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Resource-poor areas with moisture deficit lands following aerobic and direct seeded rice (DSR) methods of cultivation face severe problems of iron deficiency. In this study, Bengal and Assam Aus rice panel was phenotyped at the seedling stage using an iron-deprived hydroponic medium for various shoot and root traits. A novel iron deficiency scoring scale was used to classify the tolerance reaction and could range anywhere between 0 and 9, indicating the most tolerant and susceptible, respectively. The GWAS results identified four putative candidate genes; OsFLA for number of leaves and shoot length, OsBIDK1 for root traits; average diameter, volume, biomass, projected area, and surface area, OsHPL3 for chlorophyll index of the third leaf and AKR2B (XBOS252) was for Fe score, (which was earlier reported in relation to Xa21). The nsSNP (nsSNPs) variations in these gene sequences were used to group the panel and identify superior haplotypes and donors. BR16 was identified as a superior donor, with higher chlorophyll index and shoot length than RA23, also higher values for root traits like root average diameter, root volume, root projected area and root surface area followed by Shete Bhado. The impact of identified nsSNPs on protein structure and stability was investigated. The conserved domains detected in the mutated proteins of the superior haplotypes are very informative, highlighting that natural selection favors abiotic stress tolerant variants in resource poor areas. Thus, justifying our choice of Aus landraces for association mapping of Fe deficiency tolerant genes in rice. [ABSTRACT FROM AUTHOR]

The sustainability of rice production continues to be a subject of uncertainty and inquiry attributed to shifts in climatic conditions. In light of the impending climate change crisis and the high labor and water costs accompanying it, direct-seeded rice (DSR) is unquestionably one of the most practical solutions. Despite its resource and climate-friendly advantages, early maturing rice faces weed competitiveness and seedling establishment challenges. Resolving these issues is crucial for promoting its wider adoption among farmers, presenting it as a more effective sustainable rice cultivation method globally. Diverse traditional and contemporary breeding methods are employed to mitigate the limitations of the DSR approach, leveraging advanced techniques such as speed breeding and genome editing. Focusing on key traits like mesocotyl length elongation, early seedling vigor, root system architecture, and weed competitiveness holds promise for transformative improvements in DSR adaptation at a broader scale within farming communities. This review aims to summarize how these features contribute to increased crop production in DSR conditions and explore the research efforts focusing on enhancing DSR adaptation through these traits. Emphasizing the pivotal role of these game-changing traits in DSR adaptation, our analysis sheds light on their potential transformative impact and offers valuable insights for advancing DSR practices.

The objectives of this study were to explore the mechanism of stem mechanical strength in direct-seeded rice (DSR) as affected by paclobutrazol, especially its related endogenous hormone and cell wall component changes in culm tissue and response to the application of paclobutrazol. Field experiments were conducted in Changchun County, Jilin Province, China, by using two japonica rice varieties, Jiyujing and Jijing305, with soaking seeds in paclobutrazol at concentrations of (0 mg L−1, S0; 50 mg L−1; S1; 100 mg L−1; S2; 150 mg L−1, S3; 200 mg L−1, S4) in 2021 and 2022. The results suggest that the application of paclobutrazol increased the grain yield and reduced the lodging rate of DSR. Compared with the S0 treatments, soaking the seeds in paclobutrazol treatments rapidly shortened the length of the basal internode by decreasing the endogenous indole acetic acid (IAA) and gibberellin A3 (GA3) contents in culm tissue. The larger breaking strength (M) was attributed to a higher section modulus (SM) and bending stress (BS). The higher mechanical tissue thickness in culm tissue under paclobutrazol treatments, which was raised by higher endogenous zeatin and zeatin riboside (Z+ZR) content in culm tissue, increased the culm diameter, culm wall thickness, and section modulus (SM) of the internode. Compared with the S0 treatments, soaking the seeds in paclobutrazol treatments increased the cellulose content, lignin content, activities of lignin-related enzymes, and expression of key genes in lignin biosynthesis, as well as resulted in a higher bending stress (BS) to enhance the culm breaking strength (M). [ABSTRACT FROM AUTHOR]

The sustainability of rice production continues to be a subject of uncertainty and inquiry attributed to shifts in climatic conditions. In light of the impending climate change crisis and the high labor and water costs accompanying it, direct-seeded rice (DSR) is unquestionably one of the most practical solutions. Despite its resource and climate-friendly advantages, early maturing rice faces weed competitiveness and seedling establishment challenges. Resolving these issues is crucial for promoting its wider adoption among farmers, presenting it as a more effective sustainable rice cultivation method globally. Diverse traditional and contemporary breeding methods are employed to mitigate the limitations of the DSR approach, leveraging advanced techniques such as speed breeding and genome editing. Focusing on key traits like mesocotyl length elongation, early seedling vigor, root system architecture, and weed competitiveness holds promise for transformative improvements in DSR adaptation at a broader scale within farming communities. This review aims to summarize how these features contribute to increased crop production in DSR conditions and explore the research efforts focusing on enhancing DSR adaptation through these traits. Emphasizing the pivotal role of these game-changing traits in DSR adaptation, our analysis sheds light on their potential transformative impact and offers valuable insights for advancing DSR practices. [ABSTRACT FROM AUTHOR]

The use of allelopathic bacteria to combat weed infestation in crops is regarded as an effective technology for sustainable agriculture and environment. In this regard, six bacterial strains from the genus Pseudomonas were selected for their ability to inhibit the germination and growth of Leptochloa chinensis (L.) and Dactyloctenium aegyptium (L.) while promoting the growth of rice. These strains were applied to the target weeds and rice using different application methods viz. seed priming, liquid application, and foliar application. The results showed that all strains possessed herbicidal activity and significantly reduced growth of L. chinensis. Shoot length, root length, and fresh biomass of D. aegyptium were also significantly reduced in all strains by 60, 55, and 76%, respectively, with the exception of R15-4. Additionally, the growth suppression of both weed species was more prominent in the liquid application. The selected allelopathic strains also demonstrated plant growth-promoting traits and improved the growth and physiological parameters of rice in all three application methods, with the best results achieved with liquid and foliar applications. The survival efficiency of the bacterial strains was also tested using four different carrier materials, where the press mud was found the best carrier for controlling L. chinensis and D. aegyptium. [ABSTRACT FROM AUTHOR]

In Punjab, Pakistan, wheat production within the rice-wheat cropping system is frequently undermined by soil degradation and nutrient depletion, exacerbated by traditional agricultural practices. Addressing these challenges, this study evaluates the impact of green manuring and tillage practices on wheat productivity in rice-wheat cropping system, using a randomized complete block design (RCBD) with three replicates. The study examined twelve treatments combining green manuring (no green manuring, Sesbania, or Cluster bean) with rice cultivation methods (direct-seeded or transplanted) and tillage practices (zero or plough tillage). Wheat was sown following rice at a rate of 125 kg ha-1, with fertilizers applied in split applications. The analysis revealed significant differences across treatments. The highest number of fertile tillers (429 m-2 in 2020, 441 m2 in 2021) was recorded in Treatment 5 (Sesbania green manuring, direct-seeded rice, zero tillage wheat), while the lowest (322 m-2 in 2020, 329 m-2 in 2021) was in Treatment 4 (No green manuring, transplanted rice, plough tillage wheat). Similar trends were observed for spikelets per spike, grains per spike, and thousand grain weight, with Treatment 5 consistently performing the best. Biological yield was highest in Treatment 5 (13.12 t ha-1 in 2020, 13.42 t ha-1 in 2021), and grain yield peaked at 4.10 t ha-1 (2020) and 4.50 t ha-1 (2021) in Treatments 5 and 6. These findings underscore the benefits of integrating Sesbania green manuring with zero tillage and direct seeding of rice, significantly enhancing soil moisture retention and structure, which leads to improved wheat yields. [ABSTRACT FROM AUTHOR]

This study was carried out in Amritsar, Punjab, to find out how efficiently nutrients were used and how much energy was employed in direct-seeded rice (DSR) production. In this study, four levels of nitrogen (0, 40, 50, and 60 kg N ha−1) and three levels of phosphorus (0, 37.5, and 45 kg P2O5 ha−1) were tested. In a rice production system, the energy indices of various inputs and outputs were evaluated through the application of energy equivalency. The nutrient-use efficiencies in rice were assessed using different efficiency indices. The maximum grain yields of 38.9 q ha−1 and 36.9 q ha −1 were recorded at 50 kg N ha−1 and 45 kg P2O5 ha−1, respectively. On the other hand, application of nitrogen at 60 kg N ha−1 and phosphorus at 45 kg P2O5 ha−1 resulted in maximum straw yield of 57.1 q ha−1 and 51.1 q ha−1, respectively. In comparison with the control, application of 60 and 50 kg N ha−1 resulted in 161.9% and 151.0% higher grain yield, respectively. On the other hand, with applications of 45 kg P2O5 ha−1 and 37.5 kg P2O5 ha−1, an increase in the grain yield of 17.3 and 28.6%, respectively, over the control was recorded. Moving further towards nutrient-use efficiencies (NUEs), the highest values of partial factor productivity of nitrogen (PFPN), agronomic efficiency of nitrogen (AEN), partial nutrient balance of nitrogen (PNBN), and recovery efficiency of nitrogen (REN) were 89.1, 50.4, 1.78 and 0.72, respectively, which were obtained at 40 kg N ha−1, after which the values started decreasing steadily. In the case of phosphorus, the partial factor productivity (PFPP) of 88.6 was the maximum at 37.5 kg P2O5 ha−1, but partial nutrient balance (PNBP) of 0.36 and recovery efficiency (REP) of 0.08 were highest at 45 kg P2O5 ha−1. The main results revealed that the farmer field had an excessive amount of non-renewable energy inputs. The experimental field depicted greater energy-usage efficiency (EUE) of 4.5, energy productivity (EP) of 0.14, and energy profitability (EP1) of 3.5. These results were primarily ascribed to a significant drop in energy inputs under direct-seeded rice (DSR). In the case of non-renewable energy inputs, fertilizer made the maximum contribution to energy input (47.9%) in the farmer's field. We conclude that nutrient-use efficiencies and energy-use efficiency were highest at 50 kg N and 45 kg P2O5 ha−1. This recommendation is beneficial for farmers because lower inputs and higher outputs are the main objective of every farmer. [ABSTRACT FROM AUTHOR]

Pre-harvest yield prediction of direct-seeded rice is critical for guiding crop interventions and food security assessment in precision agriculture. Technology advances in unmanned aerial vehicle (UAV)-based remote sensing has provided an unprecedented opportunity to efficiently retrieve crop growth parameters instead of labor-intensive ground measurements. This study is aiming to evaluate the feasibility of fusing multi-temporal UAV-derived features collected at critical phenological stages in forecasting direct-seeded rice yield across different cultivars and nitrogen (N) management. The results showed that RGB sensor-derived canopy volume, canopy coverage, and spectral features including RBRI, WI etc., were identified to be most sensitive to the differences in aboveground biomass and grain yield. Heading stage was the suitable time for estimating yield performance (R2 = 0.75) for mono-temporal UAV observation. By contrast, multi-temporal features fusion could remarkably enhance the yield prediction accuracy. Moreover, the yield prediction accuracy can be further improved by integrating UAV features collected at panicle initiation and heading stages (i.e., rice reproductive phase) compared to multi-temporal features fusion (R2 increased from 0.82 to 0.85 and RMSE decreased from 35.1 to 31.5 g m−2). This can be attributed to the fact that the biomass accumulation during the reproductive phase was closely associated to the total spikelets and final yield. By using this proposed approach, the predicted yield showed a good spatial consistency with the measured yield across different cultivars and N management, and yield prediction error in the most of the plots (114 of 128 plots) was less than 45 g m−2. In summary, this study highlights that the reproductive phase is the optimal time window for UAV observing, which provides an effective method for accurate pre-harvest yield prediction of direct-seeded rice in precision agriculture. [ABSTRACT FROM AUTHOR]

BACKGROUND: Adjusting nitrogen (N) input based on actual seedling density (ASD) and plant N status is a practical approach for improving the yield stability of direct‐seeded rice. However, the adjustment of topdressing N rates has been empirical in the past. This study aimed to establish a quantitative approach for determining N topdressing rates during tillering (Ntil) and panicle development (NPI) based on ASD and crop N status in direct‐seeded rice. Field experiments were conducted involving 12 treatments, consisting of four Ntil and three seeding rates in 2017, and eight treatments combining seeding rate, Ntil, and NPI in 2020. RESULTS: Linear regression analysis revealed that the tiller number at panicle initiation (TILPI) was predominantly influenced by ASD and Ntil. The determination coefficients (R2) of the regression models ranged from 0.887 to 0.936 across the four‐season experiments. The results indicated that Ntil could be determined accurately using ASD and the target maximum tiller number. Similarly, grain yield was influenced significantly by the N uptake at panicle initiation (NUPPI) and NPI, with R2 of 0.814 and 0.783 in the early and late seasons of 2020, respectively. This suggested that NPI could be calculated based on NUPPI and the target grain yield. CONCLUSION: The findings offer a quantitative method for establishing N topdressing rates for tillering and panicle development, relying on the monitoring of actual seedling density and plant N status in direct‐seeded rice production. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Weeds are a major obstacle in the widespread implementation of direct seeding of rice (DSR). Traditional weed control methods have raised serious environmental and health concerns. In this study rhizobacterial strains were assessed for the growth inhibition of Leptochloa chinensis, Dactyloctenium aegyptium, and promotion of rice. For initial screening, hydrogen cyanide (HCN) and Escherichia coli (E. coli) was employed. After screening, plant growth-promoting traits were assessed, and two in vitro growth reduction and growth promotion trials were conducted on weeds and rice. Based on 16S ribosomal RNA (16S rRNA) gene sequencing, all selected rhizobacteria belonged to Pseudomonas spp. The results of the laboratory experiment showed that strains R4-1 (Pseudomonas plecoglossicida) and R16-10 (Pseudomonas fluorescens) exhibited significant ability to inhibit the growth of selected weeds, while potential to enhance the growth of rice. Further evaluation in pot trial under ambient light and temperature conditions showed that the selected strains significantly reduced weed growth and yield parameters of both weeds compared to the control. Strains R16-10 and R4-1 decreased the biomass of Leptochloa chinensis and Dactyloctenium aegyptium by 20% and 15%, respectively. The trial confirmed that strain R16-10 significantly increased DSR growth traits infested with Leptochloa chinensis and Dactyloctenium aegyptium, including grain yield (10% and 12%) and photosynthetic rate (9% and 7%). Furthermore, strain R4-1 was also effective in promoting the growth, yield, and physiological attributes of DSR. These results suggest that the strain R16-10 and R4-1 can reduce Leptochloa chinensis and Dactyloctenium aegyptium growth while promoting DSR growth. [ABSTRACT FROM AUTHOR]

In Northeast China, transplanted rice cultivation has been adopted to extend the rice growing season and boost yields, responding to the limitations of the cumulative temperature zone and high food demand. However, direct-seeded rice offers advantages in water conservation and labour efficiency. The precise and timely monitoring of the distribution of different rice planting types is key to ensuring food security and promoting sustainable regional development. This study explores the feasibility of mapping various rice planting types using only early-stage satellite data from the rice growing season. We focused on Daxing Farm in Fujin City, Jiamusi City, Heilongjiang Province, for cropland plot extraction using Planet satellite imagery. Utilizing Sentinel-2 satellite imagery, we analysed the differences in rice's modified normalized difference water index (MNDWI) during specific phenological periods. A multitemporal Gaussian mixture model (GMM) was developed, integrated with the maximum expectation algorithm, to produce binarized classification outcomes. These results were employed to detect surface changes and map the corresponding rice cultivation types. The probability of various rice cultivation types within arable plots was quantified, yielding a plot-level rice-cultivation-type mapping product. The mapping achieved an overall accuracy of 91.46% in classifying rice planting types, with a Kappa coefficient of 0.89. The area extraction based on arable land parcels showed a higher R2 by 0.1109 compared to pixel-based area extraction and a lower RMSE by 0.468, indicating more accurate results aligned with real statistics and surveys, thus validating our study's method. This approach, not requiring labelled samples or many predefined parameters, offers a new method for rapid and feasible mapping, especially suitable for direct-seeded rice areas in Northeast China. It fills the gap in mapping rice distribution for different planting types, supporting water management in rice fields and policies for planting-method changes. [ABSTRACT FROM AUTHOR]

Direct-seeded rice (Oryza sativa) (DSR) is gaining increasing acceptance worldwide because it saves both time and labor. A covering treatment is a simple method to improve early plant growth under direct-seeding conditions. Herein, field experiments were conducted to study the effects of different powdered organic covering materials, i.e., organic fertilizer, seedling substrate, nutrient soil A, and nutrient soil B. In addition, the effects of different covering thicknesses were studied, including 5, 10, 15, and 20 mm, on the germination and early growth of DSR varieties. The two rice varieties Wufengyou 286 and Zhongjiazao 17 were used for this study. The seedling substrate at 15 mm and nutrient soil A at 5 mm covering thickness significantly increased the rate of germination of Wufengyou 286 by 43.93% and 40.26%, respectively, compared to the control treatment. Organic fertilizer, seedling substrate, and nutrient soil A at covering thicknesses of 5 mm significantly increased the germination rate by 42.57%, 38.62%, and 40.10%, respectively, compared to the control. Notably, all the treatments increased the emergence rate, with Wufengyou 286 exhibiting the most pronounced effect. The seedling substrate at 10 mm covering thickness significantly increased the rate of emergence of Wufengyou286 by 15.42% compared to the control. Similarly, the seedling substrate at 10 mm covering thickness gave the best results by increasing the rate of emergence of Zhongjiazao 17 by 10.85% compared to the control. On average, the rate of emergence of Wufengyou 286 and Zhongjiazao 17 under the experimental treatment increased by 11.81% and 6.45%, respectively, compared to the control. The appropriate cover treatment enhanced the early growth of DSR by improving its morphological attributes, such as plant height and dry weight, and regulating the physio-biochemical responses, such as the production of antioxidants and photosynthetic pigments. The seedling growth rate of both varieties decreased as the thickness increased. This study elucidated the effects of different covering materials on the early growth of DSR, which can further guide their actual production. [ABSTRACT FROM AUTHOR]

The objectives of this study were to explore the mechanism of stem mechanical strength in direct-seeded rice (DSR) as affected by paclobutrazol, especially its related endogenous hormone and cell wall component changes in culm tissue and response to the application of paclobutrazol. Field experiments were conducted in Changchun County, Jilin Province, China, by using two japonica rice varieties, Jiyujing and Jijing305, with soaking seeds in paclobutrazol at concentrations of (0 mg L−1, S0; 50 mg L−1; S1; 100 mg L−1; S2; 150 mg L−1, S3; 200 mg L−1, S4) in 2021 and 2022. The results suggest that the application of paclobutrazol increased the grain yield and reduced the lodging rate of DSR. Compared with the S0 treatments, soaking the seeds in paclobutrazol treatments rapidly shortened the length of the basal internode by decreasing the endogenous indole acetic acid (IAA) and gibberellin A3 (GA3) contents in culm tissue. The larger breaking strength (M) was attributed to a higher section modulus (SM) and bending stress (BS). The higher mechanical tissue thickness in culm tissue under paclobutrazol treatments, which was raised by higher endogenous zeatin and zeatin riboside (Z+ZR) content in culm tissue, increased the culm diameter, culm wall thickness, and section modulus (SM) of the internode. Compared with the S0 treatments, soaking the seeds in paclobutrazol treatments increased the cellulose content, lignin content, activities of lignin-related enzymes, and expression of key genes in lignin biosynthesis, as well as resulted in a higher bending stress (BS) to enhance the culm breaking strength (M).

This study was carried out in Amritsar, Punjab, to find out how efficiently nutrients were used and how much energy was employed in direct-seeded rice (DSR) production. In this study, four levels of nitrogen (0, 40, 50, and 60 kg N ha−1) and three levels of phosphorus (0, 37.5, and 45 kg P2O5 ha−1) were tested. In a rice production system, the energy indices of various inputs and outputs were evaluated through the application of energy equivalency. The nutrient-use efficiencies in rice were assessed using different efficiency indices. The maximum grain yields of 38.9 q ha−1 and 36.9 q ha −1 were recorded at 50 kg N ha−1 and 45 kg P2O5 ha−1, respectively. On the other hand, application of nitrogen at 60 kg N ha−1 and phosphorus at 45 kg P2O5 ha−1 resulted in maximum straw yield of 57.1 q ha−1 and 51.1 q ha−1, respectively. In comparison with the control, application of 60 and 50 kg N ha−1 resulted in 161.9% and 151.0% higher grain yield, respectively. On the other hand, with applications of 45 kg P2O5 ha−1 and 37.5 kg P2O5 ha−1, an increase in the grain yield of 17.3 and 28.6%, respectively, over the control was recorded. Moving further towards nutrient-use efficiencies (NUEs), the highest values of partial factor productivity of nitrogen (PFPN), agronomic efficiency of nitrogen (AEN), partial nutrient balance of nitrogen (PNBN), and recovery efficiency of nitrogen (REN) were 89.1, 50.4, 1.78 and 0.72, respectively, which were obtained at 40 kg N ha−1, after which the values started decreasing steadily. In the case of phosphorus, the partial factor productivity (PFPP) of 88.6 was the maximum at 37.5 kg P2O5 ha−1, but partial nutrient balance (PNBP) of 0.36 and recovery efficiency (REP) of 0.08 were highest at 45 kg P2O5 ha−1. The main results revealed that the farmer field had an excessive amount of non-renewable energy inputs. The experimental field depicted greater energy-usage efficiency (EUE) of 4.5, energy productivity (EP) of 0.14, and energy profitability (EP1) of 3.5. These results were primarily ascribed to a significant drop in energy inputs under direct-seeded rice (DSR). In the case of non-renewable energy inputs, fertilizer made the maximum contribution to energy input (47.9%) in the farmer’s field. We conclude that nutrient-use efficiencies and energy-use efficiency were highest at 50 kg N and 45 kg P2O5 ha−1. This recommendation is beneficial for farmers because lower inputs and higher outputs are the main objective of every farmer.

In Northeast China, transplanted rice cultivation has been adopted to extend the rice growing season and boost yields, responding to the limitations of the cumulative temperature zone and high food demand. However, direct-seeded rice offers advantages in water conservation and labour efficiency. The precise and timely monitoring of the distribution of different rice planting types is key to ensuring food security and promoting sustainable regional development. This study explores the feasibility of mapping various rice planting types using only early-stage satellite data from the rice growing season. We focused on Daxing Farm in Fujin City, Jiamusi City, Heilongjiang Province, for cropland plot extraction using Planet satellite imagery. Utilizing Sentinel-2 satellite imagery, we analysed the differences in rice’s modified normalized difference water index (MNDWI) during specific phenological periods. A multitemporal Gaussian mixture model (GMM) was developed, integrated with the maximum expectation algorithm, to produce binarized classification outcomes. These results were employed to detect surface changes and map the corresponding rice cultivation types. The probability of various rice cultivation types within arable plots was quantified, yielding a plot-level rice-cultivation-type mapping product. The mapping achieved an overall accuracy of 91.46% in classifying rice planting types, with a Kappa coefficient of 0.89. The area extraction based on arable land parcels showed a higher R2 by 0.1109 compared to pixel-based area extraction and a lower RMSE by 0.468, indicating more accurate results aligned with real statistics and surveys, thus validating our study’s method. This approach, not requiring labelled samples or many predefined parameters, offers a new method for rapid and feasible mapping, especially suitable for direct-seeded rice areas in Northeast China. It fills the gap in mapping rice distribution for different planting types, supporting water management in rice fields and policies for planting-method changes.

Weed infestation is the major biological threat in direct-seeded rice production and can cause significant yield losses. The effective use of herbicides is particularly important in direct-seeded rice production. Anilofos, a pre-emergence herbicide, has been shown to be effective against the weed barnyardgrass. However, its impacts on crop yield and the direct-seeded rice production ecosystem remain underexplored. In this study, we conducted field trials and used untargeted metabolomics to investigate systemic effects of two different treatments (40 g/acre and 60 g/acre) on rice shoot and root as well as the rhizosphere soil during the critical tillering stage. Here, a total of 400 metabolites were determined in the crop and soil, with differential metabolites primarily comprising lipids and lipid-like molecules as well as phenylpropanoids and polyketides. Spearman correlation network analysis and a Zi-Pi plot revealed 7 key differential metabolites with significant topological roles, including succinic acid semialdehyde and riboflavin. KEGG pathway analysis showed that anilofos downregulated the amino acid metabolism while mainly promoted carbohydrate metabolism and secondary metabolites biosynthesis of the crop, which made minimal disruption on soil metabolism. Notably, we found 40 g/acre anilofos application could significantly improve the rice yield, potentially linked to the improved activity of flavonoid biosynthesis and starch and sucrose metabolism. This research provides a comprehensive evaluation of anilofos effects in the direct-seeded rice production system, offering new insights into optimizing herbicide use to improve agricultural sustainability and productivity. [Display omitted] • Anilofos' effects were studied in the whole production system of direct-seed rice. • Metabolomic variation of direct-seed rice during tillering stage was provided. • Anilofos can affect crop metabolism with minimal effects on soil metabolism. • Low-dose application (40 g/acre) is an optimal choice to promote the grain yield. [ABSTRACT FROM AUTHOR]

Brown spot (BS) disease poses a significant threat to rice cultivation globally, impacting millions of hectares annually. Research indicates that the severity of BS is closely linked to abiotic stresses and crop nutrition. A field experiment was conducted using transplanted (TP) and direct-seeded-rice (DSR) crop establishment methods to optimize the effective fungicide and nitrogen dose. The split-plot design was applied to study the effect of two factors (N-dose and fungicides) varying at different levels under two different crop establishment methods (TP and DSR) for two consecutive Kharif seasons (2021 and 2022). The BS severity was measured as the percent disease index (PDI), and the results of two seasons were pooled. The results indicated that all three factors significantly (p = 0.05) influenced the PDI and grain yield. The PDI under different fungicides was higher in DSR (30.20–88.90) than in TP rice (21.64–70.00). Similarly, increased N-dose altered the PDI negatively (p = 0.05) in both TP (32.16–46.12) and DSR (44.35–59.09) methods. The results indicated Tebuconazole 50% + Trifloxystrobin 25% WG (T 7) at 125% recommended dose of nitrogen as the best combination, as it recorded the lowest PDI of 21.6 and 30.2 in the TP and DSR, respectively. Similarly, all three factors interacted significantly (p = 0.05) and affected the final grain yield. Overall, the BS is more severe in DSR, and a higher dose of N reduces the BS severity in both TP and DSR. Therefore, N fertilizer management, especially in the DSR, is essential, along with a fungicide, for effective management of the brown spot disease. • Three factors (N-dose, fungicides and establishment method) significantly influenced the brown spot disease and grain yield • The PDI was higher in direct-seeded rice (DSR) than in the transplanted (TP) method. • Increased N-dose altered the PDI negatively in both TP and DSR methods. • N-fertilizer management, especially in the DSR, is essential, along with a fungicide, to effectively manage the BS disease. [ABSTRACT FROM AUTHOR]

Weeds are the primary pest that reduces crop yield. Herbicide-based weed control is an efficient strategy for farmers, offering economically feasible weed management for agricultural crop production. The effectiveness of agrochemicals relies on the correct calibration and exact calculations of the rates needed per unit area, uniform distribution over treated surface and spraying conditions. The current investigation aims to investigate the efficacy of selected herbicides for weed control using drones. A field experiment was carried out in a commercial plot in Sungai Besar, Sabak Bernam Selangor, from September to December 2022 and April to July 2023 to assess the effectiveness of using drones to apply herbicides in direct-seeded rice. The main goal was to assess the effectiveness of Rinskor (Loyant), Rinskor + Cyhalofop (Novlect), Cyhalofop (Clincher), Bispyribac (Nominee), and Propanil (Stam 80WG) herbicides in suppressing weeds in direct-seeded rice using drone and mist blower sprayers, as well as their operational efficiency. The experimental plot was arranged using a randomized complete block design with three replications. The results of the experiments recorded the toxicity of the herbicides on rice at early stage but rice plant was recovered at 21 days after spray. High grain yield components were recorded for the Novlect and Loyant treated plots. The density and dry weight of grasses, sedges, and broad-leaved weeds were considerably reduced when the herbicides were applied using mist blowers and drones. Nominee showed the lowest weed control efficiency compared to other applied herbicides in both seasons. Results showed that compared to the mist blower application, applying Novlect via drone is more successful for timely weed control in direct-seeded rice, which in turn reduces labor intensity and hardship. [Display omitted] • Information regarding weed control using drone in rice field is scant in Malaysia. • Several herbicides are suitable to control weeds in direct-seeded rice. • Provides valuable information on suitable chemical control options via drone in rice field. [ABSTRACT FROM AUTHOR]

Weeds are serious pests in rice sown under direct-seeded rice (DSR) technology. Herbicide-based weed management is becoming increasingly popular, but there is a dire need to choose appropriate herbicides and their effective dose for controlling weeds in DSR fields. A field trial was conducted to appraise the comparative efficacy of three post-emergent herbicides applied at different doses [Clover 20% EC (bispyribac sodium) at 39.54, 59.30, and 79.07 g a.i. ha-1, Pyranex Gold 30% WDG (bispyribac sodium + bensulfuron methyl) at 74.13, 111.20, and 148.26 g a.i. ha-1, and Puma Super 7.5% EW (fenoxaprop-p-ethyl) at 46.33 and 92.66 g a.i. ha-1] at 20 days after sowing (DAS) for weed control and paddy yield performance under DSR system. A weedy check was retained as control. Results revealed that Clover and Pyranex Gold applied at either dose significantly (p≤0.05) reduced the population and growth of Cyperus iria (90-97% weed density and 93-97% weed dry biomass) and Echinochloa colona (94-97% weed density and weed dry biomass) weeds over control, while Puma Super proved efficient in suppressing Leptochloa chinensis and Echinochloa colona weeds. Among all the tested treatments, application of Puma Super at 92.66 g a.i. ha-1 furnished the highest number of tillers (137.3 in 2014 and 141.3 in 2015), grains panicle-1 (77 in 2014 and 79 in 2015), final paddy yield (1983.8 and 1570 kg ha-1 in 2014 and 2015, respectively), and net economic returns (Rs. 95915 ha-1), followed by the use of Puma Super at 46.33 g a.i. ha-1 which offered the next best economic benefits (Rs. 81906 ha-1). Thus, applying Puma Super at 92.66 g a.i. ha-1 is appeared viable approach to control grassy weed flora and ensure higher paddy yield with higher economic returns when rice is sown under DSR technology. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of water-nitrogen coupling on the energy balance and production efficiency of rice production in Hainan Province, a region of China with tropical climatic. Results showed that the effects of water and nitrogen fertilizer on the total energy output (E o), net energy (NE), and energy production efficiency (EPE) of rice were coupled. The total energy input (E i) for rice production increased with irrigation water and nitrogen fertilizer application. Rice production currently depends heavily on indirect and nonrenewable E i s. Diesel, machinery, and nitrogen fertilizer E i s accounted for more than 75 % of the total E i s for rice production. The highest total E o and NE were observed in rice treated with F-N100 and AWD-N150, respectively. Except for the F-N150 treatment, the total E o and NE of rice increased with nitrogen fertilizer application. Higher EPE was observed for rice treated with R-N100. In conclusion, the AWD-N150 treatment is suitable for rice production areas with good irrigation conditions, while the R-N100 treatment should be adopted as the preferred water and nitrogen management strategy in rice production areas with high rainfall. Furthermore, research on reducing E i s for irrigation, tillage, and nitrogen fertilizer application for rice production should be strengthened in the future. • The effects of water and N fertilizer on the E o , NE, and EPE of rice were coupled. • The E i for rice production increased with irrigation and N fertilization. • Irrigation and N fertilization accounted for more than 75 % of the E i for rice production. • Rice treated with R-N100 had higher EPE. • The highest E o and NE were observed in rice treated with F-N100 and AWD-N150, respectively. [ABSTRACT FROM AUTHOR]