Agronomy

16 pages, 10490 KB

Open AccessArticle

Solid Grain Waste Digestate as a Peat Substrate Amendment for Tomato Seedlings: Effects of Direct Sowing and Transplanting on Growth and Photosynthesis

by Kristina Laužikė and Julė Jankauskienė

Agronomy 2026, 16(13), 1256; https://doi.org/10.3390/agronomy16131256 (registering DOI) - 29 Jun 2026

Abstract

The quality and productivity of tomato (Solanum lycopersicum L.) crops largely depend on the quality of the seedlings used for cultivation. Several factors, including cultivation strategy, fertilization practices, and abiotic and biotic stressors during early plant development, influence seedling quality. Recently, anaerobic [...] Read more.

The quality and productivity of tomato (Solanum lycopersicum L.) crops largely depend on the quality of the seedlings used for cultivation. Several factors, including cultivation strategy, fertilization practices, and abiotic and biotic stressors during early plant development, influence seedling quality. Recently, anaerobic digestate has attracted attention as a potential organic fertilizer and substrate component; however, information about its effects on tomato seedling quality remains limited, particularly when comparing different seedling establishment methods such as direct sowing and transplanting. Therefore, this study aimed to evaluate the effects of different concentrations of solid grain waste digestate (further digestate) in the peat substrate on the growth and physiological characteristics of tomato seedlings grown by means of direct sowing and transplanting. The experiment was conducted at the Institute of Horticulture of the Lithuanian Research Centre for Agriculture and Forestry in unheated greenhouses covered with double polymer film. Two cultivation strategies were applied (factor A): transplanting and direct sowing into pots. To evaluate the influence of digestate (factor B), different substrate compositions were used: peat (control) and peat mixed with 10%, 20%, 30%, 40%, and 50% digestate. The strong decline in growth parameters with increasing digestate concentration indicates that higher proportions of digestate created unfavorable conditions for seedling development in both cultivation stategies. A 10% digestate addition improved certain plant characteristics, while 20% improved some physiological indices but was associated with reduced growth. However, higher digestate concentrations (≥30%) negatively affected plant growth and physiological activity. Seedlings grown in substrates with higher digestate levels exhibited reduced transpiration rates and lower gas exchange indices, suggesting impaired water relations and stomatal regulation. These effects were more pronounced in transplanted plants compared with direct-sown seedlings, indicating greater sensitivity to changes in substrate composition after transplanting. Overall, the results demonstrate that digestate can be used as a substrate component for tomato seedling production. Still, its concentration must be carefully optimized to avoid negative effects on plant growth and physiological performance. Full article

(This article belongs to the Special Issue Recycling Nutrients and Regenerating Soils: Biosolid-Derived Fertilizers in a Circular Economy)

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22 pages, 40458 KB

Open AccessArticle

Mapping and Yield Estimation of Cultivated Alfalfa Using Cutting-Induced NDVI Peak–Trough Features from Sentinel-2 Time Series

by Jie Liu, Qisheng Feng, Shuai Fu, Tiangang Liang, Jinlong Gao and Wei Sun

Agronomy 2026, 16(13), 1255; https://doi.org/10.3390/agronomy16131255 (registering DOI) - 29 Jun 2026

Abstract

Alfalfa (Medicago sativa) is an important forage source for grassland agricultural development; developing accurate and efficient methods for alfalfa identification and yield estimation using remote sensing is of considerable interest. However, the traditional methods of identifying large areas of crops and [...] Read more.

Alfalfa (Medicago sativa) is an important forage source for grassland agricultural development; developing accurate and efficient methods for alfalfa identification and yield estimation using remote sensing is of considerable interest. However, the traditional methods of identifying large areas of crops and yield estimation have some problems, such as the limited spatial resolution of remote sensing data and a strong dependence on training data. In this study, using Sentinel-2 high-resolution imagery and the Google Earth Engine (GEE) platform, we constructed a cloud-free normalized difference vegetation index (NDVI) time-series dataset and proposed an effective method for alfalfa feature extraction and yield estimation. The results show that: (1) the producer’s accuracy, user’s accuracy, overall accuracy, and Kappa coefficient of alfalfa identification using the trough recognition algorithm were 98.51%, 91.67%, 94.26%, and 0.88, respectively. The total area of cultivated alfalfa identified in the study area in 2020 was estimated at 46,793.21 hm², and was mainly distributed in the northern region of the Qilian Mountains. (2) NDVI showed a highly significant correlation with alfalfa hay yield, and the power function regression model performed best, with an R² greater than 0.65. (3) The annual unit hay yield of four alfalfa cuttings was estimated at 17,497.55–32,962.10 kg/hm², with a total hay yield of 4.838 × 10⁸ kg and an average hay yield of 4464.95 kg/hm². The proposed method has significant application potential for automated and rapid remote sensing-based identification and yield estimation of large-scale alfalfa cultivation. Full article

(This article belongs to the Section Precision and Digital Agriculture)

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30 pages, 1483 KB

Open AccessArticle

Impact of Biochar and Its Modification on Heavy Metals and Drought in Rice: Knowns, Unknowns, and Research Directions

by Bilal Zulfiqar, Rui Chen, Qiufen Feng, Chao He, Yuxiao Sun, Yang Zhang, Yanan Wang, Xibai Zeng, Cuixia Wu and Nan Zhang

Agronomy 2026, 16(13), 1254; https://doi.org/10.3390/agronomy16131254 (registering DOI) - 29 Jun 2026

Abstract

Rice, a staple food for over half of the global population, faces significant threats from environmental stressors such as heavy metal (HMs) contamination, notably cadmium (Cd) and arsenic (As), and increasing drought severity, exacerbated by climate change. These challenges not only compromise rice [...] Read more.

Rice, a staple food for over half of the global population, faces significant threats from environmental stressors such as heavy metal (HMs) contamination, notably cadmium (Cd) and arsenic (As), and increasing drought severity, exacerbated by climate change. These challenges not only compromise rice yield and quality but also pose serious food safety risks due to HM accumulation in grains, endangering human health. Modified biochar (MBC), a carbon-rich material derived from the pyrolysis of organic matter with post-treatment enhancements, has emerged as a strategy to address these dual stressors. MBC application (typically 5–20 t ha⁻¹) reduces Cd and As bioavailability in paddy soils by 40–60% and decreases metal accumulation in rice grains by 20–85% compared to the control. Under drought conditions, MBC improves soil water-holding capacity by 11–45% and enhances crop water use efficiency by 15–24%, leading to yield improvements of 20–50% under moderate water deficit. Furthermore, MBC supports nutrient availability, fosters robust root systems, and enhances soil aeration, collectively improving rice growth under adverse conditions. Beyond its agronomic benefits, MBC provides a framework for addressing multiple challenges by integrating scientific innovation, policy alignment, and community participation. This approach not only reduces heavy metal toxicity and strengthens plant resilience but also enhances food security and advances Sustainable Development Goals (SDGs 2, 3, 4, 12, 13, 15, 17). By promoting environmentally sustainable agriculture and contributing to climate change mitigation, MBC represents a transformative tool for ensuring sustainable rice production in the face of global challenges. Full article

(This article belongs to the Special Issue Regulation of Heavy Metals Migration and Accumulation in Soil–Plant System)

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24 pages, 2721 KB

Open AccessArticle

Cultivar-Specific Expression of the Vintage Effect in Furmint Grapes from the Tokaj Wine Region; Part II: Acid Balance, Potassium Accumulation and Tannin Content

by Csaba Rácz, Krisztina Molnár, Tamás Dövényi-Nagy, Károly Bakó, István Kathy, István Szepsy, László Csige and Attila Csaba Dobos

Agronomy 2026, 16(13), 1253; https://doi.org/10.3390/agronomy16131253 (registering DOI) - 29 Jun 2026

Abstract

Understanding how interannual climatic variability shapes must composition is critical for predicting wine quality under warming conditions, particularly for acid-retaining cultivars such as Vitis vinifera L. cv. Furmint. This study—conducted as a continuation of a previous investigation on Furmint berry weight, total soluble [...] Read more.

Understanding how interannual climatic variability shapes must composition is critical for predicting wine quality under warming conditions, particularly for acid-retaining cultivars such as Vitis vinifera L. cv. Furmint. This study—conducted as a continuation of a previous investigation on Furmint berry weight, total soluble solids and total dry extract—evaluated titratable acidity, pH, potassium, ammonia and tannin content across three contrasting vintages (2022–2024) in the Tokaj wine region. Using a high-resolution meteorological dataset and an extensive climatic parameter matrix, exploratory analysis was conducted to evaluate responses, and the most influential thermal, radiation-related and water-balance related climatic factors associated with each must parameter were identified. Total acidity and pH showed consistent sensitivity to climatic variability: acidity decreased with mid-season warm nights and abundant summer rainfall, while pH was inversely associated with extreme heat events but increased under higher early-season rainfall and post-véraison irradiation. Potassium content exhibited partly atypical responses, showing positive correlations with late-season warm nights and frequent summer precipitation, and negative with early heat. Ammonia displayed weak to moderate climatic dependence, while tannic acid consistently decreased with higher thermal and irradiation loads. Overall, these results imply cultivar-specific climatic responses in Furmint and suggest that temperature extremes, nighttime heat and rainfall timing are important factors shaping must composition, providing a foundation to better understand the expression of vintage effects under climate change. Full article

(This article belongs to the Section Horticultural and Floricultural Crops)

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13 pages, 3299 KB

Open AccessArticle

Phosphorus Fertilization Overrides Intercropping-Induced Shifts in Microbial Stoichiometry to Increase Forage Yield

by Yue Lin, Lijuan Zhao, Pengxin Niu, Xueqiao Cao, Shuying Guo, Meiling Zhao and Zhiying Liu

Agronomy 2026, 16(13), 1252; https://doi.org/10.3390/agronomy16131252 (registering DOI) - 29 Jun 2026

Abstract

Legume–grass intercropping and phosphorus (P) fertilization are recognized strategies for enhancing forage productivity, but their interactive effects on soil microbial processes and plant phosphorus nutrition in a semi-arid climate remain poorly understood. We conducted a field experiment with common vetch (Vicia sativa [...] Read more.

Legume–grass intercropping and phosphorus (P) fertilization are recognized strategies for enhancing forage productivity, but their interactive effects on soil microbial processes and plant phosphorus nutrition in a semi-arid climate remain poorly understood. We conducted a field experiment with common vetch (Vicia sativa) and oat (Avena sativa) under two monocultures and three intercropping treatments (legume–grass ratios of 1:3, 2:3, and 1:1), combined with three P fertilization rates (0, 60, and 120 kg P ha⁻¹). The results showed that common vetch/oat intercropping with moderate legume–grass proportions (1:3 and 2:3) significantly outyielded monocultures across all P levels and exhibited a stronger net biodiversity effect than the 1:1 intercropping at P fertilization. Plant P concentration was primarily increased by P fertilization. Crucially, all intercropping treatments showed a significantly lower microbial biomass carbon/phosphorous ratio than the monoculture in the absence of P fertilization. However, this difference disappeared when P was applied, indicating P fertilization overrode the intercropping-induced stoichiometric shift. Correlation analyses further showed that forage yield and plant P uptake were positively linked to microbial biomass P and negatively to the microbial biomass carbon/phosphorous ratio. Together, our findings reveal that a common vetch/oat intercropping system combined with P fertilization may improve the nutrient use efficiency through microbial pathway. This improvement in nutrient use efficiency leads to higher nutrient uptake by plants, thereby causing more rapid soil reserve depletion. Full article

(This article belongs to the Section Grassland and Pasture Science)

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15 pages, 1445 KB

Open AccessArticle

Effects of One-Time Long-Term Application of Organic–Inorganic Compound Fertilizer on Wheat Photosynthetic Characteristics, Soil Properties and Grain Yield

by Xiaolin Zhou, Hongjie Li, Huali Gao, Mengyang Du, Yuxia Wang, Tongkai Zhao, Wei Wang and Zishuang Li

Agronomy 2026, 16(13), 1250; https://doi.org/10.3390/agronomy16131250 (registering DOI) - 29 Jun 2026

Abstract

Wheat production demands simplified fertilization strategies to achieve sustainable high yields. This study evaluated the effects of the one-time high-rate application of an organic–inorganic compound fertilizer on soil properties, photosynthetic characteristics, and grain yields. A multi-year field experiment was conducted with a single [...] Read more.

Wheat production demands simplified fertilization strategies to achieve sustainable high yields. This study evaluated the effects of the one-time high-rate application of an organic–inorganic compound fertilizer on soil properties, photosynthetic characteristics, and grain yields. A multi-year field experiment was conducted with a single basal application of an organic–inorganic compound fertilizer at 3600 kg·ha⁻¹, using conventional split chemical fertilization as the control. Compared with the control, this treatment significantly increased soil organic matter and available nutrient content, enhanced the bacteria/fungi ratio, elevated soil enzyme activity, and promoted the conversion of humus into more stable forms. These improvements sustained a higher flag leaf photosynthetic capacity during the grain-filling stage and delayed leaf senescence. The multi-year average grain yield was 5.28% higher than that of conventional split fertilization. The one-time high-rate application of an organic–inorganic compound fertilizer can improve soil biological properties, maintain late-season photosynthetic function, and increase yields, serving as an effective technical measure for simplified, sustainable, and high-yield wheat cultivation in the region. Full article

(This article belongs to the Section Plant-Crop Biology and Biochemistry)

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20 pages, 5109 KB

Open AccessArticle

Developmentof Multi-Unit Orchard Centrifugal Spray System and Deposition Evaluation on Pear Trees

by Shaoqing Xu, Yanfang Li, Ziqi Geng, Peng Qi and Jianli Song

Agronomy 2026, 16(13), 1251; https://doi.org/10.3390/agronomy16131251 (registering DOI) - 28 Jun 2026

Abstract

An air-assisted sprayer is a primary tool for pest and disease control in orchards. However, conventional systems often suffer from insufficient deposition at the canopy top and poor coverage on the abaxial leaf surfaces, which are highly susceptible to pests and diseases. To [...] Read more.

An air-assisted sprayer is a primary tool for pest and disease control in orchards. However, conventional systems often suffer from insufficient deposition at the canopy top and poor coverage on the abaxial leaf surfaces, which are highly susceptible to pests and diseases. To address this limitation, a centrifugal air-assisted spraying system was developed to generate finer droplets and improve deposition distribution within tree canopies, particularly on the abaxial surfaces. Vertical deposition tests were conducted to characterize the droplet distribution pattern of the system. Single-unit spray tests were then performed under Foliage Area Volume Density (FAVD, the foliage area per unit canopy volume) of 3.3 and 1.4 m²·m⁻³, and three outlet air velocities (4, 8, and 11 m·s⁻¹) to evaluate the effects of these variables on coverage and droplet density. Comparative experiments between the centrifugal and a conventional hydraulic system were also carried out at the same flow rate (3.6 L·min⁻¹), as well as at a 30% reduced application rate for the centrifugal system. The results showed that the droplet distribution pattern followed a normal distribution and correlated well with the spindle-shaped pear tree canopy. At both FAVD levels, an air velocity of 8 m·s⁻¹ produced superior leaf coverage compared with 4 and 11 m·s⁻¹. At the same flow rate, the centrifugal system achieved significantly higher coverage on the abaxial surfaces of outer canopy leaves than the hydraulic system. Remarkably, even with a 30% reduction in application volume, the centrifugal system maintained coverage and droplet density comparable to those of the hydraulic system at its full rate. We conclude that the centrifugal air-assisted orchard spraying system effectively improves pesticide deposition distribution within pear tree canopies, with particular advantages in depositing droplets on the abaxial leaf surfaces. Future work will include a systematic assessment of spray drift potential to further evaluate its field applicability and environmental compatibility. Full article

(This article belongs to the Special Issue Smart Orchard Equipment: Advances in Precision Management Technologies)

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45 pages, 6921 KB

Open AccessArticle

Multivariate Spatial Characterization and Probabilistic Source Risk Assessment of Soil Heavy Metal Pollution in the Yellow River Basin

by Dil Khurram, Tianlie Luo, Jie Tang, Ram Proshad, Sami Ullah, Tianyu He, Nadeem Iqbal, Xin Gao, Mingtan Zhu and Gratien Nsabimana

Agronomy 2026, 16(13), 1249; https://doi.org/10.3390/agronomy16131249 (registering DOI) - 28 Jun 2026

Abstract

Soil heavy metal pollution poses a threat to agricultural sustainability, food safety, and human health. The ecologically fragile Yellow River Basin is a critical hub for agriculture, energy, and mining; however, soil heavy metal studies remain fragmented, and basin-wide syntheses are limited almost [...] Read more.

Soil heavy metal pollution poses a threat to agricultural sustainability, food safety, and human health. The ecologically fragile Yellow River Basin is a critical hub for agriculture, energy, and mining; however, soil heavy metal studies remain fragmented, and basin-wide syntheses are limited almost entirely to agricultural soils. This study presents a basin-wide analysis of As, Cd, Cr, Cu, Ni, Pb, and Zn in topsoil, based on 2498 sampling locations compiled from 347 publications, using an integrated framework of receptor modeling, multivariate spatial statistics, self-organizing maps, and probabilistic human health and ecological risk assessment. Four pollution sources, namely agricultural–industrial, emissions, mining–smelting, and geogenic/lithogenic, were resolved. Agriculture–industry and emissions posed considerable ecological risks (mean PER = 367.9 and 353.4), with Cd and Pb accounting for 95.7% of the risk. The non-carcinogenic hazard was negligible for adults, but 8.6% of sites exceeded the safe threshold for children, and the carcinogenic risk surpassed 10⁻⁶ for all groups, with 2.6–9.6% of sites exceeding 10⁻⁴. Spatially, the strongest multimetal contamination corridors are the Baiyin–Lanzhou corridor (upper–middle reaches) for Cu-Pb-Zn (mining–smelting) and the Xi’an–Weinan belt (middle reaches) for Cd-Pb (agricultural–industrial and emissions). Multivariate clustering was more extensive (56.1% of sites) than single-metal clustering (13.1–26.2%), confirming coherent source-linked zones. Ecological risks were driven by Cd and Pb, whereas human health risks were driven by As, Cr, and Ni. This divergence and the strong spatial organization of the risk clusters highlight the need for source-specific, spatially targeted mitigation, which requires monitoring across all land use types. The compiled dataset, although extensive, is constrained by heterogeneity in sampling periods and analytical methods and by sparse coverage in some grassland, desert, and plateau regions. Full article

(This article belongs to the Special Issue Risk Assessment of Heavy Metal Pollution in Farmland Soil)

16 pages, 778 KB

Open AccessSystematic Review

Research Advances and Emerging Challenges in Various Types of Drought Monitoring: An Integrative Review

by Haichao Yu, Sien Li, Yang Zhang, Jiaming Zhang, Jiajin Ding and Shengwen Liu

Agronomy 2026, 16(13), 1248; https://doi.org/10.3390/agronomy16131248 (registering DOI) - 27 Jun 2026

Abstract

Drought is one of the most complex and impactful natural hazards under global climate change, exerting profound effects on water resources, agricultural productivity, ecosystem stability, and socio-economic systems. Despite extensive research, current drought studies remain fragmented due to inconsistent definitions, index-specific monitoring approaches, [...] Read more.

Drought is one of the most complex and impactful natural hazards under global climate change, exerting profound effects on water resources, agricultural productivity, ecosystem stability, and socio-economic systems. Despite extensive research, current drought studies remain fragmented due to inconsistent definitions, index-specific monitoring approaches, and limited understanding of cross-variable and cross-scale interactions. The objective of this review is to synthesize recent advances in drought monitoring and to establish an integrated understanding of drought as a coupled, multiscale process. We revisit traditional drought typologies, including meteorological, agricultural, hydrological, groundwater drought, and socio-economic drought, and critically evaluate their commonly used monitoring indices and data sources. We highlight that no single indicator can adequately capture the full dynamics of drought evolution, emphasizing the need for multi-index integration and process-based monitoring frameworks. Moreover, we examine the mechanisms of drought propagation, demonstrating that drought evolves through nonlinear and scale-dependent pathways linking atmospheric conditions, soil moisture, hydrological processes, and human water use. In particular, the emergence of flash drought reveals a shift from conventional water-deficit-driven processes to multi-process coupled dynamics, posing new challenges for early warning and prediction. Furthermore, we discuss how climate change and human activities jointly reshape drought characteristics by altering hydrological cycles, land–atmosphere interactions, and water resource management systems. The review reveals three major findings. First, drought monitoring is progressively shifting from single-index assessments toward integrated, multi-source monitoring frameworks. Second, drought propagation is inherently nonlinear and scale-dependent, involving complex interactions among climatic, hydrological, ecological, and human systems. Third, flash drought and groundwater drought have emerged as critical research frontiers due to their rapid evolution, monitoring challenges, and increasing impacts under climate change. Finally, we identify key challenges in drought research, including methodological uncertainties, data limitations, and the lack of a unified theoretical framework. These findings support a paradigm shift from traditional drought classification toward an integrated process-based perspective and provide guidance for the development of next-generation drought monitoring and early-warning systems. Full article

(This article belongs to the Special Issue Smart Sensing and Sustainable Crop Management Strategies for Agriculture in Arid and Semiarid Regions)

20 pages, 1936 KB

Open AccessArticle

Comparative Residue and Dietary Risk Assessment of Four Acaricides in Citrus Following Knapsack Versus UAV Spraying Using UHPLC-MS/MS

by Xiaotong Qin, Yalin Zhou, Yuhan Zhang, Zhuo Zhang, Yan Tao, Ping Han, Yongquan Zheng and Min He

Agronomy 2026, 16(13), 1247; https://doi.org/10.3390/agronomy16131247 (registering DOI) - 27 Jun 2026

Abstract

A sensitive and reliable analytical method based on ultra-high performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS) was developed and validated for the simultaneous determination of bifenazate, cyflumetofen, etoxazole, and abamectin B_1a in citrus leaves, whole fruit, peel, and pulp. The method exhibited good [...] Read more.

A sensitive and reliable analytical method based on ultra-high performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS) was developed and validated for the simultaneous determination of bifenazate, cyflumetofen, etoxazole, and abamectin B_1a in citrus leaves, whole fruit, peel, and pulp. The method exhibited good linearity (0.0001–0.1 mg/L, R² > 0.999), a limit of quantification (LOQ) of 0.001 mg/kg, mean recoveries of 77.3–110.5%, and relative standard deviations of 3.1–19.8%. This method was applied to compare the dissipation dynamics and dietary risks of the four acaricides following knapsack spraying versus unmanned aerial vehicle (UAV) spraying. Compared to knapsack application, UAV spraying resulted in 2.2- to 4.1-fold higher initial deposits on citrus leaves and shorter dissipation half-lives. After 21 days, all terminal residues were below the maximum residue limits (MRLs) established by China, the Codex Alimentarius Commission, the United States, Australia, Korea, the European Union, and Japan. Chronic dietary risk assessment revealed risk quotients below 1% for cyflumetofen and etoxazole, and approximately 47% for bifenazate and 93% for abamectin B_1a. Although all values were below the acceptable threshold of 100%, the risk for abamectin B_1a approached this limit, indicating that its cumulative dietary risk should not be overlooked. This study provides scientific evidence for residue monitoring of acaricides in citrus and for the safety evaluation of UAV-based pesticide application. Full article

(This article belongs to the Special Issue Risk Assessment of Pesticide Residues in Crop Production)

21 pages, 2023 KB

Open AccessArticle

Açaí-Derived Biochar Improves Soil Fertility, Microbial Activity, and Cowpea Yield in an Acidic Amazonian Ferralsol

by Criscian Kellen Amaro de Oliveira Danielli, Antonio Leite Florentino, Filipe Eduardo Danielli, Heiriane Martins Sousa, Ana Rita de Oliveira Braga, Vinicius John, Newton Paulo de Souza Falcão and Cláudia Saramago de Carvalho Marques-dos-Santos

Agronomy 2026, 16(13), 1246; https://doi.org/10.3390/agronomy16131246 (registering DOI) - 26 Jun 2026

Abstract

Biochar derived from açaí (Euterpe oleracea Mart.) processing residues represents a sustainable strategy to improve fertility and mitigate acidity in highly weathered tropical soils. This study evaluated the effects of açaí biochar (0 and 12 Mg ha⁻¹), combined with dolomitic [...] Read more.

Biochar derived from açaí (Euterpe oleracea Mart.) processing residues represents a sustainable strategy to improve fertility and mitigate acidity in highly weathered tropical soils. This study evaluated the effects of açaí biochar (0 and 12 Mg ha⁻¹), combined with dolomitic limestone (0, 75%, and 100% of the recommended rate), on chemical, biological, and agronomic attributes of a clayey Ferralsol cultivated with cowpea (Vigna unguiculata (L.) Walp) in the Amazon. A field experiment was conducted in a randomized block design with six treatments and four replicates. Soil samples were collected from the rhizosphere and from the 0–5, 5–10, and 10–20 cm layers to determine pH, exchangeable Al, pseudo-total concentrations of K, Ca, Mg, total carbon (TC), organic carbon (OC), microbial biomass carbon (MBC), β-glucosidase, and cellulase activity. Biochar increased soil pH (0–10 cm), reduced exchangeable Al, and increased pseudo-total K throughout the soil profile, whereas liming primarily increased Ca and Mg availability and contributed to acidity correction. A significant biochar × lime interaction was observed for exchangeable Al in surface layers, while Mg responses varied depending on depth and treatment combination. Biochar also enhanced cellulase activity, total carbon (TC), and microbial biomass carbon (MBC), while reducing β-glucosidase in surface layers, with no effect on organic carbon (OC) determined by the Walkley–Black method. Cowpea grain yield increased by 16% with biochar and showed additive response to lime, reaching 1460 kg ha⁻¹ under combined application, 13.6% higher than lime alone. These results indicate that açaí biochar acts as a complementary amendment for improving soil fertility, biological functioning, and crop performance in acidic tropical soils. Full article

(This article belongs to the Section Soil and Plant Nutrition)

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19 pages, 4726 KB

Open AccessArticle

Fusarium spp. Associated with Rice Bakanae Disease in Zhejiang, China

by Fang Lu, Chengxin Mao, Yanan Sun, Chuanqing Zhang and Jianyan Wu

Agronomy 2026, 16(13), 1245; https://doi.org/10.3390/agronomy16131245 (registering DOI) - 26 Jun 2026

Abstract

Rice bakanae disease (RBD) occurs at all growth stages of rice, leading to yield loss and rice seed contamination. We sampled plants with bakanae symptoms and aerial adventitious roots from early-season rice fields, and obtained a total of 152 Fusarium isolates. Based on [...] Read more.

Rice bakanae disease (RBD) occurs at all growth stages of rice, leading to yield loss and rice seed contamination. We sampled plants with bakanae symptoms and aerial adventitious roots from early-season rice fields, and obtained a total of 152 Fusarium isolates. Based on a combination of sequences from a region of the tef1 gene and morphological features, Fusarium isolates were identified as F. fujikuroi (142 isolates, 93.4%), F. proliferatum (8 isolates, 5.3%), and F. oxysporum (2 isolates, 1.3%). We found that 30 °C was suitable for the sporulation of all three Fusarium species. However, for mycelial growth, the temperature suitable for F. oxysporum was higher than that for F. fujikuroi and F. proliferatum. On a susceptible rice, F. fujikuroi caused foolish seedlings (excessive growth rate ranging from 29.87% to 116.57%); F. proliferatum and F. oxysporum led to stunted symptoms. Quantification of gibberellic acid (GA₃) by high-performance liquid chromatography (HPLC) revealed that only F. fujikuroi isolates produced large amounts of GA₃, explaining why only F. fujikuroi isolates caused bakanae symptoms. The infected rice seedlings were continuously cultivated in the greenhouse. All three Fusarium species caused crown rot in rice plants. Additionally, F. fujikuroi caused root rot and grain sterility, whereas F. proliferatum and F. oxysporum caused heading failure. Collectively, our study indicated that three Fusarium species were associated with RBD in early-season rice in Zhejiang, China, and they caused distinct symptoms in rice. Full article

(This article belongs to the Section Pest and Disease Management)

19 pages, 1389 KB

Open AccessArticle

Tea Plantation Age Shapes Soil Enzyme Activities Through Changes in Aggregate Size Distribution

by Xiujuan Yang, Shuzhong Yu, Shaoming Ye and Shengqiang Wang

Agronomy 2026, 16(13), 1244; https://doi.org/10.3390/agronomy16131244 (registering DOI) - 26 Jun 2026

Abstract

Elucidating the response mechanisms of C-, N-, and P-cycling enzyme activities within soil aggregates to tea plantation age can provide a theoretical foundation for improving soil fertility, safeguarding soil health, and promoting the sustainable use of soil resources in tea plantations. In the [...] Read more.

Elucidating the response mechanisms of C-, N-, and P-cycling enzyme activities within soil aggregates to tea plantation age can provide a theoretical foundation for improving soil fertility, safeguarding soil health, and promoting the sustainable use of soil resources in tea plantations. In the present study, soil samples were collected from the 0–20 cm layer of tea plantations with different ages (3, 9, 16, and 24 years). Then, soil samples were separated into >2, 2–1, 1–0.25, and <0.25 mm aggregate size fractions using an optimal moisture sieving method, and the activities of β-glucosidase, invertase, urease, protease, and acid phosphatase were measured in each fraction. Across all tea plantation ages, the aggregate composition was dominated by the >2 mm fraction, whose content was significantly (p < 0.05) higher than that of other size fractions, averaging 54.47%. With increasing plantation age, the content of >2 mm aggregates first increased and then decreased, reaching a relatively high level at 16 years. The activities of β-glucosidase, invertase, urease, and protease in the tea plantation soils were predominantly distributed in the >2 mm aggregates, with average activities of 261.34, 585.31, 52.24, and 84.34 mg kg⁻¹ h⁻¹, respectively; in contrast, acid phosphatase activity was less affected by aggregate size. As plantation age increased, the activities of β-glucosidase, invertase, urease, and protease initially increased and then decreased, reaching relatively high levels at 16 years (322.98, 696.66, 67.00, and 100.98 mg kg⁻¹ h⁻¹, respectively), whereas acid phosphatase activity progressively increased with age. During the aggregate fractionation process, all enzyme activities were lost to varying degrees, with average recovery rates of 80.45% (β-glucosidase), 83.13% (invertase), 80.78% (urease), 82.16% (protease), and 81.66% (acid phosphatase). As the primary carriers of soil enzymes, the formation and stabilization of >2 mm aggregates are of great importance for promoting soil organic C and nutrient cycling. In tea plantation management, therefore, attention should be directed to the breakdown and disruption of >2 mm aggregates after 16 years of cultivation to maintain soil quality and sustain soil organic C and nutrient use efficiency. Full article

(This article belongs to the Section Soil and Plant Nutrition)

19 pages, 9156 KB

Open AccessArticle

Developmental Dynamics of Anthocyanin and Carotenoid Accumulation and Associated Gene Expression in Two Red-Fleshed Apple Cultivars

by Seonae Kim, Van Giap Do, Jung-Geun Kwon, Hunjoong Kweon, Soon-Il Kwon, Rok-Yeun Hwang, Jong-Taek Park, Jeong-Hee Kim, Jingi Yoo and Dagyeong Kwon

Agronomy 2026, 16(13), 1243; https://doi.org/10.3390/agronomy16131243 (registering DOI) - 26 Jun 2026

Abstract

Fruit color, a key quality trait in apples, is primarily determined by anthocyanin and carotenoid accumulation. Although the regulation of pigmentation in red-skinned apples has been extensively investigated, comparative information regarding pigment dynamics in red-fleshed cultivars during fruit development remains limited. In this [...] Read more.

Fruit color, a key quality trait in apples, is primarily determined by anthocyanin and carotenoid accumulation. Although the regulation of pigmentation in red-skinned apples has been extensively investigated, comparative information regarding pigment dynamics in red-fleshed cultivars during fruit development remains limited. In this study, two red-fleshed apple cultivars, ‘Okanagan’ and ‘Pink Wood,’ were examined at five developmental stages, 30, 60, 90, and 120 days after full bloom (DAFB), and at harvest (135 DAFB), to evaluate changes in peel and flesh coloration, pigment accumulation, and expression of genes associated with anthocyanin and carotenoid biosynthesis. Both cultivars exhibited peak peel redness during early fruit development. The peel anthocyanin concentration was highest at 30 DAFB. Anthocyanin accumulation in flesh tissues was comparatively low but increased slightly during later stages. Transcripts of anthocyanin pathway genes and the regulatory transcription factor MdMYB10 were abundant in peel tissues during the early stages. Strong positive correlations were observed between anthocyanin-associated gene expression, peel and flesh redness (a*), and anthocyanin concentration. ‘Pink Wood’ exhibited stronger red pigmentation in flesh tissues at harvest. These findings provide comparative insights into the cultivar-dependent mechanisms regulating fruit coloration in red-fleshed apples, and may support breeding strategies targeting enhanced visual and nutritional quality. Full article

(This article belongs to the Special Issue Advances in Fruit Development and Quality: Genetic, Environmental, and Agronomic Insights)

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16 pages, 3172 KB

Open AccessArticle

Effects of Thermal Sanitization on Insect Frass Nutrient Composition and Biofertilizer Performance in a Lettuce Pot Trial

by Julietta Moustaka, Hanne Lakkenborg Kristensen and Mesfin Tsegaye Gebremikael

Agronomy 2026, 16(13), 1242; https://doi.org/10.3390/agronomy16131242 (registering DOI) - 26 Jun 2026

Abstract

Insect farming has rapidly expanded in Europe following regulatory approval of insect-derived proteins in aquaculture feed and increasing interest in the valorization of insect by-products. Insect frass, consisting of excreta and exuviae, is a nutrient-rich material with beneficial microorganisms and potential as a [...] Read more.

Insect farming has rapidly expanded in Europe following regulatory approval of insect-derived proteins in aquaculture feed and increasing interest in the valorization of insect by-products. Insect frass, consisting of excreta and exuviae, is a nutrient-rich material with beneficial microorganisms and potential as a sustainable alternative to conventional fertilizers, although its composition varies with insect species and feedstock. EU legislation requires thermal sanitization prior to market release, yet the effects of the thermal treatment on frass nutrient composition and biofertilizer performance remain poorly understood. Insect frass from black soldier flies (BSFFs) fed on a diet based on dairy industry byproducts was sanitized and mixed with sandy soil and used in two lettuce pot trials under greenhouse conditions. The aim of our study was to determine the effects of thermal sanitization on (1) macro- and micronutrient contents and dynamics (plant N and P uptake); and (2) biofertilizer potential, including plant physiology (chlorophyll, anthocyanins, flavonols, Fv/Fm), plant growth (biomass), and soil microbial activity (dehydrogenase and β-glucosaminidase). BSFF showed a clear potential to induce growth of lettuce plants by increasing chlorophyll content, biomass and microbial activity. Furthermore, the sanitization process did not significantly alter the measured agronomic performance of frass under the tested conditions or reduce its benefits on biomass growth, chlorophyll content, microbial enzyme activity and on nutrient uptake by the lettuce plants. These findings suggest that the mandatory sanitization does not compromise its agronomic functionality, supporting its strong potential within circular agricultural systems under the tested conditions. However, the results are valid under greenhouse conditions and for the specific frass, soil and crop combinations; field validation is needed to confirm these results under large-scale high-value crop production conditions. Full article

(This article belongs to the Special Issue Plant Nutrition Eco-Physiology and Nutrient Management)

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46 pages, 1335 KB

Open AccessSystematic Review

Applications of Artificial Intelligence in Soil Characterization and Agriculture: A Systematic Review of Techniques, Models, and Applications

by Cesar Augusto Navarro Rubio, Hugo Martínez Ángeles, Mario Trejo Perea, José Luis Reyes Araiza, Guillermo Ronquillo-Lomeli, Ivan Gonzalez-Garcia, Eusebio Ventura Ramos and José Gabriel Ríos Moreno

Agronomy 2026, 16(13), 1241; https://doi.org/10.3390/agronomy16131241 (registering DOI) - 26 Jun 2026

Abstract

Artificial Intelligence (AI) has become a key enabler in soil science and agriculture, supporting advanced modeling, monitoring, and decision-making processes. This systematic review synthesizes recent developments in AI-based soil characterization and agricultural applications, with emphasis on soil physicochemical properties, digital soil mapping, irrigation [...] Read more.

Artificial Intelligence (AI) has become a key enabler in soil science and agriculture, supporting advanced modeling, monitoring, and decision-making processes. This systematic review synthesizes recent developments in AI-based soil characterization and agricultural applications, with emphasis on soil physicochemical properties, digital soil mapping, irrigation management, and crop yield prediction. Following the PRISMA 2020 framework, a structured search of the Scopus database identified 196 eligible studies published between 2018 and 2026. The reviewed literature reveals a clear transition toward data-driven approaches, with machine learning and deep learning models dominating recent research. Random Forest, Support Vector Machines, gradient boosting methods, artificial neural networks, Convolutional Neural Networks, and Long Short-Term Memory architectures were the most frequently reported techniques. The primary data sources included in situ sensors, laboratory measurements, remote sensing imagery, and environmental covariates, often integrated through multi-source data fusion frameworks. The results indicate that tree-based ensemble models provide robust performance across diverse soil properties, whereas deep learning models are particularly effective for spatiotemporal prediction and remote sensing applications. AI-driven systems are increasingly used to support precision agriculture through irrigation optimization, crop yield forecasting, digital soil mapping, and soil health monitoring. However, challenges remain regarding data quality and availability, model transferability across regions, and the limited interpretability of complex models. The findings highlight current research trends, methodological challenges, and future opportunities for the development of reliable and scalable AI-driven soil and agricultural systems. Full article

(This article belongs to the Special Issue Harnessing Sensing, Artificial Intelligence, and Robotics for Digital Agriculture)

34 pages, 3402 KB

Open AccessArticle

Aromatic Plant Residues from Essential Oil Steam Distillation as a Potential Source of Antioxidants

by Giuseppe Squillaci, Virginia Carbone, Carmen Di Pipi, Francesco La Cara and Alessandra Morana

Agronomy 2026, 16(13), 1240; https://doi.org/10.3390/agronomy16131240 - 26 Jun 2026

Abstract

Steam distillation residues (SDRs) of aromatic plants were utilized to produce antioxidant extracts using hydroalcoholic solvents with increasing percentages of ethanol (0, 50, 75 and 100% v/v). The phenolic composition and antioxidant power were measured and compared to the corresponding [...] Read more.

Steam distillation residues (SDRs) of aromatic plants were utilized to produce antioxidant extracts using hydroalcoholic solvents with increasing percentages of ethanol (0, 50, 75 and 100% v/v). The phenolic composition and antioxidant power were measured and compared to the corresponding fresh aromatic plants (FAPs). The largest amount of polyphenols, ranging from 14.15 (lemon balm FAP) and 19.61 (lavender SDR) mg gallic acid equivalents/g dry matter (DM), was found in 0% ethanol (pure water) extracts. The phenolic content of lavender and spearmint SDR extracts was higher than that of the corresponding FAP extracts, while the opposite was observed with lemon balm. Rosmarinic acid was the most abundant hydroxycinnamic acid detected, ranging from 608.65 µg/g DM in lemon balm 50% ethanol FAP extract to 697.47 µg/g DM in spearmint 50% ethanol SDR extract. The lavender and spearmint SDR extracts exhibited higher antioxidant power than the FAP extracts, while the extracts from fresh lemon balm were more antioxidant than the SDR. The lavender 50% ethanol SDR extract showed the highest scavenging activity (67.16%) and ferric reducing power (16.60 mg ascorbic acid equivalents/g DM). These results prove that spent aromatic residues can be utilized to produce antioxidant blends for various industrial applications. Full article

(This article belongs to the Special Issue Agricultural Biomass Waste Conversion into Value-Added Products—2nd Edition)

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31 pages, 4889 KB

Open AccessSystematic Review

Effects of Different Radiation-Based Treatments on the Quality of Edible Mushrooms: A Systematic Review

by Renyuan Liu, Yuetong Liu, Jueru Zhang, Honghao Zeng, Xianjue Ruan, Rongjin Ma, Chunyu Shang and Yu Pan

Agronomy 2026, 16(13), 1239; https://doi.org/10.3390/agronomy16131239 - 25 Jun 2026

Abstract

Radiation-based treatments have emerged as important environmental and postharvest regulatory tools for improving the quality of edible mushrooms. Visible light, ultraviolet (UV) radiation, gamma irradiation, and pulsed-light treatments influence mushroom growth, morphogenesis, nutrient accumulation, antioxidant capacity, and storage performance through distinct physiological and [...] Read more.

Radiation-based treatments have emerged as important environmental and postharvest regulatory tools for improving the quality of edible mushrooms. Visible light, ultraviolet (UV) radiation, gamma irradiation, and pulsed-light treatments influence mushroom growth, morphogenesis, nutrient accumulation, antioxidant capacity, and storage performance through distinct physiological and molecular mechanisms. However, current findings remain fragmented, and a comprehensive synthesis of their regulatory effects and underlying mechanisms is lacking. This systematic review was conducted following the PRISMA 2020 framework. A structured literature search was performed in the Web of Science, PubMed, and CNKI databases. After screening and eligibility assessment, 111 studies were included in the qualitative synthesis. The available evidence indicates that radiation-based treatments exert stage-dependent and species-specific effects on edible mushrooms. Visible light primarily regulates morphogenesis through photoreceptor-mediated signaling pathways, whereas UV radiation promotes vitamin D₂ biosynthesis and antioxidant accumulation through photochemical and reactive oxygen species (ROS)-related mechanisms. Gamma irradiation and pulsed-light treatments are mainly applied during postharvest handling to suppress microbial contamination, delay browning and senescence, and extend shelf life. Based on the available evidence, a unified mechanistic framework linking signal perception, ROS regulation, transcriptional reprogramming, metabolic responses, and quality formation is proposed. Despite these advances, substantial challenges remain, including limited mechanistic understanding, insufficient integration of multi-omics evidence, lack of standardized treatment protocols, and difficulties in industrial-scale implementation. Future research should focus on multi-radiation synergistic strategies, precision environmental regulation, and intelligent cultivation systems. Overall, this review provides a comprehensive synthesis of current evidence regarding radiation-mediated quality regulation in edible mushrooms and offers a theoretical basis for optimizing mushroom production and developing sustainable postharvest preservation technologies. Full article

(This article belongs to the Special Issue Advances in Light Management and Controlled-Environment Agriculture for Enhancing Crop Growth, Yield and Quality)

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15 pages, 1610 KB

Open AccessArticle

Preliminary Study on Control Efficacy and Mechanism of Cyproconazole Against Southern Corn Rust

by Siqi Wang, Xiaoming Zhu, Hongxia Ma, Hua Sun, Shuo Zhang, Ning Guo and Jie Shi

Agronomy 2026, 16(13), 1238; https://doi.org/10.3390/agronomy16131238 - 25 Jun 2026

Abstract

This study clarified the field control efficacy, yield regulation effect and action mechanism of 40% cyproconazole suspension concentrate (SC) against southern corn rust caused by Puccinia polysora, aiming to provide scientific support for its registration, extension and field application. Indoor toxicity was [...] Read more.

This study clarified the field control efficacy, yield regulation effect and action mechanism of 40% cyproconazole suspension concentrate (SC) against southern corn rust caused by Puccinia polysora, aiming to provide scientific support for its registration, extension and field application. Indoor toxicity was assayed using urediniospore germination and germ tube elongation inhibition combined with seedling pot tests and field efficacy trials. Wheat germ agglutinin staining was applied to observe the pathogen infection process. Cyproconazole showed strong inhibition on spore germination and germ tube elongation, with EC₅₀ values of 70.455 mg·L⁻¹ and 21.686 mg·L⁻¹. On corn seedlings, its protective and curative control efficacies reached 91.11% and 82.19%. At 45 days after application during ear maturity, the field protective and curative efficacies were 65.93–78.38% and 69.26–80.79%, respectively. Notably, the integrated control strategy with two applications achieved even higher efficacy, ranging from 73.33% to 86.80%, and a yield loss recovery rate of 54.09–54.51%, both of which were superior to those of the conventional fungicide pyraclostrobin·epoxiconazole SC. Using WGA fluorescence staining, fluorescence microscopy directly visualized that the fungicide suppressed infection by inhibiting spore germination, germ tube elongation and appressorium formation. In summary, 40% cyproconazole SC has prominent persistent control efficacy and a yield-improving effect with a definite action mechanism, which is worthy of accelerated registration and popularization for southern corn rust management. Full article

(This article belongs to the Section Pest and Disease Management)

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