Table of Content

15 January 2023, Volume 40 Issue 1 Previous Issue    Next Issue

Weather and Climate

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Annual relationship between the West Asian subtropical westerly jet and summer precipitation over the Three River Source region HUANG Xiaomei, QI Dongmei, LI Di, SUN Yi, LYU Chunyue 2023, 40 (1):  1-8.  doi: 10.13866/j.azr.2023.01.01 Abstract ( 308 )   HTML ( 16 )   PDF (11771KB) ( 112 )   Based on the monthly gridded precipitation in China and monthly ERA-interim reanalysis dataset from 1979 to 2018, the annual relationship between the position and intensity of West Asian subtropical westerly jet (WASWJ) and summer precipitation over the Three River Source (TRS) region and their corresponding physical mechanism are discussed. The results show that the position and intensity of WASWJ have evident interannual and interdecadal variability. The position of WASWJ is characterized by north-south oscillation before 2000s and dominated by southerlies during and after 2000s. On the interannual time scale, the position of WASWJ is more important than its strength in influencing summer precipitation over the TRS region. When the WASWJ locates at latitudes more southern than normal (more northern than normal), the summer precipitation over the TRS is higher (less). Further analysis shows that when the WASWJ moves southward, the anomalous upper-level positive and middle-level negative geopotential height and significant ascending movement over the TRS region favor the development of the plateau low-value system. The combination of the anomalous southerly flow in the east of anomalous cyclonic circulation at the middle to lower troposphere, which is beneficial for the warm and humid air flow from tropical ocean to the TRS region, increases precipitation and vice versa. Figures and Tables | References | Related Articles | Metrics

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Analysis of winter snowfall variability and its influencing factors on the north slopes of the middle Tianshan Mountains MIAO Yunling, YU Yongbo, HUO Da, PAN Cunliang, LI Ruqi 2023, 40 (1):  9-18.  doi: 10.13866/j.azr.2023.01.02 Abstract ( 270 )   HTML ( 20 )   PDF (6631KB) ( 152 )   Based on the observation data of daily precipitation and temperature elements in winter from 1978 to 2020 from 17 national meteorological stations, the spatial-temporal variation characteristics of winter snowfall and its relationship with meteorological factors in the economic belt on the north slope of the middle Tianshan Mountains were analyzed by using various statistical methods. The results show that: The regional distribution of snowfall days and snowfall amount is similar, showing the distribution characteristics of ‘more urban areas, less mountainous areas’. The decrease of light snow days is the direct reason for the decrease of total snow days, while the significant increase of moderate snow and blizzard is the main reason for the increase of total snowfall. The precipitation process lasting for 1 day is the main snowfall process in winter. With the increase of the duration, the precipitation process decreases significantly, and the precipitation process ≥ 5 days only accounts for 2.8%; In the past 43 years, the climate on the north slope of Tianshan Mountains has shown an obvious warming and humidifying trend. In 1987 and 1994, the amount of snowfall changed from less to more and the average temperature changed from lower to higher; The amount of snowfall is significantly and positively correlated with the annual precipitation, the average minimum temperature in winter, and the number of snowfall days. The greater the annual precipitation, the lower the minimum temperature in winter, and the more snowfall days, the greater the amount of snowfall in winter, and vice versa. Figures and Tables | References | Related Articles | Metrics

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The response and mechanism of Pinus tabulaeformis tree-ring width to climate change in Maijishan Mountain, Tianshui, China YAO Daijun, LIU Kang, HUI Yuxiang, WANG Kaixin 2023, 40 (1):  19-29.  doi: 10.13866/j.azr.2023.01.03 Abstract ( 335 )   HTML ( 6 )   PDF (6047KB) ( 106 )   In recent decades, an unusual reduction in forest radial growth and temperature sensitivity has been widely observed in the northern high latitudes. Several studies have also suggested that unstable and nonlinear relationships exist between tree growth and its climatic drivers at mid-latitudes and even globally. However, this relationship remains poorly understood, particularly in the mid-latitudes. The climate response and growth process before and after the temperature abrupt change were investigated using dendroclimatological methods and the Vaganov-Shashkin model in order to research the variations and mechanisms of response of radial growth of Pinus tabulaeformis to climate factors in Maijishan Mountain, Tianshui, during 1980-2019. The findings revealed that: (1) According to the Mann-Kendall test, temperature changed abruptly in 1997 and then increased significantly. During 1980-1997 and 1998-2019, there were three patterns of response in radial growth to climate factors revealed in the variation in correlation with climatic factors: decline (Temperature in May), increase (Temperature and precipitation in October, precipitation in July and temperature in December), and fluctuation (Precipitation in June and temperature in July). (2) The Vaganov-Shashkin model estimated chronologies are significantly correlated with the measured tree-ring chronologies before and after the abrupt change (P<0.05). According to simulation results, significant climate warming resulted in more abundant heat supply for growth in spring and autumn, thereby significantly extending the growing season and potentially causing a change in response patterns in May and October. Furthermore, summer high temperatures and water scarcity impacted growth, potentially leading to a change in response patterns in July. (3) The change in response patterns to climate factors is primarily caused by climate warming and the lengthening of the growing season. If the climate continues to warm, the response patterns are expected to change, even more, and similar behavior may exist in other areas where the species is found. Figures and Tables | References | Related Articles | Metrics

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Quantify the impacts of four land cover types on surface temperature in the Heihe River Basin LI Erchen, ZHANG Yu, YUAN Guanghui 2023, 40 (1):  30-38.  doi: 10.13866/j.azr.2023.01.04 Abstract ( 288 )   HTML ( 9 )   PDF (4908KB) ( 99 )   Micrometeorological observations at four sites in the Heihe River basin from June to September 2012 are used to evaluate the direct decomposed temperature metric (DTM) theory and the intrinsic biophysical mechanism (IBPM), as well as to investigate the biophysical effects of land use and land cover change on surface temperature. Through the Heihe Watershed Allied Telemetry Experimental Research (HiWATER) project, the four sites were outfitted with Eddy Covariance Systems and other conventional weather instruments. The desert has the highest land surface temperature both daytime and nighttime. Compared to the desert site, the non-desert sites have average surface cooling effects of -17.8 K and -1.8 K during daytime and nighttime. Both the DTM and IBPM theories are founded on the surface energy balance equation; however, the energy balance ratios at the four sites range between 80% and 90% during the day and less than 30% at night. To revise the two theories, we distribute the imbalance term to the sensible and latent heat fluxes in proportion to the Bowen ratio. The biophysical effects of different types of land on surface temperature are then investigated by comparing the quantitative results of the two revised theories. The calculated surface temperature of DTM theory and IBPM theory agrees well with the observed results after forcing the energy balance closure to the fluxes, especially at night. The revised IBPM theory matches the observed results better than the revised DTM theory. The revised IBPM results show that the non-radiative effect related to the partitioning of available energy plays a significant role in the daytime cooling effect of non-desert sites. Changes in aerodynamic roughness (mean -4.97 K) and Bowen ratio (mean -2.43 K) both contribute a cooling signal during the day, and these cooling effects even outweigh the warming effects of the radiation term (mean +5.21 K). At night, the direct biophysical effects are weaker than during the day, and the indirect effects of the atmospheric background can even offset the direct biophysical effects. Figures and Tables | References | Related Articles | Metrics

Land and Water Resources

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Analysis of the characteristics of runoff evolution and its driving factors in a typical inland river basin in arid regions CHEN Hongguang, MENG Fanhao, SA Chula, LUO Min, WANG Mulan, LIU Guixiang 2023, 40 (1):  39-50.  doi: 10.13866/j.azr.2023.01.05 Abstract ( 209 )   HTML ( 16 )   PDF (11696KB) ( 73 )   The Ulagai River Basin in Inner Mongolia is a typical inland river basin in the pastoralist grasslands of the arid and semi-arid regions with extremely fragile ecosystems, and climate warming and human activities can directly affect hydrological changes. In this study, we used the improved SWAT (Soil and Water Assessment Tool) hydrological model, M-K trend test, precipitation-runoff double accumulation curve, and scenario analysis to systematically analyze the spatial and temporal characteristics of runoff in the Ulagai River Basin from 1981 to 2020 and to quantify the differences between climate change and human activities on runoff in different periods and river sections. The differences in the impact of climate change and human activities on the runoff in different periods and river sections were quantified. The results show that the SWAT model significantly impacted runoff in the Ulagai River Basin from 1981 to 2020. The results show that the SWAT model has good applicability in the Ulagai River Basin, with NSE and R2 above 0.62 and PBLAS less than 18.8% for both the periodic and validation periods. Under the warm and dry trend of the basin in the past 40 years, the runoff volume decreased significantly in the upper, middle, and lower reaches, then a sudden change occurred in 2000. Considering the contribution of human activities such as climate change and overgrazing, blind reclamation and construction of water conservancy reservoirs to the change of runoff in the basin was 95.84% and 4.16%, respectively. Also, the contribution of human activities to different river segments in the basin varied, with 1.69%, 4.36%, and 5.03% from upstream to downstream. The contribution rates also differed significantly across different periods, from 88.26% in 1980 to 25.47% in 2020. The trend and magnitude of runoff changes due to different human activity patterns in different periods also differed. This study’s results can provide a reference basis for the sustainable use and rational scheduling of water resources in the inland river basin of pastoral grasslands. Figures and Tables | References | Related Articles | Metrics

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Analysis of differences in pumping depth in sand diving aquifers over different time periods ZHOU Shenghui, LIU Tingxi, DUAN Limin, JI Ru, LIU Xiaoyong 2023, 40 (1):  51-58.  doi: 10.13866/j.azr.2023.01.06 Abstract ( 170 )   HTML ( 5 )   PDF (2885KB) ( 66 )   We carried out long-term water level monitoring of a well in the quaternary sandy aquifer of Maowusu Sandy Land in China, selected four pumping processes of this well at different times in 1 year, analyzed the differences in the pumping and depth reduction processes, and systematically analyzed the possible factors of such differences. On the basis of multiple influencing factors, the main controlling factors of the differences in the depth of sandy diving aquifer were clarified, and the hydrogeological characteristics of the fourth-series diving aquifer in the Hailiutu River Basin at different times were effectively revealed. We introduced the Bland-Altman method to this study for the first time and used it to quantitatively analyze the difference between the pumping depth reduction processes. Moreover, we applied the traditional wiring method to solve hydrogeological parameters and the water level restoration method to solve the hydrogeological parameters of the quaternary aquifer for differentiation. Finally, this paper analyzed the main reasons for differences in the pumping depth by evaluating the aquifer thickness, hydraulic slope, groundwater reserves, and precipitation recharge at the watershed scale. Results showed that the variation range of water conductivity coefficient of the quaternary phreatic aquifer in Hailiutu River Basin of Mu Us Sandy Land is 3.00-4.85 m2·h-1 and the infiltration and replenishment of the vadose belt by precipitation before pumping is the main controlling factor for the differences in pumping depth. Figures and Tables | References | Related Articles | Metrics

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Spatial and temporal analysis of soil salinity in Yutian Oasis by combined optical and radar multi-source remote sensing XIAO Sentian, Ilyas NURMEMET, Nuerbiye MUHETAER, Zhao Jing, Adilai ABULAITI 2023, 40 (1):  59-68.  doi: 10.13866/j.azr.2023.01.07 Abstract ( 352 )   HTML ( 21 )   PDF (14376KB) ( 101 )   Soil salinization is currently a prominent global environmental problem. Spatiotemporal variation of soil salinization in Yutian Oasis was explored, and the advantages of radar remote sensing in excavated soil salinity were investigated to monitor and evaluate the temporal and spatial variabilities of soil salinization in arid oasis. Based on Phased Array type L-band Synthetic Aperture Radar 2 (PALSAR-2), Sentinel-1 polarimetric synthetic aperture radar data, and Landsat 8 Operational Land Imager (Landsat 8 OLI) multi-source dataset, the optimal backscattering characteristics of radar images were selected, and optical images were combined based on principal component analysis. Finally, the random forest method was used to classify the images. Quantitative extraction of soil salinization information in Yutian Oasis and the spatial and temporal variation of soil salinization were analyzed. Results showed that (1) under the random forest classification approach, the total accuracy of optical images in each year was 80.36%, and the kappa coefficient was 0.77. The classification accuracy of optical images combined with radar images was higher than that of optical images, the total accuracy was 85.62%, and the kappa coefficient was 0.82. (2) From 2015 to 2021, the area of salinized soil in Yutian Oasis was mainly distributed in the north of the study area, interlaced edge of the oasis, and desert. (3) The average annual variation of saline land area from 2015 to 2021 was -1120.55 hm2·a-1, and the change rate was -10.67%. The salinization of Yutian Oasis generally showed a downward trend and was mainly mild to moderate saline land. Figures and Tables | References | Related Articles | Metrics

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Study on the change and prediction of spatiotemporal pattern of land use in Manasi region based on deep learning WANG Jiaojiao, YIN Xiaojun, LIU Shannan, WANG Dimeng 2023, 40 (1):  69-77.  doi: 10.13866/j.azr.2023.01.08 Abstract ( 382 )   HTML ( 27 )   PDF (4767KB) ( 211 )   Land use change and prediction are crucial for land resource management and optimization. In this paper, based on remote sensing spatial and temporal series data, a synergistic landscape index and long short-term memory (LSTM) model were used to characterize and predict the evolution of spatial and temporal patterns of land use in the Manasi region over a long time series. Results showed that (1) from 1992 to 2020, the cropland, grassland, and building land increased, and tree cover, water bodies, and unused land decreased. (2) The degree of fragmentation of arable land gradually decreased. The landscape indices of tree cover and water bodies were in a state of slight fluctuation. Grassland aggregation increased, fragmentation decreased, and the shape exhibited regularization. The landscape index of building land showed the most dramatic state of continuous expansion, with a deepening fragmentation and a tendency for complex shapes. The fragmentation of unused land gradually increased, but the shape tended to be regular. (3) Different models for predicting land use change, including the LSTM, multi-layer perception artificial neural network, logistic regression, and CA-Markov models, were compared. The Kappa coefficient of the LSTM model was 95.31%, which is more accurate than that of other models and consistent with the actual land use pattern. The LSTM model suggests that in 2025, land use types will still be dominated by cropland, grassland, and unused land. Figures and Tables | References | Related Articles | Metrics

Plant Ecology

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Growth promotion and mechanism of arbuscular mycorrhizal fungi (AMF) on Ammopiptanthus mongolicus seedlings WANG Zixuan, XIE Tiantian, WANG Yaru, YANG Jieyan, YANG Xiuqing 2023, 40 (1):  78-89.  doi: 10.13866/j.azr.2023.01.09 Abstract ( 337 )   HTML ( 8 )   PDF (5510KB) ( 94 )   To solve the technical problems of underdeveloped root systems, poor regeneration, and low survival rate of transplanting and afforestation of Ammopiptanthus mongolicus seedlings, as well as the effective propagation and preservation of its resources. In this experiment, AMF were used to treat the roots of Ammopiptanthus mongolicus seedlings using different inoculation methods. The infection status of AMF, the changes in plant growth and biomass, the physiological characteristics of roots and leaves, the changes in rhizosphere soil enzyme activities, and their correlation with seedling growth and biomass were analyzed. This study aimed to explore the growth promotion and mechanism of root mycorrhization in Ammopiptanthus mongolicus. The results showed that AMF (Rhiaophagus intraradice, Funneliformis mosseae) could effectively infect the roots of Ammopiptanthus mongolicus seedlings and construct a mutualistic symbiont with their roots. The degree of affinity between different strains and host plants varies. (1) The growth of single and mixed inoculations was higher than that of non-inoculation (CK), which was mainly reflected in the relatively large plant height (34.7%-47.3%) and root length (32.7%-72.9%). Compared with single inoculation, mixed inoculation significantly increased the root projection area, root volume, root-shoot ratio, root dry weight, root surface area, biomass, and seedling quality index. (2) After AMF inoculation, the root activity, cation exchange capacity, and soluble protein content of the mixed inoculated seedlings (R. i+F. m) increased significantly by 338.7%, 177.2%, and 240.4% compared with the control. The nitrate reductase and alkaline phosphatase activities of the roots were also significantly higher than those of the single inoculated (R. i and F. m) and non-inoculated seedlings. Simultaneously, the net photosynthetic rate and soluble protein content in the leaves of seedlings under this treatment increased significantly by 237.5% and 54.3% compared with the control. (3) The activities of urease, alkaline phosphatase, and invertase in the rhizosphere soil of Ammopiptanthus mongolicus seedlings increased significantly using the three inoculation methods, and the enzyme activities of the three soils increased most significantly under the mixed inoculation treatment, surging by 564.7%, 145.8%, and 154.3%, respectively, compared with the control. The comprehensive analysis of the above indicators, AMF could stimulate the production and secretion of enzymes in the rhizosphere of seedlings and promote the cation exchange capacity and root activity by infecting the Ammopiptanthus mongolicus roots, which was helpful in enhancing the enzymatic effect and nutrient accumulation, such as proteins in the process of root metabolism, and affected and improved the photosynthetic metabolism and nutrient storage of seedlings, to promote the growth and biomass accumulation of roots and seedlings of Ammopiptanthus mongolicus. Figures and Tables | References | Related Articles | Metrics

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Effects of spraying 6-BA on senescence of Nitraria tangutorum leaves at different planting densities JIN Wei, WANG Chenlin, REN Yuchen, ZHANG Huifang, YANG Xiuqing 2023, 40 (1):  90-101.  doi: 10.13866/j.azr.2023.01.10 Abstract ( 231 )   HTML ( 7 )   PDF (8427KB) ( 32 )   To explore the effect and mechanism of 6-BA and planting density on leaf senescence of Nitraria tangutorum, after spraying 6-BA of different concentrations (0, 10, 20, and 30 mg·L-1) on Nitraria tangutorum under two planting densities (low density plant spacing: 1.2 m × 1.5 m, high density plant spacing: 0.8 m × 1.0 m), we studied the dynamic changes and variation in leaf photosynthetic parameters (Pn, Tr, Gs, and Ci), chlorophyll, leaf osmoregulation substance content (Pro and SP), active oxygen metabolism, and antioxidant enzyme activity. Results showed that under 20 mg·L-1 6-BA treatment, the Pn, Tr, and Gs of Nitraria tangutorum planted at low density were significantly higher than those without 6-BA treatment by 37.72%, 117.94%, and 83.18%, respectively, and Ci was significantly lower by 32.29% than that of the control. Compared with the physiological indices related to leaf senescence under the two planting densities of other 6-BA treatments, the 20 mg·L-1 6-BA treatment of Nitraria tangutorum planted at low density can effectively promote the synthesis of Chl and SP in the early stage of leaf development (period t1 to t3); effectively alleviate the degradation of Chl, SP, and Pro; and inhibit the increase in malondialdehyde and H2O2 content in the later stage (period t4 to t5). Under the treatment of 10 and 20 mg·L-1 6-BA, the antioxidant enzymes in the early growth stage of Nitraria tangutorum can be promoted, or their peroxidase, superoxide dismutase, and catalase activities can be increased. In addition, the decline in enzyme activities in the later growth stage of Nitraria tangutorum can be slowed down. The activities of the three enzymes treated with the same concentration of 6-BA showed low density > high density. The analysis of principal components and membership functions revealed that the anti-senescence ability of leaves under low density planting was the strongest when the leaves were treated with 20 mg·L-1 6-BA every 10 days (eight times in total) from flower budding to fruit shedding. Spraying of 6-BA and reduced planting density can be used as important technical measures to alleviate leaf senescence and realize efficient planting and effective resource exploitation. Figures and Tables | References | Related Articles | Metrics

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Responses of seedling growth and biomass allocation of Malus sieversii to precipitation amount and precipitation interval ZHANG Zongfang, XU Jiang, SHI Xiaojun 2023, 40 (1):  102-110.  doi: 10.13866/j.azr.2023.01.11 Abstract ( 212 )   HTML ( 4 )   PDF (3294KB) ( 83 )   This study aimed to reveal the effects of different precipitation amount and precipitation interval on the growth of Malus sieversii seedlings. A two-factor control experiment was set up based on the average annual precipitation amount and precipitation interval in the experimental site. The three variations of precipitation amount were as follows: W (precipitation amount), W- (15% decrease of precipitation amount), and W+ (15% increase of precipitation amount). The two precipitation intervals were as follows: T (precipitation interval of 4 days) and T+ (precipitation interval of 8 days). Results showed that (1) under the same precipitation interval treatment, seedling basal diameter, leaf number, and above-and under-ground biomass increased with the increase in precipitation amount; (2) under the same precipitation amount treatment, T+ treatment can promote the elongation of the main roots and increase the root/shoot ratio; and (3) compared with W treatment, the relative growth rates of above-ground, under-ground, and total biomass under W+ treatment increased by 55.42%, 20.75%, and 34.43%, respectively. Prolonging the interval of precipitation will promote root growth and under-ground biomass accumulation of M. sieversii seedlings. Within a certain range of precipitation, the increase in precipitation amount can promote the growth and biomass accumulation of M. sieversii. Figures and Tables | References | Related Articles | Metrics

Ecology and Environment

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Identification of priority areas for forest land expansion in Shanxi Province MENG Na, ZHANG Ying 2023, 40 (1):  111-122.  doi: 10.13866/j.azr.2023.01.12 Abstract ( 207 )   HTML ( 2 )   PDF (29514KB) ( 24 )   Over the past 70 years, large-scale afforestation activities have been conducted in arid and semi-arid areas in China with remarkable success, but localized afforestation has failed due to regional human activities and climatic influences. Although the potential for afforestation in arid areas is recognized, it is unknown in which micro-region afforestation should be concentrated. Taking Shanxi Province, a typical region of the Loess Plateau, as an example, this study constructs a framework for the identification of forestable land and uses the PLUS and Markov models to simulate land use changes under different scenarios in 2030, analyzing woodland expansion, trends in internal changes in forest stands, and spatial distribution. The results show that: The current space for woodland growth in Shanxi Province is 5.38%, and the southeast is the main potential growth area; there is a possibility of woodland degradation at the edges of woodlands in the central and western parts of the province, while the degree of woodland fragmentation in the north is higher; the frequency of intra-forest conversion is higher; in order of expansion potential, there are woodland > shrubland > open woodland > other woodlands. In this context, a cautious attitude is taken toward large-scale afforestation in Shanxi Province. This study can provide a reference for effective afforestation management and enhancement of forest carbon sequestration levels in the Shanxi Province. Figures and Tables | References | Related Articles | Metrics

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Simulation of spatial pattern and future trends of grassland net primary productivity in the Loess Plateau based on random forest model LIU Huanhuan, CHEN Yin, LIU Yue, GANG Chengcheng 2023, 40 (1):  123-131.  doi: 10.13866/j.azr.2023.01.13 Abstract ( 291 )   HTML ( 46 )   PDF (10248KB) ( 100 )   The accurate estimation of grassland net primary productivity (NPP) is crucial to understanding the carbon cycle of grassland ecosystems and their adaption to climate change. Based on 1788 grassland biomass data and 19 environmental factors (climate, vegetation, soil, and topographic factors), we simulated the spatiotemporal dynamics of grassland NPP in the Loess Plateau from 2002 to 2020 using the random forest (RF) model. The future trends of grassland NPP under four future climate scenarios of shared socioeconomic pathways were estimated. Results showed that (1) the RF model had a good accuracy, which indicated that RF can be used to estimate grassland NPP in the Loess Plateau; (2) grassland NPP in the Loess Plateau exhibited a “high in southeastern and low in northwestern” pattern, with a mean value of 276.55 g C·m-2·a-1. The highest grassland NPP was observed in Guanzhong Plain of Shaanxi; (3) the grassland NPP in the Loess Plateau showed an overall increasing trend during 2002-2020. Regions experiencing an increase in grassland NPP accounted for 55.01% of the total land area, which is mainly located in Guanzhong Plain, western Gansu, and northern Shanxi; (4) under the wetter and warmer climate, grassland NPP in the Loess Plateau will continually increase by the end of this century. Grassland NPP will increase the most under the SSP585 scenario and the least under the SSP126 scenario. RF can be used to simulate the temporal and spatial trends of grassland NPP in the Loess Plateau. The results provide data support for the protection and sustainable development of grassland ecosystem in the Loess Plateau. Figures and Tables | References | Related Articles | Metrics

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Effect of spatial reconstruction of “production-living-ecology” space and precipitation changes on water yield services in the Yellow River Basin in Shanxi Province JI Qianqian, PAN Huanhuan, WU Shurong, WU Zhitao, DU Ziqiang 2023, 40 (1):  132-142.  doi: 10.13866/j.azr.2023.01.14 Abstract ( 234 )   HTML ( 2 )   PDF (9959KB) ( 52 )   The Yellow River Basin in Shanxi Province is an important energy and chemical industry base in China. In recent years, the basis has been faced with serious soil erosion and water shortage. The study of water yield services in this region can provide decision-making reference for the high-quality development of energy and chemical industries in the Yellow River Basin. Based on the integrated valuation of ecosystem services and trade-offs and scenario simulation method, this paper analyzed the impacts of production-living-ecology spatial and precipitation changes on watershed water yield services from 2000 to 2020. The results showed the following spatial pattern regarding the “production-living-ecology space” along the Yellow River Basin in Shanxi Province: Ecology space > production space > living space. The area of ecological space slightly decreased, agricultural production land significantly decreased, and the area of land used for industrial and mining production and urban and rural living lands significantly increased. The average water yields of the Yellow River Basin in Shanxi in 2000 and 2020 were 89.57 and 138.01 mm, respectively. The water yield increased from 2000 to 2020. The contribution rate of precipitation change to the change in water yield was 80.4%, and that of “production-living-ecology” space change to water yield was 19.6%. Figures and Tables | References | Related Articles | Metrics

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Effects of density and plant point distribution on shelter efficiency of artificial Haloxylon ammodendron forest NIU Danni, HAN Rong, MA Rui, WANG Zhenting, LIU Hujun, WEI Linyuan 2023, 40 (1):  143-151.  doi: 10.13866/j.azr.2023.01.15 Abstract ( 280 )   HTML ( 6 )   PDF (6000KB) ( 115 )   This study aimed to study the shelter efficiency of Haloxylon ammodendron windbreak with different density and plant point distribution to provide scientific basis for optimizing the structure of windbreak in arid areas. With the field Haloxylon ammodendron as the prototype, windbreaks with three stand densities and four plant point distributions were designed, and their flow field and shelter efficiency were measured and analyzed by wind tunnel experiments. The corresponding label and “plant spacing × row spacing” of the windbreaks were as follows: A: 17 cm × 17 cm, B1: 34 cm × 17 cm, B2: 17 cm × 34 cm, and C: 34 cm × 34 cm. Results showed that (1) the area of wind speed deceleration region (U/U0 < 1) accounted for 78.06%, 70.41%, 74.36%, and 82.80% of the whole flow field of A, B1, B2, and C windbreaks, respectively; the area of weak wind speed region (U/U0 < 0.4) accounted for 22.46%, 0.73%, 5.91%, and 0%. (2) The higher the stand density, the lower the average wind speed under the canopy, but the faster the wind speed recovered at the leeside of windbreaks. The minimum wind speed was located at 11H, 15H, 15H, and 20H behind the A, B1, B2, and C windbreaks, respectively (H was the tree height). (3) The order of shelter efficiencies of the four windbreaks from large to small was A > B2 > B1 > C. The relationship between shelter efficiency and stand density was nonlinear. The ratio of wind reduction at the near surface was A:B:C≈6:3:2 behind the windbreaks. The density of afforestation should be determined based on the soil water carrying capacity in the practice of forestation. On this basis, the plant point distribution mode of “small plant spacing, large row spacing” should be preferred. Figures and Tables | References | Related Articles | Metrics

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Study on evapotranspiration of cotton field under drip irrigation in oasis of arid region LIU Yanxue, QIAO Changlu 2023, 40 (1):  152-162.  doi: 10.13866/j.azr.2023.01.16 Abstract ( 257 )   HTML ( 22 )   PDF (4312KB) ( 110 )   Crop evapotranspiration is the main way of water consumption in the process of farmland water cycle in arid region. It plays an important role in the study of the law of water consumption and formulating scientific irrigation systems under climate change in arid regions. A large-scale weighing lysimeter was used to monitor evapotranspiration of drip irrigation cotton field for 3 consecutive years. Drip irrigation under mulch film and no mulch film were compared to analyze the influence of film mulching and meteorological factors on evapotranspiration. Results showed that (1) in the whole growth period of cotton, the average evapotranspiration of drip irrigation cotton field under mulch film and under no mulch film were 292.15 and 429.22 mm, respectively. The method of drip irrigation under mulch film can reduce evapotranspiration by 31.95%. (2) The relationship between evapotranspiration and evapotranspiration intensity in different growth stages was as follows: blooming and boll stage > budding stage > boll opening stage > seedling stage. (3) The drip irrigation cotton field condenses from 00:00 to 08:00 and evaporated and transpired from 08:00 to 23:00. The evapotranspiration reached the maximum in the afternoon. The maximum appeared at the earliest stage in seedling stage, and at the latest in blooming and boll stage. (4) Evapotranspiration is positively correlated with wind speed, radiation, and temperature and negatively correlated with humidity and air pressure. (5) Rainfall can promote evapotranspiration in cotton fields under drip irrigation. Overall, drip irrigation under mulch film can effectively reduce the evaporation and improve the water use efficiency in the process of agricultural production. Figures and Tables | References | Related Articles | Metrics