Study On The Flue-cured Tobacco Ecological Suitability Evaluation Based On GIS And Computational Intelligence

Habitats have a great effect oncrops growth and quality.Modern agriculture management aims to optimally allocate crop planting through measuring the coupling of designating crop to given land, and Crop ecological suitability evaluation is therefore hold the most effective means to assess coincidence degree between crops growth requirements for ecological environments and available ecological features.Nowdays crops ecological suitability evaluation research mainly focuses on the selection of evaluation indices as well as the assessment methods application.And the hierarchy of evaluation index is mostly built by selecting climatic factors and several soil physical and chemical features.However,crop quality is determined by site conditions,especially the comprehensive influence of soil Geochemistry and climatic elements.Evaluation methods mostly concentrate on building linear relationship between crops quality and ecological factors,which rather hardly can depict ecological environment actual consequence.Meanwhile,available successful crops ecological suitability evaluation cases just limit on some trial points and in regional level,more just use the result of a selected point to replace the situation in the entire area or simply apply single interpolation technology regardless of topography difference..With the standardization of artificial measures has been widely practiced,it is hold that the crop quality could be similar within a detailed geography grid unit and that the same cultivar quality could be similar with almost the same similar ecological environment.The more similar ecological environments,the more similar the crop quality is.Based on this premise,in this study,50m grid was chosen as basic unit,and a GIS-based decision support system was built for evaluating flue-cured tobacco ecological suitability in flue-cured tobacco-planting areas,Chongqing,China.This was done by integrating computational intelligence technology which is of strong strength in dealing with complex nonlinear relationship, spatial analysis and mathematical statistics.The spatial distribution of Climatic factors,54 soil geochemical elements as well as terrain and their influences on flue-cured tobacco quality were given detailed analyses.And climate suitability,soil geochemistry suitability,topography suitability and ecological comprehensive evaluations were punitively calculated in detailed grid scale.The results are summarized as follows:1.Flue-cured tobacco leaves quality characteristic and comprehensive evaluation(1)Flue-cured tobacco leaves quality characteristic analysis.270 flue-cured field monitored tobacco leaves from the year of 2004-2007 were chosen as samples and chemical compositions were given detailed analyses.The results showed that the concentrations of total sugar,reducing sugar and potassium are slightly higher while the concentration of chlorine is very low.The concentrations of total alkaloid,nitrogen are in fitting value range.In terms of tobacco leaves chemical compositions coordination degrees,sugar/nitrogen,sugar/alkaloid and potassium/chlorine are all slightly higher whereas nitrogen/alkaloid is slightly low.Generally,Chongqing flue-cured tobacco leaves are of good combustibility,the aroma type of flue-cured tobacco is light but the acid alkali balance is under normal.(2)The comprehensive quantitative evaluation system of flue-cured tobacco leaves quality.In this study,chemical compositions were used to assess tobacco leaves quality.Indices that influence leaves quality were selected as follows:reducing sugar,total alkaloid,chlorine,potassium,nitrogen, potassium/chlorine,sugar/alkaloid and nitrogen/alkaloid through rough sets attributes reduction.The flue-cured tobacco leaves comprehensive quantitative evaluation system was constructed by setting scoring standards for selected indexes.(3)Flue-cured tobacco leaves quality comprehensive evaluation.270 samples were scored by entropy-weight method and the evaluation results show that Chongqing flue-cured tobacco quality can be classified into 4 types.For typeⅠ,the concentrations of total sugar,reducing sugar,total alkaloid and total nitrogen as well as all chemical compositions coordination degrees all fall into fitting value range,and the concentration of chlorine is low.Leaves that belong to typeⅡcontain sufficient total sugar,reducing sugar,total potassium and total nitrogen.Sugar/nitrogen, potassium/chlorine,nitrogen/potassium all are in fitting range.However,the concentration of potassium is a bit low and sugar/potassium is a bit high.For typeⅢ,although the concentrations of total alkaloid,total nitrogen and sugar/alkaloid as well as potassium/chlorine are in fitting range,but the concentrations of total sugar,reducing sugar,potassium are on the low side,sugar/alkaloid, nitrogen/alkaloid are on the high side.Leaves that were classified as type TV contain sufficient alkaloid and total nitrogen,potassium/chlorine as well as nitrogen/alkaloid also are the fitting range, however,the concentrations of potassium,chlorine are on the low side and sugar/nitrogen, sugar/alkaloid are on the high side.In terms of regional distribution,the samples from the areas of Qianjiang,Wulong,Youyang and Penshui which all locate in the southeast of Chongqing contribute to moreⅠtype,followed by Nanchuan,Wushan,Wuxi,Fengjie and Fuling.Leaves of type I leaves from samples of Qijiang and Xiushan are almost unavailable.2.Climatic factors influence on flue-cured tobacco leaves qualityDue to distinct tri-dimensional climate character in Chongqing flue-cured tobacco planting area, the integration of GIS,multi-factors sunshine hours simulation and small grid simulation methods which consider the topographic elements including elevation,slope,aspect,hill shade,latitude and longitude was applied to simulate climatic factors spatial distributions.The characteristics of regional distribution and influences on leaves quality were given detailed analyzed.Based on analysis results,climate suitability detailed were conducted by combing fuzzy mathematics and AHP. The results are depicted as follows:(1)The spatial distributions of average temperatures within tobacco growth season show similar trend,that is,the temperature of the area of the north-central is relatively high,and then gradually decreases toward southeast and northeast,and in the areas of Sizhu and Wuxi,the average temperature are found lowest.Globally,rainfalls of the whole fields season are quiet sufficient but within different growth stages,the spatial distribution difference is obvious.The whole sunshine hours of the fields growth season range from 435.977h to 921.586h,and appear strong positive correlation with elevation element.(2)The statistics of climatic factors influences on tobacco chemical compositions from the whole fields growth season and different stages show that climatic factors have a strong relationship with tobacco chemical compositions and coordination degrees.Compared with the climatic factors from the whole fields growth season,the climatic factors within different growth stage contribute to more influence.On the whole,average temperature has more influence on tobacco total sugar,reducing sugar and sugar/alkaloid but less impact on total alkaloid,nitrogen and other chemical compositions while rainfalls and sunshine hours have an obvious impacts on most leaves chemical compositions.(3)The climatic factors on flue-cured tobacco quality of Chongqing include the following indicators:the average temperature of transplant shock and root extending period,the average temperature of fast growing period,the average temperature of maturing period,the rainfalls of transplant shock and root extending period,the rainfalls of fast growing period,sunshine hours of maturing period and the sunshine hours of the whole fields period.(4)The result of Chongqing flue-cured tobacco climate suitability evaluation indicated that highly suitable area locates in southeast,especially the area of Qiangjiang,Youyang,Xiushan, Wulong and Fuling.In some areas of Shizhun,Fengdu,Nanchuan and Qijiang,the suitable indices are relatively lower and in the northeast part,the suitable indices are the lowest typically in some regions,where the suitability values are even below 0.3.3.Soil geochemistry influence on flue-cured tobacco leaves qualityIn this dissertation,54 soil geochemiscal elements are investigated to judge flue-cured tobacco planting ecological suitability.Considering the complex terrain feature of research area and the influences from different soil types on soil elements contents,regression kriging and ordinary kriging were integrated to predict soil geochemiscal elements regional distribution.Their spatial characteristics as well as impacts on tobacco leaves quality were given detailed analyses.Soil geochemistry suitability of flue-cured tobacco planting area were finally evaluated.The conclusions can be draw as follows:(1)For the tobacco-planting soils,the contents of total P,total K are rich and the N are medium. In terras of spatial distribution,besides the north of Fengjie,the east of Fengdu and Fuling as well Qijiang,the contents of soil N are in rich or sufficient level.Compared with the northeast of Chongqing,the contents of soil total P are richer.(2)The contents of soil Ca and soil Mg of tobacco-planting area show similar spatial distribution pattern.However,the high value of soil Ca contents were found in Wuxi whereas the high value of soil Mg were found in Wuxi.For the spatial distribution of soil Scontents,it rather has opposite trend.(3)In the 54.83%of tobacco-planting areas,the contents of soil organic are ranged from 1.5-3%,and most are found in Shizhu,Nanchuan,the east of Fuling,the south of Fengdu and most Chongqing southeast regions.The acreage of areas that the contents of soil organic are below 1.5% is 18413.01km~2,which accounts for the 45.16%of the whole tobacco-planting area.Only 0.01% area,the contents of soil organic excess 3%.(4)For most tobacco-planting areas,the soil pH condition can satisfy tobacco leaves growth needs.In terms of spatial distribution,only very few areas of Wulong,Fengdu,Shizhu and Nanchuan were found obvious soil acidification.According to the abundance of soil nutrients contents,Soil types were ranked by yellow brown soil,yellow soil,lime soil and paddy soil.(5)Soil pH,soil organic,soil total nitrogen,soil potassium,soil phosphorous,soil chlorine,soil calcium,soil manganese,soil copper,soil magnesium,soil iron,soil boron,soil zinc as well as soil REE are the soil geochemical indicators that affect Chongqing flue-cured tobacco leaves quality.(6)Soil geochemistry suitability evaluation of Chongqing flue-cured planting area showed that the high suitability values concentrate on Wulong,Penshui,Qianjiang,Youyang,and the south of Nanchuan.In the area of Wushan and the north of Fengjie,the suitability values tended to decreased and reached low level in Fengdu,the west of Fuling and Fengjie as well as Qijiang.4.Topography influence on flue-cured tobacco leaves qualityCurve estimation method was used to analyze topography influence on tobacco leaves quality of the study area,and then Fuzzy mathematics and AHP were combined to evaluate topography suitability in detailed grid.The results can be concluded as follows:(1)There are many various terrains in the study area,which includes middle rolling mountain, small rolling mountain,great rolling hilly,middle rolling hilly,small rolling hilly,gentle hilly,mesa and level land.In terms of elevations,most areas are below 1200m,among which the areas that below 400m account for 10%while the areas that are between 400m and 800m,between 800m and 1200m account for 37.60%,30.57%respectively.The areas that are above 1200m only account for 21.83%.On the whole,the northeast of the study area is of higher elevation than that in the southeast.(2)In terms of slope,37.08%lands of the study area are suitable for agricultural cultivation (slope＜15°),lands that are partly suitable for cultivation account for 31.85%(slope ranges from 15 to 25°).31.07%lands(slope＞25°) are not suitable for cultivation,which account for 31.07%of the whole area and covers 12885.66 km~2.10.70%of them which are located in the small and mille rolling hillys of Wuxi are even above 35°(3)Elevation and slope both show correlation with flue-cured tobacco leaves chemical compositions.In the areas where the elevation ranges from 900m to 1200m and the slope is below 10°,the flue-cured tobacco leaves can obtain better quality.(4)Topography suitability evaluation result showed that the high suitability areas mostly locate in the center of Youyan and Shizhu,the east of Qiangjiang,Fuling and the west of Nanchuan.In the are of Xiushan,Youyang east and Qijiang,suitability level gradually decreases;the suitability of the northeast of Chongqing is relatively low,where Wuxi's suitability even cannot reach 0.1.5.Computational intelligence-based flue-cured tobacco comprehensive ecological suitability evaluation and planting planning(1)The building of the hierarchy of Chongqing flue-cured tobacco leaves growth ecology comprehensive evaluation.The whole hierarchy is composed of target level,criteria level and indexes level,which covers 20 ecological indicators that mostly influence tobacco leaves growth of study area.The 20 ecological indicators include the average temperature of transplant shock and root extending period,the average temperature of maturing period,the rainfalls of fast growing period, sunshine hours of maturing period,the sunshine hours of the whole fields period,elevation,slope, soil organic,soil pH,soil total nitrogen,soil potassium,soil phosphorous,soil chlorine,soil calcium, soil manganese,soil magnesium,soil iron,soil boron,soil zinc as well as soil REE.(2)Combining with fuzzy logic,artificial neural network and intelligent optimization technology, the model of tobacco ecology comprehensive intelligent evaluation was built.It can quantize expert experiences while using nonlinear mapping of ANN,and search interior laws between ecological suitability and ecology indicators without human interruption.The results showed that the accuracy rate is 82%.(3)Comprehensive ecological suitability evaluation results indicated that the areas that belong to the highest suitable gradation account for 9820.79 km~2,which mainly distributed in Shizhu,the east of Fengdu,Wulong,the westnorth of Pengshui,Qijiang and the middle Youyang.Some of areas of Nanchuan,Qijiang,Xiushan and Fengjie also are also found high suitability value.The areas that belong to the high suitable gradation-including the south of Fuling,the north of Nanchuan,Fengjie, and the east of Xiushan as well as some of areas of Youyan,Pengshui,Qiangjiang,Wushan and Wuxi.The total acreages are about 11148.49km~2.The areas that belong to the normal suitable gradation,the lowest suitable gradation and the worst level account for 13807.42km~2,5645.20km~2 respectively.(4)The whole study area can be divided by six different planting areas according to the suitability evaluation result.And the key development regions include most areas of Qianjiang,Youyang, Penshui,Wulong,Shizhu,Nanchuan,eastern Fengdu,eastern Fuling,odd lots of Qijiang and Xiushan,northern Fenjie,middle Fengjie,southern Wuxi and odd lots of Wushan,in which the value of suitability is above 0.85.Stable development regions include most of areas Xiushan,eastern Youyan,midlle-west Fuling and odd lots of Qianjiang,Pengshui,Qijiang,Nanchuan,Wulong as well as middle Wushan,few areas of Fengjie and Wuxi.In these areas,scale planting can be employed and for some lands,after improvements by technological measures,they can be kept as future potential key development areas.The areas whose suitability value below 0.6,in this dissertation, is hold as limited development region.Western Fengdu,western Fuling,northern Wulong,western Shizhu,odd lots of Xiushan,Pengshui,southeast Nanchuan as well as southern Fengjie,southern Wushan,northwest Wuxi and northeast WushanTo sum up,in this dissertation,54 geochemical elements combined with climatic factors,terrain are investigated to research the influence on the flue-cured tobacco quality of Chongqing,from the view of regional level.Major ecological indices that affect flue-cured tobacco quality were confirmed.An intelligent evaluation model by integrating different computational intelligence technologies for preciously depicting nonlinear and fuzzy relationship between ecology environments and crops quality was proposed.It was conduced to evaluate comprehensive ecological of Chongqing flue-cured tobacco planting area and achieved satisfying results.The whole research results not only contribute to enriching and improving crops ecological suitability evaluation indices and methodology,but can provide fundamental support for regional tobacco planning.However,crops planting suitability is a complex system which also need to consider the influence from social,economical factors.How to evaluate their influences in quantitative way and integrate with ecological evaluation results would have to been paid more attention by multidisciplinary.