| The research on food safety and related environmental quality of producing areas mostly focus on agricultural products such as food crops,vegetables,and fresh fruits,but there is less concern about dried fruits.Carya cathayensis is famous in Zhejiang Province and affected by the parent material and management methods,there may be a series of soil quality problems such as soil acidification,soil nutrient imbalance,and heavy metal pollution in the soil of Carya cathayensis forest.However,studies on Carya cathayensis and their habitats at home and abroad mostly focus on the ecological habits and suitable environment.In view of this,the study took Lin'an which is the main producing area of Carya cathayensis as the study area,189 forest soil samples were collected and the current status,evaluation,spatial distribution characteristics,variation rules and influencing factors of soil macro and trace elements?nutrients and heavy metal elements?content were studied based on geostatistics,Moran's I,combined with GIS technology and other spatial analysis methods.The results showed that:?1?The average value of soil pH was 5.23,and 87%of the soil pH values were lesss than 6.According to the standard of fertility grade in“Zhejiang soil”?The first grade represents low content,the fourth grade represents high content?,the content of soil organic matter was mainly in the third or fourth grades,accounting for 54%,soil available N was in the third grade and the proportion was 76%,The 80%of the soil available K content was more than 50 mg·kg-1.63%of the soil available P content were less than 10 mg·kg-1.Spatial analysis results shown that:Long gang,Changhua,the west of Qingliangfen and the middle of Heqiao were seriously acidified;Low-value area of available K was located in northern part of Daoshi;The whole town of Changhua and Taiyang,south and north of Longgang,south of Qingliangfeng and south of Tuankou were the low-value area of available P.?2?The mean concent of soil Fe?Mn?Cu?Zn in the study was 25 728.27?615.92?40.75?87.48 mg·kg-1,the contents of Mn,Cu,and Zn changed to vice-versa.According to the standard of the available state,the content of Fe,Mn in the study area was rich,and mainly located in the levels of“high”and“very high”,the total ratio of the two grades is 100%and 95.77%respectively.While the content of available Cu and Zn was slightly insufficient,with 7.41%and 19.58%of the samples content being lower than the critical value.Fe,Mn,Cu and Zn all had obvious spatial distribution pattern,and the low-value were distributed in Longgang and Cahnghua,high-value were located in the Taiyang,Tuankou and Heqiao.The content of trace element was closely related to soil pH and organic matter.?3?The mean concent of soil cadmium?Cd?,copper?Cu?,zinc?Zn?,lead?Pb?,nickel?Ni?,chromium?Cr?were 0.37,40.76,87.61,30.10,28.33,56.57 mg·kg-1respectively in the stydy area.The local soil had reached the pollution levels of Cd,Cu,Zn,Pb and Ni.Among them,Cd was the most serious,reached the degree of strong ecological damage,followed by Cu.The heavy metal Cd,Cu,Zn,Pb,Ni and Cr all had obvious spatial distribution patterns and local spatial aggregation phenomenon.The high-value of heavy metals in soils were mainly located in Taiyang,Daoshi,Qingliangfeng,Heqiao and Tuankou towns,and the risk probability of contamination by Cd,Cu was higher in the study area.Analysis of the source of heavy metal pollution indicated that the high values of Cd,Cu,Zn,Ni and Cr were mainly related to mining,while Pb was closely related to the fertilization. |
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