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【Objective】 Drainage modulus is an important parameter for designing drainage systems in farmland. Taking Suibin county in Sanjiang Plain as an example, this paper analyzes its runoff and drainage modulus. 【Method】 The study site was an area prone to waterlogging. We first calculated the runoff (RO) using historical data on precipitation, pumping stations and land usage, and then estimated it using the runoff generation method (RGM) and the SCS-CN method (RSCS). The drainage modulus associated with each runoff was calculated using both empirical formulae (QE) and the average draining method (QA). The runoff and drainage modulus calculated by different methods were tested against measured data in the field. 【Result】 In the same year and under the same rainfall return period, the measured runoff increased with rainfall duration, while under the same rainfall duration and the same rainfall return period, it decreased with passage of years. The runoff and drainage modulus calculated from different methods differed from the experimentally measured data. For heavy rainfalls, the runoff estimated from different methods was ranked in the order of RGM>RSCS>RO, while for other rainfalls, it was ranked in the order of RSCSQE, whereas for rainfalls lasting 3 days, QA

【Objective】 Huangshui River is a tributary of the Yellow River in China, located in Qinghai. Agricultural production has resulted in pollution to it. The purpose of this paper is to analyze the spatiotemporal evolution of nonpoint source pollution due to agriculture in this basin. 【Method】 The studied area is located at the upstream in the Xiaoxiaqiao section in the mainstream of the river. Data measured from 2010—2018 from16 sub-units in the section were used for analysis. Pollutant discharge coefficient method was used to estimate the discharge amount and intensity of total nitrogen (TN), total phosphorus (TP), chemical oxygen demand (COD) and ammonia nitrogen (NH3-N). Spatiotemporal analysis and cold-hot spot analysis were used to analyze the spatiotemporal evolution of these pollutants. 【Result】 Temporally, pollutant discharge from livestock and poultry breeding and rural areas had showed an increasing trend, while those from crop farming had exhibited a decreasing trend. The discharge and intensity of TN, COD and NH3-N had increased, while TP had decreased slightly. Spatially, discharge of the four pollutants was less in Xiameng Bridge and Jintan cross-section areas, and more in the Xinning Bridge section. The contribution from different sectors to the pollution was ranked in the following order based on their significance: livestock and poultry breeding source > rural areas > farmland, with COD being the primary pollutant. Cold-hot spot analysis showed that the hot spots are mainly in Qiaotou Bridge, Xinning Datong Bridge, Xigang Bridge and the east of Xining, while the cold spots are mainly in Jintan and Sanqi Bridge. Overall, pollutant discharge had increased slightly in the basin, despite some areas having seen a decrease in pollution. Prevention and control of the pollutants should focus on reducing discharge from livestock and poultry breeding industry, especially COD, and reducing discharge of the pollutants into the Xinningqiao Section. 【Conclusion】 Nonpoint source pollution from agriculture in Huangshui basin varied spatiotemporally, and the main contributors to the pollution are livestock and poultry breeding sector. Reducing and mitigating their discharge is hence essential to ameliorate pollution of the basin.

【Objective】 Available water for irrigation in Hetao irrigation district has been reduced consistently over the past decades. Improving its water management to alleviate soil salinity is critical to sustaining crop production in this region. The purpose of this paper is to seek optimal water-saving irrigation schemes for this region by using process-based models. 【Method】 The semi-distributed hydrological model (SahysMod) is used in our study. We consider spatial variability of numerous factors in the modelling, which include meteorology, hydrogeology, soil, irrigation and crops. The model is then combined with GIS to simulate the spatiotemporal dynamics of soil water and salt under different scenarios. Data measured from 2007 to 2012 and 2013—2016 were used to calibrate and verify the model, respectively. 【Result】 ①In a business as usual scenario, the annual drainage decreases first before gradually stabilizing, with the average annual drainage being 531 million m3; salinized lands in the middle and upper reaches of the irrigation district decrease slightly, but increase significantly in the lower reach. ②Considering water-saving in the whole irrigation district and ecological demand for water in the downstream and the Wuliangsuhai lake, the total water diversion from the canal head should be reduced by 15% from the current level. This will save up to 646 million m3 of water. ③If the current irrigation amount remains unchanged, the water utilization coefficient of the canal can be improved 17.6% at the best. ④If the reduction in total water diversion from Yellow River is the same, reducing irrigation amount in the field is the best way to boost salt leaching. In this scenario, reducing irrigation amount should be the priority, followed by improving water utilization coefficient of the canal. 【Conclusion】 In addition to saving water, considering ecological demand of the downstream for water is also important in optimizing water management in Hetao Irrigation District.

In this paper, we study a prey–predator–top predator food chain model with nonlinear harvesting of top predator. We have derived two important thresholds: the top predator extinction threshold and the coexistence threshold. We found that the top predator will die out if the nonlinear harvesting from predator to top predator is larger than the top predator extinction threshold. On the other hand, the prey, predator and top predator coexist if the nonlinear harvesting from predator to top predator is less than the coexistence threshold. While the parameter value of nonlinear harvesting from predator to top predator is between two critical thresholds, the system displays bistability phenomena, implying that the top predator species either die out or exist with the prey and predator species, which largely depend on the initial condition. Thus, a bistable interval exists between two critical thresholds, which is a significant phenomenon for the model. Meanwhile, we performed bifurcation analysis for the model, showing that the system would arise backward/forward bifurcation and saddle-node bifurcation and Hopf bifurcation. Finally, we performed numerical simulations to verify the theoretical analysis. [ABSTRACT FROM AUTHOR]

With the development of material science and increasing awareness of ecological environmental protection, liquid biodegradable mulch films (LBDMs) have garnered significant public interest. In this research, new LBDMs were developed using hydrophobically modified polymer materials, surfactants, and photosensitive catalysts. Characterization by scanning electron microscopy (SEM) revealed good material compatibility. LBDMs exhibited excellent wettability and degradability, effectively covering soil surfaces and enhancing soil moisture conservation, with a degradation rate of 76.09% after 80 days of burial. The field performance experiment was conducted over two consecutive years, 2021 and 2022, to assess differences in soil temperature and moisture, peanut agronomic traits, pod traits, and yield under four treatments: non-mulching (CK), LBDMs, clear polyethylene mulch films (CPEMs), and black polyethylene mulch films (BPEMs). LBDMs increased soil temperature by 0.56 °C and soil moisture by 19.25%, accelerated the seedling stage by 4-to-6 days, and improved the average emergence rate by 15.91%. Furthermore, LBDMs significantly promoted peanut growth, and it increased yield by 14.34% compared to CK. LBDMs performed comparably to the two types of PE films in maintaining soil conditions and different crop phenotype traits, including plant height, branch number, yield, and quality, and they even outperformed PE films in productivity per plant and 100-kernel weight. These findings suggest that LBDMs are a promising eco-friendly alternative to traditional PE films. [ABSTRACT FROM AUTHOR]

Leaf spot, a major apple disease, manifests in diverse symptoms. In this study, the pathogen was isolated from diseased 'Yanfu 3' apple leaves in Yantai, Shandong Province, and identified as Neopestalotiopsis clavispora through morphological observation, molecular identification, and multi-gene (ITS, TEF1α, and TUB2) phylogenetic analysis. Three isolates (YTNK01, YTNK02, and YTNK03) were selected for pathogenicity tests to verify Koch's postulates. To our knowledge, this is the first report of N. clavispora being responsible for apple leaf spots in China, and the disease has been named 'apple Neopestalotiopsis leaf spot'. Additionally, N. clavispora was found to infect crabapple, sweet cherry, grape, peach, and pear under laboratory conditions, indicating that these fruit trees may be potential hosts for N. clavispora in the field. The in vitro toxicity of ten fungicides to the pathogen was assessed using the mycelial growth rate method. All ten fungicides were effective in inhibiting the growth of N. clavispora. Among them, those based on pylocyanonitrile, propiconazole, pyraclostrobin, tebuconazole, diphenoxazole, and osthole showed higher toxicity to N. clavispora, with EC50 values of 0.11, 0.41, 0.47, 1.32, 1.85, and 3.82 µg/mL, respectively. These fungicides could be used as alternatives to prevent this disease in production. Overall, these findings provide valuable insights into the characteristics of N. clavispora causing apple leaf spot and are crucial for developing effective management strategies. [ABSTRACT FROM AUTHOR]

BACKGROUND: Temperature is a primary factor that determines the eco‐geographical distribution and population development of invasive insects. Temperature stress leads to various negative effects, including excess reactive oxygen species (ROS), and catalase (CAT) is a key enzyme against ROS in the antioxidant pathway. The whitefly Bemisia tabaci MED is a typical invasive pest that causes damage worldwide. Our previous studies have shown that CAT promotes whitefly adaptation to high temperature by eliminating ROS. However, the mechanism underlying the low‐temperature adaptation of whiteflies is still unknown. RESULTS: In this study, we investigated the role of CAT in the low‐temperature tolerance of B. tabaci MED by analyzing its survival rate, reproduction, and ROS levels at 25 °C (as a control, suitable temperature), 20 °C (moderately decreased temperature), and 4 °C (severely decreased temperature). Silencing of BtCAT1, BtCAT2, or BtCAT3 reduced the viability of whiteflies under a short‐term severely decreased temperature (4 °C), which manifested as decreases in survival and fecundity accompanied by significant increases in ROS levels. Moreover, even at a moderately decreased temperature (20 °C), silencing of BtCAT1 led to high ROS levels and low survival rates in adults. CONCLUSION: Silencing of BtCATs significantly increased the sensitivity of B. tabaci MED to low temperatures. BtCAT1 is likely more essential than other BtCATs for low‐temperature tolerance in whiteflies. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The purpose of this study is to discover and excavate more key factors and signaling pathways that regulate the formation intensity of biofilms and to fully reveal the possible models affecting biofilm formation. By using gene homologous recombination and bioinformatics technology, a MutL protein-directed deletion mutant strain was successfully constructed. The growth status of the mutant strain was observed, and it was confirmed that, except for the change in cell morphology, there were no significant differences in growth and reproduction between the mutant strain and the wild-type strain. By using the induced biofilm formation technique, the significant decrease in biofilm formation in the MutL mutant strain was successfully verified. The plate confrontation test confirmed that the inhibitory ability of the mutant strain against rice blast fungus was not significantly different from that of the WT strain. The colonization ability of the mutant strain on rice stems was tested, and it was confirmed that the colonization ability of the mutant strain was significantly lower than that of the WT strain. In terms of the prevention and control effect of rice blast disease, the mutant strain showed a significant decrease. By using transcriptomic big data, the gene and pathway expression differences between the mutant strain and the WT strain during biofilm formation were analyzed. The analysis revealed no significant correlation with the previously reported spo0A and tapA-sipW-tasA pathways. The key factor capB of the polyglutamic acid signaling pathway, which affects the formation of the biological model, was found to have a significant decrease in expression. A mechanical hypothesis was proposed: MutL may participate in regulating the formation intensity of Bacillus biofilms by regulating the formation of glutamic acid to polyglutamic acid. [ABSTRACT FROM AUTHOR]