Chinese Journal of Agrometeorology

Impact of Climate Change and Varieties Replacement on Maize Yield and Resource Use Efficiency in Xinjiang

WANG Yong, ZHANG Zhen-tao, ZHANG Fang-liang, GUO Shi-bo, YANG Xiao-guang

2020, 41(06): 331-344. doi:10.3969/j.issn.1000-6362.2020.06.001

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Studying the effect of varieties replacement on the heat and radiation resources use efficiency can provide a scientific reference for adapting to climate change.The Wulanwusu spring maize, Hami spring maize, Kashgar summer maize, and Korla summer maize in Xinjiang were selected as the research objects. Based on the meteorology data(1981-2019), maize field trial data(1981-2018) from agro-meteorological experiment stations, and soil data, the adaptability of APSIM-Maize model in the typical sites in Xinjiang was analyzed. The accumulated effective thermal time(AcTT) and accumulated photosynthesis radiation(AcPAR) during vegetative growing period(VGP), reproductive growing period(RGP), and whole growing period(WGP) of Xinjiagn spring maize and summer maize were calculated. Then, the influence of climate change on maize yield and heat/radiation resources use efficiency were analyzed under the scenarios of varieties replacement or notby the validated APSIM-Maize model. The results showed that: (1) the validated APSIM model had better adaptability in spring or summer maize development and yield formation at the typical sites in Xinjiang. (2)The AcTT and AcPAR in the WGP showed an increasing trend, of which spring maize mainly increased in the RGP, and summer maize mainly increased in the VGP. (3)The length of maize growing period was shortened, and yield was reduced by climate change. But the varieties replacement had alleviated these adverse effect and increased yield. Among them, the spring maize showed an extension of growing period, and the proportion of RGP in WGP was increased, while summer maize showed a decrease in the shortening trend of growing period. At the same time, the heat resources and radiation resources use efficiency during maize growing period were also significantly increased by varieties replacement.

Spatial and Temporal Variation Characteristics of Blue and Green Water Resources in Min-Tuo River Basin were Analyzed Based on SWAT Model

ZHANG Yang, DENG Yu, NI Fu-quan, NIE Chao, MA Jie

2020, 41(06): 345-356. doi:10.3969/j.issn.1000-6362.2020.06.002

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In recent years, the influenced by global climate change and common human activities, the hydrological cycle has changed into different degrees. In order to better understand the role of water resources in terrestrial ecosystems, the concepts of blue water and green water have been introduced. However, the traditional water resources assessment often focuses on the amount of blue water resources (surface runoff, soil runoff and underground runoff), and the green water (evapotranspiration water and soil water) which is important for the maintenance of terrestrial ecosystems is often neglected. The ecological process of the basin is organically coupled with the water cycle process of the basin through the link of blue and green water, which makes the water cycle and ecological process closely linked, and also reflects the relationship between vegetation and hydrological process.Therefore, this article is based on SWAT model, from the perspective of different land use types and the hydrologic cycle, simulation of large scale he river the blue water, green water resources in 1981-2014, explore he blue green water in time and space distribution characteristics of Min-Tuo river basin, the Man-Kendall (M-K) annual inspection analysis between water resources quantity change trend, simulation of blue green water resources under different land use scenarios. The results showed that :(1)from 1981 to 2014, the amount of green water resources in the Min-Tuo river basin increased, and the M-K statistical value was 0.0232, failing the significance test of M-K confidence degree of 90%. The blue water resources and precipitation in the basin showed a decreasing trend, and the M-K statistical values were -0.1729 and-0.1087, respectively, which failed to pass the significance test of M-K confidence degree of 90%, and the linear variation trend was not significant. (2) The spatial distribution trend of annual precipitation and blue and green water resources in the Min-Tuo river basin from 1981 to 2014 was basically the same. The amount of blue and green water resources in the basin gradually increased from north to south and then decreased, that is, the amount in the middle reaches was the most, followed by the amount in the downstream, and the amount in the upstream was the least. (3) The whole Min-Tuo river basin under the condition of rainfall, forest land, grass blue water resource fluctuations decrease, green water resources increase slowly, and in different land use types, blue, green water resource differences apparent, characterized by cultivated land > forest land > grassland, including arable land accounts for only 25% of total area of the basin, but the blue and green water resource of the contribution of the highest. It is proposed to strengthen the management of cultivated land in the Min-Tuo river basin, rationallutilize the blue and green water resources in the middle and lower reaches, and implement green water credit compensation measures in the arid and semi-arid areas in the upper reaches, so as to optimize the allocation of regional water resources.

Response of Radial Growth of Pinus tabulaeformis to Climatic Factors in the Lingkong Mountain, Shanxi Province

XU Ling-ling,TONG Xiao-juan,ZHANG Jin-song,MENG Ping,WANG Xin,LI Jun

2020, 41(06): 357-367. doi:10.3969/j.issn.1000-6362.2020.06.003

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In order to explore the response of Pinus tabulaeformis radial growth to climate change at different growth stages in the warm temperate subhumid zone, this paper conducted in the Lingkong Mountain of Shanxi Province,established the tree-ring standardized chronology from 1951 to 2018 in the area,and used correlation analysis to analyze tree-ring growth dynamics and its relationship with climate factors. The results showed that the tree rings of Pinus tabulaeformis contained rich and sensitive climate information, which was suitable for tree ring analysis. The response of the radial growth of Pinus tabulaeformis in different forest ages to climate was not same, and the sensitivity was in the order of over mature forest(0.354), young forest(0.338), middle age forest(0.324), near mature forest(0.308) and mature forest(0.297). The signal-to-noise ratio and the correlation coefficients of average phase of all sequences and average index of the over mature forest were larger than those of other age groups, reaching 23.803, 0.515 and 0.994, respectively. It is indicated that over mature forest was more suitable for studying ring climatology. The response function analysis showed that the young and medium forests were all sensitive to the climate factors of each month, while the near mature, mature and over-mature forests of Pinus tabulaeformis were more sensitive to precipitation and showed a significant correlation, and the correlation coefficient between radial growth and precipitation was greater than that between the young forest and the medium forest.The response function analysis showed that the radial growth of the young-aged forest has a significant negative correlation with maximum temperature and temperature amplitude in June, a significant positive correlation with minimum temperature in February and October, a significant positive correlation with precipitation in August, a significant positive correlation with the radial growth of middle-aged forest and the average lowest temperature in July, and a significant positive correlation with the temperature amplitude in January. The radial growth of near mature forest was positively correlated with precipitation in October of last year, but negatively correlated with precipitation in October of that year, and the correlation coefficient between the radial growth of Pinus tabulaeformis and precipitation in the later growth stage was greater than that of young-aged forest and middle-aged forest. The radial growth of mature forest was positively correlated with precipitation in July and August. The radial growth of over mature forest was positively correlated with precipitation in November of last year, and it had a significant negative correlation with precipitation in January and May of the same year with the correlation coefficients more than 0.7. The response of the ring width to climate variables of Pinus tabulaeformis in the Lingkong mountain was affected by age factors. Temperature and precipitation were the main factors affecting the radial growth of young and middle aged forests, while precipitation was the main factor restricting the xylem growth of near mature, mature and over mature forests.

Ecological Climate Suitability and PotentialDistribution for Tricholoma matsutakin Xiangcheng County, Sichuan Province

WANG Qing-li，HAN Yu-jiang，ZHANG Li-ping，LUO Ren-bin，YANG Wei-ming，WANG Ming-tian，GAO Gang, WANG Yan-qi

2020, 41(06): 368-380. doi:10.3969/j.issn.1000-6362.2020.06.004

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Tricholoma matsutak is a precious?edible and medicinalwild fungus withrich nutrition. Xiangcheng county is one of the main producing areas of T. matsutake, but its spatial distribution was not very clear for the vast area, sparse population, complex topography and most of the previous research methods were field surveys of typical areas. Based on the previous research results and field investigation, this paper summarized the suitability regionalization indices of the growth of T. matsutake in Xiangcheng county, such as altitude, temperature, precipitation, vegetation and terrain slope. Then, the climate ecological suitability and potential distribution of T. matsutake in this county were analyzed by using the spatial analysis method of Geographical Information System(GIS).The results showed that:(1)T. matsutake grows in 12 villages and towns,but its distribution areasare band-shaped and branch-like alongthe mountain range direction under the influence of the terrain and climate. The main producing areas are Baiyi, Reda, Dingbo, Zhengdou and Shagong in thecounty. (2)The altitude of the suitable area is from 3000 to 3900 meters above sea level, the average temperature is between 10.0and 14.5°C, and the precipitation ranges is 500-800mmfrom April to October. T.matsutake likes to grow in alpine oak forest, pine forest or mixed forest with medium and high coverage, and the slope of these forests should be 25°-35°. In the sub suitable area, the altitude is 2800-3000m or 3900-4200m, the average temperature is 7.5-10.0℃ or 14.5-16.0℃, the precipitation is 400-500mm or more than 800mm from April to October, and the vegetation is alpine oak forest, pine forest or mixed forest with low coverage, the slope of these forests should be 15°-25° or 35°-45°. Meadows or no vegetation areas are the unsuitable areas for T.matsutake.The suitable area accounts for 19% of the total area of the county, the sub suitable area accounts for 16% of the total area of the county, and the unsuitable area accounts for 65% of the total area of the county.(3)The most suitable weather condition for mushroom growing is sunny day and rainy night from late July to mid September. During this period, the average temperature is about 16℃, the total precipitation is about 260mm, the relative humidity is more than 70%, and the total sunshine hours are 228-255h.(4)The verificationresults showed that 92% of the villages and towns were consistent or basically consistent with the actual situation, which showed that the indicators of the zoning were reasonable. The conclusion of this study is of great significance to the picking, trade and resource protection of T. matsutake.

Assessment on the Freezing Injury Risk during Apple Flowering in Liquan and Xunyi

WANG Ming-chang, LIU Bu-chun, LIU Yuan, YANG Xiao-juan, HAN Shuai, QIU Mei-juan, LI qiong

2020, 41(06): 381-392. doi:10.3969/j.issn.1000-6362.2020.06.005

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Shaanxi province is an advantageous ecological area for apple cultivation and a high-risk area of freezing injury during flowering. Freezing injury during flowering has become one of the most serious natural disasters affecting the yield and quality of apples in Shaanxi. To assess the risk of flowering freezing injury of Fuji apples in two main apple-producing counties of Liquan and Xunyi, Shaanxi province, the daily average temperature was used to reconstruct the apple first flowering dates during 1967-2018 in Liquan and Xunyi, using the thermal time model. The daily minimum temperatures in the two sites during the same period were used to extract the last date of three freezing injury grades, in which the upper critical thresholds were-2, 0, and 2℃, respectively. The differences between the last date of three freezing injury grades and the first flowering date were defined as freezing injury risk indices. The linear tendency method was used to analyze variation trends in the first flowering date, last date of three freezing injury grades, and freezing injury risk indices. The results showed that the thermal time model could be used to reconstruct the first apple flowering dates in Liquan and Xunyi. The first apple flowering dates in Liquan and Xunyi advanced significantly from 1967 to 2018, with advance rates of 2.8d·10y-1 (P<0.01) in Liquan and 0.8d·10y-1 (P<0.05) in Xunyi, respectively. The last date of severe freezing injury in Liquan showed a significant advance trend with an advance rate of 3.3d·10y-1 (P<0.01), and the last dates of moderate and light freezing injury in Liquan showed no significant variation trends. There were no significant variation trends in the last dates of different freezing injury grades in Xunyi. The average first flowering date of apple in Liquan was on April 10(DOY 100), which was later than the average last date of light freezing injury on April 5(DOY 95), hence the risk of freezing injury in Liquan was low. The average first flowering date of apple in Xunyi was on April 17(DOY 107), which was later than average last date of severe freezing injury on April 3(DOY 93), but earlier than average last date of light freezing injury on April 28(DOY 118), hence the risk of freezing injury in Xunyi was higher than Liquan. There were no significant variations of freezing injury risk indices in Liquan and Xunyi, but the frequency of freezing injury risk index that higher than zero in Liquan and Xunyi increased, indicating that the freezing injury risk during apple blossoms was increasing.

Analysis of Hyperspectral Characteristics of Phragmites australis and Spartina alterniflora Leaves in Typical Beach

DU Zheng-zhen,WANG Lin, BAO Yun-xuan, ZHOU Xiao

2020, 41(06): 393-402. doi:10.3969/j.issn.1000-6362.2020.06.006

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The coastal beach has abundant resources and diverse ecological functions, and plays a crucial role in regulating climate, purifying water quality and protecting biodiversity.In recent years, frequent human activities have continued to affect the wetland ecosystem, which has been causing the wetland area to shrink gradually and destroying the living environment. As a result, the ecological function of the wetland is limited. Phragmites australis and Spartina alterniflora are typical vegetation types in coastal beaches of southeast China. Phragmites australisisa native plant which plays important ecological roles in coastal wetlands.Spartina alterniflora is an invasive species, which hinders the growth of local plants and changes the spatial distribution of original vegetation. It has been spreading continuously in recent decades and posing a serious threat to the local ecosystem and biodiversity. Traditional vegetation monitoring methods mainly rely on manual sampling, which takes a lot of time and effort and may damage the wetland. It has become a hot topic to use remote sensing technology to monitor Spartina alterniflora. However, it is very similar to Phragmites australis in leaf shape, color and other aspects. And the traditional remote sensing information is difficult to distinguish them. In the present study,Phragmites australis and Spartina alterniflorainthe coastal beach of Jiangsu Yancheng Wetland National Nature Reserve Rare Birds were selected as the research objects. The original hyperspectral reflectance curves, the reflectance spectral curves after continuum removed, and the first derivative spectral curves were utilized to accurately identify Phragmites australis and Spartina alterniflora in different growing periods, in order to realize fast and accurate identification of different vegetation in wetland and to provide references for dynamic monitoring of the wetland vegetation and protection of the wetland ecosystem. Continuum removal could effectively highlight the absorption and reflection characteristics of spectral curves, which could be used to extract characteristic bands for classification and recognition. It was shown that the original spectral curves of Phragmites australis and Spartina alterniflorawere basically the same insummer. Both of them showed a similar reflection peak near 550nm in the green band and a similar absorption valley near 670nm in the red band. Analyzing the spectral curves after continuum removed in the visible bands could effectively distinguish Phragmites australis from Spartina alterniflora in summer and the reflectance of Phragmites australis was lower than that of Spartina alterniflora(P<0.05). However, the original spectral curves in autumn showed that the reflection peak and absorption valley of Phragmites australis were higher than those of Spartina alterniflora. The analysis of the original spectral curves in the whole range of 350-1000nm made it easier to distinguish Phragmites australis from Spartina alterniflora in autumn, and Phragmites australis had higher reflectance values than Spartina alterniflora(P<0.05). The analysis of the original spectral curves of Phragmites australis in the range of 350-540nm and near-infrared bands could easily distinguish its growing periods and the spectral reflectance of Phragmites australis in summer was higher than that in autumn(P<0.05). Meanwhile, the continuum removal method was easier to distinguish them in the range of 520-700nm, and the spectral reflectance of Phragmites australis in autumn was higher than that in summer(P<0.05). In the range of 350-1000nm, the analysis of the original spectral curves of Spartina alternifloracould intuitively distinguish different growing periods and the spectral reflectance of Spartina alterniflora in summer was significantly higher than that in autumn(P<0.05). The first derivative spectra curve could not directly distinguish Phragmites australis from Spartina alterniflora, but their different growth periods could be identified according to the changes of their red edge and spectral characteristic parameters. The research could provide a basis for the identification of vegetation types and provide effective information for the protection and planning of the wetland ecosystem.

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