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• 2023 Vol.39 No.4 Published:05 February 2023

  Effects of Nitrogen Fertilizer Topdressing Rates on SPAD Value and Dry Matter Accumulation and Distribution of Upland Cotton in Southern Xinjiang DU Shanshan, LUO Jing, YAO Qingqing, SUN Huijian, HE Zhongsheng, WANG Dongli 2023, 39 (4):  1-6.  DOI: 10.11924/j.issn.1000-6850.casb2022-0083 Abstract + ( 206 )   HTML ( 12 )   PDF ( 1390KB )   ( 61 ) To figure out the effect of nitrogen fertilizer topdressing rate on the SPAD value and dry matter accumulation and distribution of upland cotton, we selected local main cultivar ‘Ba 43541’ as the material and set 4 nitrogen fertilizer topdressing levels (no nitrogen topdressing N0, 50% reduction of conventional nitrogen topdressing N1, conventional nitrogen topdressing N2, and 50% increase of conventional nitrogen topdressing N3). Leaf SPAD value, dry matter accumulation and distribution, yield and nitrogen utilization of cotton under the 4 treatments were measured. The results showed that 50% reduction of conventional nitrogen topdressing could increase the SPAD value and SPAD accumulation value of upland cotton in every growth period, the dry matter conversion ratio of reproductive organs reached the highest of 60.53%, the yield was 6581.32 kg/hm2 and increased by 1.4%-16.5% compared with that of other treatments. The partial factor productivity and the agronomic use efficiency of nitrogen fertilizer were also significantly higher than those of other treatments. Although 50% reduction of conventional nitrogen topdressing did not significantly increase the cotton yield, it could significantly increase the partial factor productivity and the agronomic use efficiency of nitrogen fertilizer, and should be recommended in production practice.

  Effects of Phosphorus Application Levels on Agronomic Characters and Yield of Coix lacryma-jobi GUI Tengfei, LI Weibiao, PU Fengya, YANG Zhiqing 2023, 39 (4):  7-13.  DOI: 10.11924/j.issn.1000-6850.casb2022-0102 Abstract + ( 169 )   HTML ( 12 )   PDF ( 1318KB )   ( 37 ) To study the phosphorus application levels for the optimal growth of Coix varieties in phosphorus-deficient soil of south China, the agronomic characters and yield of Coix varieties under different phosphorus application levels were observed. The method of plot experiment was adopted in Wenshan of Yunnan Province, random blocks were arranged, and there were 5 treatments with 3 repeats, among which no phosphate fertilizer was used as control. The growth period, agronomic characters and yield components were observed and recorded under different phosphorus application levels. The results showed that under certain conditions, the growth period of Coix variety ‘Wenyi 2’ had no significant difference under different phosphorus application levels. Compared with those of the control, the plant height, stem diameter, internode number, leaf number and uniformity were the best when phosphorus was applied at 180 kg/hm2. The effective ear number, grain number per ear and 1000-grain weight also increased significantly. From seedling stage to mature stage, the overall plant integrity was good, and the field resistance was enhanced. The grain number per ear, 1000-grain weight and effective ear number increased with the increase of phosphorus application level. The results indicated that phosphate fertilizer could promote the growth of Coix and increase the yield. In this experiment, the optimum phosphorus application level was 180 kg/hm2.

  Health Assessment and Analysis of Landscape Trees: Taking Pinus tabuliformis in the Outdoor Garden of the Museum of Chinese Gardens and Landscape Architecture as an Example LI Dapeng, ZHANG Baoxin, LI Yuechao 2023, 39 (4):  14-22.  DOI: 10.11924/j.issn.1000-6850.casb2022-0728 Abstract + ( 180 )   HTML ( 7 )   PDF ( 1472KB )   ( 55 ) To ascertain the general growth and health conditions of Pinus tabuliformis in the Museum of Chinese Gardens and Landscape Architecture and timely and accurately identify the existing problems and potential hazards of tree health can provide reference for implementing emergency measures, adjusting and formulating means and long-term scheme of rejuvenation and maintenance of the trees. The basic growth and health indexes, the score of health, and the health classification and assessment of the whole 79 Pinus tabuliformis in the garden were systematically studied. The results showed that a majority of the trees assessed were in good health, no tree was classified as weak or particularly weak grade. There were 9 trees at medium health level, accounting for 11.39% of the total. The number of trees at good and excellent level was 63 and 7 respectively, accounting for 79.75% and 8.86% of the total. The health status of P. tabuliformis on site condition of flat land and gentle slope was better than that on site condition of upland. The symptoms of crown and trunk of the trees, especially the branch and leaf pests and diseases, leaf spot or discoloration and trunk borer and disease, were the most primary factors leading to the deterioration of tree vigor and health score. High attention should be paid to the threats and impacts caused by pests and diseases, which can lead to the vitality decline of the trees. Based on the occurring regularity of pests and diseases, integrated prevention and control measures should be established. Besides, with the goal of improving the site condition of the trees, scientific and elaborate maintenance and management measures should be carried out to enhance the tree vigor and health condition. Health record should also be set up to monitor and inspect the growth conditions of the trees regularly.

  Flowering Characteristics and Dynamic Observation of Three Varieties of Fraxinus YAN Liping, LIU Cuilan, WANG Yinhua, LI Li, LIU Rong, WU Dejun 2023, 39 (4):  23-30.  DOI: 10.11924/j.issn.1000-6850.casb2022-0514 Abstract + ( 910 )   HTML ( 5 )   PDF ( 3105KB )   ( 21 ) The objective of this paper is to study the flower morphological structure and flowering characteristics of Fraxinus, and to provide a theoretical basis for its pollination and fertilization. In this paper, three varieties of Fraxinus (‘Lu la No.2’, ‘Lu la No.5’ and ‘Jinjian’) were selected to observe their flowering characteristics and morphological structure of flower. The results show that the flowering period of male plants of Fraxinus is 11-13 days, which is 13-15 days earlier than that of female plants. The flowering period of the female plants of ‘Lu la No. 2’ is only 5-6 days. The small flowers of the 3 Fraxinus varieties are dense without corolla. Their bracts become 2 lobes after flowering, and the calyx is bell-shaped with 4 deep lobes. The male flowers reveal boat-shaped anthers and extremely short filaments accompanying their blooming. The female flower reveals the pistils after its bracts are cracked and its stigma is split into two at maturity and becomes pink, and its peduncle is extremely short. Shield hairs are observed on the bracts and calyx surface of the three Fraxinus varieties under scanning electron microscope, and the morphology of shield hairs differs between different varieties. The anther and pollen structure are not significantly different between ‘Jinjian’ and ‘Lu la No.5’. There are significantly irregular folds on the entire pistil surface of ‘Lu la No.2’. The study lays a foundation for further research on the breeding of Fraxinus and the innovative utilization of Fraxinus germplasm resources.

  Effect of Soft Sandstone Compound Soil on the Growth Characteristics of Cucumis sativus QI Wei, GUO Yuefeng, GUO Zhenning 2023, 39 (4):  31-36.  DOI: 10.11924/j.issn.1000-6850.casb2022-0128 Abstract + ( 128 )   HTML ( 4 )   PDF ( 1252KB )   ( 21 ) Cucumis sativus was studied to investigate the effect of different ratios of wind-sand soil and soft sandstone compound soil on its growth and yield. The wind-sand soil was combined with soft sandstone in the ratios of 1:0, 1:1, 1:3, 1:5, 0:1, 3:1, and 5:1, and the chestnut calcium soil at a depth of 10 cm in the test area outside the greenhouse was set as the control soil sample (CK). This study investigated the most suitable compound soil ratio for cucumber growth by comparing the differences of growth characteristics of C. sativus such as plant height, crown breadth and fruit setting amount under different compound soil ratios. The results show that: (1) when the wind-sand soil is compounded with soft sandstone in the ratio of 1:3, the C. sativus plant height is 81.50 cm, the east-west crown breadth is 30.50 cm, the north-south crown breadth is 29.50 cm, the total fruit mass is 1475.80 g, and the weight of a single melon is 147.58 g; all the indexes are the optimal except the east-west crown breadth; (2) with the growth of seedlings, the growth characteristics gradually show a linear increasing trend, and C. sativus cultivated in the 1:3 ratio of compound soil has the fastest growth rate in all periods, with 73.25 cm of plant height growth, 22.50 cm of east-west crown breadth growth, and 23.00 cm of north-south crown breadth growth from July 22 to September 16. In conclusion, the 1:3 compound ratio of wind-sand soil to soft sandstone is beneficial to the growth of cucumber and can promote fruit setting.

  Effects of 6-Carbonyl Spirostane Compounds on Fruit Quality and Yield of Kiwifruit LIU Jinna, ZHANG Di, YE Jiayi, ZHOU Meng, ZHANG Cunli 2023, 39 (4):  37-43.  DOI: 10.11924/j.issn.1000-6850.casb2022-0130 Abstract + ( 152 )   HTML ( 5 )   PDF ( 1469KB )   ( 25 ) To explore the effects of 6-carbonyl spirostane compounds (LA and 3,6-TCS) on fruit quality and yield of kiwifruit, taking ‘Xuxiang’ as experimental material, the field experiment consisted of 0.500 mg/L LA, 0.500 mg/L 3,6-TCS, and 0.001% CPPU for soaking and spraying was conducted, and equal amount of clear water was taken as control. The results showed that the three plant growth regulators could significantly improve the content of leaf chlorophyll compared with the control. The chlorophyll content, net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr) were increased, while intercellular carbon dioxide concentration (Ci) was reduced, thus the fruit yield was increased. Compared with the control, the CPPU treatment and LA treatment increased the yield by 11.45% and 9.61% respectively. The rate of abnormal fruit of LA treatment was 46.57% lower than that of CPPU treatment. The three plant growth regulators could improve the taste by adjusting the soluble sugar content, reducing the amount of titratable acid, and improving sugar-acid ratio. The soluble sugar content of kiwifruit of 3,6-TCS treatment had the maximum value (9.83%), and was 50.77% higher than that of control treatment. The 3,6-TCS treatment increased soluble protein content (0.22 mg/g) by 37.5% compared with the LA. The sugar-acid ratio of 3,6-TCS treatment was up to 8.42, and there was no significant (P>0.05) difference with that of CPPU treatment. Principal component analysis (PCA) showed that CPPU treatment could obtain the highest yield, the 3,6-TCS could improve the fruit quality while ensuring fruit hardness, and LA treatment could improve both the yield and fruit shape index.

  Fruit Quality Performance of Litchi chinensis ‘Guiwei’ and Regional Test Cultivars in Yongde of Yunnan ZHENG Jian, RUI Danping, GAO Xianyu, ZHANG Huiyun, SONG Yunlian, PAN Jihong, YU Weilin, WANG Yuequan, LIU Siyuan, ZHENG Pingqing, LUO Xinping 2023, 39 (4):  44-51.  DOI: 10.11924/j.issn.1000-6850.casb2022-0833 Abstract + ( 281 )   HTML ( 9 )   PDF ( 1347KB )   ( 27 ) The fruit quality of the major litchi cultivar ‘Guiwei’ in Yongde County of Yunnan Province and seven other litchi cultivars of regional test were evaluated to make suggestions for the improvement of ‘Guiwei’ quality and cultivar breeding. The fruit quality of ‘Guiwei’ and the seven regional test cultivars collected in 30 orchards were determined, graded and ranked according to the quality weight-added score and economic benefit index. Meanwhile, the pollination source and air temperature during the flowering period were analyzed to explain the reason of the low aborted-seed rate of ‘Guiwei’. The results showed that the average fruit weight, total soluble solids (TSS), and edible percentage of ‘Guiwei’ were 22.53 g, 19.27%, and 76.61%, respectively. The average fruit weight and TSS of ‘Guiwei’ from Yongde County were higher than those of ‘Guiwei’ in most Guangdong litchi producing areas. While, the aborted-seed rate of ‘Guiwei’ in Yongde was only 44.00%, lower than that in most Guangdong litchi producing areas. The seven regional test cultivars of litchi were better than ‘Guiwei’ according to the evaluation results of the economic benefit index. According to the data of fruit quality performance of the regional test, the introduction of cultivars was successful except litchi cultivar ‘Lingfengnuo’. Mixed-planting of ‘Guiwei’ with the big kernel cultivar ‘Huaizhi’ could cause the synchronized flowering period of the two cultivars, and pollination source plus the long-term low temperature during pollination was speculated to be related to the low aborted-seed rate of ‘Guiwei’. The present paper suggests that increasing the aborted-seed rate is the key to improve the fruit quality and economic benefits of ‘Guiwei’. Some cultivars including ‘Wuheli’, ‘Guifeihong’, ‘Bingli’ and ‘Xianjinfeng’ show excellent performance in the regional test of introduction, and can be the alternatives to improve the local litchi cultivars.

  Effects of Irrigation Amounts on the Contents of Nutrient Elements in ‘MD-2’ Pineapple Fruit LIU Siru, SHI Weiqi, MA Haiyang, XIAN Aimin, XU Minggang 2023, 39 (4):  52-58.  DOI: 10.11924/j.issn.1000-6850.casb2022-0124 Abstract + ( 176 )   HTML ( 4 )   PDF ( 1325KB )   ( 21 ) To investigate the response of various nutrient elements in ‘MD-2’ pineapple fruit to different irrigation amounts in the dry season, and to provide data and theoretical basis for the scientific formulation of its dry season water management measures, this study was conducted with the ‘MD-2’ pineapple grown under natural rainfall in field as the research object, and an experiment was designed with four irrigation amount gradients [20 mm (W1), 50 mm (W2), 100 mm (W3), 150 mm (W4)], and with no irrigation as the control (0 mm). We analyzed the N, P, K, Ca, Mg, Fe, Cu and Mn contents’ change in ‘MD-2’ pineapple fruit under different irrigation levels in the dry season. The results showed that: the increase of irrigation amount was beneficial to the increase of the fresh weight and dry matter weight of ‘MD-2’ pineapple fruit. Both the fresh weight (797.42 g) and dry matter weight (99.14 g) of W4 were the largest. The overall performance of the contents of all nutrient elements in ‘MD-2’ pineapple fruit was K> N> Ca> P> Mg> Mn> Fe> Cu, in which, K content was the highest, followed by that of N and Ca, and the Cu content was the lowest. The K content increased with the increase of irrigation amount in fruit, but the Ca, Mg and Mn contents decreased with the increase of irrigation amount, while the N, P, Fe and Cu contents under W2 were the largest. The increase of irrigation amount promoted the accumulation of K in fruit, but inhibited the accumulation of Mg in fruit, while the accumulation amounts of N, P, Fe, Cu, Ca and Mn in pineapple fruit reached the maximum value under W2. Taking into account the growth of fruit and the change characteristics of nutrient elements’ contents and accumulation amounts, irrigation in the dry season is essential. According to the actual rainfall, proper adjustment of irrigation (W2) to keep the total water supply at about 300 mm is beneficial to the accumulation amounts of dry matter in ‘MD-2’ pineapple fruit, and can significantly increase the contents of nutrient elements in ‘MD-2’ pineapple fruit. It ensures sufficient and balanced supply of nutrient elements in pineapple fruit to achieve the purpose of high yield, high efficiency and high quality.

  Study on Breeding Status of Mosquitoes in Plant Communities in Kunming Residential Areas HUANG Yingrong, PAN Rui, HU Yuwen, FAN Xiaohua 2023, 39 (4):  59-68.  DOI: 10.11924/j.issn.1000-6850.casb2022-0140 Abstract + ( 313 )   HTML ( 4 )   PDF ( 1420KB )   ( 23 ) To study the mosquito problem caused by mosquito breeding by different types of plant communities in residential area, the mosquito breeding status of plant planting communities and common plants in 10 residential areas in Kunming was analyzed. The typical sample plot survey method is adopted to study the directly collected mosquito quantity in the plant space of the communities from 17:00 to 20:00 after rain in the four seasons, and investigate the mosquito breeding quantity of each layer of arbors, shrubs and grasses in the artificial plant community. And SPSS was used to analyze the differences of mosquito breeding affected by plant communities and seasons. The results showed that the plant communities in the 10 residential areas were mainly arbor-shrub-grass, arbor-shrub / arbor-grass, shrub-grass and monolayer; the mosquito breeding mount of the four community types was not significantly different in winter and spring, but there was significant difference between shrub-grass and monolayer in summer and autumn. Among the four types of plant communities, the mosquito breeding amount of monolayer is the least, and that of shrub-grass is the most. Taking into consideration the current status of plants in residential areas in Kunming City, the best optional plants for landscape can be Yulania denudata, Chlorophytum comosum and Cerasus.

  Modeling of Soil Salinity Interpretation in Manas County Based on EM38 YAN Jie, GU Haibin, WU Hongqi, ZHANG Li, YAN An, SHENG Jiandong 2023, 39 (4):  69-75.  DOI: 10.11924/j.issn.1000-6850.casb2022-0116 Abstract + ( 143 )   HTML ( 1 )   PDF ( 1368KB )   ( 20 ) Geodetic conductivity meter (EM38) is an effective method for rapid and nondestructive determination of soil salinity. To establish the relationship model between soil salinity and EM38 test value of farmland in Xinjiang, farmland soil in Manas County of Xinjiang was taken as the research object, EM38 was used to measure soil apparent conductivity in the field, and soil profile was excavated for stratified sampling, then the soil salinity content was measured in the laboratory. Based on this, a soil salinity interpretation model based on EM38 was constructed. The results showed that: (1) based on the measured soil salinity and EM38 conductivity data, the EM38 vertical model and horizontal model and their combined binary linear regression soil salinity interpretation model at different soil depths were established; (2) the R2 of the three EM38 salinity interpretation models increased with the increase of soil depth, and the accuracy of the vertical model was higher than that of the horizontal model when the soil depth was less than 20 cm, but the accuracy was conversed when the soil depth was greater than 20 cm; (3) the interpretation accuracy of binary linear regression model was obviously better than that of unitary linear regression model. The EM38 soil salinity interpretation model constructed in this study could provide reliable inversion parameters and models for the rapid investigation and dynamic monitoring of soil salinity in oasis farmland.

  Analysis of Soil Nutrient Status in Yellow River Floodplain of Henan Province ZHANG Jiajia, ZHANG Yue, LI Huawei, LI Hui 2023, 39 (4):  76-82.  DOI: 10.11924/j.issn.1000-6850.casb2022-0112 Abstract + ( 182 )   HTML ( 6 )   PDF ( 1204KB )   ( 30 ) The study aims to achieve the ecological protection and high-quality development of the Yellow River basin, clarify the soil nutrient status of the Yellow River floodplain in Henan Province, and develop a reasonable fertilization scheme for planting suitable non-timber forests in this region. The soil samples were collected in the Yellow River floodplain of Yuanyang County, Henan Province. The contents of abundant available nutrient N, P and K, medium trace element exchangeable Ca and Mg, available S, Zn, Cu, Fe, Mn and B, and organic matter, as well as pH and CEC (cation exchange capacity) were determined, and the correlations between soil nutrients and soil texture types were analyzed. The results showed that soil texture types in the Yellow River floodplain of Henan Province were divided into sandy soil, loamy sand, sandy loam, loam, silt loam and silt soil. The average pH value of the soil was 8.43, so the soil was alkaline. The contents of soil organic matter and abundant available nutrient N, P and K, and CEC were deficient. Except available boron, the contents of other medium trace elements were abundant. The correlation analysis showed that most of the nutrient elements were significantly correlated, and the organic matter, CEC, total N, available P and K, exchangeable Mg, available Cu, Fe, Mn and B were negatively correlated with pH, and the exchangeable Ca, and available S and Zn were less correlated with other elements. The Yellow River floodplain of Henan Province is very suitable for non-timber forests. In the process of cultivation management of non-timber forests in this region, it is necessary to pay attention to increase the application of organic fertilizer, rationalize the ratio of organic fertilizer and inorganic fertilizer, and at the same time, add proper amount of B fertilizer by foliar spraying, to achieve the purpose of improving quality and efficiency.

  Available Trace Elements in Cultivated Soil in Pingliang City: Abundance and Deficiency Evaluation and Influencing Factors LIU Yuanyuan, TU Guoliang 2023, 39 (4):  83-92.  DOI: 10.11924/j.issn.1000-6850.casb2022-0153 Abstract + ( 150 )   HTML ( 2 )   PDF ( 1382KB )   ( 23 ) The study aims to clarify the abundance and deficiency of available trace elements in cultivated soil systematically in the study region, and explore the correlation between trace elements and their influencing factors, in order to provide a scientific basis for soil testing for formula fertilization, and improve fertilizer utilization rate and soil fertility in Pingliang City. The authors used Cu, Zn, Fe, Mn, B, Mo and S as the main research objects, and evaluated the abundance and deficiency of available trace elements in cultivated soil in Pingliang City. The correlation analysis and regression analysis of trace elements and their influencing factors were conducted by statistical method. The statistical results showed that the average content of available Cu, Zn, Fe, Mn, B, Mo and S was 1.04, 0.92, 13.18, 11.03, 0.51, 0.11 and 15.11 mg/kg, respectively. The content of available S had strong spatial variation, while the content of other elements were moderately variable. The results showed that the abundance and deficiency level of available Cu and Zn in cultivated soil in different regions were from low to medium, that of available Fe and Mn were from low to high, that of available Mo was from relatively low to low, and that of available B and S were from very low to relatively low. The content of available Cu in different soil types was from low to medium, that of available Zn, Fe and Mn were from low to high, that of available B was from relatively low to low, that of available Mo was from relatively low to medium, and that of available S was extremely low. There were certain correlations among soil pH, organic matter and available trace elements. In general, the cultivated soil in Pingliang City was deficient in available B, Mo and S, and available S was extremely deficient. Meanwhile, the available Cu, Zn, Fe and Mn were generally above moderate level. Therefore, according to the evaluation results and the correlation characteristics of soil pH, organic matter and available trace elements, it is suggested to take measures such as reasonable application of organic fertilizer, appropriate adjustment of soil pH, appropriate supplementation of B and Mo fertilizers according to local conditions, more application of S fertilizer, and carrying out experiments and demonstration of trace element fertilizer efficiency, to achieve the high-yield and high-quality crop production and ensure food security.

  Soil Physicochemical Properties of Pinus sylvestris var. mongolica Plantations of Different Ages in Minqin TANG Weidong, WEI Linyuan, KANG Caizhou, WANG Duoze, QIU Xiaona, ZHANG Weixing, ZHANG Xiaojuan 2023, 39 (4):  93-98.  DOI: 10.11924/j.issn.1000-6850.casb2022-0791 Abstract + ( 151 )   HTML ( 5 )   PDF ( 1249KB )   ( 22 ) Taking the artificial forest land of Pinus sylvestris var. mongolica of different ages in Minqin National Study Station on Desert Steppe Ecosystem as the object, the soil physicochemical properties of P. sylvestris var. mongolica of different ages were measured, and the nutrient status of P. sylvestris var. mongolica forests were compared and analyzed. The results are as follows. (1) The vertical change of soil water content of different forest ages is not significant, and the soil water content changes significantly in the same soil layer of different forest ages. The surface soil water content of the middle-aged forest is the lowest of 4.34%, and the water content of the 40-50 cm soil layer of the near-mature forest is the highest of 17.21%, significantly higher than that of other forest ages (P<0.05). (2) There are significant differences in soil pH and electric conductivity in the P. sylvestris var. mongolica plantations of different ages. The pH of the middle-aged forest is the lowest at different soil depths. The soil pH in different soil layers of each forest age group is greater than 8, showing weak alkalinity. The soil electric conductivity is in the order of middle-aged forest> young-aged forest> near-mature forest, and the soil electric conductivity of the middle-aged forest is significantly higher than that of the young forest, showing a decreasing-rising trend with the increase of the soil depth. (3) The forest age has a significant effect on the soil nutrients of P. sylvestris var. mongolica plantations. The content of total nitrogen, organic matter, NH3-N (ammonia nitrogen), available phosphorus and effective phosphorus in the middle-aged forest are higher than those of other forest ages, and the difference is significant (P<0.05). (4) Principal component analysis of soil fertility of different forest ages shows that the total soil nitrogen, organic matter, available phosphorus, NO2-N (nitrous nitrogen) and NH3-N are in the first three main components.

  Variation Characteristics of Climate Production Potential in Guangdong Province from 1988 to 2018 ZHANG Tao, GU Mingmei, ZHANG Min, ZHAO Weiwen, ZOU Futong, WU Yongzhi 2023, 39 (4):  99-105.  DOI: 10.11924/j.issn.1000-6850.casb2022-0094 Abstract + ( 227 )   HTML ( 9 )   PDF ( 1898KB )   ( 58 ) Based on the climatic data of 21 prefecture-level cities in Guangdong Province from 1988 to 2018, the authors used the Thornthwaite Memorial model to calculate the climate production potential and study the change mechanism and temporal and spatial variation characteristics of the climate production potential. The results showed that the climate production potential of Guangdong Province showed a decreasing trend from 1988 to 2018, and the climate tendency rate was 18.4 g/m2 per decade. In terms of spatial variation characteristics: the climate production potential was distributed in a step-like pattern, decreased from the coast to the inland. The first EOF vector analysis showed that the change trend of climate production potential had the distribution characteristics of more or less climate production potential in the whole province at the same time. The second eigenvector exhibited a zonal dipole spatial distribution. There was a strong positive correlation between climate production potential and precipitation, but temperature had little influence. The warm-humid type increased climate production potential, but the cold-dry, cold-wet and warm-dry types reduced it. The climate production potential of Guangdong Province will show an increasing trend in the next 10 years.

  Application Rates and Proportions of Organic Fertilizers: Control Effects on Three Diseases of Grain Pea LI Yanlan, YANG Jincheng, JIN Hongyun, LUO Zhimin, LI Xiang, LI Zaofu, ZHANG Chunfan, HU Xinzhou, YU Zonghong, LIU Jianjian, GAO Shilan, AN Zhengyun, WANG Aiming, CAI Shujiang 2023, 39 (4):  106-111.  DOI: 10.11924/j.issn.1000-6850.casb2022-0072 Abstract + ( 180 )   HTML ( 4 )   PDF ( 1144KB )   ( 22 ) In order to explore the control effect of organic fertilizers with different application rates and proportions on common diseases of grain pea, a multi-level randomized block experiment was conducted, and the field control efficacy of organic fertilizer applied at sowing stage, and N and K water-soluble organic fertilizer or ammonium dihydrogen phosphate applied at seedling stage on fusarium wilt, powdery mildew and brown spot disease were studied. The results showed that combined application of 4500 kg/hm2 organic fertilizer as base fertilizer with N and K water-soluble organic fertilizer as topdressing had good control effect on fusarium wilt and brown spot disease of pea at middle and high altitudes, the highest control efficiency of fusarium wilt was 100%, the highest control efficiency of brown spot disease was 48.23%, but organic fertilizer with different application rates and proportions had no control effect on powdery mildew. The application of 4500-9000 kg/hm2 organic fertilizer as base fertilizer and 2 times of N and K water-soluble organic fertilizer as topdressing could increase the yield of grain pea, and the highest increase rate at high altitude was 25.55%, and the highest increase rate at middle altitude was 19.71%. According to the experiment results, the application of 4500 kg/hm2 organic fertilizer as base fertilizer and 2 times of water-soluble organic fertilizer as topdressing have the effect of disease control and yield increase.

  Isopyrazam and Its Mixture Against Powdery Mildew of Four Different Cucurbit Crops in the Field WEN Junhui, YAO Beibei, CAI Jianying, ZHU Qi, ZHONG Guohua 2023, 39 (4):  112-118.  DOI: 10.11924/j.issn.1000-6850.casb2022-0133 Abstract + ( 884 )   HTML ( 3 )   PDF ( 1133KB )   ( 29 ) To screen effective fungicides to control powdery mildew of cucurbit crops, clarify the field control efficiency of isopyrazam and its mixture on powdery mildew of balsam pear, zucchini, melon and watermelon, and provide a scientific scheme for the green control of powdery mildew of cucurbit crops, some field control efficacy trials were carried out for three years according to the guidelines of field efficacy test GB/T 17980.30—2000. According to the development of different crops and diseases, by 2-4 times applications with 7-14 days intervals and spraying at the initial stage of powdery mildew, the control efficiency of isopyrazam 11.2% EC 67.2 g(a.i.)/hm2 (preparation 600 mL/hm2) and isopyrazam· azoxystrobin 29% SC 87-261 g(a.i.)/hm2 (preparation 300-900 mL/hm2) were more than 80%. The duration was 10-14 days, significantly higher than that of the conventional dosage of azoxystrobin· boscalid 30% SC, difenoconazole 10% WG, triadimefon 25% WP or myclobutanil 12.5% EC. Therefore, isopyrazam 11.2% EC and isopyrazam· azoxystrobin 29% SC have good control efficiency on powdery mildew of balsam pear, zucchini, melon and watermelon, which indicated that they are worthy of further research and development.

  Investigation of Occurrence of Apple Powdery Mildew and Screening of Pesticide in Field HOU Hui, WANG Li, YUAN Hongbo, ZHOU Zengqiang, HUANG Tianxiang, TU Hongtao 2023, 39 (4):  119-124.  DOI: 10.11924/j.issn.1000-6850.casb2022-0118 Abstract + ( 173 )   HTML ( 3 )   PDF ( 1368KB )   ( 33 ) To find out effective prevention and control measures of apple powdery mildew, the method of combining general survey and fixed-point survey was adopted. The occurrence period and harm degree of powdery mildew in apple orchards were investigated regularly. By field control test, the control effects of biological agents, inducers and highly effective chemical agents were evaluated. The results showed that apple powdery mildew occurred from April to May in spring, and around September in autumn. It was found that the incidence of powdery mildew on ‘Huashuo’ was more severe than that on ‘Fuji’. The field screening results showed that the control effect of 8% pyrimidine nucleotide antimicrobial was 75.27%, followed by 10% polyantimycin with a control effect of 62.09%. The three kinds of inducers had certain effect on the control of apple powdery mildew, and the effect of 50 μg/mL salicylic acid treatment was the best, up to 66.85%. The control effect of oxalic acid treatment with high concentration was more than 50%. The treatment effect of 5% amino-oligosaccharide 2000 times was close to that of 50 μg/mL salicylic acid, which was 65.26%. Among the 5 commonly used chemical agents, 50% propiconazole had the best control effect against powdery mildew, which was as high as 98.59%, followed by 10% phenylecloprazole (92.80%), and 5% hexaconazole, 30% picoxystrobin and 40% myclobutanil also had satisfying control effect, which were all above 80%. The results of this experiment can provide technical guidance for the technology integration and demonstration of apple pest integrated control system in the future.

  Research Progress of Grape Downy Mildew LI Boya, RAN Longxian, SHI Liming, ZHANG Kecheng, GE Beibei 2023, 39 (4):  125-131.  DOI: 10.11924/j.issn.1000-6850.casb2022-0110 Abstract + ( 205 )   HTML ( 4 )   PDF ( 1237KB )   ( 50 ) The article introduced the symptoms of grapevine downy mildew and the process of infestation cycle. Moreover, it summarized the formation and development of oospores, the production and changes of the relevant secretory proteins after the infection of the fungus, and the pathogenic mechanism of grapevine downy mildew. At the same time, the control methods of grapevine downy mildew were reviewed from the aspects of the selection of resistant varieties, physical control, biological control, chemical control and integrated control, aiming to provide reference for subsequent research and disease control of grapevine downy mildew.

  Effect of Main Farming Systems in Guizhou on the Occurrence and Damage of Ageratum conyzoides YE Zhaochun, RAN Haiyan, CHEN Shihong, LAN Xianmin 2023, 39 (4):  132-138.  DOI: 10.11924/j.issn.1000-6850.casb2022-0099 Abstract + ( 151 )   HTML ( 3 )   PDF ( 1334KB )   ( 20 ) To explore the correlation between the main farming systems and the invasive damage of Ageratum conyzoides in Guizhou, the main invasion areas were selected for 3-year fixed-point tracking monitoring. The results showed that there were 51 species of weeds in the monitored fields, and A. conyzoides had the highest field coverage and highest relative abundance, its value of field coverage ranged from 50.03 to 66.54 with the 3-year average value of 59.11, and its relative abundance ranged from 36.98 to 59.59 with the 3-year average of 46.27. The damage of A. conyzoides in Guizhou was much greater than that of other weeds, and its damage remained stable in general. A long-term single farming management mode could result in the occurrence and damage of A. conyzoides. Therefore, it is suggested that the farming system should be changed in time in agricultural production, and more field management methods should be adopted to control the invasion and damage of A. conyzoides.

  Research Progress of Biological Control of Nematodes Based on CiteSpace YANG Yaoquan, LI Feiteng, LI Yanpeng, SHE Rong, YANG Xiaoyan 2023, 39 (4):  139-148.  DOI: 10.11924/j.issn.1000-6850.casb2022-0200 Abstract + ( 169 )   HTML ( 4 )   PDF ( 1888KB )   ( 29 ) The aim of this paper is to learn about the current research status in the field of biological control of nematodes, and provide information for the development of nematode biological control in China. The published literature on biological control of nematodes from Web of Science and China National Knowledge Infrastructure was collected and analyzed quantitatively with CiteSpace and other bibliometric analysis software. Results show that biological control of nematodes is a hotspot in domestic and international research. The annual number of related publications has an overall increasing trend, and more and more institutions, including many companies, have started to do this research. Compared with English literature, Chinese literature is mostly limited to the control of single species of nematodes, the cross-disciplinary research is not obvious and the ecological aspects are less involved. At present, research on biological control of nematodes is widespread, but the effect of actual application is not so satisfactory. Related studies about the biological control of nematodes should consider screening biocontrol strain from indigenous species to solve the problem of environmental adaptation. At the same time, cross-disciplinary research should be strengthened and community ecology should be considered more for new breakthrough.

  Prediction of Rice Canopy SPAD Value Based on UAV Multispectral Images TIAN Ting, ZHANG Qing, XU Wen 2023, 39 (4):  149-153.  DOI: 10.11924/j.issn.1000-6850.casb2022-0176 Abstract + ( 177 )   HTML ( 4 )   PDF ( 1379KB )   ( 31 ) The aim of this study is to compare and screen SPAD estimation models of rice canopy, and to provide a basis for inversing SPAD value of rice by unmanned aerial vehicle (UAV) multispectral remote sensing. This paper used UAV to obtain the canopy multispectral images of rice at jointing stage, heading stage and milky maturity stage. Seven commonly used vegetation indices were selected and three regression methods were used to establish the SPAD value inversion model of rice leaves. The results showed that the vegetation indices with the highest correlation coefficient with SPAD value of rice leaves were different at different growth stages. GNDVI was the highest at jointing stage, CIGreen was the highest at heading stage, and CIRededge was the highest at milky maturity stage. The heading stage was the best inversion stage of SPAD value, and the model had good modeling precision and estimation effect. According to the accuracy test, multivariate linear regression model had relatively high modeling accuracy, and partial least squares regression had the best estimation effect. Thus, this research provides a new technology to supervise the growth information of rice and other crops. The experimental results can provide methods and reference for the real-time and nondestructive monitoring of rice growth.

  Drying Method and Component Analysis of Apios americana CHEN Lulu, WANG Huili 2023, 39 (4):  154-159.  DOI: 10.11924/j.issn.1000-6850.casb2022-0263 Abstract + ( 248 )   HTML ( 2 )   PDF ( 1812KB )   ( 17 ) To solve the problem of making powder from dried Apios americana, the sensory characteristics and functional components of A. americana were studied by freeze-drying, microwave drying, baking, hot air drying, natural sun drying and natural shade drying. Through sensory evaluation and detection result analysis of functional components, it was found that the best drying method was freeze-drying, which could minimize the loss of functional components and retain the sensory characteristics, such as color and aroma. But freeze-drying had high cost and was time-consuming, which was not conducive to practical production and application. Based on this, microwave drying had obvious overall advantages, the content of vitamin C and flavonoids were only lower than those of freeze-drying by 6 mg/100 g and 0.1 g/100 g respectively, but far higher than those of other drying methods, and the drying cost was low and the drying time was short. Therefore, microwave drying is selected as the drying method of A. americana.

  Change Law of Water Loss in Fresh Tea Leaves Under Different Spreading Environments LIAO Jun, FANG Hongsheng, SU Youjian, WANG Yejun, ZHANG Yongli, SUN Yulong, FANG Yage 2023, 39 (4):  160-164.  DOI: 10.11924/j.issn.1000-6850.casb2022-0146 Abstract + ( 174 )   HTML ( 5 )   PDF ( 1246KB )   ( 29 ) To clarify the dynamic changes of water loss during the spreading process of fresh tea leaves under different environmental conditions, a prediction model for the changes of the moisture content of fresh tea leaves was constructed to predict the degree of spreading. In this experiment, different temperature and humidity were set to investigate the change of moisture content of fresh tea leaves during a certain spreading time, and the prediction model was established by response surface analysis software. The results showed that the moisture content of fresh tea leaves decreased quickly and then slowly with the extension of spreading time in different environments, and the low temperature and high humidity environment could significantly delay the water loss rate of fresh leaves. The prediction model (R2=0.9977) of the relationship between fresh tea leaf moisture content and temperature, humidity and time was obtained by response surface analysis, which had high significance and fitting degree, and good prediction effect. Therefore, the model constructed in this experiment could be used to forecast the moisture changes of fresh tea leaves under different temperature and humidity conditions and have practical application value for the regulation of the spreading process.