Environmental Analysis Of The Production Area Of Rose Orange

Rose orange,the new variety of tarocco blood orange,originated in Sicily,Italy.After being improved and cultivated by the Citrus Research Institute of Chinese Academy of Agricultural Sciences,it was introduced to Wanzhou in 2004.Rose orange is sought after for its seasonal characteristics,late maturity,and rich rose aroma.Understanding the environmental conditions of the production area of rose oranges is of great significance to the scientific and standardized management of orchards and to improve the quality and yield of rose oranges.In this paper,a total of 326 surface soil samples,10 rock samples,40 root soil samples and 20 orange plant samples were collected.And according to DZ / T 0295-2016 "Land Quality Geochemical Evaluation Specification",the soil pH and soil nutrients are graded.The main research contents are as follows,firstly,the geochemical grade evaluation of the soil status of the rose orange origin;secondly,the study of the migration and enrichment rules of heavy metal elements between rock-soil-rose orange;thirdly,the influence of the quality of rose orange,and the key factors affecting the quality of orange are determined through the classification and regression tree model.The main findings are as follows:(1)The soil in the study area is mainly acid soil(pH: 5 ~ 6.5),accounting for 61.04%.Followed by neutral soil(pH: 6.5 ~ 7.5),accounting for 28.22%.There is a small amount(2.45%)of strong acid soil(pH <5),but there is no strong alkaline soil(pH ?8.5)distribution.The result of the classification of soil organic matter content was 7.06% or more,and the lack ratio was 77.3%.(2)In soil nutrients,the order of the degree of deficiency of soil rich elements is nitrogen> phosphorus> potassium;the order of the degree of deficiency of soil moderate elements is calcium(calcium oxide)= sulfur> magnesium(magnesium oxide);the order of the degree of deficiency of soil trace elements is Molybdenum> Boron> Copper> Meng> Zn> Iron(iron oxide).Among the heavy metal elements in the soil,0.61% of the soil was slightly polluted by cadmium,and 1.53% of the soil was slightly polluted by nickel.As a result of the comprehensive grade evaluation of soil quality and geochemistry,the ratio of inferior and inferior was 4.6%.(3)The order of the content of heavy metal elements cadmium,mercury,and lead in the tree is leaf> root> stem> fruit,and the order of content of arsenic,chromium,and nickel in the tree is root> leaf> stem> fruit.From the perspective of biological enrichment factors,the order of the enrichment factors of cadmium,arsenic,and nickel is root> leaf> stem> fruit,while the order of enrichment factors of mercury,lead,and chromium is leaf> root> stem> fruit.In summary,the fruit is the lowest in terms of the element content of each part of the tree and the bioconcentration coefficient.Although the soil has the risk of heavy metal pollution,the cadmium and lead content in the fruit are lower than the national food safety standards.Therefore,it is considered that there is no risk of heavy metal pollution in the rose orange fruit.(4)The results of the classification regression tree show that the key factors affecting the external quality of the fruit(single fruit weight,horizontal diameter)are: soil calcium and soil pH;the internal quality of the fruit(soluble solids,titratable acid,solid acid ratio,the key influencing factors are: soil boron,zinc,copper,potassium,pH,elevation,slope,aspect;the key influencing factors of fruit functional quality(flavonoids,anthocyanins,carotenoids)are: soil magnesium,Calcium,sulfur,elevation,slope,aspect.(5)By grading the key environmental factors obtained from the classification regression tree,and studying the effect of different factor grading on the quality of rose orange,the optimal environmental conditions of rose orange were obtained.Specifically,the soil pH is 5.5 ~ 6.5,soil potassium is 1.9 ~ 2.1%,soil calcium is 0.73 ~ 0.98%,soil magnesium is 0.96 ~ 1.12%,soil sulfur is less than 200 mg / kg,soil copper is at 20 ~ 23.5mg / kg,soil zinc is at 82 ~ 97 mg / kg,soil boron is at 27 ~ 36 mg / kg,the elevation is less than 400 meters,the slope is less than 6 °,and the slope direction is sunny slope.