Chinese Journal of Agrometeorology

Evaluation of Methods for Estimating Greenhouse Eggplant Daily Evapotranspiration Based on the Values of Weighing Lysimeter Measurements

LI Yin-kun，GUO Wen-zhong，HAN Xue，WANG LI-chun，LIN Sen，ZHAO Qain，CHEN Hong

2020, 41(03): 129-137. doi:10.3969/j.issn.1000-6362.2020.03.001

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The daily evapotranspiration of greenhouse eggplant measured by weighing lysimeter was used as the standard value, four kinds of model methods, such as FAO-56 P-M method(P-Ms), modified P-M method(P-Mm), Priestley-Taylor method(P-T) and Irmak-Allen method(I-A) were applied to comparatively and analyze the daily evapotranspiration of greenhouse eggplant, and the applicability of each method in greenhouse was also evaluated. The results showed that the daily evapotranspiration of greenhouse eggplant that calculated by the four model methods had a similar variation rule with the measured value(ETc). However, the calculation accuracy of each method was obviously different. The ETc-m that calculated by P-Mm method was overestimated by 32.1mm, while the ETc-s, ETc-PT and ETc-IA that calculated by P-Ms, P-T and I-A methods were underestimated by 132.3mm, 80.0mm and 53.5mm, respectively. ETc-m is much more correlated with ETc than others, and the equation coefficient R2 was 0.905(P<0.01), the consistency index was 0.944, and RMSE was only 0.769mm·d-1. The correlation of ETc-IA with ETc was better than ETc-s and ETc-PT, and the equation coefficient R2 was 0.775(P<0.01), the consistency index was 0.828. Large errors were observed when methods P-Ms and P-T were applied in greenhouse, and the ETc-s and ETc-PT were only 59.4% and 74.8% of the measured value (ETc). Meanwhile, the consistency indexes were only 0.723 and 0.748, respectively, and RMSE were 1.672mm·d-1 and 1.304mm·d-1, respectively. Therefore, the P-Mm method could be preferred to calculate the evapotranspiration of greenhouse crops, while I-A method is an alternative method in greenhouse in the case of insufficient meteorological data.

Characteristics of Ammonia Emissions from Trough Composting of Swine Manure Biogas Residue and Corn Cob

YU Xin, ZHENG Yun-hao, ZHU Zhi-ping, ZHANG Yu, CAO Qi-tao

2020, 41(03): 138-145. doi:10.3969/j.issn.1000-6362.2020.03.002

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Composting is a promising way of animal manure treatment and a major source of ammonia (NH3) emissions. However, such studies related to swine manure biogas residue were few and the NH3 emissions data from the field processing were still lacked. To fill this research gap, NH3 emissions from an industrial trough composting system treating swine manure biogas residue and corn cob were investigated in this study. A real-time online gas monitoring system was established to continuously monitor the changes of NH3 concentrations in the plant, calculate the NH3 emission flux and analyze the characteristics of NH3 emissions. Results showed that NH3 concentrations in the composting plant during a composting period (38 days) ranged from 0.85 to 22.40mgm-3, with a mean value of 3.63±1.34mgm-3. The NH3 concentration in the first two weeks(4.70±3.64mg·m-3) was significantly higher than that in the last two weeks(3.00±1.49mg·m-3), and the concentration was higher than the limit value of the emission standard for odor pollutants in most time. Due to the impact of ambient temperature and compost turning, the NH3 concentrations in the daytime were higher than that in the nighttime, with the highest mean value of 6.77±4.37mgm-3 during time of 12：00-16：00, followed by 4.26±2.07mgm-3 during 16：00-20：00, and 3.62±1.46mgm-3 during 8：00-12：00. In this plant, NH3 emission flux per volume unit of compost was 50.25 to 103.99mg·m-3·h-1, with an mean value of 103.99±37.93mg·m-3·h-1. During the whole composting process, the NH3 emission per unit of compost was 94.84gm-3. The conclusions indicate that the NH3 concentrations in the composting plant are primarily impacted by the raw materials and the ventilation and management system. It is suggested to choose appropriate emission reduction measures based on the NH3 concentrations and operational parameters in the actual production process. Results of this study can provide scientific support for the control of NH3 emissions during swine manure composting.

Climate Regionalization of Hybrid Hazel Planting in Xinjiang

ZUO Chen, SONG Feng-hui, SHI Yan-jiang, LUO Da

2020, 41(03): 146-155. doi:10.3969/j.issn.1000-6362.2020.03.003

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Based on the continuous 10 years (2009-2018) meteorological data and geographic information data of 40 meteorological stations in Xinjiang, four factors including altitude, annual average temperature, annual average precipitation and sunshine duration were selected as the regional indicators. Multiple regression was used to establish the spatial model of meteorological factors, and geographic information system(GIS) was used to carry out data grid interpolation analysis on four factor parameters. According to the analytic hierarchy process (AHP), the index weight value was calculated, and GIS superposition analysis function was used to obtain the thematic map of the hazel growing area of Corylus heterophylla×Corylus avellanay hybrid hazels. The results showed that the hybrid hazel growing areas were divided into the most suitable area, the suitable area, the sub-suitable area and the unsuitable area. The results showed that the planting was divided the most suitable area, the suitable area, the sub-suitable area and the unsuitable area. The most suitable area is 27.722×104km2, accounting for 16.7% of the total land area of Xinjiang; it is mainly distributed in Kashgar region, Aksu region, Yili river valley, Changji Hui autonomous prefecture, Urumqi city, northern Bayingolin Mongolian autonomous prefecture, Turpan region and northern Hami region. The suitable area is 69.056×104km2, accounting for 41.6% of the total land area of Xinjiang, it is mainly distributed in Kashgar region, Kizilsukirgiz autonomous prefecture, northern Hotan region, northern Bayingolin Mongolian autonomous prefecture, Aksu region, Tacheng region and part of Altay region.

Rainfall Effect of Rainfall on the Quality of Wine Grape during the Ripening Stage at the East foot of Helan Mountain

JIANG Lin-lin, WANG Jing, ZHANG Xiao-yu, CHEN Ren-wei, HU Hong-yuan

2020, 41(03): 156-161. doi:10.3969/j.issn.1000-6362.2020.03.004

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In order to study the effect of rainfall at the ripening stage on the quality of wine grape, taking Cabernet Sauvignon as the main variety, the artificial rainfall experiments on grapes were conducted at the beginning of September in the region of the Helan Mountain East, located in Ningxia Hui Autunomous Region(38°16′N, 105°58′E).The soil type is light sierozem, and the grape plant is 5-year-old Cabernet Sauvignon of the winery. The natural rainfall from September 1 to harvest (10.3mm) were taken as the control (CK), and four different rainfall treatments were designed: P1 (20.3 mm), P2 (40.3 mm), P3 (50.3 mm) and P4 (60.3 mm),which including the total of natural and artificial rainfall. At the end of September, the grape fruits from four treatments and CK were sampled, separately, and the six substances of fruit juice including soluble solids, reducing sugar, titratable acid, total phenol, tannin and anthocyanin were tested. The results showed that the content of soluble solids, reducing sugar, sugar acid ratio and total phenol had the same trend, climbing firstly and then fell down with the increase of rainfall, while the content of titratable acid and anthocyanin presented the opposite trend. The contents of tannin were fluctuation with the increasing of rainfall, the values were all higher in four treatment than the control. In general, the rainfall which was less than10.3mm or exceeded than 40.3mm would have a negative impact on the quality of wine grape. When the rainfall is 30mm (the total rainfall is 40.3mm), the quality of grape berry is the best.

Seedling Freezing Risk Regionalization of Winter-Sowing Potato in Hubei Province

YE Pei, LIU Ke-qun, SHEN Shuang-he, LIU Zhi-xiong,TANG Yang, FANG Zhi-guo

2020, 41(03): 162-172. doi:10.3969/j.issn.1000-6362.2020.03.005

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Using the meteorological data and potato phenology survey data in Hubei province from1963 to 2018, the potato seeding dates were calculated by growing degree days method, and then the spatiotemporal distribution characteristics of potato freezing damage during seedling stage were analyzed dynamically, finally, the risk index model of freezing damage was constructed to distinguish the risk level of freezing damage in Hubei province. The results showed that: (1) freezing damage of winter-sowing potato during seedling stage was mainly occurred in the last ten-day of February and the first ten-day of March, especially in the first ten-day of March. (2) Most parts of the southwest of Hubei province were low risk areas, so that the cultivation of winter-sowing potato could be widespread in this region; the northwest and the east of Hubei province were moderate risk areas; and other areas of Hubei province were high risk areas. (3) In warm winters, potato seedlings sprout early and the freezing damage risk is relatively high; while in cold winters, the facts are just the opposite. However, if measures were taken to raise the temperature, the freezing damage risk could be reduced and would make it earlier for market.

Hyperspectral Features of Rice Canopy and SPAD Values Estimation under the Stress of Rice Leaf Folder

ZHOU Xiao, BAO Yun-xuan, WANG Lin, DU Zheng-zhen, TANG Qian, CHEN Can

2020, 41(03): 173-186. doi:10.3969/j.issn.1000-6362.2020.03.006

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The second instar larvae of Cnaphalocrocis medinalis Guenee (Rice Leaf Folder, RLF) cultured in the Laboratory of Agrometeorology and Insect Ecology of Nanjing Agricultural University were used as the experimental objects in 2017-2018. In the rice field of the agricultural meteorological experimental station of Nanjing University of Information Science & Technology, six levels treatments, including 50, 100, 200, 300, 400 RLFs·100plants-1and Control Treatment (CK) were set, in order to test the relationship between spectral characteristics and SPAD values under such different initial pest population condition. During the experiments, the spectral reflectance of rice canopy and the SPAD values of the flag leaves were measured by ASD Field Spec3 (Analytical Spectral Devices Inc) and SPAD-502 (Soil and Plant Analyzer Development), respectively. The variation patterns of original spectrum, trilateral parameters and SPAD values in different growth stages were analyzed. Consequently, the vegetation indices and trilateral parameters based on the observed spectral data were calculated using the reflectance values in the bands with strong correlations with SPAD. And the regression estimation models of the SPAD valuesof rice were established.The results showed that: (1) the spectral reflectance values of rice canopy damaged by RLFs were significantly different from those of the control (P<0.05). In the visible bands, the reflectance values of the former were lower than those of the latter during tillering-booting stages, and was higher than the latter during the flowering-maturity stages.(2) In the near-infrared band, the reflectance values of the injured treatments were lower than those of the control. And they decreased with the increase of the pest’s population, among which the reflectance of 300 RLFs·100plants-1(Level 4) was the lowest.(3) With the increase of the pest’s population, the red-edge position values appeared the ‘blue-shift’ trend. (4) The SPAD values decreased gradually with the increase of the pest’s population, and the Level 4 treatment had the lowest values. (5) The Normalized Difference Vegetation Index (NDVI), Red-Edge Normalized Difference Vegetation Index (NDVI705) and the position of red-edge had a close correlation with SPAD values.(6)The single factor estimation model and multiple stepwise regression model of SPAD were constructed using the hyperspectral features of rice. The exponential model with NDVI had the best estimation effect, with the highest coefficient of determination (0.72) among all the estimation models. The results indicate that it is feasible to use the spectral parameters of rice canopy to establish a model for estimating the SPAD values of rice leaves under the stress of rice leaf folder in the whole growth stages. This method is fast and nondestructive, and is convenient for continuous, dynamic and long-term located observation.

2020, 41(03): 187-190. doi:10.3969/j.issn.1000-6362.2020.03.007

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