Through a paddy soil column experiment, we comprehensively evaluated the effects of three irrigation practices and three nitrogen (N) fertilizer application strategies on NH3 volatilization, N2O emissions, and rice yields during the rice growing season to identify the optimal irrigation and fertilization combination technique to reduce both NH3 and N2O losses in paddy soil while sustaining rice yield. In addition, we integrated molecular biology techniques (Quantitative PCR) to establish correlations between environmental factors and the abundance of N cycling-related soil microbial functional genes, revealing the intricate interactions between NH3 volatilization and N2O emissions under varied coupling irrigation and fertilization schemes. Our results clearly showed a trade-off relationship between N2O and NH3 emissions under water-saving irrigation practices (controlled irrigation (CI) and intermittent irrigation (II)) coupling with traditional fertilizer urea. Compared with continuous flooding (CF) practice, both CI and II treatments reduced NH3 volatilization by 36.3-73.9%, while increasing N2O emissions by 1483.2-2246.2% during the rice growing season. Notably, the combination application of CRF under CI mode (CI-CRF) significantly reduced NH3 volatilization by 65.0% during the rice growing season, compared to the conventional II-Urea approach. Although the impact on N2O emissions was modest, CI-CRF strategy still achieved a 4.6% reduction in N2O emissions, thus tackling the trade-offs between two important environmentally damaging gases under water-saving irrigation. The suppression of NH3 volatilization was primarily attributed to the CI-CRF strategy lowering NH4+-N concentrations in flooding water, while the reduction in N2O emissions was associated with an increase in soil nirS and nosZ gene abundances. Further estimates indicated that the CI-CRF strategy could potentially reduce NH3 volatilization by 259.2 Gg N yr-1 and N2O emissions by 3.1 Gg N yr-1 in single-crop paddy field in China, compared with traditional II-Urea approach. Therefore, the optimal reduction of gaseous N loss, coupled with yield enhancement, could be achieved through the synergistic strategy of CI-CRF in single-crop rice cultivation ecosystems. Future studies should focus on fieldbased experiments that explore the long-term effects of CI-CRF combinations under varying soil types, climates, and rice cultivation systems.

Soil shrinkage during the drying process (water stress) is one of the main issues in expansive soils of paddy fields. It occurs due to decrease in soil water content, resulting in changes in soil volume and the geometry of pores, leading to the formation of cracks and higher water loss. The aim of this study was to assess the shrinkage characteristic curve and pore size of paddy soils to determine the shrinkage -swelling behavior in Guilan province, Iran. 120 soil samples were collected from the study area. Pore size was determined using soil moisture retention curve (SMRC). It was established by plotting the soil water content (theta) versus the corresponding matric suction (h), and the shrinkage curve by plotting the void ratio (e) against the moisture ratio (upsilon). The suction-pore relationships were also determined. Furthermore, the geometric factors indicating the change in vertical (subsidence) and horizontal (crack) volume of the soils were determined and varied from 1.23 to 2.53, indicating that the vertical change in soil volume is predominant. The zero, residual and proportional shrinkage phases accounted for less than 2 %, 8-38 %, and 61-91 % of the total soil volume change, respectively. The shrinkage capacity of the soils ranged from 0.52 to 1.37. Cation exchange capacity and clay content were identified as the most important factors affecting soil shrinkage properties. In general, the studied paddy soils have great potential for swelling- shrinkage and cracking during the drying process due to the large percentage of expandable clays and the medium to fine pores. The resultant cracks negatively affect crop yield by damaging plant roots and increasing water losses through the soil profiles.

Lead (Pb) contamination in agricultural soils poses a significant threat to both ecosystems and human health. While nano-Fe3O4 exhibits promising potential for Pb remediation, its practical application in the soil is hindered by its' biotoxicity, easy aggregation, and the risk of secondary pollution. Thus, this study presents a novel approach wherein Fe3O4 was incorporated into hydrogel via a one-pot synthetic strategy (Fe3O4@LH). This incorporation enhanced the mechanical properties and environmental stability of the hydrogel composites. Based on the mechanical properties, environmental stability, and single-point adsorption results for Pb, we selected Fe3O4@LH-4 for further research. The removal mechanism and the feasibility of employing Fe3O4@LH-4 for Pb removal from paddy soil were investigated through batch adsorption experiments and soil culture studies. Results showed that the adsorption process was primarily governed by swelling adsorption, electrostatic adsorption, ion exchange, precipitation, nanometer effect, and complexation mechanisms. The application of Fe3O4@LH-4 significantly led to the reduction of 16.7 %-25.4 % in soil Pb content, with removal rates escalating alongside increased dosage and application periods of Fe3O4@LH-4. Fitting results of the prediction model indicated that the Pb content in mildly Pb-contaminated soil (186.55 mg/kg) would decrease to be below the risk control standard for soil contamination of agricultural land in China (140 mg/kg) after 112 days of continuous application. Concurrently, cadmium and arsenic contents in the soil decreased by 5.2 %-10.8 % and 7.1 %-16.7 %, respectively. Moreover, the application of Fe3O4@LH-4 positively influenced soil nutrient levels, with total nitrogen and soil organic matter content significant increments of 13.6 %-41.0 % and 4.6 %-16.1 %, respectively. Furthermore, Fe3O4@LH-4 recovery exceeded 88.3 % after a 90-day application period. These findings underscore the potential of Fe3O4 incorporated hydrogel as a promising agent for the sustained removal of heavy metal Pb from paddy soil.

Farmers' open-field burning of paddy straw and the indoor burning of paddy residues as domestic fuels are significant environmental concerns since they emit dangerous pollutants. The worldwide burning of paddy residues totals 90 million tons (MT). Around 24 MT emanated from India, accounting for approximately 27% of the world's paddy straw burning. Burning residues emit smog particles, polyaromatic amines, nitrous oxides, sulfur dioxide, carbon dioxide, and carbon monoxide, methane, seriously degrading the air quality and risking human health. The combustion of dry paddy straw emits massive volumes of methane and nitrous oxide, 65 and 1.6 kilotons, respectively. This study analyzes the consequences of burning paddy residue outdoors and indoors by reviewing the relevant literature and data. Open-field burning causes air pollution, damages soil health, and harms human health. Indoor burning of paddy residues as domestic fuels harms women's and children's health in rural areas. To mitigate the adverse effects of this practice, we magnified our research using the various literature and recent statistics to link with mushroom cultivation as an alternative to paddy residue burning. Recently, India produced almost 240,000 tons of mushrooms; Odisha, Maharashtra, and Bihar are the three leading states for mushroom production. The cultivation of mushrooms is considered advantageous for both health and the environment. This study has concentrated on mushrooms' economic potential, medicinal value, and health benefits.

Interest in soil health and biodiversity conservation has become increasingly important. Consequently, studies comparing the chemical and biological characteristics of organic and traditional paddy soils have been increasing. Soil microorganisms are essential in nutrient cycling; however, their diversity is challenging to ascertain because of their environmental sensitivity and complex interactions. Particularly, in domestic rice cultivation, the soil undergoes multiple irrigation and drainage processes during crop growth, providing a diverse ecological environment for soil microorganisms. The objective of this study is to compare the microbial community and diversity between paddy soils in two agricultural systems. We selected organic and conventional paddy fields in Yangpyeong, Gyeonggi Province, and collected monthly samples from August to November 2022 for analysis. Bacteria and fungi were amplified from the 16S rRNA V3V4 region, ITS 3-4 region respectively, For the comparison of microbial diversity, Alpha diversity indices (Chao1, Shannon, Gini-Simpson indices) were analyzed. The results indicated genus-level differences in microbial communities, with the genera Mucor and Sirastachys exclusively present in organic paddy soils, while the genus Ustilaginoidea was exclusively found in conventional paddy soils. Among them, Ustilaginoidea is reported to be a fungus causing false smut disease, causing damage to crop growth and quality. Additionally, the comparison of microbial diversity between the two farming showed no significant differences (p>0.05). In conclusion, When the microbial communities present in both farming systems were examined, organic farming appeared to be more advantageous than conventional farming regarding crop disease and health. This study provides essential soil chemical and microbiological data for understanding the fundamental characteristics of paddy soils in South Korea.

Yellow stem borer of rice Scirpophaga incertulas, significantly reduce rice production throughout Asia. Silicon (Si) amendment in rice for resistance against biotic stress is gaining importance to protect crops from insect herbivory. Exogenous application of silicon in form of DAE (diatomaceous earth) at 0.5 to 2.5 g kg(-1) and RHA (rice husk ash) at 5.0 to 15.0 g kg(-1) soil significantly improved silicon uptake and reduced borer damage in both susceptible (TN1) and moderately resistant (GNR3) rice cultivars exhibiting the enhanced resistance against S. incertulas with a yield benefit to the tune of 1.91- fold over control. Si addition through DAE at 2.0 g kg(-1) soil registered a maximum of 1.55 and 2.27- fold increased Si uptake by TN1 and GNR3 plants respectively as against a corresponding increase of 2.37 and 2.24-fold by 12.5 g RHA kg(-1) soil. Chlorophyll was highest in plants receiving low dose of silicon and showed a downward trend with increase in dose. Feeding stimuli from S.incertulas larvae led to intense leaf silicificationly with significant increased silica cell deposit per mm row length, increased lobe size, and minimal distance between adjacent silica cells as evidenced from scanning electron microscopic studies. Increased Si content along with biotic stress activated antioxidant enzyme (super oxide dismutase, catalase, and peroxidise) defense in rice to mitigate oxidative stress. RHA supplemented plants with YSB infestation showed increased activity of the non-oxidative enzymes like phenylalanine lyase (3.5- fold) and tyrosine ammonia lyase (13.0 -fold) over control conferring a greater defense to paddy through induction of signal transduction process. The study thus, demonstrated the benefit of soil amendment with DAE and RHA in inducing host resistance against S. incertulas, as an eco-holistic approach in pest management in rice. Further, the finding is expected to be helpful in genetic mapping of known YSB resistance gene markers of candidate genes like hexose transporter, amino acid transporter and other genes related to defense signal mechanisms via jasmonic acid pathway.

Weeds compete with rice for sunlight and nutrients and are prone to harboring pathogens, leading to reduced rice yields. Addressing the issues of low weeding efficiency and weed mortality rates in existing inter-row weeding devices, the study proposes the design of a combination paddy field inter-row weeding wheel. The device's operation process is theoretically analyzed based on the weed control requirements in the northeastern region of China, leading to the determination of specific structural parameters. This research conducted experiments on the mechanical properties of weed cutting to obtain geometric parameters for paddy field weeds. It was found that the range for the cutting gap of the dynamic-fixed blade is between 0.6 mm to 1.4 mm and the cutting angle is between 5 degrees to 15 degrees, resulting in the lowest peak cutting force for weeds. Using LS-DYNA R12.0.0 dynamic simulation software, a fluid-structure interaction (FSI) model of the weeding wheel-water-soil system was established. By employing the central composite experimental design principle and considering the soil stir rate and coupling stress as indicators, the optimal structural parameter combination for the device is obtained: a dynamic-fixed blade cutting gap of 1.4 mm, a cutting angle of 10.95 degrees, and a dynamic blade install angle of -3.44 degrees. Field experiments demonstrated that the device achieved an average weeding rate of 89.7% and an average seedling damage rate of 1.9%, indicating excellent performance. This study contributes to improving weed mortality rates and provides valuable guidance for inter-row mechanical weeding technology.

On Earth, there is an abundance of soil that has been utilized to build homes for millions of people. Manufacturing compacted stabilized adobe blocks requires adequate water added to the appropriate soil type that has been admixed with binders and fibers to attain maximum density. The mixture is then compressed using the appropriate adobe-forming machine. Currently, the major environmental and human health risks worldwide come from industrial and agricultural wastes because of disposal concerns. The production and use of cement and cement blocks bring numerous economic and environmental issues. Utilizing locally available resources and enhancing standard production and testing methods are two feasible options for sustainable growth. Researchers have seen the promise of earthen construction as an alternative building material, and it is becoming more popular in the context of sustainable development. Marble dust (MD) (Industrial waste), sugarcane bagasse ash (SBA), and paddy straw fiber (PSF) (Agricultural wastes) were utilized in this research to manufacture the unfired admixed soil blocks. This study utilizes marble dust composed up to 25%-35%, paddy straw fiber constituted 0.8%-1.2%, and bagasse ash made up 7.5%-12.5% of the soil. The marble-dust-bagasse-ash-soil mix was strongly adherent to PSF, according to SEM investigation. In addition, as is apparent from the image, the number of pores is insignificant. These images support the preceding conclusions regarding this sample's increased flexural and tensile strength. The primary constituents discovered on the surface of an unfired ad-mixed soil block strengthened with PSF of length 75 mm were silica (Si) and oxygen (O), according to the EDS examination. Aluminum (Al) and magnesium (Mg) were found in trace amounts. The endurance characteristics of the block were determined by conducting different tests on the eighty-one (81) design mixes of the produced unfired ad-mixed adobe blocks, followed by modeling, optimization and microstructural analysis. The results show that the recommended technique improves the durability characteristics of admixed soil blocks without burning better than burnt bricks.