Greenhouse Soil Research Articles

Sodium accumulation vs. nitrate leaching under different fertigation regimes in greenhouse soils in South Uruguay

In greenhouse conditions, soil salinity and N leaching depend on the provision of irrigation, the irrigation water quality and the application of fertilizers and organic amendments. The objective of this study was to quantify and analyze the accumulation and/or leaching process of NO3- and Na+ in greenhouse tomato production in the south region of Uruguay in fine-textured soil under different fertigation regimes. The study was conducted in four tomato crops during 2019/20/21 seasons. Three fertigation regimes were applied. Irrigation volume was the same for all treatments. Drainage was determined by using free drainage lysimeters. Concentration in soil solution and leaching of NO3- and Na+ was measured by monitoring soil solution and drainage solution. Yield, N uptake and N utilization efficiency were determined for each treatment. Soil total drainage was the main factor explaining N and Na+ leaching. The leaching of N ranges from 0 to 23.4 kg N ha-1 per tomato crop with total drainage between 0 and 46.2 % of total irrigation. Drainage necessary to avoid Na+ accumulation was 13 % of total irrigation. This drainage produced 8.4 kg of N leaching per ha-1 during tomato cropping period. Optimizing irrigation is the key factor to the salinity-nitrogen leaching paradox. Irrigation amount and timing should attempt: (1) to avoid excessive irrigation when NO3- concentration in soil solution is high, and (2) to apply leaching irrigation when Na+ concentration in soil solution is high. Soil solution monitoring with suction probes and rapid chemical analysis systems could be a useful tool to identify periods of high risk of N leaching and the right time for leaching irrigation.

Optimized Fertilizer–Water Management Improves Carrot Quality and Soil Nutrition and Reduces Greenhouse Gas Emissions on the North China Plain

In order to improve carrot quality and soil nutrition and reduce the environmental pollution caused by intensive carrot production, more comprehensive combined water–fertilizer management strategies are necessary. This study hypothesizes that optimal management of water and fertilizer can improve carrot yield and quality and reduce greenhouse gas emissions and soil nutrient residues. Thus, coordinated water–fertilizer management strategies were tested for carrot production on the North China Plain over two consecutive growing seasons. Four treatments were tested: local standard fertilization and irrigation practices (FNP); optimized irrigation and chemical nitrogen, phosphorus, and potassium fertilizer (OPT); OPT treatment with partial replacement of chemical fertilizer with peanut shell (PS); and OPT treatment with partial replacement of chemical fertilizer with mushroom residue (M). Compared to the FNP treatment, there were statistically significant increases in soluble sugars (12–27%) and free amino acids (14–26%), and decreases in the nitrate content (7–17%) of fleshy root in the OPT, PS, and M treatments. In autumn carrots, the OPT and M treatments decreased yield, whereas PS increased yield; spring carrot yield was significantly decreased in the OPT, PS, and M groups compared to the FNP group. There were no significant effects of the treatment group on carrot growth rates, nutrient accumulation, or nutrient distribution. However, the OPT, PS, and M treatments were associated with significantly increased partial productivity of phosphate fertilizer (233–363%), reduced residual levels of nitrate and available phosphorus in the top 80 cm of soil, and decreased greenhouse gas emissions by 8–18% compared to the FNP treatment. These results highlight the effectiveness of partial organic fertilizer substitution and integrated water–fertilizer management to produce high-quality carrots with minimal environmental damage.

Phthalate ester levels in agricultural soils of greenhouses, their potential sources, the role of plastic cover material, and dietary exposure calculated from modeled concentrations in tomato

Soil samples collected from 50 greenhouses (GHs) cultivated with tomatoes (plastic-covered:24, glass-covered:26), 5 open-area tomato growing farmlands, and 5 non-agricultural areas were analyzed in summer and winter seasons for 13 PAEs. The total concentrations (Σ13PAEs) in the GHs ranged from 212 to 2484 ng/g, wheeas the concentrations in open-area farm soils were between 240 and 1248 ng/g. Σ13PAE in non-agricultural areas was lower (35.0 - 585 ng/g). PAE exposure through the ingestion of tomatoes cultivated in GH soils and associated risks were estimated with Monte Carlo simulations after calculating the PAE concentrations in tomatoes using a partition-limited model. DEHP was estimated to have the highest concentrations in the tomatoes grown in both types of GHs. The mean carcinogenic risk caused by DEHP for tomato grown in plastic-covered GHs, glass-covered GHs, and open-area soils were 2.4 × 10−5, 1.7 × 10−5 and 1.1 × 10−5, respectively. Based on Positive Matrix Factorization results, plastic material usage in GHs (including plastic cover material source for plastic-GHs) was found to be the highest contributing source in both types of GHs. Microplastic analysis indicated that the ropes and irrigation pipes inside the GHs are important sources of PAE pollution. Pesticide application is the second highest contributing source.

Reduced Growth in Eustoma under High Nutrient and Phytotoxic Organic Acid Concentrations and Recovery through Hot Water Conditioning of Continuously Cropped Soil

Stunted vegetative growth and delayed or absent flowering are commonly observed in eustoma (Eustoma grandiflorum) when cultivated continuously in the same greenhouse soil. These effects are likely caused by the excessive accumulation of soluble salts and/or phytotoxic organic acids in the soil. This study aimed to clarify the mechanism of continuous cropping obstacles and formulate prevention measures of eustoma. Seedlings of eustoma ‘Croma III White’ were grown hydroponically with 0%, 25%, 50%, 75%, 100% (full), 125%, 150%, 175%, or 200% strength of Johnson’s solution. Plant height, leaf area, and shoot dry weight increased steadily as solution strength increased from 25% to 125% [solution electrical conductivity (EC) of 2.4 dS⋅m−1] and then gradually decreased as solution strength further increased from 125% to 200% (solution EC of 3.8 dS⋅m−1). When grown hydroponically in 200% strength Johnson’s solution, plant height, leaf area, and root length increased with increasing equimolar mixtures of organic acids, including maleic acid, benzoic acid, malic acid, and hydroxybenzoic acid, up to 1.2 to 1.6 mM and decreased thereafter. Node number and the percentage of flower bud visibility declined beyond 1.6 mM organic acid mixtures. Plants with 2.0 and 2.4 mM organic acid mixtures had the lowest net photosynthetic rate, stomatal conductance, transpiration, and intercellular carbon dioxide concentration. Plants had normal growth and produced flower buds when the continuously cropped soil was preconditioned with 100 °C reverse-osmosis water before planting.

Review on Rooting and Shooting Growth Performance of Populus Alba in Hydroponic Soil Cultures

In a greenhouse soil and hydroponic media experiment was carried out with plastic bottles to examine the effects of biochar, azolla, and moss as growth media components on root and shooting development performance in tiny cuttings of populous plants. Root installations were observed using the cutting length, cutting thickness, and cutting ages. The information showed that certain modifications and root media had a major impact on the populus establishment. The number of roots, length of roots, number of leaves, shoot height, and rooting percentage of the rooted mini-cuttings were also measured. Out of all the supplements and rooting media, moss (25 mg L-1) outperformed water in the current study in terms of rooting percent (100%), number of roots (16.33), and root formation.

Implications of Vegetal Protein Hydrolysates for Improving Nitrogen Use Efficiency in Leafy Vegetables

Climate change and the degradation of ecosystems is an urgent issue to which the agricultural sector contributes through the overuse of productive inputs such as chemical fertilizers. A disproportionate use of nitrogenous fertilizers combined with low efficiency inevitably results in worsening environmental problems (greenhouse gas emissions, soil degradation, water eutrophication, and groundwater pollution). Nevertheless, increasing population growth puts additional pressure on the already struggling agricultural world. Awareness of these problems has pushed the world of research towards the development of more sustainable but equally efficient strategies in terms of production. The use of biostimulant substances and/or micro-organisms promoting yield, resilience to abiotic stresses in plants, and increasing the functional quality of products have been indicated as a valid strategy to improve the sustainability of agricultural practices. In modern horticulture, the use of vegetable–protein hydrolysates (V-PHs) is gaining more and more interest. These biostimulants could influence plants directly by stimulating carbon and nitrogen metabolism and interfering with hormonal activity, but also indirectly as V-PHs could improve nutrient availability in plant growth substrates and increase nutrient uptake and utilization efficiency. By exploiting this aspect, it would be possible to reduce the use of chemical fertilizers without affecting potential yields. After a brief introduction to the issues related to the intensive use of nitrogen fertilizers, this review focuses on the use of V-PHs as a strategy to increase nitrogen use efficiency (NUE). Starting with their heterogeneous origins and compositions, their effects on nitrogen metabolism, as well as the physiological and biochemical processes involved in these products, this review concludes with an in-depth discussion of the effects of V-PHs on major leafy vegetables.

NaHCO3 impairs the growth and fruit yield of tomato plants

Underground water enriched in NaHCO3 is used in farms of the Buenos Aires province for tomato crop irrigation. This farming practice leads to salt accumulation and soil impairment after several seasons of cultivation inside the greenhouses. This work assayed the effect of NaHCO3 on tomato fruit production. Plants of the Elpida variety of Solanum lycopersicum L were grown in a hydroponic system. The presence of NaHCO3 (from 5 mM, as measured in the underground water to 10 or 20 mM) reduced K+/Na+ ratio and whole plant biomass and fruit yield; however, no effect was observed on fruit quality parameters. To test the participation of ascorbic acid in the tolerance to this stress, two slggp1 Micro-Tom mutant lines deficient in this antioxidant were used. In these experiments plants were treated with 0, 5 and 10 mM NaHCO3 causing an impairment of K+/Na+ ratio, photosynthesis, fruit yield, leaf and shoot dry weight (but without effect in root biomass) and delaying of fruit ripening time. Wild type and mutants plant responses showed no differences at stress conditions. Although NaHCO3 treatments caused a similar impairment in ascorbic acid mutants and wild type plants, these results reinforced the physiological importance of ascorbic acid levels to optimize plant growth under non-stressful conditions. Taken as a whole, the results presented here demonstrated the importance of avoiding the accumulation of this salt in greenhouse soils to optimize tomato production.

Burning and plume flow behaviors of annular pool fires: with and without air entrainment through the pool center.

Annular pool fires, frequently happened in chemical industries, have a significant influence on environmental pollution. Air pollution, greenhouse gas emissions, water pollution, and soil contamination are general ways of environmental hazards caused by the annular pool fires. This study built upon our previous study (Environ. Sci. Pollut. Res., 2023, 30(21): 59781-59792.), and extended to investigate the combustion and fire plume flow behaviors of annular pool fires, both with and without air entrainment through the hollow center of the annular pool. Results show that when there is no air entrainment through the hollow center, the low combustion intensity area at the plume's central axis gradually extends while the high combustion intensity area concentrates at higher places and the flame height increased by nearly 40% from a solid pool (Din/Dout = 0) to the annular pool (Din/Dout = 0.80). Additionally, the area with high combustion intensity is more concentrated at a higher position. The combustion of annular pool fires was found to be dominated by non-premixed diffusion combustion. The center of the annular pool fires is dominated by air prior to flame merging and by fuel vapor after the merging occurs. For annular pool fires with air entrainment through the center of the pool, the combustion intensity increases as Din/Dout at the plume base increases. And, the flame height decreased by nearly 25% as Din/Dout increases. Flame burning occurs both on the outside and inside of the plume, exhibiting a "double layer" combustion characteristic. It reveals that the combustion of the fire plume transitions to premixed diffusion combustion. The center of the annular pool fire is predominantly composed of air. Understanding and controlling annular pool fires can lead to new methods for remediating fuel spills, reducing pollution from combustion, and advancing research in fluid mechanics.

Forecasting greenhouse air and soil temperatures: A multi-step time series approach employing attention-based LSTM network

Greenhouses stand as key infrastructural components in contemporary agriculture, facilitating the perennial availability of vegetables. Harnessing accurate, real-time environmental data, particularly air and soil temperature, is pivotal to promoting the facility’s efficiency in pest and disease alarming and vegetable production. Nevertheless, despite consistent long-term temperature trends, short-term fluctuations prove to be considerably nonlinear, time-lagged, and multivariate-coupled due to the unique microclimate of the greenhouse. Addressing this, we propose a novel short-term multi-step prediction model that assimilates a range of environmental data including air temperature, humidity, soil temperature, and soil moisture content at diverse greenhouse heights. This model utilizes an Attention-LSTM based time series approach to accurately predict multi-step short-term temperature variations within the greenhouse. By employing a modest amount of historical data (approximately 48 h), the model provides future temperature forecasts within a range of 30 to 480 min with high accuracy. When benchmarked against renowned models such as RNN, GRU, and LSTM networks, our proposed models display impressive performance. It achieved R2 values of 0.93, 0.94, 0.95, and 0.86 for 1, 4, 8, and 16-step predictions, respectively, in the domain of air temperature forecasting. The corresponding MSE values stood at 0.42, 0.32, 0.27, and 0.81. In parallel, for soil temperature forecasts, our model recorded R2 values of 0.96, 0.94, 0.92, and 0.89 for 1, 4, 8, and 16-step predictions, respectively, alongside MSE values of 0.36, 0.48, 0.73, and 0.99 for the equivalent steps. To conclude, these results reveal the exceptional predictive aptitude of our model for both air and soil temperature forecasts within greenhouse environments, validating its standing as an effective tool for the optimization of vegetable farming practices. Consequently, our model demonstrates its ability to yield precise predictions of environmental variables within greenhouses, offering crucial early warning mechanisms for the enhancement of vegetable cultivation processes.

Virulence of Local Isolates of The Entomopathogenic Fungus Beauveria bassiana on Egg and Adult Stages of Tomato Leaf Miner, Tuta absoluta

Hasan, A.H., M. Ahmad, O. Hamoudi and M. Moufleh. 2024. Virulence of Local Isolates of The Entomopathogenic Fungus Beauveria bassiana on Egg and Adult Stages of Tomato Leaf Miner, Tuta absoluta. Arab Journal of Plant Protection, 42(3): 340-348. https://doi.org/10.22268/AJPP-001252 The efficacy of four local isolates of the entomopathogenic fungus Beauveria bassiana (Ascomycota: Hypocreales), (b6 isolated from citrus orchard soil (Harisoon), b7 from greenhouse soil (Alkhrab), b8 from palm weevil pupae (Lattakia) and b10 from olive orchard soil (Mengella), were tested on the egg and adult stages of the tomato leafminer Tuta absoluta by direct spraying for each stage with three different concentrations of fungal spore suspensions 2×104 , 2×106 and 2×108 spores/ml. The results obtained showed that both insect stages were very sensitive to fungal infection to varying degrees and there were significant differences in the hatching rate and adult mortality rate caused by the four isolates in comparison with the control treatment. The b8 and b10 isolates were the most effective on both insect stages at all concentrations tested. Corrected mortality rates at the highest concentration (2×108 spore/ml) were 82.59% for b8 isolate and 86.30% for b10 isolate on eggs and LC50 was 1×106 spores/ml for b8 isolate and 8×105 spores/ml for b10 isolate, whereas the corrected mortality rate for both were 100% on adults, 8 days after treatment, and by using the highest spore concentration. The LT50 was 3.2 days for both isolates and the LC50 was 2×104 spores/ml for b8 isolate and 1×105 spores/ml for b10 isolate under laboratory conditions. Keywords: Biological control, Beauveria bassiana, Tuta absoluta, mortality, LT50, LC50

Effects of microplastics on soil C and N cycling with or without interactions with soil amendments or soil fauna

AbstractMicroplastics (MPs) enter the global soil ecosystem in significant quantities, and in agricultural lands, interact with soil amendments (e.g, fertilisers, pesticides, biochar), pollutants (e.g., heavy metals and acid rain) and soil fauna (e.g., earthworms and microbial biomass) which impacts carbon (C) and nitrogen (N) cycling in soil in ways that are largely unexplored. Here, we analysed the difference in the responses of soil C and N contents, greenhouse gas emissions and soil enzyme activities in experiments where MPs alone or MPs in combination with other soil amendments or soil fauna had been explored, by conducting a global meta‐analysis of 2543 observational data extracted from 84 published studies. The results show that MPs alone are associated with significantly increased soil C storage and altered soil N pool composition, increased soil carbon dioxide (CO2) and nitrous oxide (N2O) emissions, reduced soil ammonia (NH3) emissions, increased activity of one of the five major enzymes related to C cycle, and increased activity of three of the four major enzymes related to N cycling in soil. Experiments that explored the combined effects of MPs combined with fertilisers on soil C and N contents and enzyme activities indicated greater effects than MPs alone. However, the effects of MPs combined with soil fauna, heavy metals, acid rain, glyphosate, and carbon nanotubes on soil C and N cycling differed from findings of studies that considered the effects of MPs alone. The results of this meta‐analysis provide a theoretical basis for further study of the effects of MPs on C and N cycling in fertilized agricultural soil, compound‐contaminated soil and acidified soil. We also show that, despite the global importance of MPs in soil, the number of studies of their effects on soil C and N cycling is relatively few, and further research on the mechanisms of interactions of MPs with multiple soil amendments in soil systems is urgently needed.

Life cycle analysis of anaerobic digestion processes of poultry litter

This article presents results of life-cycle assessment of anaerobic digestion processes of poultry litter (PL) preceded or not by thermal pretreatment (autohydrolysis). For this, the environmental impact categories, greenhouse gas (GHG) emissions, eutrophication, and soil acidification were evaluated using the ReCiPe Midpoint (H) method. Based on primary data provided by a partner company, life-cycle inventories were constructed for three forms of poultry waste management: i. disposal of in natura PL into the soil, which is the commonly used management technique; ii. anaerobic digestion of in natura PL; and iii. thermal pre-treatment by autohydrolysis of PL before its anaerobic digestion. It is concluded that anaerobic digestion of PL reduces GHG emissions compared to the “business as usual” scenario of soil disposal. The use of digestate (liquid fraction generated by PL anaerobic digestion) as soil fertilizer would result in avoided GHG emissions of 34%, while thermal pre-treatment by autohydrolysis of PL prior to its anaerobic digestion would result in a slightly lower reduction (27%) in GHG. Anaerobic digestion of in natura PL would also reduce the eutrophication potential by 98.2% (kg eq PO4-3/t litter) and the acidification potential by 98.4% (kg eq SO2/t litter) compared to its soil disposal. These results show that anaerobic digestion is a more sustainable way to manage PL than its environmental discharge.

Assessment of Physicochemical Properties and Heavy Metal Content of Floriculture Soil in Amhara Region of Northwest Ethiopia.

Floriculture is a new and rapidly expanding sector in Ethiopia that aids economic growth but has also come under blame for pollution of the surrounding soil. The purpose of this study was to assess the soil physicochemical properties and heavy metal contents in floriculture in the Amhara Region of Northwest Ethiopia. Soil samples were collected from seven different greenhouses (2ABC, 4DEF, 5ABC, 7DEF, 8ABC, 9DEF, and 11DEF), and a control soil sample was taken on the 15-cm depth from a nearby agricultural area. They were analyzed for soil physicochemical parameters and heavy metal compositions. Soil texture showed a significant difference between the soils sampled from the greenhouses and the control group. The highest average clay, silt, and sand contents were recorded in the control group, 4DEF, and 9DEF, respectively. The lower clay content was at 9 DEF, silt at 11 DEF, and sand in the control group. Clay was positively correlated to soil pH (r = 0.66) and TN (r = 0.38) but showed significant negative correlation with the sand fraction (r = -0.96). The average bulk density (BD) values of the soils from the greenhouses were within acceptable ranges; however, the mean BD value of 7DEF was relatively highest (1.34 g/cm3). There were significant (P < 0.05) changes in soil pH and electrical conductivity, with pH values ranging from 5.8 to 7.17 and EC from 0.08 to 1.72 mScm-1. Soil organic carbon, available phosphorus, total nitrogen, and carbon-to-nitrogen ratio of the soil samples from the greenhouses and the control group were significantly different. There were also significant differences in soil exchangeable aluminum and acidity between greenhouse soil samples and the control group. Soil contents of some of the heavy metals (Pb, Cd, Mn, and Cu) in the floriculture soil were above the permissible limits, while Cr, Zn, and Ni contents were below. The soil in floriculture showed low quality compared to the control group and international standards, indicating the need for improved soil quality management. This study recommends reducing agrochemical use, increasing bio-fertilizers, using botanicals, and transitioning to organic farming. Further studies are needed to assess soil microbial diversity and abundance for soil fixation.

Potential of compound bacterial agent in the biocontrol of muskmelon pathogens

The bacterial strain TG6 was screened from the soil of a muskmelon greenhouse, which could effectively inhibit the growth of Sphaerotheca fuliginea, Fusarium oxysporum, Phytophthora melonis and Pseudoperonospora cubensis of muskmelons. TG6 was identified as Bacillus subtilis through morphological, physiological, biochemical and molecular studies. Taking TG6 as the original strain, TG67 and TG69 were obtained by He-Ne laser mutagenesis. The microbial compound antagonist strain TG67 and TG69 was prepared in the ratio of 1:1 and applied to the biological control of greenhouse melon. Muskmelon field experiments showed that the bactericide could effectively control the occurrence of various diseases of muskmelon in greenhouse. Bangladesh J. Bot. 52(4): 1047-1053, 2023 (December)

Effects of PGPR Bacteria Applications on Soil Properties, Plant Growth and Yield Values in Karaerik and Narince Grape Varieties

Plant growth-promoting rhizobacteria (PGPR) are beneficial bacteria that promote plant growth by adhering to the root surfaces in the rhizosphere region of plants. In addition to improving the physical properties of soils, these bacteria increase plant growth and yield by positively affecting nitrogen fixation, phosphorus solubility, water and nutrient uptake of plants. In this study, the effects of bacteria applications on the vegetative development and yield levels of Karaerik and Narince grape varieties, which are important table varieties of Erzincan and Tokat regions, grown in greenhouses in Erzurum central conditions were investigated. In the study, 4 different bacterial combinations (Pseudomonas chlororaphis + Paenibacillus pabuli + Bacillus simplex + Pseudomonas fluorescens) that promote plant growth were applied to the plant root zone as a solution. In the study, the effects of PGPR applications on the vegetative growth of vines, some pomological characteristics, yield levels, macronutrient contents of leaves and physical and chemical properties of greenhouse soils were determined. While aggregate stability and porosity values of PGPR treated soils increased, water permeability and bulk density values decreased. Bacterial applications in both grape varieties showed a positive effect on shoot length, shoot diameter, number of nodes, berry width, berry length, cluster width, cluster length, number of seeds, number of clusters, cluster weight, number of berries, berry weight, total yield and macronutrient content of leaves. According to the control group, PGPR applied soils; organic matter content increased by 76.2%, aggregate stability values increased by 49.5% and porosity by 5.5%, while water permeability decreased by 18.3% and bulk density by 3.9%. Depending on the application, it was determined that the yield increased by 42.8% in Karaerik grape variety and 35.7% in Narince grape variety.

Relationship between Greenhouse Gas Budget and Soil Carbon Storage Measured on Site in Zhalainuoer Grassland Mining Area

Grassland has great potential for carbon sequestration; however, the relationship between carbon storage (CS) and greenhouse gas (GHG) budget and their influencing factors in the natural restoration process in grassland mining areas are rarely studied. In this study, taking Zhalainuoer mining area in Inner Mongolia as an example, the subsidence soil for 1-, 2-, 5-, 10-, and 15-year and non-subsidence soil were selected as the research objects to explore the relationship between CS and the GHG budget and their influencing factors. The results show that there is a significant negative correlation between CS and the GHG budget. Soil organic carbon storage accounts for 99% of CS. CS is positively correlated with SOM and AP, and with the bacteria Entotheonellaeota. The GHG budget is mainly affected by CO2 emission, which is positively correlated with subsidence time, plant biomass, and coverage, negatively correlated with the bacteria Actinobacteriota and Deinococcota, and positively correlated with Cyanobacteria. In summary, soil plays a major role in storing carbon. Carbon sequestration is a physiological process produced by plants and organisms. Subsidence affects soil CS by changing soil properties and thus affecting its aboveground vegetation and soil microorganisms. This study investigates the changes in soil carbon storage following subsidence caused by mining activities. The findings contribute to our understanding of the impact of mining subsidence on soil CS and can inform the development of low-carbon remediation technologies.

Source apportionment and risk assessment of heavy metals in typical greenhouse vegetable soils in Shenyang, China.

In this study, the concentrations of Cr, Cu, Ni, Pb, Zn, Cd, As, and Hg in the typical greenhouse vegetable soils in Shenyang, Northeast of China, were determined, and the pollution characteristics and primary sources of heavy mental pollution in soil were analyzed. Results showed that the sum of the mean values of eight typical heavy metals in the soil of the greenhouse soils was 219.79 mg/kg. According to the "Chinese Environmental Quality Evaluation Standard for Farmland of Greenhouse Vegetables Production" (HJ/T 333-2006), the concentrations of Cu (33.50 ± 11.99 mg/kg), Cd (0.246 ± 0.156 mg/kg), and Hg (0.214 ± 0.177 mg/kg) exceeded the limit values in 14.29%, 39.29%, and 39.29% of sampling points, respectively. The single factor pollution index and the Nemerow comprehensive pollution index of heavy metal elements showed that most greenhouse soils were at safety, alert, or light pollution levels. The potential ecological risk index (RI = 505.19) showed that 42.86% of the samples were at high or very high risk and Cd and Hg were the main ecological risk factors. Based on the result of correlation analysis, the Positive Matrix Factorization (PMF) differentiated sources of heavy metal pollution in the study area into four components, including fertilizer input, soil parent material, pesticide spraying and raw coal combustion, and plastic film mulching, which accounted for 36.76%, 22.64%, 20.89%, and 19.71%, respectively, of the total sources of heavy metals.

Valorization of cattle manure via a thermo-chemical process

World population growth and improvements in income levels have led to an increase in the global consumption of animal-sourced proteins. However, the massive production of animal manure has resulted in significant environmental burdens, such as increasing greenhouse gas emissions, eutrophication, and water and soil contamination. As such, this study proposed a sustainable and rapid disposal platform for animal manure as a precautionary approach to attenuate the environmental burdens caused by manure. A pyrolysis process was used to convert cattle manure into value-added products with the aim of achieving both rapid volume reduction and sustainable conversion. CO2 was fed into the process to increase the green/sustainable benefits and the results were compared with pyrolysis with the addition of N2 (inert gas). Pyrolysis oil was the major product of cattle manure pyrolysis. However, because of its complicated composition, pyrolysis oil cannot be considered a beneficial product. Thus, pyrolysis oil was converted into value-added syngas (H2/CO). Under pyrolysis with an introduction of CO2, the homogeneous reaction converted the volatile compounds and CO2 into CO at ≥ 510 ˚C. However, the reaction rate leading the CO2 reactivity was insufficient. To improve CO2 reactivity, supported Ni catalyst was introduced for catalytic pyrolysis. The concentration of CO from CO2-induced pyrolysis jumped 3.5 times (42.0 wt%) when the supported Ni catalyst was loaded in comparison with catalyst free pyrolysis setup. The increase in CO generation led to a decrease in the pyrolysis oil content (benzene analogs and polycyclic aromatic hydrocarbons) because the carbon was mostly reallocated to CO. The results of this study offer a strategic means of valorizing manure into syngas by tailoring the carbon length of the pyrogenic products.

Intermediate irrigation with low fertilization promotes soil nutrient cycling and reduces CO2 and CH4 emissions via regulating fungal communities in arid agroecosystems

The field practices, including irrigation and fertilization, strongly affect greenhouse gas emissions and soil nutrient cycling from agriculture. Understanding the underlying mechanism of greenhouse gas emissions, soil nutrient cycling, and their impact factors (fungal diversity, network characteristics, soil pH, salt, and moisture) is essential for efficiently managing global greenhouse gas mitigation and agricultural production. By considering abundant and rare taxa, we determine the identities and relative importance of ecological processes that modulate the fungal communities and identify whether they are crucial contributors to soil nutrient cycling and greenhouse gas emissions. The research is based on a 4-year field fertigation experiment with low (300 kg/ha P2O5 with 150 kg/ha urea) and high (600 kg/ha P2O5 with 300 kg/ha urea) fertilization level and three irrigation levels, that is, low (200 mm), medium (300 mm), and high (400 mm). The α-diversity (richness and Shannon index) of fungal subcommunities was significantly higher under medium irrigation (300 mm) and low fertilization (300 kg/ha P2O5 with 150 kg/ha urea) than under other treatments. Intermediate irrigation with low fertilization treatment yielded the most significant higher multinutrient cycling index and the lowest CO2 and CH4 emissions. The null model indicated that abundant taxa are mainly regulated by stochastic processes (dispersal limitation), and rare taxa are mainly regulated by environmental selection, especially by soil salinity. The co-occurrence network of rare taxa explained the changes in the entire fungal network stability. The abundant taxa played vital roles in regulating soil nutrient status, owing to the stronger association between their network and multinutrient cycling index. Furthermore, we have confirmed that soil moisture and fungal network stability are crucial factors affecting greenhouse gas emissions. Together, these results provide a deep understanding of the mechanisms that reveal fungal community assembly and soil fungal-driven variations in nutrient status and network stability, link fungal network characteristics to ecosystem functions, and reveal the factors that influence greenhouse gas emissions.

Reaction of Tomato Hybrids to Different Ripeness in Conditions of a Multi-Tube Hydroponic, Soil and Lighting Options

The aim of the study was response tomato hybrids in a multi-tube hydroponic technology in a polycarbonate greenhouse and the effect of different lighting in a phytotron on tomato plants. A study was conducted at All-Russian Research Institute of Vegetable Production, Moscow region, Russia and the laboratory of artificial climate (RSAU – MTAA). Eleven tomato hybrids were studied, differing in ripeness groups, by comparing their reactions in a hydroponic system (Phytopyramide) and a greenhouse system (soil). The effect of seven different spectral lighting modes on four hybrids under phytotron conditions (growth chamber) was also studied. Observations revealed a significant effect of hydroponic on maturation period. Hydroponic vertical cultivation has shown excellent results in obtaining an early tomato harvest and an increase in yield per m2 compared to a ground greenhouse. A higher marketable production was obtained with Ruddy ball F1 (25.51 kg/m2) compared to (9.92 kg/m2) in the soil greenhouse. Dichromatic light had the greatest effect on photosynthesis, while monochromatic light had the greatest effect on height growth. An increase in leaf chlorophyll content (SPAD) was obtained with (blue+red) light (620.06) compared to monochromatic green light (319.88). Monochromatic red (23.81 cm) had the greatest lighting effect on plant height compared to monochromatic blue (12.62 cm) the least.