Ecological Geochemical Evaluation Of Tumorous Stem Mustard Land In Tuojiang Town, Sichuan Province

Tumorous stem mustard, as a kind of vegetable, is the raw material of tubermustard. Well-known at home and abroad, Tuber mustard of Sichuan has rich nutrition,including amino acid, vitamin, protein, sugar, fat, etc., and processes a unique flavor offresh, fragrant, tender and crisp. As a good food for family cooking and tourism, it issuitable for both the old and the young. With the development of science andtechnology, people’s living standard got improved, and they paid more and moreattention on food quality and safety. Tuojiang Town of Sichuan Province, as the mainproducing area of tumorous stem mustard, why the tumorous stem mustard producedhere has good quality? How about the ecological geochemical features here? The softrot problem of tumorous stem mustard appearing largely in recent years and theirrelationship became an urgent issue to be studied and solved.Using geological and geochemical methods in this paper, agro-geological surveywas held in the Maopengsi Village, Lanjiasi Village, Zhongxin Village and NongmenVillage of Tuojiang Town, Neijiang City, to find out the geochemical features of landcomposing elements like soil, water, air and biology. Through soft rot experiment andpotassium fertilizer experiment in the study area, it found out the pathogen inducingsoft rot, and found that potassium fertilizer had the function to resist soft rot and speedthe growth of tumorous stem mustard. Meanwhile, the research on absorption andaccumulation of tumorous stem mustard was held, which was useful for the tumorousstem mustard planning of the study area. Through study on content of geochemical elements in the soil of the tumorousstem mustard producing area of Tuojiang Town, it indicated that the soil in this areawas mainly neutral or light alkaline, and the content of elements distributed unevenly.Compared with the national soil background value, contents of Cd, Mg, P in this areawere higher, with the enrichment coefficients of3.41,1.68,1.42respectively, whilecontent of CaO, Se, As, I were lower, with the enrichment coefficients of0.72,0.70,0.33,0.22respectively, and that of other elements were close to the nationalbackground value. In the topsoil, the content of heavy metal elements As, Cu, Cr, Hg,Ni, Pb, Zn in85%of samples were lower than the first order of national soil qualitystandard. The content of Cd in85%of samples was within the second order, whichattributed to the affect from daily increasing human activities.The soft rot experiment proved that the pathogen inducing soft rot mainlybelonged to Gram-negative enterobacteriaceae, it was a kind of bacteria belonged toErwinia aroideae genus. Meanwhile, the fertilization experiment indicated that usingpotassium fertilizer could decrease the pHenomenon of tumorous stem mustard soft rot,no matter what kind of stratum and soil. When the concentration of potassium fertilizerwas300(385ppm), the disease infection index of tumorous stem mustard was thelowest, which means using potassium fertilizer of300～400ppm could preventtumorous stem mustard from being infected by soft rot. Besides, in such condition,timorous stem mustard grew higher, useful for the growth of basal stem.Most of the elements in plants come from soil and biological enrichmentcoefficient can show the transfer degree of elements from soil to plants. The rhizomeof tumorous stem mustard in the study area could absorb Fe element18times of that insoil, indicating it had the feature of enriching Fe. Rhizome is the main edible part oftumorous stem mustard, and its high enriching of heavy metals may influence itsquality in a certain degree. Therefore, strict control of Fe content in soil is veryimportant. Based on the intersection-union theory of grapH theory, it delineated thecultivation area of tumorous stem mustard, and formed a comprehensive evaluationmap which divided the whole area into main cultivation zone, extending cultivationzone and non cultivation zone. Most area of Tuojiang Town belonged to the suitablecultivation zone of tumorous stem mustard. The delineation of such cultivation zonesadvanced planning and suggestion for the cultivation of in Tuojiang Town.