Search Results (81)

Remote sensing tools have been proposed to assist with rice crop monitoring but have been developed and validated on ponded rice. This two-year study was conducted on a commercial rice farm with irrigation automation technology aimed to (i) understand how canopy reflectance differs between high-yielding ponded and aerobic rice, (ii) validate the feasibility of using the squared simplified canopy chlorophyll content index (SCCCI²) for N uptake estimates, and (iii) explore the SCCCI² and similar chlorophyll-sensitive indices for grain quality monitoring. Multispectral images were collected from an unmanned aerial vehicle during both rice-growing seasons. Above-ground biomass and nitrogen (N) uptake were measured at panicle initiation (PI). The performance of single-vegetation-index models in estimating rice N uptake, as previously published, was assessed. Yield and grain quality were determined at harvest. Results showed that canopy reflectance in the visible and near-infrared regions differed between aerobic and ponded rice early in the growing season. Chlorophyll-sensitive indices showed lower values in aerobic rice than in the ponded rice at PI, despite having similar yields at harvest. The SCCCI² model (RMSE = 20.52, Bias = −6.21 Kg N ha⁻¹, and MAPE = 11.95%) outperformed other models assessed. The SCCCI², squared normalized difference red edge index, and chlorophyll green index correlated at PI with the percentage of cracked grain, immature grain, and quality score, suggesting that grain milling quality parameters could be associated with N uptake at PI. This study highlights canopy reflectance differences between high-yielding aerobic (averaging 15 Mg ha⁻¹) and ponded rice at key phenological stages and confirms the validity of a single-vegetation-index model based on the SCCCI² for N uptake estimates in ponded and non-ponded rice crops. Full article

Cadmium (Cd) mobilization in paddy soils during redox fluctuations poses significant risks to rice safety. This study investigated the efficacy of nano-calcium carbonate (NCC), nano-hydroxyapatite (NHAP), and their composite (C+P) in immobilizing Cd under simulated flooding–drainage cycles. Soil treatments (0.5% and 1.0% w/w) were subjected to 40 day anaerobic and 20 day aerobic incubation. The results demonstrated that NCC and C+P elevated the soil pH by 1.35–1.39 and 0.72–1.01 units during the anaerobic and aerobic phases, respectively. These amendments suppressed Fe(II) and Mn(II) release by 41–75%, correlating with reduced Cd bioavailability. While nanomaterials minimally influenced Cd speciation during flooding, aerobic conditions triggered a marked shift: residual Cd fractions increased by 80.8–116.4% under NCC, driven by CdCO₃ precipitation and phosphate complexation. Cd release rates decreased by 53.6–66.8% in NCC and C+P treatments during oxidation. Microbial analysis revealed diminished bacterial diversity but enriched Firmicutes (up to 58.9%), which positively correlated with pH and residual Cd. Redundancy analysis identified pH and Fe/Mn dynamics as key regulators of the microbial community structure. NCC emerged as the most effective amendment. This study highlights the potential of NCC-based strategies for mitigating Cd risks in acidic paddy soils, particularly during post-flooding drainage. Full article

The observation time and water background can affect the remote sensing estimates of the nitrogen (N) content in rice crops. This makes the use of vegetation indices (VIs) for N status monitoring and topdressing recommendations challenging, as the timing of panicle initiation and the water level in bays usually differ between farms even when managed using the same irrigation technique. This study aimed to investigate the influence of standing water levels (from 0 to 20 cm) and the time of image acquisition on a set of N-sensitive VIs to identify those less affected by these factors. The experiment was conducted using a split-plot experimental design with two side-by-side bays (main plots) where rice was grown ponded for most of the growing season and aerobically (not permanently ponded), each with four fertilization N rates. The SCCCI and SCCCI² were the only indices that did not vary depending on the time of the day when the multispectral images were collected. These indices showed the lowest variation among water layer treatments (5%), while the Clg index showed the highest (20%). All VIs were significantly correlated with N uptake (average R² = 0.73). However, the SCCCI² was the index that showed the lowest variation in N-uptake estimates resulting in equal N-fertilizer recommendations across water level treatments. The consistent performance of SCCCI² across different water levels makes this index of interest for different irrigation strategies, including aerobic management, which is gaining increasing attention to improve the sustainability of the rice industry. Full article

Plants known as obligate aerobes developed different mechanisms to overcome the damage incurred under oxygen limitation. One of the survival strategies to have commonly appeared in hydrophytic plants is the escape strategy, which accelerates plant axial organs’ growth in order to escape hypoxic conditions as soon as possible. The present study aimed to distinguish the alterations in coleoptile elongation, viability and metabolic profiles in coleoptiles of slow- and fast-growing rice varieties. All the parameters were tested at 3, 5 and 7 days after sowing, to highlight changes during seedling development in normal and submerged conditions. The obtained results indicated that coleoptile elongation correlated with higher resistance to oxygen deprivation. GS-MS-based metabolic profiling indicated that coleoptiles of the fast-growing cultivar accumulated higher amounts of sugar phosphates, disaccharides, fatty acid derivatives and sterols, which are important for maintaining growth, membrane stability and viability. The slow-growing variety was characterized by a greater abundance of carboxylates, including lactate and phosphoric acid, indicating an energy crisis and cytosol acidification, leading to cell damage and low tolerance. Therefore, a metabolomics approach could be used for phenotyping (chemotyping) in the large-scale screening of newly developed varieties with higher tolerance to oxygen deprivation. Full article

Seed germination is crucial for plant survival, crop stand establishment, and achieving optimal grain yield. The main objective of this review is to explore the physiological and molecular mechanisms governing rice seed germination under aerobic (water stress) and anaerobic (hypoxic) conditions in direct-seeded rice (DSR) systems. Moreover, it discusses the recent genomic advancements and innovations to improve rice seed germination. Here, we discuss how coleoptile and mesocotyl elongation plays a vital role in anaerobic germination (AG) and the function of raised antioxidants, including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in maintaining Reactive Oxygen Species (ROS), and malondialdehyde (MDA) homeostasis for stabilizing seed germination in water-scarce conditions. This study comprehensively highlights the functions and dynamics of phytohormones—GA (gibberellic acid) and ABA (abscisic acid)—key regulatory genes, transcription factors (TFs), key proteins, and regulatory metabolic pathways, including glycolysis, the pentose phosphate pathway (PPP), and the tricarboxylic acid cycle (TCA), in regulating seed germination under both conditions. Conventional agronomic and cultural practices, such as seed selection, seed priming, seed coating, and hardening, have proven to improve seed germination. Moreover, the utilization of molecular and novel approaches—such as clustered regularly interspaced short palindromic repeat (CRISPR-Cas9) mediated genome editing, marker-assisted selection (MAS), genome-wide associations studies (GWAS), single nucleotide polymorphisms (SNPs), multi-omics, RNA sequencing—combined with beneficial quantitative trait loci (QTLs) has expanded knowledge of crop genomics and inheritance. These advancements aid the development of specific traits for enhancing seed germination in DSR. Full article

Paddy fields are the main agricultural source of greenhouse gas methane (CH₄) emissions. To enhance rice yield, various fertilization practices have been employed in rice paddies. However, the key microbial and abiotic factors driving CH₄ emissions under different fertilization practices in paddy fields remain largely uncharted. This study conducted field experiments in a traditional double-cropping rice area in South China, utilizing five different fertilization practices to investigate the key factors influencing CH₄ emissions. High-throughput sequencing and PICRUSt2 functional prediction were employed to investigate the contributions of soil physicochemical properties, CH₄-metabolizing microorganisms (methanogens and methanotrophs), and key genes (mcrA and pmoA) on CH₄ emissions. The results showed that CH₄ emission fluxes exhibited seasonal variations, with consistent patterns of change observed across all treatments for both early- and late-season rice. Compared to the no-fertilization (NF) treatment, cumulative CH₄ emissions were lower in early-season rice with green manure (GM) and straw returning (SR) treatments, as well as in late-season rice with GM treatment, while rice yields were maintained at higher levels. High-throughput sequencing analysis revealed that potential methanogens were primarily distributed among four orders: Methanobacteriales, Methanocellales, Methanomicrobiales, and Methanosarcinales. Furthermore, there was a significant positive correlation between the relative abundance of the CH₄-related key gene mcrA and these microorganisms. Functional analysis indicated that these potential methanogens primarily produce methane through the acetoclastic and hydrogenotrophic pathways. Aerobic CH₄-oxidizing bacteria, predominantly from the genus Methylocystis, were detected in all the treatments, while the CH₄ anaerobic-oxidizing archaea ANME-1b was only detected in chemical fertilization (CF) and cow manure (CM) treatments. Our random forest analysis revealed that the relative abundance of two methanogens (Methanocellales and Methanosarcinales) and two environmental factors (pH and DOC) had significant impacts on the cumulative CH₄ emissions. The variance decomposition analysis highlighted the CH₄-metabolizing microorganisms explained 50% of the variance in the cumulative CH₄ emissions, suggesting that they are the key microbial factors driving CH₄ emissions. These findings provide guidance for the development of rational measures to reduce CH₄ emissions in paddy fields. Full article

The purpose of the current research was to evaluate the influence of lactic acid bacteria and cellulase supplementation on the chemical composition, fermentation parameters, aerobic stability, microbial count, and in vitro nutrients digestibility of silage prepared with Pennisetum giganteum and rice straw. This study consisted of four treatments: a control group with no additive supplementation (CON), a lactic acid bacteria supplementation group (LAB), a cellulase supplementation group (CEL), and a combined supplementation group (LAC). After ensiling for 60 d, the chemical composition, fermentation parameters, microbial count, and aerobic stability were determined. Additionally, ruminal fermentation characteristics were evaluated by an in vitro incubation technique. Compared with CON silage, the quality of LAB and CEL silages was enhanced to a certain degree. Combined supplementation with lactic acid bacteria and cellulase in mixed silage of Pennisetum giganteum and rice straw noticeably increased (p < 0.05) the dry matter, crude protein, and lactic acid contents, whereas it reduced (p < 0.05) the pH and ammonia nitrogen/total nitrogen as well as the neutral detergent fiber and acid detergent fiber concentrations. The lactic acid bacteria count in LAC silage was higher (p < 0.05) than that of CON silage, whereas an opposite trend of yeast, aerobic bacteria, and mold was observed between the two groups. The aerobic stability time, in vitro crude protein, and neutral detergent fiber digestibility in LAC silage were significantly increased (p < 0.05) compared with those in CON silage. Moreover, the in vitro ruminal ammonia nitrogen content was reduced (p < 0.05), and the microbial protein and propionic acid concentrations were increased (p < 0.05) in silage after combined inoculation with additives. Taken together, the quality of Pennisetum giganteum and rice straw mixed silage can be improved by inoculation with lactic acid bacteria and cellulase, and combined supplementation shows the greatest improvement in silage quality. Full article

Nitrogen is a vital nutrient for rice growth; however, its inefficient use often results in nutrient loss, environmental degradation, and the emission of greenhouse gases. In this study, a rice paddy simulation was conducted under different water levels (1–4 cm), incorporating a comprehensive analysis of nitrogen dynamics, environmental factors, and microbial communities to evaluate the impact of water levels on nitrogen concentrations and microbial composition. The results indicated that the water level had a greater impact on nitrogen concentrations in surface water than in soil water. Compared to low water level conditions (1 cm), the average concentrations of ammonium nitrogen, nitrate nitrogen, and nitrite nitrogen in surface water under 2–4 cm water levels decreased by approximately 53.8%, 36.7%, and 78.9%, respectively. Water levels also influenced the microbial composition and nitrogen cycling in paddy soil, with lower water levels promoting aerobic processes such as nitrification, while higher water levels facilitated anaerobic processes such as denitrification and dissimilatory nitrate reduction to ammonium. Correspondingly, microbial composition shifted, with aerobic bacteria predominating in shallow water conditions and anaerobic bacteria flourishing under deeper water. These findings suggest that optimized water management, particularly through shallow irrigation, may mitigate nitrogen loss and improve nitrogen use efficiency. Nevertheless, additional field studies are necessary to validate these results and explore their interaction with other agricultural practices. Full article

This work aimed to assess microbial inoculants (Lactiplantibacillus plantarum and Lentilactobacillus buchneri), chemical additives (natamycin and hexanoic acid), and their combination on fermentation characteristics and aerobic stability in total mixed ration (TMR) silage. The TMR consisted of 30% water bamboo shell (WBS), 10% alfalfa, 20% rice straw, and 40% concentrate. There were six treatments as follows: (1) deionized water (control, CON). (2) lactic acid bacteria (Lactiplantibacillus plantarum + Lentilactobacillus buchneri; LPB, 1 × 10⁶ cfu/g FW). (3) natamycin (NT, 0.02 g/kg FW). (4) hexanoic acid (HA, 0.02 g/kg FW). (5) lactic acid bacteria + natamycin (SLNT, 0.02 g/kg FW). (6) lactic acid bacteria + hexanoic acid (SLHA, 0.02 g/kg FW). After fermentation, laboratory silos (10 L) were opened to assess fermentation quality, followed by a 6-day aerobic stability test. The results showed that all silages were well fermented with high lactic acid (LA) content, low ammonia nitrogen (NH₃-N), and negligible butyric acid (BA) levels. Among all silages, SLNT silage exhibited the greatest LA, acetic acid (AA) levels, LAB counts, and the lowest pH and NH₃-N. For aerobic stability, all additives significantly (p < 0.05) enhanced aerobic stability, delayed (p < 0.05) the decrease in LA and water-soluble carbohydrates (WSC) and the increase in pH, and significantly (p < 0.05) minimized yeast proliferation. The SLNT silage showed the best aerobic stability, with SLHA, NT, HA, and LPB following. In conclusion, SLNT is recommended as the optimal additive in improving the fermentation quality and aerobic stability of TMR silage, with SLHA, NT, HA, and LPB following. Full article

Anammox, a reaction in which microorganisms oxidize ammonia under anaerobic conditions, is used in the industry to remove ammonium from wastewater in an environmentally friendly manner. This process does not produce intermediate products such as nitrite or nitrate, which can act as secondary pollutants in soil and water environments. For industrial applications, anammox bacteria should be obtained from the environment and cultivated. Anammox bacteria generally exhibit a slow growth rate and may not produce a large number of cells due to their anaerobic metabolism. Additionally, their habitats appear to be limited to specific environments, such as oxidation-reduction transition zones. Consequently, most of the anammox bacteria that are used or studied originate from marine environments. In this study, anammox bacterial evidence was found in rice paddy soil and cultured under various conditions of aerobic, microaerobic, and anaerobic batch incubations to determine whether enrichment was possible. The anammox-specific gene (hzsA) and microbial community analyses were performed on the incubated soils. Although it was not easy to enrich anammox bacteria due to co-occurrence of denitrification and nitrification based on the chemistry data, potential existence of anammox bacteria was assumed in the terrestrial paddy soil environment. For potential industrial uses, anammox bacteria could be searched for in rice paddy soils by applying optimal enrichment conditions. Full article

In large-scale dairy farming, the use of high-temperature-fermented dairy manure bedding instead of rice husk-based bedding and other commercial types of bedding is widely favored. Strip-stacking aerobic fermentation is the main production method of dairy manure bedding, but it has problems including unstable fermentation and the secondary breeding of pathogens. In this work, a multi-probe, integrated, online monitoring system for temperature and relative humidity was used for fermentation process optimization. The effects of the temporal and spatial distribution of fermentation temperature and relative humidity on the nutrient content curve and the moisture and ash content of manure bedding materials were systematically studied. The effect of the fermentation process on the retention rate of effective bedding materials (cellulose, hemicellulose, and lignin) was analyzed. The experiments proved that high-quality bedding material can be obtained through reasonable stacking fermentation. The fabricated bedding material has a total dry base content consisting of cellulose, hemicellulose, and lignin of 78%, an ash content of 6%, and a nutrient content of 17%. The obtained bedding material was produced to increase the bed rest rate and continuously inhibit the bedding bacteria content, keeping it at a low level for 5 days. This study proves that temperature and humidity monitoring can guide the optimization of the strip-stacking fermentation process of dairy manure and that it can be applied to large-scale farms to improve fermentation parameters. Full article

This study investigates the application of microwave combined induction heating (MCIH) to steam ready-to-eat pork with rice powder, emphasizing the advantages of rapid and uniform heating. The experimental setup included a mixture of 180 g pork strips, 30 g rice powder, and 10 g water in a CPET tray using MCIH with 1080 W microwave (MW) and 130 °C induction heating (IH) for 150 s. The results showed a quick temperature increase rate of 0.56 °C/s that achieved pasteurization against a variety of pathogenic bacteria, such as Listeria monocytogenes, but not Clostridium botulinum, by lethality calculation. Compared to typical electric cooker steaming, MCIH significantly shortened cooking time (8.6 times faster). To address rice starch gelatinization, two-stage heating techniques to steam pork with rice powder were MCIH: 150 s, and then IH: 60 s (MW1), and MCIH: 180 s, and then IH: 30 s (MW2), with no significant differences seen in color or the nine-point taste scale between treatment groups. MCIH groups had smaller shear forces than control. After MCIH cooking, no microbial counts were detected in the MW1 and MW2 groups initially, and the pork with rice powder had a shelf life of 14 days at 4 °C based on aerobic plate count assay. Full article

A stable aerobic consortium was enriched to degrade crystalline cellulose (Whatman filter paper 1). The degradation efficiency of the consortium after 7 days of incubation was 91% compared to the control. One bacterial isolate, C7, capable of degrading various cellulosic substrates, was obtained from the consortium under aerobic conditions. The sequencing of 16s rDNA revealed that it was related to Paenibacillus sp. It degraded 83% of cotton after 3 days of incubation. The degradation efficiency of Paenibacillus sp. C7 for filter paper, cotton, and avicel was 90%, 90%, and 92% after 5 days of incubation compared to the control. It also degraded non-pretreated agricultural residues efficiently by 70% for rice straw and 46% for wheat bran in 10 days. Scanning electron micrographs (SEMs) of degraded filter paper after 2 days of incubation indicated smoother and thinner fabrics in its structure. It is a potential cheaper candidate for the degradation of lignocellulosic biomass without any pretreatment. Full article

To explore the effects of different water-saving treatments on rice plant growth and select suitable water-saving irrigation strategies for aerobic rice varieties, we conducted relevant field experiments from June to October 2023 at Jiangsu Runguo Agricultural Development Co., Ltd., China, which is located in a north subtropical monsoon climate where the soil is alkaline sandy loam. Four water treatments were set up, including the control of local conventional irrigation (CK, without water stress), mild water-saving treatment (W1, 20% more water saved than CK), moderate water-saving treatment (W2, 30% more water saved than CK), and severe water-saving treatment (W3, 40% more water saved than CK). The experiment results showed that rice plant heights were inhibited and leaf chlorophyll contents increased under all water-saving treatments compared to CK. Among them, the MDA content in paddy leaves under the W1 treatment decreased, while the activities of SOD and POD were enhanced and the membrane lipid peroxidation capacity of rice was also enhanced. Meanwhile, the results showed that the rice yield and quality under the W1 treatment significantly improved. Based on those experiments, a comprehensive evaluation of rice plant height, chlorophyll content, grain yield, yield components, and rice quality was conducted using the TOPSIS entropy weight method. It was preliminarily concluded that the suitable irrigation scheme for south and central Jiangsu was 20% water-saving irrigation compared with CK. In summary, under the premise of maintaining the economic yield of rice cultivation, an appropriate water irrigation plan helped save water resources and promote rice growth. Full article

Background: It has been suggested that supplementation with Tongkat Ali may affect testosterone concentrations; moreover, whether this influences body composition is unclear. Thus, the purpose of this investigation was to determine if four weeks of Tongkat Ali (400 mg daily dose) supplementation affected body composition and salivary free testosterone concentrations. Methods: Thirty-three exercise-trained males (n = 19) and females (n = 14) volunteered for this investigation (mean ± standard deviation: age 33.1 ± 13.0 years; height 171.1 ± 11.3 cm; body mass 77.4 ± 16.8 kg; average total years of training 13.9 ± 13.2; average hours of resistance training/week 4.2 ± 2.5; average hours of aerobic exercise/week 3.4 ± 2.8; average hours of other exercise/week 1.1 ± 2.0). Research participants were pre- and post-tested for body composition (InBody 270), Profile of Mood States (POMS), handgrip strength, and sleep (Pittsburgh Sleep Quality Index [PSQI]). In a subset of the research participants, saliva samples were collected and analyzed for cortisol and free testosterone. The research participants consumed 400 mg of Tongkat Ali or a placebo (rice flour) daily for four weeks. Results: There were no between-group differences (p > 0.05) for body composition (delta score, mean ± SD: lean body mass kg-treatment −0.5 ± 1.9, placebo −0.4 ± 0.7; fat mass kg-treatment −0.5 ± 1.6, placebo 0.3 ± 1.0, % fat treatment −0.1 ± 1.4, placebo 0.5 ± 1.1). Moreover, there were no differences between groups for any additional assessments (e.g., handgrip strength, mood, sleep, and salivary free testosterone and cortisol). Conclusions: Four weeks of supplementation with Tongkat Ali in exercise-trained males and females does not affect body composition, mood, sleep, vigilant attention, handgrip strength, cortisol, and free testosterone. Full article