Effects of Different Chemical Fertilizer Reduction Techniques on Flue-cured Tobacco Production

[Objectives]This study was conducted to find out the most suitable special formula fertilizer for flue-cured tobacco production in tobacco-growing areas of Zhaotong City,so as to provide a basis for scientific fertilization and reduced application of inorganic fertilizers with improved efficiency in tobacco production in Zhaotong City.[Methods]Different formulas of special base fertilizer and special topdressing for tobacco were designed by optimizing and adjusting the application amounts and proportions of nitrogen,phosphorus,potassium and medium trace elements in fertilizer formulas,and the formulas of special base fertilizer and special topdressing for flue-cured tobacco production were selected through a field plot experiment.[Results]The combination of special base fertilizer and special topdressing was conducive to the early growth and rapid growth of tobacco plants under the condition of reduced fertilizer application,and the treatment using organic-inorganic compound fertilizer as the special base fertilizer was the most obvious,with an average growth period of two days increased.Compared with conventional fertilization,the yield,output value,average price,proportion of superior tobacco and proportion of medium and superior tobacco increased in the organic-inorganic compound fertilizer treatment,with the yield increasing by 5.96%,the output value increasing by 17.08%,the average price increasing by 10.49%,the proportion of superior tobacco increasing by 4.63%,and the proportion of medium and superior tobacco increasing by 2.44%.It was concluded from indexes including growth period,agronomic traits,disease incidence and economic traits,the fertilization mode of organic-inorganic compound fertilizer with the addition of trace elements(boron,magnesium and zinc)applied as the base fertilizer and nitrogen and potassium topdressing was most efficient and economic.[Conclusions]This study provides a basis for scientific fertilization and reduced application of inorganic fertilizers with improved efficiency in tobacco production in Zhaotong City.

Changes of Granule Structure and Enzyme Hydrolysability of Starch in Upper Flue-cured Tobacco Leaves During Bulk Flue-curing

[Objective] This study aimed to investigate the changes of granule struc- ture, characteristic and related enzymatic activity of starch in upper flue-cured tobac- co leaves during bulk flue-curing process, to provide theoretical basis for reasonably regulating the starch content in upper flue-cured tobacco leaves and improving the quality of upper flue-cured tobacco leaves. [Method] Changes of amylase activity, enzyme hydrolysability and granule structure of starch in upper flue-cured tobacco leaves were studied during flue-curing process using conventional physical and chemical analysis and SEM. [Result] During the flue-curing process, the starch con- tent of tobacco leaves changed greatly at yellowing stage, and the activity of amy- lase presented the double-peak curve. The SEM observation results showed that most of the starch granules in fresh tobacco leaves were spheroidal and long cylin- drical, while some individuals were in irregular shape, with obvious groove-like in- vagination and layered structure on granule surface; during the flue-curing process, a large amount of starch granules showed layered structure on the surface at yellow- ing stage, and the long cylindrical starch granules were reduced greatly; at the end of flue-curing, there were barely any long cylindrical starch granule in flue-cured to- bacco leaves. Average long-axis-diameter of starch granules in fresh tobacco leaves was 3.21 μm, showing an overall gradually increasing trend during the flue-curing process, which was significantly enhanced at 38 and 42 ℃. The diameter of starch granules increased by more than 60% at the end of 42 ℃ and there was no re- markable difference after 47 ℃. During the flue-curing process, enzyme hydrolysabil- ity of starch in flue-cured tobacco leaves first increased, reached a peak at 38 ~C, and then decreased. [Conclusion] During the bulk flue-curing, the yellowing stage is the critical period for starch content, granule structure and characteristic changes of flue-cured tobacco leaves, it is of positive effects to improve the quality of upper flue-cured tobacco leaves by regulating the flue-curing conditions at yellowing stage.

Effects of Plant Growth Regulator on Absorption,Circulation and Contents of Potassium in Flue-cured Tobacco

[Objective] This study was to investigate the effects of plant growth regulator on accumulation and circulation of potassium in flue-cured tobacco.[Methods] Hydroponics experiment was adopted to study the effects of plant growth regulator（NAA,GA3,BR） on accumulation and circulation of potassium in flue-cured tobacco.[Results] The BR treatment increased the absorption of potassium,calcium and magnesium in flue-cured tobacco,reduced the potassium emission from the root,enhanced the accumulation and contents and promoted the circulation of potassium in the tobacco plants.There was no statistical difference between the NAA and GA3 treatment.And BR treatment was 0.52%,0.30%,0.28% higher than NAA treatment in enhancing potassium content in tobacco plants at 2,7,12 d after topping.In a word,the results showed that BR treatment was the most.[Conclusion] BR treatment could effectively enhance potassium content in tobacco plants after topping.

Construction of Anti-breaking Models of the Main Veins of Flue-cured Tobacco Leaves and Principal Component Analysis

[Objective] This study aimed to explore the related mechanisms of the breaking of flue-cured tobacco leaves. [Method] Anti-breaking models of the main veins of flue-cured tobacco leaves were constructed for principal component analysis on the anti-breaking index, leaf traits and cellulose contents. [Result] The results showed that the growth traits had certain relevance with the cellulose contents while the leaf weight assumed a significant negative correlation with the anti-breaking index, indicating that the heavier the leaf weight was, the weaker the anti-breaking capacity of flue-cured tobacco would be; the cross-sectional area of main veins and the cellulose contents had shown a positive correlation with the anti-breaking index, indicating that the thicker the main vein of flue-cured tobacco was, the higher the cellulose contents would be, and the stronger the anti-breaking capacity of flue-cured tobacco leaves would be. [Conclusion] This study provided theoretical basis and reference to improve tobacco production and enhance the quality of flue-cured tobacco.

Effects of Biological Organic Fertilizer on Flue-cured Tobacco Chemical Composition

Through field experiment,special biological fertilizer and cake fertilizer were applied collectively to tobacco,and chemical compositions of Wanxi flue-cured tobacco leaves were researched.The results showed that the increase of biological organic fertilizer would significantly improve soil nutrient supplying capacity.Compared with conventional fertilization,the contents of reducing sugar,total sugar and starch in different parts of tobaccos which were applied with biological organic fertilizer were closer to standards of excellent tobacco.In the treatment,the ratio of reducing sugar and nicotine in tobacco was more suitable in middle and lower parts of the plant and the contents of total N,nicotine and chlorine in tobacco were lowered,improving tobacco quality.

Effects of Vermicompost on Agronomic Characters and Yield and Quality of Flue-cured Tobacco

The effects of vermicompost on the agronomic characters and yield and quality of flue-cured tobacco were investigated. The results showed that, the field growth periods of various treatments were 117-118 d, 1-2 days longer than that of the CK. The numbers of effective leaves of the treatments applied with vermicompost were 0.1-0.3 leaf more than the CK. The highest yield and the highest proportion of high-grade tobacco occurred in treatment 3 as 2 095.5 kg/m^2 and 49%, respectively, which were higher than those in the CK by 6.58 kg and 5.3%. In conclusion, the treatment with the application of vermicompost at 7 500-10 500 kg/hm^2 was the best.

Effects of Different Transplanting and Harvest Dates on Yield and Quality of Flue-cured Tobacco Leaves

In this study,the effects of nine different combinations of transplanting and harvest dates on yield and quality of flue-cured tobacco leaves were investigated.The results showed that different combinations of transplanting and harvest dates had few effects on growth period and agronomic characters of tobacco plants but exerted remarkable effects on economic characters and chemical composition of flue-cured tobacco leaves.With the postponing of transplanting stage,output value of flue-cured tobacco leaves increased.Output value of flue-cured tobacco leaves in C1treatment（normal harvest） was higher than that in C2（harvest 7 d later） and C3（harvest 14 d later） treatments.Different combinations of transplanting and harvest dates had significant effects on chemical composition of flue-cured tobacco leaves,which exhibited no obvious law.Overall,flue-cured tobacco leaves in T3C1treatment（transplanting 14 d earlier,normal harvest） displayed excellent performance compared with other treatments.

Effects of Soil Amendment on Growth,Yield and Output of Flue-cured Tobacco in South Anhui Province

[Objective] The aim of this study was to evaluate the effects of soil amend- ment composed of biochar and inorganic mineral material on growth and develop- ment, yield and output value of flue-cured tobacco in South Anhui Province. [Method] A field plot experiment was conducted. The agronomic traits, yield and output value, as well as appearance quality and flavor of flue-cured tobacco were evaluated. [Re- suit] The soil amendments composed of biochars and inorganic mineral materials could significantly increase plant height, stem diameter, leaf size, yield and output of flue-cured tobacco, as well as proportion of first-grade tobacco leaves at the middle and late growth period. The yield in the X3 treatment group （70% T20 ＋ 30% ZC） was highest, and it was higher than that in the control group by 398 kg/hm2. Com- pared with that in the control group, the output of flue-cured tobacco in the X3 treatment group was increased by 10 290 yuan/hm2. In terms of appearance quality and flavor, the flue-cured tobacco leaves in the soil amendment treatment groups were all better than those in the control group. [Conclusion] The application of soil amendment composed of biochar and inorganic mineral material is an effective mea- sure to improve tobacco-growing soil, promote tobacco growth and development, im- prove tobacco yield and output and improve tobacco leaf quality in South Anhui re- gion.

Variation of Enzyme Activity in Flue-cured Tobacco-growing Soil Planted with Different Lastseason Crops

The rice soil （last crop was rice） and arid red soil （last crop was corn） were used as a test material for the pot experiment. The variation of enzyme activi-ty in flue-cured tobacco-growing soil planted with different last-season crops was in-vestigated at different growth stages in this study. The results showed the activity variation of the 3 enzymes differed in the 2 soils at different growth stages. The catalase activity in the arid red soil trended to decrease overal from the vigorous growing stage to harvesting stage; while it decreased gradual y in the rice soil until the harvesting stage. The phosphatase activity in the 2 soils al increased with the proceeding of growth period. The urease activity in the arid red soil decreased gradual y at different growth stages, but the variation of urease activity in rice soil was irregular. During the growth of flue-cured tobacco, the catalase and urease ac-tivity in the arid red soil increased first and then decreased, and the phosphatase activity increased gradual y. ln rice soil, the catalase activity increased first and then decreased; the phosphatase activity decreased first and then increased; the urease activity increased first, then decreased and increased last. The activity of al the en-zymes in the 2 soils showed significant differences compared to the control except some enzymes at the vigorous growing stage. lt was suggested the planting of flue-cured tobacco would affect greatly the soil enzyme activities.

Effects of Applying Bio-bacterial Fertilizer on Aroma Components of Flue-cured Tobacco

Objective] This research aimed to investigate the effects of bio-bacterial fertilizer on quality of flue-curved tobacco. [Method] The various concentrations of bio-bacterial fertilizer were applied to flue-cured tobacco as leaf fertilizer and base fertilizer respectively. [Result] The effect of bio-bacterial fertilizer on flue-cured tobac-co differed among different treatments. Compared with the control, the bio-bacterial fertilizer significantly affected the quality of flue-cured tobacco. Among al the treat-ments, Treatment 3（leaf fertilizer） showed the best treatment effect, and it significant-ly improved the quality of flue-cured tobacco. [Conclusion] The bio-bacterial fertilizer showed significant improving effect on quality of flue-cured tobacco if spayed as leaf fertilizer.

Effects of Bamboo Vinegar on Seed Germination and Seedling Growth of Different Flue-cured Tobacco Varieties

[Objective] The present experiment was conducted to study the effects of bamboo vinegar on seed germination and seedling growth of different flue-cured to- bacco varieties, so as to provide some references for its application in tobacco pro- duction. [Method] By using indoor culture dish method and greenhouse seedling- raising plate culture,four different concentrations of bamboo vinegar dilution （50, 100, 200 and 400 times）were designed and clean water was used as the control （CK）. The germination indices of Yunyan 97, Guiyan 2, Jiucaiping 2 and Bina 1 were de- termined after seed germinating. The seedling growth indices of Yunyan 97 were investigated after 10 days of spaying bamboo vinegar on seedling leaves at the 3r~ time. [Result] Compared with CK, different bamboo vinegar dilutions could inhibit the seed germination and seedling growth of all flue-cured tobacco varieties. The seed germination rate and index, vigor index, whole length, root length, stem length and fresh weight of seedlings of all varieties presented decreasing trend to varying de- grees, moreover, most of them reached significant level. Compared with CK, spray- ing different concentrations of bamboo vinegar dilution at the seedling stage could improve the quality of seedlings. In all bamboo vinegar treatments, the plant height, the maximum leaf length and root volume under 100 times dilution treatment were the highest with 3.36 and 10.14 cm, and 0.92 ml, respectively. And the stem girth, dry weight and the maximum leaf width of seedlings under 400 times dilution treat- ment also showed the highest with 1.82 cm, 0.262 g and 5.74 cm, respectively. [Conclusion] Supplying different concentrations of bamboo vinegar solution on culture dish could inhibit the seed germination and seedling growth of flue-cured tobacco, while spraying 100-400 times bamboo vinegar solution to leaves could promote the seedling growth and improve the quality of Yunyan 97 to varying degrees.

Analysis of F_1 Heterosis of Potassium Content on Self-bred High-potassium New Strains of Flue-cured Tobacco

F1 potassium heterosis of 8 flue-cured tobacco varieties and 6 self-bred high-potassium new strains were studied. The results showed that the F1 mean het- erosis of potassium content had differences between different parts of plants, showing B2F （8.45%）〉X2F （7.59%）〉C3F （5.64%）; the F1 over-parent heterosis of potassium content of various parts was not obvious, showing X2F （0.05%）〉C3F （-0.43%） 〉B2F （-0.48%）; the F, control heterosis of potassium content of different parts showed B2F （17.81%）〉X2F （4.06%）〉C3F （1.12%）. The variance of GCA of potassium content in various parts of the 6 self-bred high-potassium new strains was significant or extremely significant, and all leaves of GK2 had greater GCA effect on potassium content; C3F and X2F of GK7 had good GCA effect on potassium con- tent, but GCA effect was bad in B2F; GK9 preformed well in B2F but badly in C3F. The variance of SCA in all combinations was extremely significant, and the good combinations included Duoye 87xGK7 （17.19%） in B2F, Duoye 87xGK2 （25.63%）, ChangbohuangxGK5 （19.43%）, Yunyan 87xGK7 （22.78%）, and Yunyan 87xGK9 （24.38%） in C3F, Coker176xGK7 （19.87%）, 101xGK9 （15.89%）, Yunyan 85xGK9 （19.15%）, and Yunyan 87xGK9 （20.74%） in X2F.

Investigation and Analysis of Continuous Cropping of Flue-cured Tobacco in Henan Province

The continuous cropping of flue-cured tobacco in the major producing areas of Henan Province by designing questionnaire, fieldwork, enquiry and phone calls, mails, and other forms, the data were obtained then classified and analyzed. The results showed that the main planting areas of flue-cured tobacco were in Nanyang, Xuchang, Luoyang, Sanmenxia, Pingdingshan, and Luohe where were the major producing areas of succession cropping of flue-cured tobacco with percentage of 20%-40% for three years and over three years, and a few places up to 50%. Morbidity was common with wide distribution, and the main diseases were black shank, viral disease, and black rot. It proved that tobacco was not suitable for continuous cropping. Both of tobacco disease and pest rate and mortality significantly increased by more than 40% under continuous cropping for three years and over three years, and the yield and quality of flue-cured tobacco also decreased after continuous cropping. For many places, the tobacco yield started to decrease in the second year of continuous cropping, and after three-year cropping, the yield decreased in the range of 9%-24%. Continuous cropping for a long time would make a serious decline in the quality of tobacco, resulting in non-economic benefits. Therefore, in order to reduce the occurrence of diseases and economic loss in tobacco production, it is recommended to avoid continuous cropping, or to adopt appropriate measures to control tobacco continuous cropping obstacles in the unavoidable case.

Variation and Influence Factors of Yield Gravity Center of Flue-cured Tobacco in Hunan

The variation and influence factors of yield gravity center of flue-cured tobacco in Hunan were studied in 2006-2015 by regional gravity center method and grey correlation analysis. The results showed that the yields of flue-cured tobacco in various areas in Hunan were mainly of the growing with fluctuation type. The yield gravity centers in the whole province and eastern, southern and western Hunan tobacco-growing areas overall moved in the north by west, south by west, west by south, and south by east directions, respectively; and the movements in the south-north direction were in order of eastern Hunan tobacco-growing area 〉whole province 〉western Hunan tobacco-growing area 〉southern Hunan tobacco-growing area, and the movements inthe east-west direction showed an order of eastern Hunan tobecco-growing area〉western Hunan tobacco-growing area〉whole province〉 southern Hunan tobacco-growing area. The main influence factors of the coordinates of the longitudes and the latitudes differed. The main influence factor was planting area in most cities or counties in the whole province, and was per unit area yield in a few cities or counties. It is advised to construct the ＂one main body and two wings＂ development pattern of flue-cured tobacco production in Hunan with southern Hunan tobacco-growing area as the main body and western and eastern Hunan tobacco-growing areas as the two wings.

Effects of Different Yellowing Conditions on Neutral Aroma Components and Smoking Quality of Flue-cured Upper Leaves

A heated air circulation standard curing barn was used for baking tobacco leaves, and the effects of different yellowing conditions during the baking process on contents of neutral aroma components and smoking quality of upper leaves were studied by setting different yellowing time and color-fixing time. The results showed that during the baking process, only by prolonging the yellowing time by 24 h on the basis of control, the content of every kind of neutral aroma components in- creased obviously and the content of solanone increased by nearly 2.20 times. It was unfavorable for the degradation and accumulation of aroma components when only prolonging color-fixing time by 24 h. Prolonging both yellowing time and color- fixing time by 24 h mainly promoted the accumulation of chlorophyll degradation product neophytadiene, which increased by 33.24%, while the degradation and ac- cumulation of some aroma components were inhibited, indicating that only prolonging the yellowing time by 24 h could promote the accumulation of various kinds of neu- tral aroma components and improve the quality of tobacco leaves. The regression models were established of neutral aroma components in the first and second prin- cipal components to total aroma content, which were y=x＋0.053 47 （R^2=0.919 7） and y=x＋0.147 5 （R^2=0.698 4）, respectively, and they were verified to be feasible.

Effects of Tobacco-dedicated Plant Nutrition Regulators on Yield and Quality of Flue-cured Tobacco Leaves

During 2012-2014,field trials were carried out in Huili County,Dechang County and Mianning County of Liangshan Yi Autonomous Prefecture to investigate effects of tobacco-dedicated plant nutrition regulators on yield and quality of fluecured tobacco leaves,aiming at providing reference for tobacco production.According to the results,in tobacco fields applied with tobacco-dedicated plant nutrition regulators,growth period of tobacco was shortened compared with control group;botanical characters（plant height,stem girth,the maximum leaf length,the maximum leaf width,internode length and leaf number） were superior to control group;after application of tobacco-dedicated plant nutrition regulators,yield,output value and the proportion of high-grade and middle-grade leaves were significantly improved compared with control group;moreover,flue-cured tobacco leaves exhibited more coordinated chemical composition.

Characterization of 124 Flue-cured Tobacco Germplasm Resources

[Objective] This study aimed to characterize 124 flue-cured tobacco germplasm resources, and to provide reference for making the best use of the existing flue-cured tobacco germplasm resources. [Method] A total of 124 flue-cured tobacco germplasm resources were studied via field experiment and statistic analysis to investigate characteristics of their growth period, morphologic characters, main agronomic traits, and economic characters. [Result] There were significant differences among the 124 flue-cured tobacco germplasm resources in growth period, morphologic characters, main agronomic traits, and economic characters. The coefficients of variation （CV） varied in a range of 7.9%-22.5%. Among them, CV of bud stage was higher, and that of corolla length was lower. Many germplasm resources were attacked seriously by black shank disease at the end of field experiment, including those with disease index higher than 90, like Kutsaga 110, TI706, Ky 151, KM10, Longshe, Chaoxian Kangchi, Kutsaga 51E, Yongding No.1, and those with disease index among 75-90 such as Liaoyan No. 8, Lingnong No.2, Shandong Duoye, 581, Cunjingyan, KRK26, and Special 400. The tobacco root knot nematode invasion was light in some germplasm or never happened in other germplasm resources. TMV happened sporadically. CV 87, Yunyan 99, Yunyan 85, K326, Yunyan 87, Zhubuo No.1, T64 and T66 produced higher yield, production value, proportion of good leaves and sold at a higher price. Finally, we screened out the germpalsm resources with good comprehensive economic values and high disease resistance such as CV 87, Yunyan 99, Yunyan 85, K326, Yunyan 87, Zhubuo No.1, T64, T66, Honghuadajinyan, G-28, Taiyan No. 8, 77089-12, Yunyan 97, K346, V2, K149, NC567, NC297, Yunyan 201, Yunyan 203, KRK22. [Conclusion] This study provides reference for making better use of tobacco germplasm resources, and breeding new varieties.

Suitable Region for Flue-cured Tobacco (Nicotiana glauca L.) Planting Based on Spatial Scene Similarity

[Objective] The aim was to establish a model based on spatial scene similarity, for which soil, slope, transport, water conservancy, light, social economic factors in suitable planting areas were all considered. A new suitable planting area of flue-cured tobacco was determined by comparison and analysis, with consideration of excellent area. [Method] Totaling thirty natural factors were chosen, which were clas- sified into nine categories, from Longpeng Town （LP） and Shaochong Town （SC） in Shiping County in Honghe Hani and Yi Autonomous Prefecture. [Result] According to weights, the factors from high to low were as follows： soil〉light〉elevation〉slope〉 water conservancy〉transport〉baking facility〉planting plans over the years〉others. The similarity of geographical conditions in the area was 0.894 3, which indicated that the planting conditions in the two regions are similar. If farmer population in unit area, farmland quantity for individual farmer, labors in every household, activity in planting flue-cured tobacco and work of local instructor were considered, the weights of different factors were as follows： farmer population in unit area〉farmland quantity for individual farmer〉farmers＇ activity in planting flue-cured tobacco〉educational back- ground〉labor force in every household〉instructor〉population of farmers＇ children at- tending school. The similarity of geographical conditions was 0.703 1, which indicated that it is none-natural factors that influence yield and quality of flue-cured tobacco. [Conclusion] According to analysis on suitable planting area of flue-cured tobacco based on assessment of spatial scene similarity, similarity of growing conditions in two spatial scenes can be analyzed and evaluated, which would promote further exploration on, influencing factors and effects on tobacco production.

The Effects of Climate,Soil and Cultivar on the Content of Surface Trichome Exudates from Fresh Flue-cured Leaves

[Objective] The aim was to study the effect of climate and soil on the content of surface trichome exudates from fresh flue-cured leaves. [Method] The experiment was conducted in 2009 in Longgang, Weining and Tianzhu of Guizhou Province with flue-cured tobacco variety Yun 85. Mature tobacco leaves were taken from lower, middle and upper plant positions respectively and major cuticular com-ponents of the leaves were extracted with methylene chloride and their chemical compositions were analyzed with GC-MS. [Result] The result showed that there was large difference among trichome exudates of leaves grown under different climatic conditions. The leaf trichome exudates from Tianzhu were quite higher than those from Weining and Longgang, and trichome exudates difference between Tianzhu and Longgang was significant. Soil conditions had considerable effect on the content of tobacco leaf surface trichome exudates, leaf from Longgang soil had highest con-tent, fol owed by Tianzhu soil leaf, Weining soil leaf had lowest content. Under vari-ous climatic conditions, the contents of leaf trichome exudates of same soil were in-consistent, indicating the presence of certain climate and soil factor interaction; The contents of leaf trichome exudates from four cultivars in Longgang showed large difference, Nanjiang 3 was the lowest, fol owed by K326, Guiyan 201 was high, and Yunyan85 the highest. The content of leaf trichome exudates of Yunyan85 was more than two times of that of Nanjiang 3. [Conclusion] The Effect of climate factor on the content of leaf trichome exudates was greater than that of cultivar, which was then larger than soil condition.

Major Cultivation Technology of HQ No.1, a New Flue-cured Tobacco Cultivar

The transplanting period, density, the number of left leaves and fertilizer amounts of HQ No.1 were explored in Hengyang. The results showed that with transplanting periods of March 5-March 15, and planting space of 120 cmx（50-60） cm, agronomic and economic characters of tobaccos showed insignificant differences. Specifically, plant height was growing upon the number of left leaf and fertilizer amount; tobacco yield and output value kept increasing upon fertilizer, and both reached maximums with pure N at 195 kg/hm^2, showing significant differences with the treatment of pure N at 135 kg/hm^2; the number of left leaf had the least effects on agronomic and economic characters of tobaccos. The research indicated that highly-qualified HQ No.1 can be produced, given that tobaccos are transplanted during March 10-March 15, planting density of 15 000-16 500 seedlings/hm^2, the number of left leaves of 22-24 leaves per seedling, and pure N of 150-165 kg/hm^2 in Hengyang.