The precipitation concentration index (PCI) is a measure of precipitation during the year. Based on the monthly precipitation data of 15 meteorological stations in the Yarlung Zangbo River Basin (YZRB) from 1981 to 2024, the spatiotemporal variation characteristics of PCI, the amount of seasonal precipitation, its frequency and intensity over the last 44 years, and the reasons for a change in PCI were analyzed using a linear equation, Person coefficient, and five mutation tests, including the Mann-Kendall and Cramer tests. The results indicated that (1) The PCI increased from east to west in YZRB, whereas annual precipitation, precipitation frequency, and precipitation intensity decreased from east to west. (2) Over the past 44 years, the PCI decreased at a rate of -0.26 per decade, indicating a trend toward more evenly distributed monthly precipitation throughout the year. Precipitation exhibited an increasing trend from January to July and October (the fastest increase in July), and it decreased in other months (the most in September). Monthly precipitation accounted for the proportion of annual precipitation (MPAP), which increased in February and April-July (the largest in May). MPAP was decreased in other months (the largest decrease in September). (3) The increase of precipitation in spring, summer, and winter was primarily due to the increase in precipitation intensity, whereas the decrease of precipitation frequency played a major role in the decreased amount of precipitation during autumn. Furthermore, the increase in annual precipitation intensity resulted from the significant increase of the Tibetan Plateau-1 index and the western Pacific warm pool intensity index. The decrease in the PCI was related to a decrease in the seasonal difference under the background of warming. (4) The PCI was lower only in the 2000s, but was higher in the other three decades, although there was a sudden change in the early 1990s. The abrupt changes in annual precipitation, frequency, and intensity occurred during the first 10 years of the 2000s and the middle and late 1990s.
Based on the 2022 daily precipitation data from weather stations in the eastern Tibetan Plateau, this study evaluated the accuracy of three datasets from the China Meteorological Administration: the Multi-source Precipitation Analysis System (CMPAS), Land Data Assimilation System (CLDAS), and Global Atmospheric Reanalysis (CRA)—via error indices and grading methods. The results indicate: (1) CMPAS exhibits the lowest error and highest correlation, making it the most reliable for annual precipitation analysis. (2) CMPAS monthly data align closely with observations, while CRA overestimates and CLDAS underestimates precipitation in most months. (3) During two large-scale precipitation events, CLDAS best captures accumulated rainfall, while CMPAS more accurately reflects precipitation centers, intensities, timing, and location. Overall, CMPAS is the most effective dataset for analyzing precipitation in the region, supporting improved monitoring of sparse areas and laying a solid foundation for climate operations and disaster prevention.
Using MODIS snow product data, this study investigates the spatiotemporal variation characteristics of the snowmelt period over the Mongolian Plateau during the 2003-2022 hydrological years. The movement of the snowmelt line toward higher latitudes and its response to air temperature are tracked and analyzed at 15-day intervals. The results show that: (1) The proportion of snow-covered area to the total area of the Mongolian Plateau during the 2003-2022 hydrological years ranged from 55.59% to 87.61%, with the smallest snow cover in 2018 and the largest in 2009. Additionally, over the past 20 years, the snowmelt start time on the Mongolian Plateau exhibited a significant advancing trend at a rate of 0.18 days per decade (P<0.05), while the stable snow-cover area showed a delaying trend. (2) Spatially, snowmelt occurred significantly later in northern regions of the Mongolian Plateau compared to southern regions. Stable snow-cover areas were primarily concentrated in the western Mongolia and northeastern Inner Mongolia, where snowmelt times were generally later. Approximately 64.9% of these areas showed an advancing trend in snowmelt, while regions with delaying trends were mainly distributed in the northwestern part of the study area. (3) Observational analysis at half-monthly scales from January during the winter season revealed that the movement of the snowmelt line demonstrated successive synchronicity with the -5 ℃ and 0 ℃ isotherms. Correlation coefficients between snowmelt line positions and temperature, except for the year 2018 (with the least snow cover), generally fell within the higher range of 0.72 to 0.98, indicating that temperature is a key factor influencing the position of the snowmelt line.
Salinization in the irrigation areas of watersheds in downstream arid regions exacerbates soil degradation, crop yield reduction, and river water salinization, severely limiting agricultural production and harming ecological stability. It arises in a manner influenced by the depth of groundwater and poor irrigation and drainage management. Scientifically formulating measures to regulate soil water-salt is key to addressing these issues. In this study, field experiments were conducted in a typical farmland area of the riparian zone by the downstream part of Aksu River. Based on dynamic observations and field survey data, an unsaturated model was established using the HYDRUS-1D software to simulate soil water and salt transport patterns during the cotton growing season, determine appropriate regulatory strategies, and explore the relationship between the stable groundwater evaporation depth and riparian soil structure. The results revealed that the identification and validation accuracy of the soil moisture content and total dissolved solids were 0.862 and 0.752 with root mean square errors of 0.033 and 0.008, respectively, indicating that the model was highly reliable. Irrigation infiltration accounted for 85% of the total soil water recharge, introducing 127.164 mg·cm-2 of salt, while soil water discharge to groundwater accounted for 59.67% of the total discharge, removing 267.78 mg·cm-2 of salt. The water balance error was 9.2% and the desalination rate was 33.89%. Considering the demand for water for crops and soil salinity dynamics, setting the irrigation water depth to 70 cm while maintaining the groundwater depth at approximately 220 cm can effectively reduce the soil salinity in the root zone. In sandy loam structures, the position of the loam layer has little effect on the critical evaporation depth of groundwater (150 cm), but significantly influences the stable evaporation depth and actual evaporation. If the loam layer is closer to the surface, the stable evaporation depth becomes shallower and the actual evaporation decreases. The findings provide a reference for preventing salinization and managing water resources in arid regions.
Evapotranspiration, as a crucial component of the water cycle, is vital for regulating water resources and protecting the environment, especially in arid regions where it plays a significant role in water consumption and redistribution. This study focused on Aksu River Basin and used MOD16 evapotranspiration product data from 2001 to 2022 to systematically analyze the patterns of spatial and temporal variation of actual evapotranspiration (AET ) and potential evapotranspiration (PET ), along with an exploration of the factors influencing them. The findings provide a scientific basis for managing regional water resources and protecting the environment. The results indicate the following: (1) The MOD16 product data are consistent with ET0 data (R2=0.8133), and the product accuracy meets the requirements for studying the spatial and temporal distribution of evapotranspiration in Aksu River Basin. (2) The multi-year average AET and PET are 168.36 mm and 1569.03 mm, respectively. AET shows an overall increasing trend, while PET exhibits a decreasing one. There are significant differences in the spatial distribution of AET and PET, with the opposite trends being exhibited. (3) Over the last 22 years, AET in Aksu River Basin has significantly increased, mainly in cultivated land, forestland, and oases, while PET has decreased overall but increased near the edges of oases and along river channels. AET is less stable than PET, and the Hurst indices of both indicate that the trends may change in future, with 56% of the area showing anti-persistence for AET and 89% for PET. (4) Changes in AET and PET are intrinsically linked to changes in climatic factors, with wind speed and relative humidity being the main factors influencing regional variations in these two variables. This study provides an important scientific reference for managing and using water resources in arid regions.
There are high levels of boron in surface water and groundwater in the oasis area of Qiemo County, Xinjiang, which seriously affects the health of residents. To clarify the chemical characteristics of the oasis water and the main source of the boron, 24 groundwater samples from each of 20 locations were collected in 2023. They were then analyzed using a Piper three-line plot, Gibbs diagram, and correlation analysis, along with evaluations of hydrogen-oxygen isotopes. An APCS-MLR (absolute principal component-multiple linear regression) model of the chemical characteristics of surface water and groundwater and the source of the boron was also constructed, as well as quantitative evaluation of the contribution of different factors to water boron levels and other hydrochemical components. The results showed that the surface water and groundwater in the oasis area of Qiemo County are weakly alkaline, the mean pH is 8.22, the groundwater is mainly brackish water, and the anode ions are mainly and Na+. There are many types of hydrochemistry, with surface water and groundwater mainly containing SO4·Cl-Na·Mg. The mean level of boron in the surface water in the study area was 2.34 mg·L-1, with an exceeding rate of 100%; meanwhile, the corresponding value in the groundwater was 1.73 mg·L-1, with an exceeding rate of 70%. APCS-MLR receptor model analysis revealed that the hydrochemical components and boron sources were mainly soluble filter-enrichment factors (F1: 58.21%), native geological factors (F2: 15.42%), human activity factors (F3: 11.18%), and unknown sources. These findings clarify the cause of the excessive boron in the area, and show that the geological environment has a great influence on the accumulation of boron in water.
As the fundamental terrain of deserts, sand ridges play a crucial role in shaping the surface water and thermal environment at different slope positions, which profoundly influences how biological soil crusts develop and their spatial distribution patterns. Lichen crusts are widely distributed on the desert surface. However, issues such as how lichen crusts at different slope positions affect the soil phosphorous cycle and what factors play key roles in influencing this remain unclear. Against this background, this study was conducted in Gurbantunggut Desert, involving a systematic analysis of the changes in phosphorus fractions and related enzyme activities in the lichen crust and 0-5 cm soil layer beneath the crust at different slope positions. The results showed that stable phosphorus in the soil (HCl-Pi, HHCl-Po, HHCl-Pi, and Residual-P) accounted for over 75% of the total phosphorus (TP) content, followed by medium labile phosphorus (NaOH-Pi and NaOH-Po) and labile phosphorus (Resin-P, NaHCO3-Pi, and NaHCO3-Po). The slope position had a significant impact on stable phosphorus, and the soil layer had a significant impact on medium labile phosphorus (P<0.05). The data on the contents of stable phosphorus, TP, organic phosphorus (Po), and inorganic phosphorus (Pi) all revealed that, in the crust layer, the values at the bottom of the slope were significantly higher than those on the east and west slopes, while in the 0-5 cm soil layer, the values on the west slope were significantly lower than those at the bottom of the slope and on the east slope (P<0.05). However, the content of NaOH-Pi was significantly higher on the east and west slopes than at the bottom of the slope in the crust layer, and it was significantly higher on the west slope than on the east slope and at the bottom of the slope in the 0-5 cm soil layer. In terms of soil enzymes, the east slope exhibited the lowest activity of alkaline phosphatase activity (ALP) and β-glucosidase activity (GC) in the crust layer, but the highest in the 0-5 cm soil layer. Random forest model analysis showed that the changes in moisture and temperature brought about by the slope position were the most important factors affecting the levels of labile phosphorus and stable phosphorus in the crust soil, respectively. This provides scientific support that enriches the theoretical framework of soil phosphorous cycling in desert ecosystems.
To examine the mineralization characteristics and their effect on soil organic carbon components in sandy loamy soils following the application of organic fertilizers in conjunction with trace elements, indoor culture experiments and field trials were conducted. We assessed the decomposition rate and residue ratio as well as the influence of varying amounts of organic fertilizer on soil organic carbon, active organic carbon, particulate organic carbon, organo-mineral-bound organic carbon, and microbial carbon content, as well as the level of amino sugars, N-galactosamine, and galactomannan. Compared with the application of organic fertilizers alone, the addition of trace elements to the indoor culture significantly decreased the amount of mineralized organic carbon in the sandy loam soils. In field trials, this addition further increased active organic carbon (1.79%-1.99%), low-active organic carbon (2.20%-4.91%), organo-mineral-bound organic carbon (3.89%-7.95%), and microbial carbon (1.71%-8.10%) content, while also enhancing the level of amino sugars (3.46%-6.32%), N-galactosamine (1.21%-13.32%), galactomannan (2.41%-6.14%), and microbial residual carbon (2.70%-4.99%). However, the increase was less pronounced for high-active organic carbon (0.71%-1.48%) and particulate organic carbon (4.91%-5.86%) content. The addition of micro and trace elements to organic fertilizers may, to some extent, mitigate the mineralization process of organic fertilizers in sandy soils, thereby enhancing the level of labile organic carbon, recalcitrant organic carbon, organic carbon bound with minerals, and microbial biomass carbon in the soil, ultimately promoting the turnover and retention of organic carbon in the soil.
Exploring the quantitative pre assessment of the climate impact of vegetation greenness changes in the Qaidam Basin can help promote the integrated protection and systematic management of mountains, waters, forests, fields, lakes, grasses, sands, and gases. This article is based on MODIS NDVI data, meteorological data, and climate change prediction datasets. It monitors the changes in vegetation greenness with NDVI ≤ 0.3 in the Qaidam Basin from 2000 to 2023, analyzes the climate driving factors of vegetation with different greenness, and predicts the future trends of vegetation changes with different greenness. The results showed that in the past 24 years, vegetation types Ⅰ, Ⅱ, and Ⅲ in the Qaidam Basin accounted for 49.33%, 19.81%, and 30.86% of low green vegetation, respectively. Among them, the vegetation areas of Ssum, SⅠ, and SⅡ decreased significantly (P<0.001), while the vegetation area of SⅢ increased significantly, indicating a clear improvement in vegetation quality; The cumulative effect of water and heat conditions on precipitation of low green vegetation for 2-3 years and temperature for 5 years is significantly (P<0.01) greater than that of the current year, indicating that a warm and humid climate promotes the healthy development of grasslands; Under the three emission scenarios of RCP2.6, RCP4.5, and RCP8.5 in the future, the overall trend of low green vegetation in the Qaidam Basin is decreasing, and future climate conditions are favorable for vegetation restoration and expansion. The research results can provide scientific basis for the development of ecological environment protection and desertification control measures in the Qaidam Basin.
Litter decomposition has an important role in the carbon and nutrient cycling of terrestrial ecosystems. Climatic conditions are the main factors involved in litter decomposition. Currently, few studies have examined litter decomposition in alpine grassland ecosystems. To determine the effects of meteorological factors on the litter decomposition and nutrient release processes under a climate change background, the Stipa purpurea endophytic fungal symbiont was used along with the litter decomposition bag method to analyze the decomposition characteristics with endophytic fungi (E+) and without endophytic fungi (E-). The effect of meteorological factors on the decomposition rate of Stipa purpurea was analyzed. The results indicated that the decomposition rate of E+ was higher compared with that of E-, whereas the decomposition cycle was shorter. With the extension of time, the total nitrogen content of Stipa purpurea showed an increasing trend, lignin content gradually changed from significantly higher in E+ to no significant difference between the two, and the cellulose content gradually changed from significantly lower in E+ compared with E- (P<0.05). Regardless of endophytic fungi, the litter weight and mass loss rate of Stipa purpurea were correlated with the mean monthly temperature and the mean ground temperature (P<0.05). Precipitation was positively correlated with the litter decomposition rate of Stipa purpurea, and the total nitrogen content of the litter was positively correlated with temperature and precipitation (P<0.05). The lignin and cellulose content were negatively correlated with temperature and precipitation. The duration of sunshine had a positive effect on the decomposition of litter, and the lignin, cellulose, and litter weight content were strongly correlated with sunshine duration. Overall, endophytic fungi accelerate the decomposition of Stipa purpurea litter. For E+ and E-, the effect of meteorological factors on the decomposition of Stipa purpurea litter was consistent.
Against the backdrop of a gradual decline in global atmospheric nitrogen deposition, the legacy effects of long-term nitrogen addition on alpine grassland ecosystems remain unclear. This study investigated such legacy effects on plant communities in alpine grasslands through a 16-year controlled experiment conducted in the Bayinbuluke alpine grassland of the central Tianshan Mountains. The results revealed that: (1) Four years after the end of fertilization and regarding the functional traits of the dominant species, high nitrogen treatment (N15) significantly increased the plant height (+20%), leaf area (+16%), and specific leaf area (+5%) of Leymus tianschanicus but reduced the plant height (-23%) and specific leaf area (-1.5%) of Festuca kryloviana. Moreover, the legacy effects on F. kryloviana gradually weakened over the recovery time. (2) At the community level, long-term nitrogen addition exhibited positive legacy effects on rhizomatous grasses but adverse legacy effects on brunch grasses, significantly enhancing the cover and aboveground net primary productivity of the community. However, these legacy effects exhibited a diminishing trend over time. Under the N15 treatment, the increase in community cover declined from 32% to 18%, while the ANPP decreased from 64% to 44%. (3) Regarding soil chemical properties, adding nitrogen had significant positive legacy effects on the total soil nitrogen content but no significant legacy effects on the total soil phosphorus or organic carbon content. The negative legacy effect on soil pH gradually weakened, with the inhibitory effect under N15 treatment decreasing from -3.4% in 2023 to -1.4% in 2024. Soil total phosphorus and organic carbon content exhibited low correlations with vegetation characteristics, and the four soil factors collectively explained only a small proportion of the vegetation variation. This study demonstrates that, against the background of reduced or ceased atmospheric nitrogen deposition, historical nitrogen deposition continues to exert persistent legacy effects on grassland ecosystems, with some of these effects gradually diminishing over the recovery time.
Ammopiptanthus nanus is an endangered evergreen shrub that is endemic to the desert area of Central Asia. It exhibits strong cold and drought resistance, serves as a model species for examining the mechanisms of plant adaptation to extreme environments, and is a focus of conservation research in desert biodiversity. In this study, black and green Ammopiptanthus nanus seeds were used to study the germination and viability of newly harvested seeds and their storage by three methods. The results indicated that the germination rate of the newly harvested seeds increased with an increase in temperature, and the viability of the newly harvested seeds reached 100%. There was a significant difference in the germination of seeds with the two colors under dry-cold and -hot storage conditions, with green seeds showing significantly higher germination rates compared with black seeds (P<0.05). However, there was no significant difference in germination under wet-cold storage conditions. Wet-cold storage promoted seed germination, whereas dry-cold and -hot storage resulted in inhibition. The three storage methods had little effect on the viability of either color seed, and viability after storage was >95%. Temperature and humidity are important ecological factors that influence seed germination and viability in Ammopiptanthus nanus. The difference in seed germination represents a strategy for adapting to harsh habitats, which is conducive to increasing its survival and reproduction ability. Wet-cold storage increases the seed germination rate and maintains viability, thus providing valuable technical guidance for the conservation of germplasm resources and nursery breeding.
Invasive plants have significantly impacted the function and biodiversity of the global ecosystem. In the context of global climate change, the effective control of invasive plants is important for maintaining the stability of grassland ecosystems. The spectral differences between invasive plants and native dominant species during phenological stages provide an opportunity for remote sensing technology to monitor their spatiotemporal distribution. Previous studies have primarily focused on single-phase monitoring and the classification of plants, with relatively fewer studies on multitemporal continuous monitoring, particularly during early phenological stages. In this study, we focused on Pedicularis kansuensis, an invasive species of the Bayinbuluk grassland of Xinjiang, using UAV-based multispectral data and machine learning algorithms to extract spatial distribution data for P. kansuensis during key phenological stages in 2023 (emergence, initial flowering, peak flowering, and senescence stages) and the peak flowering stage in 2024. We examined the feasibility of extracting P. kansuensis at each phenological stage and analyzed changes in inter-annual spatial distribution. The results indicated that (1) The random forest algorithm slightly outperformed the support vector machine, with model accuracy varying with the growth stages of P. kansuensis; specifically, peak flowering stage (late July to late August) > initial flowering stage (late June to early July) > emergence stage (mid-June) > senescence stage (mid-September). Throughout the growth season, spatial distribution during the early growth stages (emergence and initial flowering) exhibited a high spatial overlap with the peak flowering stage, and the key features were consistent with those of the peak flowering stage. This suggests that the random forest algorithm can effectively map the distribution of P. kansuensis during the emergence stage, which provides important technical support for the early-stage monitoring of invasive plants; (2) The spatial distribution of P. kansuensis exhibited significant inter-annual variation, with less than 15% spatial overlap between the two years; (3) During the growth season, the most important feature for distinguishing P. kansuensis (excluding the senescence stage), from other co-occurring species was the normalized difference index, calculated from the 555 nm and 720 nm bands, followed by the green band. Because P. kansuensis had entered the senescence stage, there was a noticeable change in feature importance, with significant differences in various background environments. These results demonstrate the feasibility of using UAV-based multispectral remote sensing technology for monitoring the early phenological stages of P. kansuensis and offer technical support for early warning and control measures.
Water supply services sustain the survival and development of human society and are key to promoting the construction of China’s ecological civilization and the high-quality development of river basins. As a significant component of ecosystem services, it is central to ensuring the stability of watershed ecosystems and promoting the construction of ecological civilization in arid and semi-arid regions. This study focuses on the Ili River Valley in Xinjiang, analyzing the equilibrium characteristics of water supply and demand from 2005 to 2020. Using statistical yearbook and remote-sensing data, we apply models of water supply services, the water resources security index (FSI), and supply-demand matching analysis. The results indicate: (1) The FSI of the Ili River Valley fluctuates from “rising to falling,” and the supply-demand balance exhibits a three-stage evolution from “general deficit to general surplus to deficit persistence.” The spatial difference is significant: five counties and cities continue to deficit (i.e., Yining City, Yining County, Huocheng County, Qapqal Xibe Autonomous County, and Xinyuan County), while three counties and one city (i.e., Nilek County, Tekes County, Zhaosu County, and the city of Horgos [2020]) maintain the surplus that appeared in 2010 during the surplus inflection point. (2) The match between water supply and demand presents three dominant types: “low supply-high demand,” “low supply-low demand,” and “high supply-low demand.” The spatial distribution of supply-demand matching types is differentiated by gradients in the east, middle, and west. Counties and cities with the same matching types display spatial agglomeration and industrial convergence. They are significantly driven by the regional economic structure, which manifests in the following ways: the livestock areas with superior ecological fundamentals maintain a high supply capacity, while the arable land-intensive agricultural areas continue to face high demand pressure. To support regional sustainable development, this study analyzes county-level water supply-demand matching in the Ili River Valley, considering socioeconomic and natural geographic factors. Based on the analysis, ecological management zones—conservation, control, and improvement—are defined to promote integrated development, ecosystem sustainability, and efficient water resource use.
The sandy lands of northeastern China, located near the edge of the East Asian monsoon zone, are highly sensitive to climate change, making them ideal for investigating the evolutionary history of regional aeolian processes. This study presents optically stimulated luminescence dating of aeolian sediments from two representative profiles situated near the edge of the Horqin Sandy Land (KE) and the Otindag Sandy Land (HS). By integrating sedimentary facies data from the two profiles with additional regional paleoenvironmental records, we reconstructed the regional aeolian evolution history and examined the factors influencing sand and paleosol formation. The results revealed that: (1) The KE profile indicated the development of dark black sandy paleosols between about 9.8 and 3.0 ka, likely reflecting weak aeolian activity. In contrast, thick light gray sandy paleosols formed from around 0.2 ka, indicating intensified aeolian activity and continuous reworking of surface sediments, preventing older deposit formation. (2) In the HS profile, gray-yellow aeolian sand layers were deposited around 13.4 ka, 1.2-0.5 ka, and since 0.5 ka, indicating episodes of strong aeolian activity. Dark black sandy paleosols formed between about 11.6 and 1.9 ka, corresponding to a period of weaker aeolian activity. (3) Since about 13.4 ka, the region has undergone three stages of climatic and aeolian evolution: (i) a warming period from 13.4 ka to the early Holocene, associated with relatively strong aeolian activity; (ii) a warm and humid midHolocene, marked by reduced aeolian activity; and (iii) a late Holocene period of fluctuating cooling, during which aeolian activity increased again. (4) Variations in the timing of dark black sandy paleosol development between the KE and HS profiles, compared with records from the central parts of these sandy lands, suggest that regional topography and paleoclimatic differences may significantly influence aeolian sediment development.
In arid areas, farmlands are few, water-holding capacity is poor, seepage is considerable, and crop yield is low. Understanding soil moisture movement in sandy loam farmland is crucial for conserving water resources and enhancing crop yields. This study focused on the sandy loam maize farmland in the middle reaches of the Heihe River, and three experimental plots—flat film irrigation, ridge mulching irrigation, and drip irrigation under film irrigation—were set up. The HYDRUS-2D model was used to simulate the soil moisture migration process of the maize farmland under different irrigation modes. The results revealed that: (1) The simulated values of the HYDRUS-2D model agreed strongly with the measured data, with R2 reaching more than 0.864 and RMSE remaining below 0.006 cm3·cm-3, which verified the feasibility and reliability of the model in the dynamic simulation of soil moisture in sandy loam farmland. (2) Compared with the flat land mulching irrigation mode, the ridge mulching irrigation mode could increase the soil volume water content of the crops’ root zone by about 20% and reduce the seepage loss by 13.3% when the irrigation water volume was reduced by 2099 m3·hm-2. Compared with the flat land mulching irrigation mode, the drip irrigation mode under film irrigation could reduce the irrigation water consumption by 50% and the leakage by 50.7%. (3) The drip irrigation mode under film displayed “frequent irrigation and small amount” so that the water could be more directly and efficiently replenished in the crops’ root zone, which significantly improved the soil volume water content in the root zone of maize and further reduced the seepage. The sandy loam farmland in the middle reaches of the Heihe River should be irrigated by drip irrigation under film to save water and increase yield. (4) The HYDRUS-2D model’s parameter system can also provide a reference for the dynamic simulation of irrigation water in the same type of sandy loam farmland in northern China.
The damaging pest Agrilus viduus Kerremans was recorded for the first time in Ili Prefecture, Xinjiang. This pest has entered the core area of wild fruit forest, where it has damaged wild apples and wild apricots. Through field surveys, fixed-point observations, and laboratory rearing, the distribution range, life history, damage characteristics, and host plants of this pest in the wild fruit forest area were preliminarily studied. This pest is distributed in Xinyuan County, Gongliu County, Huocheng County, and Tekes County and has entered the wild fruit forests of Xinyuan County, Gongliu County, and Huocheng County. In terms of its reproduction, this pest exhibits one generation per year, starts to be active in the first half of May and begins to emerge in early July, with the peak emergence period in late July. Adult insects start to lay eggs in mid-July, and the emergence process ends in early August. In early November, the second-and third-instar larvae begin to overwinter. The damage mainly takes the form of larvae boring into the phloem, cambium, and xylem of host plants. When substantial infestation occurs, death of the host can occur. This pest can damage wild apricots, wild apples, and some other economically important fruit trees in the wild fruit forest. The oviposition characteristics of this pest are rather special. Eggs are laid in clusters on the bark surface and then covered with secretions to form egg cases. The distribution of this species’ egg cases is highly correlated with the height of apricot trees, with them mainly being found at heights of 120-240 cm; the distribution of the egg cases is also related to the basal diameter, being found mainly on branches with diameters of 2-3 cm. A literature review and field investigation revealed that this insect is a pest that has been newly introduced into the wild fruit forest of Xinjiang, posing a significant threat and requiring the attention of local authorities. There is an urgent need for physical control, biological control, and chemical control methods to be applied to eradicate it in accordance with its biological characteristics.
