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Agronomy, Volume 14, Issue 6 (June 2024) – 235 articles

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19 pages, 808 KiB  
Article
Examining the Effect of Agrochemicals on Soil Microbiological Activity, Micronutrient Availability, and Uptake by Maize (Zea mays L.) Plants
by Tariku Neme Afata, Seblework Mekonen, Trine Aulstad Sogn, Manoj K. Pandey, Eshetu Janka and Gudina Terefe Tucho
Agronomy 2024, 14(6), 1321; https://doi.org/10.3390/agronomy14061321 (registering DOI) - 18 Jun 2024
Abstract
Agricultural practices profoundly influence soil microbial populations and physicochemical properties, vital for crop growth and quality. This study aims to explore the impact of diverse agrochemical applications on soil microbial dynamics, physicochemical properties, and maize yield and proximate properties. Topsoil samples, collected at [...] Read more.
Agricultural practices profoundly influence soil microbial populations and physicochemical properties, vital for crop growth and quality. This study aims to explore the impact of diverse agrochemical applications on soil microbial dynamics, physicochemical properties, and maize yield and proximate properties. Topsoil samples, collected at depths of 1 to 15 cm, were transported to Jimma University for maize cultivation. Over 120 days, soil and maize samples were collected at specified intervals for analysis, including soil pH, microbial populations, and nutrient content. Statistical analysis using one-way ANOVA (p < 0.05) was conducted. Soil bacterial and fungal populations were measured on days 5, 10, 20, 40, 80, and 120. The highest total mesophilic bacterial count (TMBC) was in compost-treated pots (G) and the lowest in those receiving macronutrient fertilizers and glyphosates (B). The highest total mesophilic fungal count (TMFC) was in pots with glyphosates and compost (F), and the lowest was in pots treated with macronutrient fertilizers and glyphosates (B). Pots treated with macronutrient fertilizers and glyphosates (B), macronutrient fertilizers (A), and micronutrient fertilizers (C) showed the lowest Fe and Zn levels. Maize in pots treated with macronutrient fertilizer combined with glyphosate (B) exhibited the lowest protein, fats, and carbohydrates. Notably, compost-treated soils showed the highest bacterial and fungal counts, Fe, and Zn concentrations, while micro-mineral fertilizer combined with glyphosate (B) depleted the soil. Agrochemical treatments negatively affected maize yield quality, indicating complex treatment-related changes in soil parameters. Full article
(This article belongs to the Section Soil and Plant Nutrition)
19 pages, 5666 KiB  
Article
Sunflower Origin Identification Based on Multi-Source Information Fusion Technique of Kernel Extreme Learning Machine
by Limin Suo, Hailong Liu, Jin Ni, Zhaowei Wang and Rui Zhao
Agronomy 2024, 14(6), 1320; https://doi.org/10.3390/agronomy14061320 (registering DOI) - 18 Jun 2024
Abstract
This study constructs a model for the rapid identification of the origins of edible sunflower (Helianthus) using Kernel Extreme Learning Machine (KELM) with multi-source information fusion technology. Near-infrared spectroscopy (NIRS) and nuclear magnetic resonance spectroscopy (NMRS) were utilized to analyze 180 sunflower samples [...] Read more.
This study constructs a model for the rapid identification of the origins of edible sunflower (Helianthus) using Kernel Extreme Learning Machine (KELM) with multi-source information fusion technology. Near-infrared spectroscopy (NIRS) and nuclear magnetic resonance spectroscopy (NMRS) were utilized to analyze 180 sunflower samples from the Xinjiang, Heilongjiang, and Inner Mongolia regions. Initially, the identification models for the origin of sunflowers using NIR and NMR data were compared between two algorithms: the Extreme Learning Machine (ELM) and KELM, combined with various spectral preprocessing methods. The experiment found that the NIR spectral model preprocessed with standard normal variate (SNV) using the KELM algorithm was the most accurate, achieving accuracies of 98.7% in the training set and 97.2% in the test set. The spin-echo NMR spectral model preprocessed with non-local means (NLMs) using the KELM algorithm was the second best, with accuracies of 98.4% in the training set and 96.4% in the test set. To further improve the accuracy of the identification models, innovative sunflower origin identification models were developed based on data layer fusion and feature layer fusion using NIRS and NMRS. In the data layer fusion model, the KELM algorithm model was optimal, achieving a test set accuracy and F1 score of 98.2% and 98.18%, respectively, an improvement of 1.0% over the best single data source model. In the feature layer fusion model, four types of feature-layer information-fusion identification models were established using two feature extraction algorithms, Competitive Adaptive Reweighted Sampling (CARS) and Variable Importance Projection (VIP), combined with joint feature and simple merging feature strategies. The CARS-KELM algorithm combined with the joint feature method was found to be the best, achieving 100% accuracy in both the training and test sets, an improvement of 2.8% over the best single data source model. Identifying the origin of edible sunflower using NIRS and NMRS is demonstrated as feasible by the results. The best single-spectrum sunflower origin identification model was achieved using the KELM algorithm with SNV preprocessing. The feature layer fusion method combining NIRS and NMRS data is suitable for handling the task of sunflower origin identification. This method significantly improves the recognition accuracy of the model compared to a single model, achieving fast and accurate origin identification of edible sunflowers. The research results provide a new method for rapid identification of sunflower origin. Full article
(This article belongs to the Section Precision and Digital Agriculture)
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12 pages, 2280 KiB  
Article
Submergence Stress Reduces the Ability of Rice to Regulate Recovery after Disaster
by Yanmei Yu, Yan Meng, Peng Chen and Kaihua Cao
Agronomy 2024, 14(6), 1319; https://doi.org/10.3390/agronomy14061319 (registering DOI) - 18 Jun 2024
Viewed by 60
Abstract
Flood submergence has devastating effects on agricultural production in China, with rice being particularly vulnerable to its impacts. Previous studies on rice submergence stress have primarily focused on immediate yield reduction and short-term growth. In this study, a submergence stress experiment was carried [...] Read more.
Flood submergence has devastating effects on agricultural production in China, with rice being particularly vulnerable to its impacts. Previous studies on rice submergence stress have primarily focused on immediate yield reduction and short-term growth. In this study, a submergence stress experiment was carried out by using the method of potted rice flooding. The growth recovery characteristics of rice under different submergence stress were analyzed through the continuous observation of rice growth after the disaster. The results showed that submergence stress had a persistent effect on rice growth, which persisted until the recovery period after the disaster. The recovery ability of rice plants decreased with the aggravation of stress, leading to increased damage to the plant. The average yield decreased by 17.07% and 15.56% due to submergence stress during the jointing and booting stage, respectively. The current study pointed out that the growth traits of and, furthermore, the mechanism of physiological changes in rice during the recovery period need to be explored in order to understand the effects of flooding stress on rice. Full article
(This article belongs to the Special Issue Rice Germplasm Innovation and Tolerance to Abiotic Stress)
12 pages, 3347 KiB  
Article
Prohexadione Calcium and Gibberellin Improve Osmoregulation, Antioxidant Response and Ion Homeostasis to Alleviate NaCl Stress in Rice Seedlings
by Meiling Liu, Naijie Feng, Dianfeng Zheng and Rongjun Zhang
Agronomy 2024, 14(6), 1318; https://doi.org/10.3390/agronomy14061318 (registering DOI) - 18 Jun 2024
Viewed by 99
Abstract
Prohexadione calcium (EA) and gibberellin (GA) are two different types of plant growth regulators that have different effects on the regulation of plant development. The objective of this study was to evaluate the impacts of EA and GA on rice plant growth, development [...] Read more.
Prohexadione calcium (EA) and gibberellin (GA) are two different types of plant growth regulators that have different effects on the regulation of plant development. The objective of this study was to evaluate the impacts of EA and GA on rice plant growth, development and morph-physiological traits in two rice varieties: ‘Huang Huazhan’ and ‘Guang Hong 3’. At the three-leaf seedling stage, the plants were treated with 50 mM NaCl 24 h after foliar application of EA (100 mg·L−1) and GA (1 mg·L−1). Data on morphological indexes, osmotic regulators and antioxidant activities were compared with the treatment of EA and GA on the 4th, 7th, 10th and 13th days after NaCl stress. Our data analysis showed that NaCl stress inhibited the leaf area growth of rice seedlings, altered the microstructure and disrupted the antioxidant system, ion uptake and transport balance. The significant increase in malondialdehyde (MDA) content and superoxide anion production rate (O2·¯) indicated that NaCl stress caused a severe oxidative stress response to rice seedlings. Treatment with EA and GA activated the antioxidant system under NaCl stress, significantly elevated superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities and suppressed the increase in MDA content and the O2·¯ production rate. Under NaCl stress, EA and GA treatments improved the osmoregulatory balance, significantly increased soluble protein and proline contents and maintained lower Na+/K+ levels. EA and GA treatments significantly increased the K+ and Ca2+ contents, thereby maintaining ionic balance, which was favorable for maintaining the growth of rice seedlings. In this study, moth plant growth regulators maintained the growth and development of rice seedlings under NaCl stress by inducing an increase in osmoregulation and antioxidant levels, reducing the degree of membrane damage and regulating the selective uptake of ions by rice seedlings. Current findings also clarified that foliar application of EA was more effective than GA in three-leaf seedlings by enhancing the morph-physiological and antioxidant parameters under NaCl stress. Full article
(This article belongs to the Section Plant-Crop Biology and Biochemistry)
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16 pages, 4746 KiB  
Article
The Impact of Different Phosphorus Fertilizers Varieties on Yield under Wheat–Maize Rotation Conditions
by Chutao Liang, Xiaoqi Liu, Jialong Lv, Funian Zhao and Qiang Yu
Agronomy 2024, 14(6), 1317; https://doi.org/10.3390/agronomy14061317 - 18 Jun 2024
Viewed by 103
Abstract
The global phosphate (P) rock shortage has become a significant challenge. Furthermore, the misalignment between crops, soil, and P usage exacerbates P rock wastage in agriculture. The distinctions among various types of phosphorus fertilizers influence the phosphorus cycle, which subsequently impacts biomass, the [...] Read more.
The global phosphate (P) rock shortage has become a significant challenge. Furthermore, the misalignment between crops, soil, and P usage exacerbates P rock wastage in agriculture. The distinctions among various types of phosphorus fertilizers influence the phosphorus cycle, which subsequently impacts biomass, the number of grains per ear, the weight of a thousand grains, and, ultimately, the overall yield. In a four-year field experiment conducted from 2017 to 2021, we assessed the impact of various P fertilizer types on crop yield in a continuous wheat–maize rotation system. Prior to planting the crops, P fertilizers were applied as base fertilizers at a rate of 115 kg P2O5 ha−1 during the wheat season and 90 kg P2O5 ha−1 during the maize season. Additionally, nitrogen (N) was applied at rates of 120 kg ha−1 for wheat and 180 kg ha−1 for maize. The P fertilizers used included ammonium dihydrogen phosphate, ammonium polyphosphate, calcium–magnesia phosphate, ammonium phosphate, and calcium superphosphate. Urea was used as the N fertilizer with a split application—60% at planting and 40% at the jointing stage for wheat or the V12 (twelve leaf collar) stage for maize. The results showed that different P fertilizers increased the average yield of wheat and maize by 21.2–38.0% and 9.9–16.3%, respectively. It was found that ammonium polyphosphate, calcium superphosphate, and monoammonium phosphate were more suitable for application in a summer maize–winter wheat rotation system on loess soil. Full article
(This article belongs to the Special Issue Advances in Application Effects and Mechanisms of Fertilizer Products)
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26 pages, 3874 KiB  
Article
Use of Biofertilizers as an Effective Management Strategy to Improve the Photosynthetic Apparatus, Yield, and Tolerance to Drought Stress of Drip-Irrigated Wheat in Semi-Arid Environments
by Chayma Ikan, Fatima-Ezzahra Soussani, Redouane Ouhaddou, Lahoucine Ech-Chatir, Farid Errouh, Abderrahim Boutasknit, Amine Assouguem, Essam A. Ali, Riaz Ullah, Essaid Ait Barka, Rachid Lahlali and Abdelilah Meddich
Agronomy 2024, 14(6), 1316; https://doi.org/10.3390/agronomy14061316 - 18 Jun 2024
Viewed by 109
Abstract
Irrigation scheduling, coupled with the use of biofertilizers, constitutes an effective management strategy to overcome soil drought. This study aimed to assess the individual and combined effects of three selected biofertilizers—(R) Bacillus sp. and Bacillus subtilis, (M) native arbuscular mycorrhizal fungi, and [...] Read more.
Irrigation scheduling, coupled with the use of biofertilizers, constitutes an effective management strategy to overcome soil drought. This study aimed to assess the individual and combined effects of three selected biofertilizers—(R) Bacillus sp. and Bacillus subtilis, (M) native arbuscular mycorrhizal fungi, and (C) compost—on Triticum durum L. The agro-physiological and biochemical traits, along with the soil properties, were evaluated under two different water regimes, 100% crop evapotranspiration (ETc) for the well-watered regime and 30% ETc for the drought-stressed regime under field conditions, using a drip irrigation system. Drought stress (DS) led to significant reductions in the biomass, physiological parameters, and biochemical markers. Furthermore, the application of CM and MR significantly boosted the shoot and root dry weight by 137% and 72%, respectively, under DS compared to the control. Moreover, CM and R resulted in a notable increase of 167% and 130% in the grain and straw yield, respectively, under the same conditions. The normalized difference vegetation index showed improved values in the plants inoculated with MR and CMR, respectively, under DS conditions. Additionally, the soil quality was positively influenced by the application of M and/or R and/or C biofertilizers. These findings provide valuable insights into the intricate soil–plant interactions and the beneficial effects of combined biofertilizers in enhancing wheat’s resilience to drought stress. Full article
(This article belongs to the Section Water Use and Irrigation)
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13 pages, 3237 KiB  
Article
Effect of Three Novel Thiazolidiones on the Development, Reproduction, and Trehalase Activity of Spodoptera frugiperda (Lepidoptera: Noctuidae)
by Liuhe Yu, Fan Zhong, Xinyi Jiang, Biner He, Haoyu Fu, Xiangyu Liu, Qixuan Mao, Ying Zhao, Shigui Wang, Yan Wu, Hongxia Duan and Bin Tang
Agronomy 2024, 14(6), 1315; https://doi.org/10.3390/agronomy14061315 - 18 Jun 2024
Viewed by 102
Abstract
Spodoptera frugiperda was used to investigate its role as a trehalase inhibitor of three new thiothiazolidone compounds—6d, 6e, and 6f. The development and reproduction of S. frugiperda were investigated to evaluate the potential of these compounds as a novel [...] Read more.
Spodoptera frugiperda was used to investigate its role as a trehalase inhibitor of three new thiothiazolidone compounds—6d, 6e, and 6f. The development and reproduction of S. frugiperda were investigated to evaluate the potential of these compounds as a novel pesticide for pest control. Compounds 6d, 6e, and 6f were injected into larvae and female pupae. Molecular changes in trehalose and chitin metabolism genes were monitored. Pupal trehalase activity, the female pupal emergence rate, ovarian development, and SfVg and SfVgR gene expression levels were assessed. The results revealed that all three compounds significantly inhibited trehalase activity in the larvae. The expression of TRE was significantly downregulated, and compounds 6d and 6f significantly downregulated the expression of TRE2. Treated larvae exhibited significantly decreased survival rates and a higher incidence of abnormalities. The egg production and hatching rates were markedly diminished by the inhibitors, and the ovaries displayed blackening and clumping. These compounds exhibit promise as eco-friendly insecticides, but further experiments are required to test their multifaceted capabilities. Full article
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20 pages, 3772 KiB  
Article
Examining Nicotinamide Application Methods in Alleviating Lead-Induced Stress in Spring Barley
by Beata Smolik and Maja Sędzik-Wójcikowska
Agronomy 2024, 14(6), 1314; https://doi.org/10.3390/agronomy14061314 - 18 Jun 2024
Viewed by 107
Abstract
Cereals are a staple food in many regions of the world and are essential for global food security. Lead is one of the most significant environmental stressors, impacting plants throughout their life cycle and causing substantial damage to plant growth and development. It [...] Read more.
Cereals are a staple food in many regions of the world and are essential for global food security. Lead is one of the most significant environmental stressors, impacting plants throughout their life cycle and causing substantial damage to plant growth and development. It disrupts intracellular processes, thereby reducing plant productivity. The aim of this study was to determine the effect of exogenously applied vitamin PP (100 µM) (nicotinamide) on the morphological, physiological, and biochemical parameters of spring barley var. Eunova under lead stress (1 mM Pb(NO3)2) and to determine the most effective method of applying this vitamin in a pot experiment. Vitamin PP was applied exogenously through three different methods: seed soaking, foliar application, and soil irrigation. The application of 1 mM Pb(NO3)2 resulted in decreased root (from 13.9% to 19.9%) and shoot length (from 16.2% to 24.8%) and increased catalase (CAT) activity from 45% to 106%, and peroxidase (POX) activity from 39% to 46% compared to the control. Lead stress led to an increase in proline (Pro) content from 30 to 63% and comparatively in malondialdehyde (MDA) content (rising from 61% to 79.4%), as well as elevated assimilatory pigment content (by 35%) in barley grown in the pot experiment. Exogenous vitamin PP significantly and positively influenced the improvement of the measured morphological, biochemical, and physiological parameters, reducing the toxicity of lead salts. It was shown that the most effective method of vitamin PP application was achieved through foliar spraying and irrigation. Full article
(This article belongs to the Topic Effect of Heavy Metals on Plants, 2nd Volume)
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18 pages, 7977 KiB  
Article
Integration of Unmanned Aerial Vehicle Spectral and Textural Features for Accurate Above-Ground Biomass Estimation in Cotton
by Maoguang Chen, Caixia Yin, Tao Lin, Haijun Liu, Zhenyang Wang, Pingan Jiang, Saif Ali, Qiuxiang Tang and Xiuliang Jin
Agronomy 2024, 14(6), 1313; https://doi.org/10.3390/agronomy14061313 - 18 Jun 2024
Viewed by 140
Abstract
Timely and accurate estimation of Above-Ground-Biomass (AGB) in cotton is essential for precise production monitoring. The study was conducted in Shaya County, Aksu Region, Xinjiang, China. It employed an unmanned aerial vehicle (UAV) as a low-altitude monitoring platform to capture multispectral images of [...] Read more.
Timely and accurate estimation of Above-Ground-Biomass (AGB) in cotton is essential for precise production monitoring. The study was conducted in Shaya County, Aksu Region, Xinjiang, China. It employed an unmanned aerial vehicle (UAV) as a low-altitude monitoring platform to capture multispectral images of the cotton canopy. Subsequently, spectral features and textural features were extracted, and feature selection was conducted using Pearson’s correlation (P), Principal Component Analysis (PCA), Multivariate Stepwise Regression (MSR), and the ReliefF algorithm (RfF), combined with the machine learning algorithm to construct an estimation model of cotton AGB. The results indicate a high consistency between the mean (MEA) and the corresponding spectral bands in textural features with the AGB correlation. Moreover, spectral and textural feature fusion proved to be more stable than models utilizing single spectral features or textural features alone. Both the RfF algorithm and ANN model demonstrated optimization effects on features, and their combination effectively reduced the data redundancy while improving the model performance. The RfF-ANN-AGB model constructed based on the spectral and textural features fusion worked better, and using the features SIPI2, RESR, G_COR, and RE_DIS, exhibited the best performance, achieving a test sets R2 of 0.86, RMSE of 0.23 kg·m−2, MAE of 0.16 kg·m−2, and nRMSE of 0.39. The findings offer a comprehensive modeling strategy for the precise and rapid estimation of cotton AGB. Full article
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20 pages, 5560 KiB  
Article
Silicon Fertilization Improves Sunflower Rhizosphere Microbial Community Structure and Reduces Parasitism by Orobanche cumana Wallr.
by Tengqi Xu, Jihong Ke, Yufan Wang, Yiqiong Zhang, Jiao Xi, Xiaomin Wei, Yongqing Ma and Yanbing Lin
Agronomy 2024, 14(6), 1312; https://doi.org/10.3390/agronomy14061312 - 18 Jun 2024
Viewed by 101
Abstract
Sunflower broomrape (Orobanche cumana Wallr.) has severely restricted the development of the sunflower industry in China, and more efficient and convenient control methods are urgently needed. In this experiment, we investigated the effects of N, P and silica fertilizers on the parasitism [...] Read more.
Sunflower broomrape (Orobanche cumana Wallr.) has severely restricted the development of the sunflower industry in China, and more efficient and convenient control methods are urgently needed. In this experiment, we investigated the effects of N, P and silica fertilizers on the parasitism rate of O. cumana, as well as on the yield of sunflower and native microbial communities in the field. Firstly, pot experiments were conducted to select the most effective fertilization method and to determine the physiological and biochemical indexes of sunflowers. Subsequently, field application studies were carried out to determine the physiological indexes, yield, O. cumana parasitism on sunflower, and the effect on the indigenous microbial community. The results demonstrate that compared with the CNP treatment (Control), the number of parasites under the N1P5 treatment significantly decreased by 66.15%. The exogenous application of silica can significantly reduce the number of O. cumana parasites. The treatments with N1P5 (N/P = 1:5) and available SiO2 content higher than 40 mg/kg (NS2, NS3, SF2 and SF3) significantly increased superoxide dismutase (SOD) activity and decreased malondialdehyde (MDA) content in sunflower leaves. In the field, fertilization significantly decreased the number of O. cumana parasites. The S treatment improved the native microbial community structure and enriched beneficial microorganisms, including Vicinamibacteria and Pyrinomonadaceae. Additionally, applying the S treatment significantly increased sunflower yield by 23.82% and crude protein content by 20.20%. In summary, the application of silicon fertilizer can effectively improve the host microbial community, reduce O. cumana parasitism and improve the yield and quality of sunflower. Full article
(This article belongs to the Special Issue Soil Microbe and Nematode Communities in Agricultural Systems)
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14 pages, 3424 KiB  
Article
Influence of Vermicompost on the Concentration of Exogenous Indole-3-Acetic Acid and Its Effect on the Development of Tomato Plants (Lycopersicum esculentum L.)
by Miguel Ángel Segura-Castruita, Mariano Ángel Valdivia-Dávila, Pedro Yescas-Coronado, Juan Florencio Gómez-Leyva and Saraí Cueto-Medina
Agronomy 2024, 14(6), 1311; https://doi.org/10.3390/agronomy14061311 - 18 Jun 2024
Viewed by 233
Abstract
Indole-3-acetic acid (IAA) concentration is directly proportional to the amount of vermicompost (VC) added to sand substrates. The objectives of this work were to establish the effect of the amount of VC in sand substrates on the concentration of IAA and to determine [...] Read more.
Indole-3-acetic acid (IAA) concentration is directly proportional to the amount of vermicompost (VC) added to sand substrates. The objectives of this work were to establish the effect of the amount of VC in sand substrates on the concentration of IAA and to determine its influence on tomato plants. Sand substrates with VC percentages (0, 20, 40, and 50%) were placed in pots; in each one, the concentration of IAA was determined at the beginning and the end (after supporting tomato plants), and its bacterial load was determined. In tomato plants, some vegetative and yield components were measured. The results show that by adding 1 kg of VC in a sand-based substrate, the concentration of exogenous IAA increases by 0.0470 and 0.0642 mg g−1 (at the beginning and the end, respectively). This increase was reflected in the development of the plants; for example, their roots demonstrated their maximum development (370.20 cm−3) when the amount of VC in the substrate was 3.95 kg. Therefore, the amount of VC used in the preparation of substrates influences the concentration of IAA in them, which is reflected in the development of tomato plants. Full article
(This article belongs to the Section Farming Sustainability)
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15 pages, 2473 KiB  
Article
Assessing the Effectiveness of Vermi-Liquids as a Sustainable Alternative to Inorganic Nutrient Solutions in Hydroponic Agriculture: A Study on Diplotaxis muralis
by Sami ur Rehman, Alessio Aprile, Federica De Castro, Carmine Negro, Danilo Migoni, Michele Benedetti, Erika Sabella and Francesco Paolo Fanizzi
Agronomy 2024, 14(6), 1310; https://doi.org/10.3390/agronomy14061310 - 18 Jun 2024
Viewed by 187
Abstract
Organic products are gaining popularity due to their positive impact on human health and the environment. While hydroponics is commonly used in vegetable production, it relies on mineral fertilizers derived from limited and non-renewable resources. As a result, farmers are actively seeking sustainable [...] Read more.
Organic products are gaining popularity due to their positive impact on human health and the environment. While hydroponics is commonly used in vegetable production, it relies on mineral fertilizers derived from limited and non-renewable resources. As a result, farmers are actively seeking sustainable farming solutions. This study comprehensively evaluated the effectiveness of vermi-liquids (organic nutrient solutions) as a replacement for conventional inorganic nutrient solutions in promoting growth and nutrient acquisition in Diplotaxis muralis plants in a controlled environment. The results showed that plant biomass and SPAD values of D. muralis grown in Hoagland solution and enhanced vermitea (vermitea having relatively low pH and high EC) were higher compared to standard vermitea (high pH and low EC). The findings also revealed improved nutrient assimilation of phosphorus, potassium, calcium, iron, manganese, copper, and zinc in the enhanced vermitea plants. The heavy metal contents in D. muralis leaves were evaluated, too, and they were found to fall significantly below the safe threshold, rendering them safe for human consumption. However, the standard vermitea, with its high pH and low EC, performed poorly as a hydroponic solution. This research suggests that enhanced vermitea can completely replace chemical nutrient solutions in hydroponic agriculture. This substitution could lead to reduced production costs and improved product quality. Full article
(This article belongs to the Section Plant-Crop Biology and Biochemistry)
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18 pages, 13265 KiB  
Article
Estimation of Winter Wheat Chlorophyll Content Based on Wavelet Transform and the Optimal Spectral Index
by Xiaochi Liu, Zhijun Li, Youzhen Xiang, Zijun Tang, Xiangyang Huang, Hongzhao Shi, Tao Sun, Wanli Yang, Shihao Cui, Guofu Chen and Fucang Zhang
Agronomy 2024, 14(6), 1309; https://doi.org/10.3390/agronomy14061309 - 17 Jun 2024
Viewed by 201
Abstract
Hyperspectral remote sensing technology plays a vital role in advancing modern precision agriculture due to its non-destructive and efficient nature. To achieve accurate monitoring of winter wheat chlorophyll content, this study utilized 68 sets of chlorophyll content data and hyperspectral measurements collected during [...] Read more.
Hyperspectral remote sensing technology plays a vital role in advancing modern precision agriculture due to its non-destructive and efficient nature. To achieve accurate monitoring of winter wheat chlorophyll content, this study utilized 68 sets of chlorophyll content data and hyperspectral measurements collected during the jointing stage of winter wheat over two consecutive years (2019–2020), under various fertilization types and nitrogen application levels. Continuous wavelet transform was applied to transform the original reflectance, ranging from 21 to 210, and the correlation matrix method was utilized to identify the spectral index at each scale, with the highest correlation to winter wheat chlorophyll content as the optimal spectral index combination input. Subsequently, winter wheat chlorophyll content prediction models were developed using three machine learning methods: random forest (RF), support vector machine (SVM), and a genetic algorithm-optimized backpropagation neural network (GA-BP). The results indicate that the spectral data processed through continuous wavelet transform at seven scales, from 21 to 27, show the highest correlation with winter wheat chlorophyll content at a scale of 26, with a correlation coefficient of 0.738, compared with the correlation of 0.611 of the original reflectance, and the accuracy is improved by 20.7%. The average highest correlation value between the spectral index at scale 26 and winter wheat chlorophyll content is 0.752. As the scale of wavelet transform increases, the correlation between the spectral index and winter wheat chlorophyll content and the accuracy of the predictive model show a trend of first increasing and then decreasing. The optimal input variables for predicting winter wheat chlorophyll content and the best machine learning method are the spectral data at a scale of 26 processing combined with the GA-BP model. The optimal predictive model has a validation set coefficient of determination (R2) of 0.859, root mean square error (RMSE) of 1.366, and mean relative error (MRE) of 2.920%. The results show that the prediction model can provide a technical basis for improving the hyperspectral inversion accuracy of winter wheat chlorophyll and modern precision agriculture. Full article
17 pages, 1271 KiB  
Article
Soil Microbial Functions Linked Fragrant Rice 2-Acetyl-1-Pyrroline with Soil Active Carbon Pool: Evidence from Soil Metagenomic Sequencing of Tillage Practices
by Xiangwen Huang, Jiajun Lin, Qihuan Xie, Jingdan Shi, Xiaoxu Du, Shenggang Pan, Xiangru Tang and Jianying Qi
Agronomy 2024, 14(6), 1308; https://doi.org/10.3390/agronomy14061308 - 17 Jun 2024
Viewed by 124
Abstract
Improved tillage management in fragrant rice cropping systems can enhance soil organic carbon (SOC) and the content of 2-Acetyl-1-Pyrroline (2-AP), a crucial volatile compound contributing to the aroma of fragrant rice. Despite this, the interplay between 2-AP content in fragrant rice and SOC [...] Read more.
Improved tillage management in fragrant rice cropping systems can enhance soil organic carbon (SOC) and the content of 2-Acetyl-1-Pyrroline (2-AP), a crucial volatile compound contributing to the aroma of fragrant rice. Despite this, the interplay between 2-AP content in fragrant rice and SOC metabolism, alongside the influences exerted by soil microbial functions, remains poorly understood. This study introduces a comprehensive 6-year field experiment which aims to correlate SOC with rice grain 2-AP content by analyzing soil microbial KEGG functions, such as carbon and amino acid metabolism, using metagenomic sequencing. The experiment assessed three tillage practices, conventional tillage (CT), reduced tillage (RT), and no tillage (NT), with soil samples collected on three dates in 2022. The results indicated that NT significantly (p < 0.05) enhanced SOC content and modified carbon metabolism by upregulating the Calvin cycle (K01601) and reducing hemicellulose degradation (K01710). Additionally, NT notably increased the soil levels of alkaline amino acids, such as histidine and ornithine, which were 165.17% and 1218.42% higher, respectively, than those in CT, possibly linked to an increase in soil pH. Furthermore, the 2-AP content in fragrant rice under NT was significantly higher by 52.02% and 13.90% compared to under RT and CT, respectively. NT also upregulated K00250 (alanine, aspartate, and glutamate metabolism) and K00290 (valine, leucine, and isoleucine biosynthesis), leading to significantly higher levels of 2-AP biosynthesis-related amino acids proline and glutamate in fragrant rice grain. This study links SOC and 2-AP biosynthesis via soil microbial functions, presenting a novel strategy for improving the quality of fragrant rice through soil management practices. Full article
(This article belongs to the Special Issue Sustainable Management and Tillage Practice in Agriculture)
11 pages, 2522 KiB  
Article
Efficacy of Extreme Temperatures on All Life Stages of the Mediterranean Flour Moth, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae)
by Maria K. Sakka, Marina Gourgouta and Christos G. Athanassiou
Agronomy 2024, 14(6), 1307; https://doi.org/10.3390/agronomy14061307 - 17 Jun 2024
Viewed by 213
Abstract
In the present study, we examined the effect of extreme temperatures on different life stages of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae). The individuals were exposed to different temperatures ranging between 5 and −18 °C for cold treatment, and between 30 and 55 °C [...] Read more.
In the present study, we examined the effect of extreme temperatures on different life stages of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae). The individuals were exposed to different temperatures ranging between 5 and −18 °C for cold treatment, and between 30 and 55 °C for heat treatment, and different exposure intervals, ranging from minutes to days. Complete control was achieved at −10 and −15 °C for cold treatment and 50 and 55 °C for heat treatment at all exposure intervals. Considering the efficacy of extreme temperatures for the control of E. kuehniella, our study provides specific temperature exposure modules that can be effective for the control of this species. Full article
(This article belongs to the Special Issue Post-harvest Pest and Disease Management—2nd Edition)
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16 pages, 2216 KiB  
Article
Brackish Water, Phosphate Fertilization and Trichoderma in the Agronomic Performance of Beet Crops
by Andreza Silva Barbosa, Alexsandro Oliveira da Silva, Geocleber Gomes de Sousa, Maria Vanessa Pires de Souza, Márcio Henrique da Costa Freire, Geovana Ferreira Goes, Arthur Prudêncio de Araújo Pereira, Thales Vinícius de Araújo Viana, Raimundo Nonato Távora Costa, Claudivan Feitosa de Lacerda, Geronimo Ferreira da Silva and Mário Monteiro Rolim
Agronomy 2024, 14(6), 1306; https://doi.org/10.3390/agronomy14061306 - 17 Jun 2024
Viewed by 267
Abstract
The study hypothesis proposes that the use of Trichoderma, associated with fertilization with 100% of the recommended phosphorus, may mitigate saline stress and maximize the productivity and quality of the tuberous root. This study aims to evaluate the mitigating effects of phosphate [...] Read more.
The study hypothesis proposes that the use of Trichoderma, associated with fertilization with 100% of the recommended phosphorus, may mitigate saline stress and maximize the productivity and quality of the tuberous root. This study aims to evaluate the mitigating effects of phosphate fertilization and Trichoderma harzianum in beet plants under salt stress, by measuring the initial growth, leaf gas exchange, productivity and quality of the beet. The experimental design used was entirely randomized, in a 3 × 2 × 2 factorial scheme, referring to three doses of phosphate fertilization (25%, 50% and 100%), with and without the use of Trichoderma-based inoculation, and two levels of electrical conductivity of the irrigation water (0.5 and 6.2 dS m−1). Salt stress negatively affected the leaf area of the beet. The shoots’ dry mass was reduced as the electrical conductivity of the irrigation water increased, especially in the treatment with the 25% P2O5 dose. Salt stress reduced photosynthesis to a greater extent at the 25% P2O5 dose and in the absence of Trichoderma harzianum. Increasing the electrical conductivity of the irrigation water reduced transpiration and increased leaf temperature at the 25% P2O5 dose and in the presence of Trichoderma harzianum. The 25% P2O5 dose increased the stomatal conductance of the beet. The higher electrical conductivity of the irrigation water negatively affected water use efficiency, most significantly at the 25% P2O5 dose. Our data showed that the doses of 50% and 100% P2O5 were more efficient at increasing the productivity and quality of the beet, with the tuberous root diameter being higher under the lower electrical conductivity of the water and the absence of Trichoderma harzianum. The pH was high under the lowest electrical conductivity of the water, with a dose of 25% P2O5 and the absence of Trichoderma harzianum. Full article
(This article belongs to the Special Issue Effect of Brackish and Marginal Water on Irrigated Agriculture)
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13 pages, 4838 KiB  
Article
Rapid Identification of Rhizobia Nodulating Soybean by a High-Resolution Melting Analysis
by Karolina Jarzyniak and Dorota Narożna
Agronomy 2024, 14(6), 1305; https://doi.org/10.3390/agronomy14061305 - 17 Jun 2024
Viewed by 302
Abstract
Soybean [Glycine max (L.) Merr.] is one of the most important and oldest crops. Due to its ability to form symbiotic interactions with nitrogen-fixing bacteria, it is a valuable source of nitrogen for agriculture and proteins for humans and livestock. In Europe, [...] Read more.
Soybean [Glycine max (L.) Merr.] is one of the most important and oldest crops. Due to its ability to form symbiotic interactions with nitrogen-fixing bacteria, it is a valuable source of nitrogen for agriculture and proteins for humans and livestock. In Europe, for instance, in Poland, the soybean cultivation area is still not large but is gradually increasing due to climate change. The lack of indigenous soybean microsymbionts in Polish soils forces the application of commercial strains to establish effective symbioses. Fast and reliable identification methods are needed to study the persistence, competitiveness, and dispersal of bradyrhizobia introduced as inocula. Our study aimed to apply real-time PCR coupled with high-resolution melting curve (HRM) analysis to detect and differentiate bacterial strains occupying soybean nodules. HRM-PCR was performed on crude extracts from nodules using primers specific for recA, a highly conserved nonsymbiotic gene. By comparing them with the reference strains, we were able to identify and assign Bradyrhiobium strains that had been introduced into field locations in Poland. In conclusion, HRM analysis was proven to be a fast and accurate method for identifying soybean microsymbionts and might be successfully used for identifying other legume-nodulating bacteria. Full article
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21 pages, 5735 KiB  
Article
Drought-Stressed Apple Tree Grafted onto Different Rootstocks in a Coastal Sandy Soil: Link between Fast Chlorophyll a Fluorescence and Production Yield
by Andrea Colpo, Sara Demaria, Marzio Zaccarini, Alessandro Forlani, Antonia Senatore, Elena Marrocchino, Angela Martina and Lorenzo Ferroni
Agronomy 2024, 14(6), 1304; https://doi.org/10.3390/agronomy14061304 - 16 Jun 2024
Viewed by 367
Abstract
Domesticated apple is a drought-sensitive species that spread from continental to Mediterranean temperate regions, where it can particularly experience prolonged water stress. One strategy to improve drought resistance in apple is engrafting on selected rootstocks. This study explores the potential of fast chlorophyll [...] Read more.
Domesticated apple is a drought-sensitive species that spread from continental to Mediterranean temperate regions, where it can particularly experience prolonged water stress. One strategy to improve drought resistance in apple is engrafting on selected rootstocks. This study explores the potential of fast chlorophyll a fluorescence for the comparison of rootstock sensitivity to drought, looking for significant correlations with fruit productivity. The experiment was conducted in a field located in the coastal Po River Plain, Northern Italy, characterized by a loamy sandy soil, particularly prone to drought (86% sand). Mature plants of apple cv. Superchief® Sandidge engrafted on three different rootstocks (CIVP21pbr, MM106, M26) were monitored throughout the summer of 2021 and compared between irrigated and non-irrigated parcels, and at the end of the season, fruit production was evaluated. Despite soil water tension only reaching −13 kPa, the non-irrigated plants experienced a small but consistent loss of Photosystem II (PSII) activity and a lesser capacity of light energy conservation in the photosynthetic electron transport chain. The fruit weight correlated with PSII photochemical indexes recorded during early drought, particularly FV/FM and PIABS; a correlation emerged between fruit number per plant and median values of electron transport parameters, including PITOT. Although all rootstocks underwent a 40% loss of productivity, the fluorescence parameters revealed a graded susceptibility to drought, M26 > CIVP21pbr > MM106, which matched well with the plant vigour. The least drought-sensitive MM106 produced less numerous but heavier fruits than the other two rootstocks. Full article
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20 pages, 3233 KiB  
Article
Climate-Informed Management of Irrigated Cotton in Western Kansas to Reduce Groundwater Withdrawals
by R. L. Baumhardt, L. A. Haag, R. C. Schwartz and G. W. Marek
Agronomy 2024, 14(6), 1303; https://doi.org/10.3390/agronomy14061303 - 16 Jun 2024
Viewed by 297
Abstract
The Ogallala aquifer, underlying eight states from South Dakota to Texas, is practically non-recharging south of Nebraska, and groundwater withdrawals for irrigation have lowered the aquifer in western Kansas. Subsequent well-yield declines encourage deficit irrigation, greater reliance on precipitation, and producing profitable drought-tolerant [...] Read more.
The Ogallala aquifer, underlying eight states from South Dakota to Texas, is practically non-recharging south of Nebraska, and groundwater withdrawals for irrigation have lowered the aquifer in western Kansas. Subsequent well-yield declines encourage deficit irrigation, greater reliance on precipitation, and producing profitable drought-tolerant crops like upland cotton (Gossypium hirsutum (L.)). Our objective was to evaluate deficit irrigated cotton growth, yield, and water productivity (CWP) in northwest, west-central, and southwest Kansas in relation to El Niño southern oscillation (ENSO) phase effects on precipitation and growing season cumulative thermal energy (CGDD). Using the GOSSYM crop growth simulator with actual 1961–2000 location weather records partitioned by the ENSO phase, we modeled crop growth, yield, and evapotranspiration (ET) for irrigation capacities of 2.5, 3.75, and 5.0 mmd−1 and periods of 4, 6, and 8 weeks. Regardless of location, the ENSO phase did not influence CGDD, but precipitation and lint yield decreased significantly in southwest Kansas during La Niña compared with the Neutral and El Niño phases. Simulated lint yields, ET, CWP, and leaf area index (LAI) increased with increasing irrigation capacity despite application duration. Southwestern Kansas producers may use ENSO phase information with deficit irrigation to reduce groundwater withdrawals while preserving desirable cotton yields. Full article
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18 pages, 654 KiB  
Article
Nighttime Warming Reduced Copper Concentration and Accumulation in Wheat Grown in Copper-Contaminated Soil by Affecting Physiological Traits
by Xianghan Cheng, Feifei Liu, Peng Song, Xiaolei Liu, Qin Liu and Taiji Kou
Agronomy 2024, 14(6), 1302; https://doi.org/10.3390/agronomy14061302 - 16 Jun 2024
Viewed by 206
Abstract
Abstract: The changes in biomass (including yield), copper (Cu) concentration, and the accumulation of wheat (Triticum aestivum. L) in response to soil Cu pollution under nighttime warming had still not been explored. Hence, this study was carried out, and these [...] Read more.
Abstract: The changes in biomass (including yield), copper (Cu) concentration, and the accumulation of wheat (Triticum aestivum. L) in response to soil Cu pollution under nighttime warming had still not been explored. Hence, this study was carried out, and these variations were analyzed from a physiological perspective. Pot trials were performed at two levels of ambient temperatures (no-warming (NT) and average nighttime warming of 0.28 °C (WT)) and two levels of soil Cu concentrations (control check without Cu application (CK) and 100 mg/kg Cu application (Cu)). Soil was collected from the carbonate cinnamon soil region of central China. The warming effects of the passive nighttime warming system were prominent, and the average increment was 0.28 °C. Antioxidant enzyme activities were promoted by warming (p < 0.05) and Cu. The highest yield was achieved in NT-Cu, mainly attributed to relatively strong root activity and photosynthesis caused by supplemental Cu, but the Cu concentration in its grains was close to the threshold (10 mg/kg) for Cu concentration in foodstuff and could present a potential food safety risk. Though nighttime warming did not increase the total biomass and yield of wheat, it decreased the Cu accumulation of wheat grown in Cu-contaminated soil, especially in grains. Moreover, WT-CK and WT-Cu increased the Cu concentration in the roots and glumes and reduced the Cu concentration in grains by 13.09% and 55.84%, respectively, probably because of a lower transpiration rate. Among them, the Cu concentration of grains in WT-Cu was the lowest and significantly lower than other applications. Our findings reveal that nighttime warming has the potential to reduce the Cu risk of grains in wheat grown in the Cu-contaminated carbonate cinnamon soil region of central China and could then provide a theoretical reference for risk assessment of food quality for wheat subjected to dual stress from nighttime warming and Cu pollution. Full article
(This article belongs to the Section Plant-Crop Biology and Biochemistry)
14 pages, 534 KiB  
Article
Optimizing Nitrogen Application for Enhanced Yield and Quality of Strong-Gluten Wheat: A Case Study of Zhongmai 578 in the North China Plain
by Fangang Meng, Ludi Zhao, Wenlu Li and Changxing Zhao
Agronomy 2024, 14(6), 1301; https://doi.org/10.3390/agronomy14061301 - 15 Jun 2024
Viewed by 255
Abstract
Abstract: This study was designed to determine the optimal nitrogen application rate for strong-gluten wheat cultivation in the North China Plain. Employing Zhongmai 578, a strong-gluten wheat variety, a field experiment was conducted with the following four nitrogen levels: 0 kg/ha (N0), 150 [...] Read more.
Abstract: This study was designed to determine the optimal nitrogen application rate for strong-gluten wheat cultivation in the North China Plain. Employing Zhongmai 578, a strong-gluten wheat variety, a field experiment was conducted with the following four nitrogen levels: 0 kg/ha (N0), 150 kg/ha (N1), 210 kg/ha (N2), and 270 kg/ha (N3). The research focused on examining the impact of nitrogen application on the photosynthesis, yield, and quality of strong-gluten wheat. The findings revealed that the N2 treatment (210 kg/ha) yielded the highest results compared to the N0 treatment. Photosynthetic parameters, including chlorophyll content in wheat flag leaves, generally exhibited an increase followed by a decrease, peaking at 7 days after anthesis (except for the transpiration rate, which peaked at 14 days post-anthesis). In the first year, quality indices such as water absorption, capacity, sedimentation value, ductility, protein, and wet gluten initially increased and then decreased with rising nitrogen levels. Conversely, in the second year, these quality indices, including hardness, showed a progressive increase with elevated nitrogen application. These results indicate that enhanced nitrogen application can significantly improve the photosynthetic characteristics of strong-gluten wheat, thereby augmenting both yield and quality. Within the parameters of this experiment, an application of 210 kg/ha of nitrogen emerged as the optimal rate, promoting the superior yield and quality of strong-gluten wheat in the North China Plain. Full article
(This article belongs to the Section Agroecology Innovation: Achieving System Resilience)
16 pages, 2213 KiB  
Article
Influence of Long-Term Mulched Drip Irrigation on Upward Capillary Water Movement Characteristics in the Saline–Sodic Region of Northwest China
by Yu Chen, Jinzhu Zhang, Zhenhua Wang, Haiqiang Li, Rui Chen, Yue Zhao, Tianbao Huang and Pengcheng Luo
Agronomy 2024, 14(6), 1300; https://doi.org/10.3390/agronomy14061300 - 15 Jun 2024
Viewed by 345
Abstract
Capillary water, serving as a crucial intermediary between groundwater and crop root layer moisture, is important for both soil retention and crop utilization. To investigate the effect of mulched drip irrigation (MDI) on upward capillary water in cotton fields with different application years [...] Read more.
Capillary water, serving as a crucial intermediary between groundwater and crop root layer moisture, is important for both soil retention and crop utilization. To investigate the effect of mulched drip irrigation (MDI) on upward capillary water in cotton fields with different application years (0, 10, 14, 18, 20, and 24 years) in the saline–sodic region of Northwest China, an indoor soil column test (one-dimensional capillary water rise experiment) was conducted. The results showed that the wetting front transport law, capillary water recharge, and wetting front transport rate over time exhibited an increasing trend in the early stages of MDI application (10 and 14 years), peaking at 18 years of application, followed by a decreasing trend. The relationship between the capillary water recharge and rising height was fitted based on the Green–Ampt model, and their slopes reveal that 14 and 18 years of MDI application required the largest amount of water per unit distance, indicating an excellent water-holding capacity beneficial for plant growth. Conversely, 0 years required the smallest amount of water per unit distance. Based on the movement characteristics of upper capillary water, we confirmed that the MDI application years (0–18 years) improves soil infiltration capacity, while the long-term application years (18–24 years) reduces groundwater replenishment to the soil. Furthermore, the HYDRUS-1D model was employed to simulate the capillary water rise process and soil moisture distribution under different MDl application years. The results showed an excellent consistency with the soil column experiments, confirming the accuracy of HYDRUS-1D in simulating the capillary water dynamics in saline–sodic areas. The results would provide suggestions to achieve the sustainable development of long-term drip-irrigated cotton fields. Full article
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20 pages, 4760 KiB  
Article
Synergistic Remediation of Cd-Contaminated Soil with Pure Natural Adsorption Material and Hyperaccumulator Plant
by Jun Guo, Honggen Xu, Fengxiang Yin, Jian Cao, Xuesheng Xu, Cong Li, Fengcun Huang, Fangwei Chen, Xiong Mao and Qi Liao
Agronomy 2024, 14(6), 1299; https://doi.org/10.3390/agronomy14061299 - 15 Jun 2024
Viewed by 308
Abstract
In recent years, cadmium (Cd) contamination in agricultural soil has emerged as a significant global environmental issue, posing irreversible harm to crops and human health. As a result, efficient soil remediation techniques are urgently needed. For this issue, synergistic remediation by material and [...] Read more.
In recent years, cadmium (Cd) contamination in agricultural soil has emerged as a significant global environmental issue, posing irreversible harm to crops and human health. As a result, efficient soil remediation techniques are urgently needed. For this issue, synergistic remediation by material and plant is an effective approach. In this study, a natural and green adsorption material (starch/montmorillonite composite, SMC) of Cd was prepared, which was further employed in synergistic remediation toward soil Cd contamination with the cadmium hyperaccumulator plant Bidens bipinnata. The results of the pot experiment demonstrated that an available Cd removal rate of 77.92 could be obtained, and the results of the field experiments demonstrate that the concentrations of Cd in contaminated soil could be reduced below the risk-screening values for agricultural land. Further analyses, including a microbial community diversity study, changes in soil BCR fraction components, and a TCLP toxicity leaching experiment, unequivocally elucidated that the synergy of SMC and Bidens bipinnata enhanced the remediation efficiency of Cd in contaminated soil. This study confirmed the application potential of the synergy of SMC and Bidens bipinnata toward Cd-contaminated soil. Full article
(This article belongs to the Section Soil and Plant Nutrition)
17 pages, 2088 KiB  
Article
Effect of Ridge–Furrow with Plastic Film Mulching System and Different Nitrogen Fertilization Rates on Lodging Resistance of Spring Maize in Loess Plateau China
by Yan Zhang, Yufeng Lv, Yuncheng Liao and Guangxin Zhang
Agronomy 2024, 14(6), 1298; https://doi.org/10.3390/agronomy14061298 - 15 Jun 2024
Viewed by 221
Abstract
The ridge–furrow with plastic film mulching (RF) system has been widely adopted in rain-fed crop planting due to its potential to enhance crop yield and water use efficiency. However, the impact of the RF system on maize lodging resistance, particularly when nitrogen fertilizer [...] Read more.
The ridge–furrow with plastic film mulching (RF) system has been widely adopted in rain-fed crop planting due to its potential to enhance crop yield and water use efficiency. However, the impact of the RF system on maize lodging resistance, particularly when nitrogen fertilizer is applied, remains uncertain. Therefore, a two-year field experiment was carried out with two planting systems (FP: flat planting and RF) and two nitrogen application rates (N180: 180 kg·N ha−1 and N300: 300 kg·N ha−1) to assess the risk of lodging in maize. The results showed that compared to FP, RF resulted in a significant increase of 78.7% in lodging rate. In addition, the lodging rate increased by 22.6% with increasing nitrogen fertilizer application. The lignin content increased by 43.4%, while the stalk bending strength rose by 42.5%, under RF compared to the FP system. These improvements in the mechanical properties of maize stalks contributed to the improved lodging resistance index of RF, which was found to be approximately 21.3% higher than that of FP. In addition, high nitrogen application rates increased the risk of lodging for different planting patterns over two years. In conclusion, fertilization of spring maize with 300 kg·N ha−1 under the RF system led to higher yields but increased lodging rates. The risk of lodging should be considered when planting maize under the RF system. The results of this study can provide scientific basis and technical support for the optimization of rain-fed maize cultivation measures in the Loess Plateau. Full article
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18 pages, 3114 KiB  
Article
Bacterial Communities, Network Complexity, and Multifunctionality Affected by Soil Types in Northeastern China
by Meng Hou, He Yu, Yao Wang, Liangqian Ma, Xiaorui Zhao, Yimin Chen, Xiaoguang Jiao and Yueyu Sui
Agronomy 2024, 14(6), 1297; https://doi.org/10.3390/agronomy14061297 - 15 Jun 2024
Viewed by 173
Abstract
The Northeast China Plain (NCP) is the country’s most important grain-producing area. Unraveling how bacterial communities in this region assemble and distribute according to soil type is essential for sustainable agricultural development and optimizing the precise management of soil resources. In this study, [...] Read more.
The Northeast China Plain (NCP) is the country’s most important grain-producing area. Unraveling how bacterial communities in this region assemble and distribute according to soil type is essential for sustainable agricultural development and optimizing the precise management of soil resources. In this study, 106 soil samples were collected from three typical zonal soil types (black calcium soil (BCS), black soil (BS), and dark brown soil (DBS)) spanning from west to east in the NCP. By combining soil field surveys and high-throughput microbial sequencing analysis, we found that bacterial diversity and community structure differed significantly by soil type. Proteobacteria, Gemmatimonadetes, and Acidobacteria were enriched in BCS, BS, and DBS, respectively. Compared to BSC and DBS, BS had the highest nutrient concentration and most neutral pH values, which may recruit more diverse bacterial communities and construct a more connected ecological network. Network analysis further identified Burkholderiales, Sphingomonadales, and SC_I_84 as key hubs in BS, BCS, and BCS, respectively. The majority of classified hubs consistent with the results of the linear discriminant analysis effect size belonged to the predominant biomarkers. Redundancy and Mantel test analyses revealed that the bacterial composition in various soil types showed distinctive responses to heterogeneity in soil physicochemical properties. Soil pH and TP were the primary factors shaping the soil bacterial community structure in these three soil types on the NCP. Moreover, bacterial composition and diversity were strongly related to changes in soil multifunctionality in BCS, and the relative abundances of three classes (TM1, Opitutae, and Deinococci) were the most important biotic variables for predicting BCS ecosystem multifunctionality. In summary, our results suggest that soil type variation has a strong influence in terms of shaping bacterial community structure and affecting soil multifunctionality. Correspondingly, diverse co-occurrence patterns were observed in different soil types. Full article
(This article belongs to the Special Issue Soil Microbe and Nematode Communities in Agricultural Systems)
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15 pages, 995 KiB  
Review
Are Heat Shock Proteins Important in Low-Temperature-Stressed Plants? A Minireview
by Iwona Sadura and Anna Janeczko
Agronomy 2024, 14(6), 1296; https://doi.org/10.3390/agronomy14061296 - 15 Jun 2024
Viewed by 180
Abstract
Heat shock proteins (HSPs) are mainly known to play important roles in plants against high-temperature (HT) stress. Their main function is to act as molecular chaperones for other proteins. It has also been proven that HSPs have a protective effect during other environmental [...] Read more.
Heat shock proteins (HSPs) are mainly known to play important roles in plants against high-temperature (HT) stress. Their main function is to act as molecular chaperones for other proteins. It has also been proven that HSPs have a protective effect during other environmental stresses including low temperature (LT). To the best of our knowledge, the expression and role of HSPs in plants that have been exposed to LT have not yet been sufficiently reviewed. The aims of this minireview were (1) to briefly describe the origin, classification, structure, localisation and functions of HSPs, (2) to present the current knowledge about the changes in the accumulation of HSPs in plants that have been exposed to LT, (3) to discuss some of the molecular changes that occur during LT action and that lead to the accumulation of HSPs in plants and (4) to discuss the potential role of HSPs in acquiring tolerance to cold and frost in plants including economically important crop species. Some directions of research on the role of HSPs in plants growing in LT conditions are proposed. Full article
(This article belongs to the Special Issue New Insights into Plants’ Defense Mechanisms against Stresses)
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26 pages, 11230 KiB  
Article
Nodulating Aeschynomene indica without Nod Factor Synthesis Genes: In Silico Analysis of Evolutionary Relationship
by Mengguang Zhao, Jingyi Dong, Zhenpeng Zhang, Entao Wang, Dandan Wang, Huijie Xie, Chao Wang and Zhihong Xie
Agronomy 2024, 14(6), 1295; https://doi.org/10.3390/agronomy14061295 - 15 Jun 2024
Viewed by 172
Abstract
Aeschynomene indica rhizobia (AIRs) are special classes of bacteria capable of nodulating without nodulation factors and have photosynthetic capacity. With an aim to characterize the structural variations in Bradyrhizobium genomes during its evolution, the genomes of AIRs and the reference Bradyrhizobium strains were [...] Read more.
Aeschynomene indica rhizobia (AIRs) are special classes of bacteria capable of nodulating without nodulation factors and have photosynthetic capacity. With an aim to characterize the structural variations in Bradyrhizobium genomes during its evolution, the genomes of AIRs and the reference Bradyrhizobium strains were compared utilizing molecular biology, bioinformatics, and biochemistry techniques. The presence of symbiotic nitrogen fixation (nif) genes and photosynthetic genes, as well as components of the T3SS (Type III secretion system) and T3CP (Type III chaperone) in the genome of AIRs, was also assessed. Additionally, the origin, evolutionary history, and genes associated with the NF-independent nodulation pattern in AIRs were explored. The results indicate that horizontal gene transfer events have occurred in AIRs, and three distinct origins of AIRs were estimated: early differentiated AIRs, non-symbiotic Bradyrhizobium, and non-AIRs. In contrast to the significant genetic transformations observed in the second and third groups, the first group of AIRs displays a rich evolutionary history, exhibits high species diversity, and primarily relies on vertical transmission of nitrogen fixation and photosynthetic genes. Overall, the findings provide a fundamental theoretical foundation for gaining a deeper understanding of the phylogeny and genealogy of AIRs. Full article
(This article belongs to the Special Issue Rhizosphere Microorganisms—Volume II)
13 pages, 827 KiB  
Article
Glycine Betaine Induces Tolerance to Oxidative Stress in Cherry Radishes under High-Temperature Conditions
by Zexi Zhang, Chunhua Jia, Yuezhuo Zhuang, Min Zhang and Baocheng Chen
Agronomy 2024, 14(6), 1294; https://doi.org/10.3390/agronomy14061294 - 14 Jun 2024
Viewed by 145
Abstract
Cool-season plant growth and development are impacted by high temperatures. As a biostimulant, glycine betaine is responsible for inducing tolerance to both biotic and abiotic stressors. However, the mechanism by which glycine betaine protects cool-season crops against high-temperature stress is not clear. In [...] Read more.
Cool-season plant growth and development are impacted by high temperatures. As a biostimulant, glycine betaine is responsible for inducing tolerance to both biotic and abiotic stressors. However, the mechanism by which glycine betaine protects cool-season crops against high-temperature stress is not clear. In the present study, under the conditions of high temperatures (35 °C/30 °C day/night), cherry radishes (Raphanus sativus var. radicula Pers.) (Brassicaceae) were cultured for 9, 18, and 27 days, and different concentrations (0, 0.067, 8.79, 11.72, 14.65, and 17.58 mg L−1) of glycine betaine were applied to investigate the influence of glycine betaine on cherry radish biomass, quality, net photosynthetic rate, chlorophyll content, antioxidant enzyme activity, and endogenous hormone content under high-temperature stress. The results showed that, under high-temperature conditions, cherry radishes grew best with the 17.58 mg L−1 glycine betaine treatment. At day 27, comparing the 17.58 mg L−1 glycine betaine treatment with 0 mg L−1 glycine betaine under high-temperature stress, the cherry radish biomass increased by 44.7%, while the soluble protein and vitamin C content increased by 14.4% and 21.6%, respectively, the net photosynthetic rate and chlorophyll a content increased by 7.8% and 44.1%, respectively, and the peroxidase and catalase levels increased by 81.0% and 146.3%, respectively. On day 9, the auxin, abscisic acid, and glycine betaine contents significantly increased by 67.4%, 6.8%, and 32.9%, respectively, in comparing the 17.58 mg L−1 glycine betaine treatment with 0 mg L−1 glycine betaine under high-temperature stress. Therefore, the application of 17.58 mg L−1 betaine to cherry radishes grown under high-temperature stress had positive effects. The appropriate concentration of glycine betaine can improve the resistance of cherry radish to high temperatures and maintain yield. Full article
(This article belongs to the Section Horticultural and Floricultural Crops)
5 pages, 181 KiB  
Editorial
Genetic Analysis in Crops
by Fang Bai and Kevin Begcy
Agronomy 2024, 14(6), 1293; https://doi.org/10.3390/agronomy14061293 - 14 Jun 2024
Viewed by 205
Abstract
Crops contribute to global food production, energy, and medicine [...] Full article
(This article belongs to the Special Issue Genetic Analysis in Crops)
16 pages, 2011 KiB  
Article
Morphological, Histological and Genetic Evaluation of Gamma Radiation-Induced Mutation and Its Potential Application in Rudbeckia hirta (L.)
by Szilvia Kisvarga, Katalin Horotán, Dóra Hamar-Farkas, Zsófia Kovács, Antal Szőke, Muneeb Ahmad Wani and László Orlóci
Agronomy 2024, 14(6), 1292; https://doi.org/10.3390/agronomy14061292 - 14 Jun 2024
Viewed by 238
Abstract
Many cultivars of annual ornamental horticulture have great phenotypic qualities but are less tolerant to the effects of current climate change and urbanization. A good example of this in Hungarian ornamental breeding is the Rudbeckia hirta cultivar “Őszifény”. The objective of this study [...] Read more.
Many cultivars of annual ornamental horticulture have great phenotypic qualities but are less tolerant to the effects of current climate change and urbanization. A good example of this in Hungarian ornamental breeding is the Rudbeckia hirta cultivar “Őszifény”. The objective of this study was to determine whether gamma mutation breeding (using 5 Gy, 10 Gy, 30 Gy doses) can be employed to enhance genetic variability and create mutants with novel trait values. Furthermore, it is important to ascertain whether the altered genetic traits are proportionate to the observed changes in phenotype. As an original and innovative aspect of the research, this will assist in establishing appropriate dose rates for the species. Changes induced by gamma radiation have been mapped using morphological, histological, and genetic methods. The radiation dose of 5 Gy resulted in plants with the most favorable characteristics, including significant increases in branching and flower number. Additionally, the phenomenon of hormesis was observed. Beyond these, the dose of 30 Gy also had a significant effect because it resulted in plants with many flowers and bushy habits, making them suitable for use as ornamental potted plants. The 10 Gy dose resulted in a heterogeneous stand but showed the greatest genetic variation. These results may contribute to future breeding work and may pave the way for further urban application of R. hirta in the light of urbanization. Full article
(This article belongs to the Section Horticultural and Floricultural Crops)
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