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20 November 2019, Volume 40 Issue 11

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Comparison of CH4 Flux Measurement by Open- and Close- Path Eddy Covariance System

YUAN Wen-wen，ZHANG Jin-song，MENG Ping，TONG Xiao-juan，PAN Qing-mei，HE Fang-jie，LI Jian-xia

2019, 40(11):  669-677.  doi:10.3969/j.issn.1000-6362.2019.11.001

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The eddy covariance technique provides a useful tool to directly measure CH4 exchange between the vegetation and the atmosphere. The open-path (OPEC) and close-path (CPEC) systems have uncertainties in measuring methane flux in forests. Therefore, it is necessary to compare the measured CH4 flux obtained from the OPEC and CPEC systems. In this study, CH4 flux was measured using the OPEC and CPEC systems in a mixed plantation in the Xiaolangdi area during the growing season of 2016 (July 24th to August 5th). The (co)spectra were analyzed and the time lag was estimated. Moreover, CH4 flux from the OPEC and CPEC systems was discussed. The results showed that the (co)spectra showed a good agreement with the -5/3 for spectra and -4/3 for co-spectra. Under different sampling flow rate (40, 37.5, 35.5, 33.5 and 31.5L·min-1) conditions, the time lag was 4.6, 7.7, 5.3, 10.8 and14.3s, respectively, and the average lag time was 8-9 s. CH4 flux derived from the CPEC system was 12% lower than that measured by the OPEC system in sunny days, while CH4 flux obtained by the CPEC system was 32% higher than that measured by the OPEC in rainy days. The OPEC system was more suitable measuring CH4 flux in comparison with the CPEC system in sunny days. The lag time should be corrected for the CPEC system in rainy days since it can be used for compensate for missing values in the OPEC system. Higher quality data of CH4 flux can be obtained by using the CPEC and OPEC systems together.

Areas Suitable for Growing Apples Moved Northward and Westward in China under the Background of Climate Change：Climatic Degionalization of Apple Based on High-resolution Meteorological Grid Data

ZHANG Yue-ying, LIU Bu-chun, QIU Mei-juan, LIU Yuan, WU Xin-yue, XIAO Nan-shu

2019, 40(11):  678-691.  doi:10.3969/j.issn.1000-6362.2019.11.002

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The interannual and spatial distributions of the climatic indicators affecting apple planting such as the air temperature, precipitation, relative humidity were analyzed, while climate trend rate and ArcGIS spatial interpolation were applied, based on 3h meteorological grid data of 5km × 5km spatial resolution from 1981 to 2010. In detail, the unplantable areas where climatic conditions cannot meet the basic requirements for apple cultivation were excluded firstly by one-vote veto indicator. Climatic suitability evaluation was carried out for plantable areas secondly with scoring standard for apple climatic regionalization factors. The interannual variation characteristics in the suitable for growing apples areas are analyzed finally. Findings are shown as below: apple can be grown in north China, northwest, southwest and parts of east and south China; in the plantable areas, the suitable regions were mainly located in most areas of the Loess Plateau and the Bohai rim area; the sub-suitable regions are mainly located in the North China Plain and a small part of the Loess Plateau, as well as the Tarim Basin and the Yunnan-Guizhou Plateau; the unsuitable regions are mainly distributed in the Northeast, most areas south of the Yangtze River, the Qinghai-Tibet Plateau, and parts of northern Xinjiang; Compared with the 1980s, in the 1990s and the 2000s, the Shandong Peninsula and the southern Loess Plateau had evolved from suitable planting regions into sub-optimal planting regions, however, the border areas between Liaoning and Mongolia, the Yunnan-Guichuan border areas, the northern Loess Plateau, and the border between Shaanxi and Gansu had evolved from the sub-suitable planting regions into the suitable planting regions. On the whole, the change was obvious that areas suitable for growing apples had moved northward and westward in China under the background of climate change.

Effect of Heat Stress on the Boll Setting Quality of Island Cotton on Different Fruiting Branches

CHEN Zhen, ZHANG Ju-song, CHEN Ping, ZHANG Wei-tao, Abudukadier·kuerban, CUI Jian-ping

2019, 40(11):  692-701.  doi:10.3969/j.issn.1000-6362.2019.11.003

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In order to study the effects of net photosynthetic rate, boll setting rate, yield and quality of island cotton on different fruiting branches under different warming days, the warming experiment on island cotton with plastic shed was conducted under the flowering period, taking two cotton varieties(XH43 and XH49)with different heat tolerances as material, and 3 different warming days treatments were designed: H3 (3 days shading), H6 (6 days shading), H9 (9 days shading). The natural temperature in the field was used as the control (CK). The results showed that heat stress reduces the yield and yield components of XH43 and XH49. Among them, H6 and H9 treatments reached significant levels. Heat stress significantly decreased the boll number, boll weight, lint percentage and seed cotton yield of the middle fruit branch, but significantly increased the boll number of the upper fruit branch and promoted the yield of the upper fruit branch. Heat stress had no significant effect on the fiber quality of XH43 and XH49, but resulted in a significant decrease in the upper half mean length, uniformity index and breaking tenacity of the upper fruit branch. However, heat stress significantly increased the breaking tenacity of upper fruit branches, in which H6 and H9 treatments reached a significant level, which increased by 2.19% ?5.12% and 4.48%?7.59%, respectively, compared with the control. The changes of yield and quality of different fruit branches of XH49 were greater than those of XH43 under heat stress. The results showed that the effect of heat stress on XH49 was more serious. Short-term heat stress will lead to a large number of bolls shedding and development hindering of cotton bolls in the middle fruit branches during the boll stage. The net photosynthetic rate of cotton treated with H6 and H9 was significantly higher than that of the control, which enhanced the photosynthetic capacity of cotton in the later stage, and then increased the boll number, yield and breaking tenacity of upper fruit branches.

Response of Root-Canopy Index of Winter Wheat on Persist Drought

LIU Rong-hua, CHENG Lin, HU Cheng-da

2019, 40(11):  702-711.  doi:10.3969/j.issn.1000-6362.2019.11.004

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In order to clarify the response characteristics of winter wheat root and canopy index to drought sustainable development, two years of drought persist experiments in 2015/2016 and 2016/2017 after returning green stage of winter wheat were conducted, and the influence of soil moisture persistently reduction on leaf water content, root activity, stomatal conductance, etc. were studied. The results indicated that, under the condition of soil moisture reduced continuously, the water content in different organs of winter wheat decreased nonlinearly, and the decreasing rate was much more obviously after jointing, among them, the leaf sheath water content decreased the most by 41.9% on average. With drought duration, the difference of leaf gas exchange parameters between treatments of drought persistent and control was increased, the net photosynthetic rate decreased further with continuous drought, the stomatal conductance as well as transpiration rate of leaves increased differently at returning green stage, and turned decline continuously after jointing. The longer the drought lasted, the more obvious that non-stomatal limiting factors affecting photosynthesis. The continuous drought changed root distribution in deep soil. Root volume percentage in 60?80cm soil layer in drought treatment was significantly higher than that in the control group. Meanwhile, the physiological function of the root system was senescent prematurely, especially during jointing and booting stage, the root activity dropped sharply, and after booting stage, the root activity reduced more than 60% comparing with the control group. On the whole, the indices such as plant water content, leaf gas exchange parameters and root activity had generality and individuality response to persistent drought, the sensitive coefficient of root activity to soil moisture variation was highest, and the response speed of plant water content to soil moisture was lowest.

Risk Assessment for Meteorological Disasters of Early Rice in the Southern Double- Season Region Based on Information Diffusion Theory

WANG Xue-lin, HUANG Qin-qin, LIU Jun

2019, 40(11):  712-722.  doi:10.3969/j.issn.1000-6362.2019.11.005

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Grain buds cold and high temperature damage are the most important agro-meteorological disasters affecting growth-development and yield formation of early rice in southern China.In order to improve the forecasting ability of double-season early rice meteorological disasters, in this paper, based on critical meteorological indicators related to grain buds cold and high temperature damage of previous studies, conventional meteorological observation data was used coming from 142 basic stations of double-season rice regions from 1960 to 2012, the occurrence for grain buds cold and high temperature damage was analyzed. Using information diffusion theory, conducted a refined risk assessment for different stations of early rice planting area. The results showed that, (1)annual mean numbers for early rice grain buds cold and high temperature damage distributed significant difference, and annual mean numbers for early rice grain buds cold basically showed progressively increasing from south to north, showing obvious zonal distribution. However, prone areas of high temperature damage mainly located in Hengyang, Shuangfeng, Binzhou areas of Hunan Province, and most parts in Jiangxi of Province areas, and Jinhua, Quzhou, Lishui of Zhejiang Province, and Jiayu, Wuhan, Huangshi Hubei Province, and some areas of Anqing in Anhui Province.(2)The spatial distribution characteristics of transcend probability value occurred in least one time and above for grain buds cold and high temperature damage were similar, and most areas showed significant high probability areas, as well as shorter return period and higher reproduction rate. The low probability zone of transcend probability value for grain buds cold and high temperature damage decreased as the number of years of occurrence increases.(3)With the significant increase in the number of occurrences, the station numbers of short return period for grain buds cold and high temperature damage of early rice reduced and station numbers of longer return period corresponding increased.

Climatic Risk Regionalization of Mango Planting in Fujian Province Based on Cold Injury Process

YANG Kai，CHEN Bin-bin，CHEN Hui，LI Li-chun，CHEN Bin-yuan，LI Zheng

2019, 40(11):  723-732.  doi:10.3969/j.issn.1000-6362.2019.11.006

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Based on the 39 mango cold disaster samples collected through four channels which were disaster investigation of cold injury in winter, orchard positioning observation, geographic displacement experiment and low temperature disaster experiment of artificial climate chamber, the critical temperature of cold injury for mango was determined to be 2.0℃. On this basis, 28 cold injury processes were screened out in winter from 2001 to 2014 in Fujian major mango producing counties and cities. By correlating the meteorological factors such as temperature and precipitation in the process of cold injury with the relative meteorological yield, the disaster-inducing factors for cold injury of mango was determined as extreme minimum temperature of cold injury process, accumulated value of cold injury process for the extreme minimum daily temperature ≤2.0℃, sustained days of cold injury process for the temperature ≤2.0℃, and cooling range of cold injury process for the temperature ≤2.0℃. By using the method of principal component analysis to simplify comprehensively four disaster-inducing factors, the integrated climatic index of cold injury evaluation of mango was obtained, and the index classification was determined by combining the relative meteorological yield. According to the grade of comprehensive climatic index of cold injury, the climatic risk regionalization of mango planting for cold injury was completed by using GIS method in Fujian Province. The region with no or mild cold injury mainly distributes in the coastal areas, which is the region with the lowest risk of cold injury for introducing high-quality mango varieties.