance (NMR) of the artificial soil substrate with different proportions of cement and foaming agent were measured. Increasing the cement content to 30% of un-crushed artificial soil substrate specimens improved strength, whereas 40% reduced it due to the diminished pore-filling effect. Water absorption rates ranged from 29.22% to 36.68%, increasing with more foaming agent and decreasing with more cement, while the water retention time was 12-14 days, and incorporating foaming agent significantly increased water absorption. Leachate pH ranged from 11.99 to 12.18, and reduced to 7.82-8.28 with 5% phosphoric acid. The EC of the artificial soil substrate decreased by 88.64% to 93.59% after 10 wet-dry cycles, aligning with the standard. Artificial-soil-substrate-predominant products include calcite, quartz, and dolomite, with a pronounced silica content and soil substrate porosity ranging from 27.96% to 51.80%. From the microstructural test, calcium silicate hydrate gel, produced by cement hydration, effectively bound the sand-washing slurry, thereby improving strength.

Substituting peat moss with compost derived from organic waste in plant nurseries presents a promising solution for reducing environmental impact, improving waste management, and enhancing soil health while promoting sustainable agricultural practices. However, selecting the appropriate proportions of both materials is crucial for each plant species. This study investigates the effects of different ratios of compost and peat mixtures on the growth and development of pepper seedlings. The compost mixtures used in the study included the following combinations: sewage sludge with sawdust (A), sewage sludge with sawdust and biodegradable garden/park waste (B), and biodegradable garden/park waste with sawdust (C). The final substrates used for seedling production were composed of composts (A, B, C) and peat (O) as a structural additive, mixed in different proportions by mass: I-O 25%, II-O 50%, and III-O 75%. Seedlings grown in these substrates were assessed using biometric and physiological measurements. Nematode species present in substrates were identified by metabarcoding analysis. The results revealed that substrate productivity depended not only on nutrient content but also on structural properties, which were significantly influenced by the peat proportion. Among the tested compost mixtures, variant A I emerged as the most effective substrate, promoting optimal seedling growth. Molecular nematode analysis revealed significant nematode contamination in substrates with higher peat proportions (C II and C III), including Meloidogyne sp. Lichtenburg (26%), Meloidogyne hispanica (5%), Meloidogyne sp. Mi_c1 (3%), Meloidogyne ethiopica (2%), and Meloidogyne thailandica (1%). The findings underscore the critical importance of achieving an optimal balance between nutrient content and structural properties in substrates to support the healthy growth and development of pepper seedlings. To further enhance crop performance and reduce the risk of pest-related damage, it is essential to prioritize the improvement of substrate selection strategies. Monitoring for nematode contamination is crucial to prevent potential compromises in seedling quality and overall productivity.

Since the characteristics of plug seedlings affect the effectiveness of automatic transplanting, this study aimed to explore the effect of the addition of biochar into substrates on the growth of plug seedlings before and after transplanting. The physicochemical properties of substrates with 0%, 5%, 10%, 15%, 20%, and 25% biochar addition all met the requirements of seedling cultivation. The growth trend, root systems, and mechanical properties of seedlings before transplanting and the leaf gas exchange parameters of seedlings after transplanting were measured in this study. The results indicated that the seedlings cultivated with 10% biochar added to the substrate achieved the best growth trend and physiological indices, and the root systems under this treatment were also stronger than those of other treatments, while the seedlings cultivated with 25% biochar treatment were the worst, with less than 22.23% of the growth seen in the 10% biochar treatment, and even less than 1.5% of the growth of the seedlings cultivated without biochar treatment. Since the strong root systems could enhance the mechanical properties of seedling pots, the seedling pots cultivated with 10% biochar added into the substrate possessed the best compression resistance properties, with the maximum value of 49.52 N, and could maintain maximum completeness after free-fall impacting, wherein the loss of root and substrate was only 8.22%. The analysis results of seedlings cultivated after impacting proposed that the seedlings with better growth trends and root systems before transplanting could obtain better leaf gas exchange parameters during the flower stage after transplanting, so the seedlings cultivated with 5%similar to 10% biochar added into the substrate grew better after impacting and then transplanting. It was noticed that the seedlings cultivated with appropriate biochar added into the substrate were able to achieve the optimal growth parameters and mechanical properties before and after transplanting, which were better able to meet the requirements of automatic transplanting. Thus, this study can promote the development of automatic transplanting technology to some extent.

In recent years, organic electronics have been explored as a potential paradigm for renewable, transient, and biodegradable systems. In this study, we used fish scales as raw materials for fabricating a biopolymer substrate (BPS) and evaluated its application in an organic metal-insulator-metal capacitor. Evaluation of the morphological and optical properties of BPS revealed an average surface roughness value of 1.19 nm, 90% transmittance in the UV-visible range, and an absorption coefficient of 5.29 cm(-1) at 3.5 eV. Fourier transform infrared spectroscopy showed the presence of amide A, amide I, amide II, and amide III bonds in the substrate, and 42 degrees +/- 5 degrees was the rollover contact angle. The substrate was dissolved in water within 40 min at room temperature and degraded by more than 90% within 30 days in natural soil. Further, mechanical property analysis showed that the substrate exhibited a flexural strength of 8.33 MPa and a tensile strength of 4 MPa. The capacitance density and leakage current of the Al/bovine serum albumin/Pt/BPS structure are found to be 1.05 fF/mu m(2) (1 MHz, 1 V) and 1.15 mu A/cm(2) (at 1 V), respectively. The proposed substrate can be used as a cost-efficient, ecofriendly, biocompatible, and transparent charge storage device for transient electronics in the near future.

Nitrous oxide (N2O) is the third most important greenhouse gas, and can damage the atmospheric ozone layer, with associated threats to terrestrial ecosystems. However, to date it is unclear how extreme precipitation and nitrogen (N) input will affect N2O emissions in temperate desert steppe ecosystems. Therefore, we conducted an in -situ in a temperate desert steppe in the northwest of Inner Mongolia, China between 2018 and 2021, in which N inputs were combined with natural extreme precipitation events, with the aim of better understanding the mechanism of any interactive effects on N2O emission. The study result showed that N2O emission in this desert steppe was relatively small and did not show significant seasonal change. The annual N2O emission increased in a non-linear trend with increasing N input, with a much greater effect of N input in a wet year (2019) than in a dry year (2021). This was mainly due to the fact that the boost effect of high N input (on June 17th 2019) on N2O emission was greatly amplified by nearly 17-46 times by an extreme precipitation event on June 24th 2019. In contrast, this greatly promoting effect of high N input on N2O emission was not observed on September 26th 2019 by a similar extreme precipitation event. Further analysis showed that soil NH4+-N content and the abundance of ammonia oxidizing bacteria (amoA (AOB)) were the most critical factors affecting N2O emission. Soil moisture played an important indirect role in regulating N2O emission, mainly by influencing the abundance of amoA (AOB) and de-nitrification functional microorganisms (nosZ gene). In conclusion, the effect of extreme precipitation events on N2O emission was greatly increased by high N input. Furthermore, in this desert steppe, annual N2O flux is co-managed through soil nitrification substrate concentration (NH4+-N), the abundance of soil N transformation functional microorganisms and soil moisture. Overall, it was worth noting that an increase in extreme precipitation coupled with increasing N input may significantly increase future N2O emissions from desert steppes.

As a global strategy for mitigating climate change, organic amendments play critical roles in restoring stocks in carbon (C) depleted soils, preserving existing stocks to prevent further soil organic carbon (SOC) loss, and enhancing C sequestration. However, recent emerging evidence of a significant proportion of micro-and nanoplastics (M/NPs) occurrence in most organic substrates (e.g., compost manure, farmyard manure, and sewage sludge) compromises its role in climate change mitigation. Given the predicted surge of soil M/NPs proliferation in the coming years, we argued whether organic amendment remains a reliable climate change mitigation strategy. Toxicity effects of M/NPs influx within the soil matrix disrupt plants and their associated key microbial taxa responsible for crucial biogeochemical processes and restructuring of SOC, leading to increasing emissions of potent greenhouse gases (GHGs, e.g., CO2, CH4, and N2O) that feedback to aggravate the rapidly changing climate. Here, we summarize evidence based on literature that the discovery of M/NPs in organic substrates compromises its role in the climate change mitigation strategy. We briefly discuss the overview of synthetic fertilizers and their impact on SOC and atmospheric emissions. We discuss the role of organic amends in climate change mitigation and the emergence of M/NPs in it. We discuss M/NPs-induced damages to SOC and subsequent emissions of GHGs. We briefly highlight management approaches to clean organic substrates of M/ NPs to improve their use in agrosystems and provide recommendations for future research studies. We found that organic amendment plays pivotal role in modulating the biotic and abiotic drivers responsible for climate mitigation. However, M/NPs in organic amendments weaken the regulatory mechanisms of organic amendments in plant-soil systems. We conclude that organic amendments of soils are critical for restoring SOC and mitigating the rapidly changing climate; yet, the discovery of M/NPs in organic substrates put their usage in a dilemma.