Current issue

• 2020 Vol.36 No.10 Published:05 April 2020

  Research article

  Effects of No-tillage Years and Re-tillage Times on Soil Bulk Density and Rice Growth in Paddy Fields Huaizhou Hu, Bangyou Hu, Xulin Zhang, Zhongcheng Liu, Junyan Liu, En Ci 2020, 36 (10):  1-7.  DOI: 10.11924/j.issn.1000-6850.casb20190900668 Abstract + ( 606 )   HTML ( 38 )   PDF ( 1395KB )   ( 160 ) To explore the effects of different no-tillage years and re-tillage times on soil bulk density and rice growth in paddy fields, the research includes no-tillage for 1 to 10 years of paddy field and re-tillage once, re-tillage twice and re-tillage 3 times after no-tillage for 3 to 6 years of paddy field. The results showed that the soil bulk density of no-tillage soil was always higher than that of conventional tillage soil at surface soil and sublayer soil, with the increase of no-tillage time, soil bulk density increased. The soil bulk density significantly increased after 3-year no-tillage compared to that of conventional tillage (P<0.05). With the increase of re-tillage time, soil bulk density gradually decreased. In the paddy fields with no-tillage for 1 to 5 years, the highest seedlings, effective panicles and yield of rice under no-tillage cultivation were higher than that of conventional tillage cultivation. The tillering ability and yield of rice treated with 6-year no-tillage were relatively flat and stable and that of rice treated after 7-year no-tillage decreased significantly. The tillering ability and yield of rice in paddy fields under the re-tillage treatment were always lower than that of the corresponding no-tillage treatment, and the gap gradually widened with the increase of re-tillage times. The tillering ability and yield of rice treated with no-tillage for 7 years were the same as that treated with the corresponding re-tillage once after no-tillage for 6 years. In summary, 6-year no-tillage treatment is the best measure for paddy production in the study area, when the continuous no-tillage of paddy fields exceeds the optimum years, it is necessary to re-tillage the paddy fields once.

  Simulation of Grain Filling Rate of Winter Wheat Under Water and Nitrogen Stress Yuli Chen, Ping Yang, Fajiang Gong, Haibin Bi, Minghui Gao, Gui Qi, Huawei Li 2020, 36 (10):  8-12.  DOI: 10.11924/j.issn.1000-6850.casb18120113 Abstract + ( 440 )   HTML ( 14 )   PDF ( 1365KB )   ( 83 ) To quantitatively analyze the effects of water and nitrogen stress on winter wheat grain filling rate, we carried out field experiments in 2016-2017 and 2017-2018 growing seasons using winter wheat variety ‘Jimai 22’ under various water and nitrogen application levels. On the basis of experiment data collected in the 2017-2018 growing season, a simulation model of winter wheat grain filling rate under water and nitrogen stress was built by analyzing the influence rule of water and nitrogen stress on winter wheat grain filling rate, as well as introducing the water and nitrogen impact factors, and could be specifically described as: S(j,t)=S(W3N300,t)×(1+FN)×(1+FW). The model was then validated with an independent dataset collected in the 2016-2017 growing season. Except the ratio of mean absolute error (da) to the mean observation (dap), the root mean squared error (RMSE), mean absolute error (da), and correlation (r) all showed that the simulated values were well identical to the measured ones. The model can be used to simulate the effects of water and nitrogen stress on winter wheat growth and yield.

  Breeding Value of Wheat Key Parent Material ‘Lumai 14’ Nina Sun, Ming Zhao, Dongmei Wang, Liang Sun, Meiling Yan, Qian Zhao, Hongming Jiang, Jingchuan Yu, Linzhi Li 2020, 36 (10):  13-17.  DOI: 10.11924/j.issn.1000-6850.casb18120068 Abstract + ( 522 )   HTML ( 12 )   PDF ( 1178KB )   ( 379 ) To carry out a theoretical research on wheat and improve the breeding effect, the design and creative thinking, the prominent characteristics and the varieties bred with ‘Lumai 14’ as parent were analyzed in this paper. From 2001 to 2018, 39 new wheat varieties were bred directly and 92 new wheat varieties were bred indirectly with ‘Lumai 14’ as parent by 89 scientific research units and breeding enterprises including Chinese Academy of Sciences, Chinese Academy of Agricultural Sciences, China Agricultural University and those in Shandong, Jiangsu, Hebei, Anhui, Henan, Shanxi, Shaanxi, Xinjiang, Guizhou and Tianjin. All the varieties were authorized 166 times in 9 provinces and 2 municipalities and obtained national authorized certification 36 times. ‘Lumai 14’, as a new generation of key parents, has contributed greatly to the wheat production and breeding in China.

  Seeding Dates Influence the No-till Rapeseed Agronomic Traits and Yield in Low Altitude Mountain Areas Jincheng Yang, Jianjian Liu, Jiaojiao Lin, Xinzhou Hu, Zhengyun An, Hongyan Li, Guan Qu, Junhua Feng, Yuecai Bai, Zhilin Wu, Li’an Shi, Ru Li 2020, 36 (10):  18-24.  DOI: 10.11924/j.issn.1000-6850.casb19010125 Abstract + ( 429 )   HTML ( 15 )   PDF ( 1383KB )   ( 80 ) To comprehensively assess and recommend the optimum seeding date of no-till rapeseed in low altitude mountain areas, comparisons of no-till rapeseed agronomic traits and yield of 10 seeding dates in 4 altitude areas were carried out from 2011 to 2015 in Yuxi by using grey relation analysis and fuzzy clustering analysis. The results indicated that: (1) there was significant difference of main agronomic traits among different seeding dates, the main agronomic traits of rapeseed of earlier seeding date were better than that of conventional seeding date (October 10); (2) the correlation between yield and main agronomic traits varied in different degrees; (3) the yield of different seeding dates varied in different degrees; (4) the optimum seeding date of no-till rapeseed depended on climate, the best seeding date in warm year was around August 10 -September 10, whereas in cold year it was around August 30 - September 30. Therefore, according to the comprehensive evaluation of the yielding ability and stability of rapeseed of 10 seeding dates during 5 years, the optimum seeding date of August 30 - September 10 is recommended for no-till rapeseed in low altitude mountain areas.

  Abundance Evaluation of Nutrient Content in Tobacco Soil of Longlin Zilin Li, Leifeng Zhao, Yachun Lu, Wenliang Zhou, Gang Luo, Xiaolin Liao, Fuzhao Nian, Dongsheng Fan 2020, 36 (10):  25-32.  DOI: 10.11924/j.issn.1000-6850.casb19010073 Abstract + ( 306 )   HTML ( 5 )   PDF ( 1268KB )   ( 138 ) The paper aims to evaluate the status of soil nutrient abundance in tobacco planting areas in Longlin, and provide reference for tobacco planting and rational fertilization. The Longlin tobacco-growing area was used as the evaluation unit, and the mathematical statistics were adopted to study the nutrient content and nutrient abundance status of the tobacco soil. The results showed that the soil pH value and total nitrogen were relatively good in the tobacco-growing area of Longlin, soil organic matter, available sulfur, available potassium, available phosphorus, exchangeable magnesium were less appropriate, soil active chlorine, available boron, exchangeable calcium had high suitability. The soil nutrient content in the tobacco-growing area was evaluated for abundance and deficiency, and the results indicated that in the process of tobacco planting, scientific fertilization should be carried out, to control nitrogen, phosphorus, chlorine and calcium, increase potassium, sulfur, magnesium and boron, and reduce the large-scale application of alkaline fertilizers, with more application of organic fertilizers, to achieve the goal of organic, high quality, ecological, characteristic and safe production of tobacco leaves.

  Research Status and Future Prospect of Taraxacum kok-saghyz(TKS) Rubber Industry Shuyang Cui, Jichuan Zhang, Liqun Zhang, Yong Ma, Qiuhai Nie, Feng Wang, Yiyang Dong 2020, 36 (10):  33-38.  DOI: 10.11924/j.issn.1000-6850.casb18120080 Abstract + ( 685 )   HTML ( 8 )   PDF ( 1089KB )   ( 184 ) Taraxacum kok-saghyz(TKS) is a unique rubber-producing plant, which is of great significance for alleviating the shortage of natural rubber and ensuring the security of national strategic resources. To accurately and reasonably evaluate the development potential of the dandelion rubber industry, we reviewed the fundamental research of TKS at home and abroad, summarized the current research focus on germplasm resources, cultivation techniques, extraction technology, and the rubber particles synthetic mechanism. We pointed out that the indirect product of dandelion rubber, inulin and ethanol, had great potential industry value. In view of the gap between China and foreign countries in the field of dandelion rubber, industrial development suggestions were put forward as government support, enterprise leading, and the combination of independent research and international cooperation.

  Phenology Research on the Common Ligneous Species in Wuhan Urban Forest: An Example of Jiufeng National Forest Park Xiaorong Wang, Hongdong Pang, Wenjie Hu, Hongyu Niu, Jingjin Zheng, Ruiwen Wang, Wanpeng Tang 2020, 36 (10):  39-46.  DOI: 10.11924/j.issn.1000-6850.casb19010093 Abstract + ( 587 )   HTML ( 1 )   PDF ( 1557KB )   ( 118 ) To explore the phenological characters of common ligneous species in Wuhan urban forest, based on the phenological observation data of 18 tree species for 3 consecutive years, the main phonological characters of tree species were studied, the phenological spectrum was drawn and the correlation between phonological phenomena was analyzed. The relationship between tree phenological phase and environmental factors such as temperature and precipitation was studied using principal component analysis. The major environmental impact factors for sprouting period, leaf-expansion period, flowering period and fruit maturation period were ≥5℃ temperature accumulation, average temperature and cumulative rainfall, and those for defoliation period were average temperature, average rainfall and ≥5℃ temperature accumulation. In addition, different environmental factors had different positive and negative effects in different phenological periods. Phenotypic cluster analysis was carried out on sprouting period, leaf-expansion period, flowering period and fruit maturation period, 3 types of sprouting period, 2 types of leaf-expansion period, 3 types of flowering period and 3 types of fruit maturation period were determined preliminarily. Moreover, different phenological types were connected and combined according to “sprouting type+ leaf-expansion type+ flowering type+ fruit maturation type”, 18 tree species were classified into 9 phonological types. The study is helpful to understand the phenological change characters of common tree species in Wuhan, and provides a scientific basis for the species selection, tree cultivation management and benefit evaluation of urban forest.

  Effects of Ginkgo biloba Exocarp Extracts on Mulberry Leaf Growth, Physiological Indexes and Cocoon Quality Xiaocong Zhang, Wanwen Yu, Jinfeng Cai, Ying Guo, Guibin Wang 2020, 36 (10):  47-52.  DOI: 10.11924/j.issn.1000-6850.casb20191100842 Abstract + ( 420 )   HTML ( 4 )   PDF ( 1369KB )   ( 80 ) In this study, ‘Qiangsang No.1’ mulberry tree was used as a test material, and five different concentrations of Ginkgo biloba exocarp extracts treatment (A-E: 2.5, 5.0, 10.0, 15.0, 20.0 g/L) and one blank control treatment CK were set up by field foliar fertilization test. The effects of different treatments on physiological and biochemical indexes of mulberry leaves were analyzed. Further, the processed mulberry leaves were used to feed the silkworm, and the effect of the treated mulberry leaves on the quality of the silkworm pupa was analyzed. The results showed that the branch length, leaf length, net photosynthetic rate, mulberry leaf yield, total carbon content, total phosphorus content, soluble sugar content and soluble protein content of mulberry trees reached the maximum at treatment C. Compared with the control, they increased by 20.12%, 24.71%, 18.37%, 32.99%, 20.69%, 21.00%, 24.88% and 42.82%, respectively. The leaf width, leaf area and total nitrogen content of mulberry leaves reach the maximum at treatment D. Compared with the control, they increased by 19.87%, 45.06% and 19.55%, respectively. The cocoon weight, cocoon shell weight, cocoon shell rate reached the maximum at treatment C, which increased by 11.64%, 25.64% and 11.42%, respectively. The processing order based on the comprehensive evaluation of the membership function was C>D>E>B>A>CK, among them, treatment C (10 g/L) had the best effect on the growth of mulberry branches, the yield and quality of mulberry leaves, and the quality and quality of silkworm cocoons. In summary, appropriate concentration of Ginkgo biloba exocarp extracts treatment can significantly promote the growth of mulberry branches, improve mulberry yield and quality, and the yield and quality of silkworm cocoons obtained by feeding with treated mulberry leaves are also increased accordingly.

  Preliminary Test Report on Cultivation of Chenopodium quinoa in Beijing Greenhouse Li Mei, Jihua Zhou, Junying Wang 2020, 36 (10):  53-59.  DOI: 10.11924/j.issn.1000-6850.casb19010100 Abstract + ( 324 )   HTML ( 8 )   PDF ( 1311KB )   ( 61 ) To explore the cultivation methods of quinoa vegetables in greenhouse, quinoa seeds harvested in Beijing were used as experimental materials. The dynamic monitoring of quinoa vegetable growth, the comparison of sowing amount and sowing method, the influence of fertilizer on quinoa, the optimal suitable mechanical sowing amount of quinoa, and the comparison of quinoa leaves and grains and other vegetables in nutritional composition were reported to provide a technical reference for the cultivation of quinoa vegetables. The results show that quinoa is a healthy vegetable which is rich in protein, dietary fiber, potassium, magnesium, and low in sodium. From sowing to harvesting, ≥10℃ accumulated temperature is 933.24℃. To facilitate mechanized production and ensure the neat of the group, it is better to choose drill sowing. When the sowing amount was 22.5-24 kg/hm 2, the yield could reach 15143.55-15442.95 kg/hm 2. Compared with the application of chicken dung and non-fertilization, the yield of quinoa under sheep dung is better, and the yield of edible part is 15722.10 kg/hm 2.

  Effects of Different Fertilization Treatments on Fruit Yield and Quality of Citrus grandis var. longanyou Rongfei Li, Mingming Wang, Yi Yang, Yaodong Chang, Kangping Zhang, Guolu Liang, Zhiming Lu, Tao Hu, Youwen Yi, Lirong Su, Qigao Guo 2020, 36 (10):  60-68.  DOI: 10.11924/j.issn.1000-6850.casb18210062 Abstract + ( 522 )   HTML ( 2 )   PDF ( 1532KB )   ( 140 ) 12-year-old Longanyou was used in this experiment as the material, the effects of different fertilization treatments on fruit yield and quality and the correlation between fruit color and luster and inherent quality were analyzed by measuring fruit yield, single fruit weight, fruit color and luster, fruit firmness and inherent quality. The results showed that (1) in 2017, the per plant yield of T1, T2 and T3 increased by 60.10%, 19.11% and 46.17%, respectively, compared with that of 2016, while the per plant yield of T4 decreased by 30.38%, and T2 had the highest per plant yield in both 2016 and 2017 (95.40 kg/plant and 113.63 kg/plant), indicating that fertilization had obvious effect on per plant yield; (2) the effect of fertilization on the color luster of pericarp was not significant, but the color of pulp was significantly affected, the pulp color of each fertilization treatment was orange red, and the color of T2 was darker than that of other treatments, while the color of CK was yellowish green; (3) fertilization significantly affected the pericarp, cysts and flesh firmness of Longanyou, especially on the fruit firmness of upper and lower layers of T2; (4) the content of invert sugar, total sugar, sugar acid ratio and vitamin C all reached the highest in the upper layer fruits of T2, the total soluble solids (13.07% and 13.07%) and solid acid ratio of T3 were the highest, and the content of titratable acidity in both T2 and T3 was relatively low, showing that T2 and T3 were beneficial to improve the inherent quality of fruit; (5) according to the analysis of the correlation between fruit color and fruit quality, it was found that each index of fruit color was closely related with the content of fructose. In conclusion, the amount of sugar may affect the fruit color of Longanyou.

  Comparis on In Vitro Culture of Mature Embryos of Nelumbo from Eight Provenances Worldwide Mi Qin, Fengluan Liu, Qingqing Liu, Jianguo Cao, Yuchu Chen, Daike Tian 2020, 36 (10):  69-78.  DOI: 10.11924/j.issn.1000-6850.casb18120105 Abstract + ( 302 )   HTML ( 1 )   PDF ( 1858KB )   ( 56 ) Establishing a feasible disinfection system for obtaining the germfree mature lotus (Nelumbo) embryos as explants and understanding the differences of in vitro growth of lotus from different provenances is the basis for material selection and evaluation method to construct an efficient in vitro culture and genetic transformation system. Plant preservative mixture (PPM) at different concentrations was used in the pre-culture stage to develop a suitable disinfection system of lotus seeds and a method of acquiring the germ-free lotus embryos. Through this sterilization approach, the in vitro cultured seedlings of lotus from 9 worldwide provenances were successfully obtained. Based on the morphological indexes at different culture periods, the membership function method was used to evaluate the growth differences under the in vitro culture conditions. The results showed that the ideal disinfection system for lotus seeds was 75% alcohol 30 s + 2% PPM 2 h + 0.05% PPM 3-5 d soaking during germination. The in vitro growth differences of the seedlings from the tested lotuses of 8 provenances were mainly observed in the later culture stage, such as the number of leaves, the length and thickness of rhizomes, the number of roots and lateral shoots. The seedlings of lotus from Vietnam and Thailand had the highest growth potential and higher reproduction rate under the same culture conditions. The pre-culture method by soaking lotus seeds with PPM to successfully obtain germ-free lotus embryos has solved the technique problem in disinfecting lotus seeds in the past. The in vitro clones of lotus embryos from the tropical or subtropical regions in both Vietnam and Thailand have stronger growth capacity and therefore are the materials more ideal for establishing regeneration and genetic transformation system of Nelumbo.

  Quality Evaluation of Introduced Phellodendron chinense in Beijing Medicinal Plant Garden Shuo Xu, Xuewei Duan, Zhao Zhang, Jing Yu, Xinlei Zhao, Yongfang Fan 2020, 36 (10):  79-86.  DOI: 10.11924/j.issn.1000-6850.casb20191100855 Abstract + ( 390 )   HTML ( 1 )   PDF ( 1541KB )   ( 150 ) The paper aims to explore the quality and expand the planting area of the Phellodendron chinense introduced into Beijing Medical Plant Garden. The water, total ash, extract, berberine and phellodendron content of the bark of P. chinense introduced into Beijing Medical Plant Garden were determined and compared with the cultivated P. chinense bark in the main producing area and the commercial Phellodendri chinensis cortex, and the quality of the introduced phellodendron bark in Beijing Medical Plant Garden was comprehensively evaluated. The results showed that the moisture content, total ash content, extract content, berberine content and phellodendron content of the dry bark of P. chinense introduced in Beijing Medical Plant Garden was (5.63±0.12)%, (7.30±0.12)%, (23.83±1.68)%, (7.02±0.25)% and (0.44±0.01)%, respectively, which met the requirements of Phellodendri chinensis cortex of Pharmacopoeia of the People's Republic of China(2015, PartⅠ). Compared with the cultivated and commercial Phellodendri chinensis cortex in the main production area, the index components’ content of Phellodendri chinensis cortex from Beijing Medicinal Plant Garden belonged to the middle level. The results show that the quality of the P. chinense introduced into Beijing Medical Plant Garden is good and it could be used as Phellodendri chinensis cortex, which could provide a scientific basis for the northward migration of the cultivation area of Phellodendri chinensis cortex.

  Genetic Diversity of Rice Landraces in Yuanyang Hani Terraced Rice Fields Under In-situ Conservation: Research Progress Liu He, Yingjie Song, Chunlin Long 2020, 36 (10):  87-94.  DOI: 10.11924/j.issn.1000-6850.casb20191100820 Abstract + ( 385 )   HTML ( 3 )   PDF ( 1192KB )   ( 91 ) Taking the current situation of rice landrace in Yuanyang terrace rice fields as an example, the genetic diversity of phenotype and molecule of rice landraces, the effects of ecological environment under in-situ conservation, mainly including geographical conditions and biological factors and the influence of local traditional knowledge and culture on the diversity of rice landrace in Yuanyang County were reviewed. The superiority of protecting rice varieties under in-situ conservation was explored to provide a scientific basis for the protection of rice landraces and related agricultural crop resources.

  The Soil Nutrient Status and Spatial Distribution Characteristics in Luonan Forsythia Planting Area Jiao Zhang, Xiaohu Zhang, Peiyun Yan 2020, 36 (10):  95-101.  DOI: 10.11924/j.issn.1000-6850.casb18120066 Abstract + ( 461 )   HTML ( 4 )   PDF ( 3597KB )   ( 74 ) The purpose is to reveal the spatial variability law of soil nutrients in Luonan County, and provide technical support for scientific fertilization in Forsythia suspensa planting and precision agriculture. We used geographic information technology and geostatistical principles, and based on the information collection of soil samples, analyzed the main nutrients’ status in soil and the spatial variation trend of main nutrients’ indicators. The results showed that soil pH value in Forsythia suspensa planting area was mostly neutral, organic matter was deficient as a whole, especially in the southeast region. Nitrogen decreased from north to south, and it was deficient in southeast region. Available phosphorus content was at a suitable level, decreased from west to east and increased from south to north. Available potassium content was higher, increased from west to east and from south to north. As to the available content of microelements, iron was rich, and manganese, copper and zinc were at suitable level, while boron was deficient. The results can be used for the rational fertilization on Forsythia suspense and its planting layout.

  Spatial Variability of Soil Nutrients in Cultivated Land in Typical County of Hetao Plain Qiang Chen, Jingsong Yang, Rongjiang Yao, Xiangping Wang, Wenping Xie, Fule Zheng, Hai Zhu, Shulin Wang 2020, 36 (10):  102-108.  DOI: 10.11924/j.issn.1000-6850.casb20191000781 Abstract + ( 457 )   HTML ( 9 )   PDF ( 1644KB )   ( 118 ) The paper aims to study the soil nutrient status in Hetao Plain and explore the spatial variability and distribution characteristics of soil nutrients at county scale. By taking the arable land in Hangjinhouqi County as the object, the content of soil organic matter, total soil nitrogen, available phosphorus and rapid available potassium in the cultivated soil were studied, the spatial variability and distribution characteristics of soil nutrients were analyzed by field investigation and geostatistics. The results showed that the average content of soil organic matter, total nitrogen, available phosphorus and available potassium in topsoil in the arable layer was 13.90 g/kg, 0.93 g/kg, 16.25 mg/kg and 170.79 mg/kg, respectively. The soil organic matter and total soil nitrogen in the arable layer were in a deficient state, the content of available phosphorus was moderate, and the rapid available potassium was abundant. From the perspective of spatial variation and correlation, the variation degree of soil nutrients was moderate, the organic matter and rapid available potassium were moderately correlated, and the total nitrogen and available phosphorus were weakly correlated. From the perspective of spatial distribution pattern, the soil organic matter came to a trend of high level in the northwest, low level in the southeast and northeast, and the distribution of soil total nitrogen was similar to that of soil organic matter. The overall distribution of available potassium in soil was relatively balanced; the spatial difference of available phosphorus was obvious, showing a pattern of east high and west low. Concerning the soil nutrient content and distribution in the region, the process of nutrient management should be as following: control the nitrogen, stabilize the phosphorus, stabilize the potassium, combine the planning of the whole district with the key response, and adhere to the organic fertilizer, organic and inorganic combined fertilization strategy. The investigation and statistical analysis of soil nutrient status at the county scale clarified the spatial distribution characteristics of regional soil nutrients and their relationship with land using patterns, providing a scientific basis for soil nutrient management, soil fertility and rational fertilization planning in Hetao Plain.

  Regionalization of the Climate Suitability on Pomegranate Planting in Xianyang Based on GIS Yan Liu, Jin Liu, Wenting Quan, Jinting Wang, Zixuan Wang, Qichen Liang 2020, 36 (10):  109-113.  DOI: 10.11924/j.issn.1000-6850.casb19020036 Abstract + ( 462 )   HTML ( 1 )   PDF ( 2314KB )   ( 127 ) To study the climate suitability of pomegranate planting, make full use of climate resources, and find suitable areas for pomegranate cultivation in Xianyang, based on the latest meteorological observed data of 12 stations in Xianyang from 1988 to 2017, GIS technology was used to carry out climatic suitability regionalization of Xianyang pomegranate cultivation, aiming to provide a basis for pomegranate production and agricultural structure adjustment. There were 8 indices of climatic division for pomegranate, namely, ≥10℃ active accumulate temperature from bud emergence to fruit maturity, ≥10℃ active accumulate temperature during the annual growth period, sunshine hours of the year, sunshine hours on September, precipitation from July to September, the average temperature difference between day and night at 18-21℃, extreme minimum temperature of the year, extreme minimum temperature of ten days. The results showed that: the quality area of pomegranate cultivation accounted for 14.9%, mainly distributed in Sanyuan, most of Jingyang, northwest of Weicheng District, eastern Liquan, and northern Qianxian; the suitable area accounted for 21.3%, distributed in Xingping City, Qindu District, Weicheng District, the southern part of Liquan County, the southern part of Qianxian County and the Taiyuan District of Wugong north; the inferior area accounted for 16.6%, and the unsuitable area accounted for 47.2%. Except Wugong, the south of Xianyang dry belt is a suitable area for pomegranate planting, the light, heat and water climate resources in this area meet all the meteorological factors needed for high-quality production of pomegranate, and the cultivation of pomegranate can be developed in this region vigorously.

  Climatic Characteristics and Forecast Method of Strong Cooling in Eastern Hexi Corridor Jinxiu Zhang, Xiaoling Yang, Zhanfeng Sun, Xiangrong Peng 2020, 36 (10):  114-121.  DOI: 10.11924/j.issn.1000-6850.casb18120061 Abstract + ( 458 )   HTML ( 0 )   PDF ( 1582KB )   ( 208 ) Using strong cooling data [the lowest temperature decline rate of 24 (48) h was ≥8 (10)℃ and the lowest temperature was ≤4℃] of five meteorological stations in eastern Hexi corridor during 1961 to 2010, climatic characteristics of temporal and spatial distribution and intensity of strong cooling were analyzed systematically by statistical methods. The results showed that strong cooling times were more obvious in high elevation mountainous and northern desert edge than that in oasis plain area. Strong cooling times of age and year had an overall reducing tendency. Strong cooling weather occurred mainly from January to May and from September to December, mostly in April. The variable rate of strong cooling times of each strength was relatively large, and strong cooling times reduced rapidly with the cooling intensity increased. The strong cooling intensity of 24 h showed an overall weak reducing tendency, and that of 48 h showed a weak increasing tendency. Selecting ECMWF numerical forecast grid field data at 20:00 day by day from January to May and from September to December during 2004 to 2013, forecast factors were selected initially and precisely by Press criterion and stepwise regression method. The monthly lowest temperature forecast equations of each region were built with optimal subset regression, and the overall situation and optimal forecast equations were determined finally with the CSC double grading criterion. The forecast equations passed significance level examination of α=0.01. Forecast marginal value and forecast rank of strong cooling were determined with the biggest approaches principle. Forecast fitting rate of 24 and 48 h was 80.0%-83.3% and 81.3%-86.2%, respectively, and the forecast accuracy rate of 24 and 48 h was 71.4%-75.0% and 73.3%-77.1%, respectively, reaching high fitting and forecast level, and could provide objective and effective guiding products for strong cooling forecast and early warning.

  Analysis of a Rainstorm Forecast Error in Guangxi on June 12, 2018 Huining Ou, Xin Li, Wei Zhou 2020, 36 (10):  122-126.  DOI: 10.11924/j.issn.1000-6850.casb18110051 Abstract + ( 440 )   HTML ( 2 )   PDF ( 2873KB )   ( 96 ) The paper aims to study the reasons for the omissive forecast in western Guangxi and the empty forecast in eastern Guangxi on a rainstorm in June 12, 2018, and provide reference for future forecast. Based on the conventional ground observation data, sounding data and numerical forecast data, the weather situation and the physical quantity field were analyzed. The results showed that the rainstorm process forecast should not only focus on the large circulation situation, but also consider the moisture and energy conditions. The forecasters’ preconceived forecasting ideas and over-reliance on numerical forecast data made the emphasis on the process of other factors different, and the analysis of moisture, energy and dynamic conditions were not fully grasped. When the effect of short-term and medium-term forecast was not good, it could be compensated by short-term forecast.

  Main Cultivars of Chinese Cabbage in Chengdu Plain: Identification and Evaluation of Clubroot Resistance Wenxian Wu, Lei Zhang, Xiaoqin Huang, Xiaoxiang Yang, Yong Liu 2020, 36 (10):  127-132.  DOI: 10.11924/j.issn.1000-6850.casb19010152 Abstract + ( 334 )   HTML ( 1 )   PDF ( 1181KB )   ( 90 ) To clarify the resistance level of Chinese cabbage varieties against clubroot in Chengdu plain, a total of 45 main cultivars of Chinese cabbage were screened for resistance in three counties, Longxing in Chongzhou, Mengyang in Pengzhou and Taixing in Xindu in 2018. The identification was carried out under field condition by using the method of natural infection, and the resistance level analysis was conducted by investigating the symptom on plant roots. The results showed that the resistance level of the tested Chinese cabbage cultivars to clubroot disease was variable. Four cultivars showed immune to clubroot (disease index=0) in the Chongzhou natural disease nursery, and the ratio was 8.9%, and the other cultivars showed susceptibility (35<disease index≤55) or high susceptibility (55<disease index≤100), accounting for 91.1%. The evaluation of resistance identification in Pengzhou showed that six cultivars were immune to clubroot, eleven cultivars were tolerant to clubroot disease (15<disease index≤35), and the remaining twenty eight cultivars were susceptibility or highly susceptibility. But in Xindu, only two cultivars showed immune resistance, sixteen tolerant cultivars were screened out and twenty six cultivars showed susceptibility or high susceptibility. The resistance of most of the cultivars was susceptible to clubroot, and the resistance of some cultivars showed instability in different areas. Only cultivar Meichun and Shangpin exhibited stable immune to clubroot in the three regions, which were suitable for planting in the epidemic areas of clubroot disease, and could be used for further study on resistance breeding.

  Effect of Bemisia tabaci B Infestation on Growth of Three Cucurbitaceae Host Plants Xin Liang, Haipeng Zhao, Xia Sun, Yanan Xu, Zhifei Jia, Ming Xue 2020, 36 (10):  133-139.  DOI: 10.11924/j.issn.1000-6850.casb19010126 Abstract + ( 387 )   HTML ( 2 )   PDF ( 1350KB )   ( 83 ) In this study, the effect of Bemisia tabaci B infestation on the growth and development of zucchini, pepo and towel gourd were investigated through measuring the growth indexes and chlorophyll content of these three Cucurbitaceae host plants by ruler measurement, oven drying and spectrophotometry after B. tabaci infestation. The results showed that feeding of B. tabaci B had a significant negative effect on the growth of all the three Cucurbitaceae host plants. After 30 d of infestation, the plant height, stem diameter and leaf area of zucchini all significantly decreased, with an inhibition ratio of 35.08%, 4.38% and 20.73%, respectively, compared with the uninfested plants, and the dry weight was 31.86% lower than that of the control. Plant height of the affected towel gourd significantly reduced compared with that of uninfested control plants, and the inhibition rate was 31.47%, while the stem diameter, leaf area and dry weight of towel gourd were not significantly affected after B. tabaci infestation. Similarly, the stem diameter and dry weight of pepo all obviously decreased compared with that of the control plants, however, the plant height and internode length of pepo increased, with an inhibition rate of -28.69% and -42.63%, respectively. Biochemical assays showed that the leaf chlorophyll content of the three host plants decreased significantly after B. tabaci B infestation, especially the zucchini, of which the chlorophyll a and b content decreased by 68.22% and 64.63%, respectively.

  Design of Centralized Feed System for Biomass Pellet Fuel and Its Application in Tobacco Leaf Baking Duzhong Jiang, Honglang Chen, Yang He, Shen Tang, Xinbai Nie, Dawei Zhang, Qingsong Cheng, Quanliu Yang 2020, 36 (10):  140-144.  DOI: 10.11924/j.issn.1000-6850.casb19010042 Abstract + ( 352 )   HTML ( 2 )   PDF ( 1548KB )   ( 76 ) To explore the efficient application of biomass particle burner in baking workshops or baking barns, a centralized feed system for biomass pellet fuel was designed to realize the automatic supply of biomass particle fuel in baking barns. The results showed that using biomass pellet fuel for heating tobacco curing could control temperature and humidity accurately, and the curing process was easy to be in place, which was conducive to improving the quality of tobacco curing and reducing the energy consumption cost of tobacco curing. The centralized feed system for biomass pellet fuel could realize the automatic supply of biomass pellet fuel in each curing room, and there was no material shortage during the whole baking process. So it could reduce the labor of tobacco leaf curing operation, and cut the labor and cost of tobacco leaf curing.

  Nutritional Quality of Allium cepa Varieties: Analysis and Assessment Haifeng Yang, Wei Chen, Linchong Hui, Guolei Huan, Weiya Li, Linyu He, Zhentai Chen, Meihua Miao, Meihong Pan 2020, 36 (10):  145-149.  DOI: 10.11924/j.issn.1000-6850.casb19010080 Abstract + ( 537 )   HTML ( 5 )   PDF ( 1275KB )   ( 134 ) To evaluate the nutritional quality of onion (Allium cepa) varieties from different sources and screen germplasms rich in nutrients, four nutritional quality parameters including compactness, dry matter content, soluble solid content and pyruvic acid content of 30 onion varieties were determined. A comprehensive evaluation on nutritional quality of onion was conducted with membership function from the fuzzy math and correlation analysis. The results showed that there were some differences of compactness, dry matter content, soluble solid content and pyruvic acid content in the 30 onion materials. The variation coefficient of compactness was the smallest, while that of pyruvic acid content was the largest. In addition, this study found that the dry matter content was extremely significantly correlated with soluble solids content, and significantly correlated with pyruvic acid content. Among the 30 onion materials, ‘Sterile line A1’ has the best comprehensive nutritional quality, which can provide the material foundation for onion quality breeding.

  Research on the Development Strategic of Family Farm in China Based on SWOT-AHP Model Peng Wang, Gang Yang 2020, 36 (10):  150-157.  DOI: 10.11924/j.issn.1000-6850.casb20191100805 Abstract + ( 513 )   HTML ( 3 )   PDF ( 1331KB )   ( 365 ) The paper aims to comprehensively analyze all factors affecting the development of family farm, and formulate its reasonable development strategy. We combined SWOT analysis method with analytic hierarchy model to construct the analysis model of family farm, then calculated the weight of those factors, and determined the development strategy of the family farm. Research shows that: first, the best way to develop family farm is focusing on striving strategy at present, in other words, using the external opportunities of family farm to overcome the internal obstacles, such as improving the land transfer system actively, enhancing the infrastructure construction and cultivating new professional farmers; second, taking pioneering strategy as the supplementary, consolidating the advantage of scale efficiency and product competitiveness, such as speeding up the circulation of land, and introducing advanced science technology and management technology.

  Study on the Specific Performance and Induced Problems of Rural Decline in Southwest China Ligui Tang 2020, 36 (10):  158-164.  DOI: 10.11924/j.issn.1000-6850.casb18120053 Abstract + ( 512 )   HTML ( 7 )   PDF ( 1270KB )   ( 75 ) The paper aims to study the decline of rural areas in the southwest mountainous areas through the case of three villages in Chongqing. The study found that the phenomena and problems of rural decline in the southwestern region have become more serious due to the influence of geographical features, production conditions and living patterns. It has shown a large outflow of population, an increase in farmland abandonment, an increase in the vacancy rate of agricultural houses, aging of farmers, a low level of farming willingness, a decline in the proportion of agricultural income in household income, an outbound shift of compulsory education, and a weakening of village self-governing organizations. These phenomena have caused problems of rural pension, agricultural industry development, rural governance and rural civilization. The article proposes that to promote rural revitalization, we should fully consider regional differences and make decisions based on local conditions, highlight local culture and rural pension issues, activate rural resources, enrich agricultural forms, and boost the rural economy.