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Relationship between geochemical anomalies and fruit quality
Fruit trees growing on the ground and underground rock and soil resources together constitute the agro-ecological geological system of fruit forest. Most of the nutrients needed in the life process of fruit forest growth results from the supply and transportation of geotechnical resources, so the geochemical characteristics of geotechnical resources (nutrient status) have a very important impact on the growth status and fruit quality of fruit trees. This paper systematically analyzes the geochemical background characteristics of gneiss area. Different types of gneiss areas have different geochemical backgrounds. Due to the heterogeneity of diagenetic process, the differences of various elements' enrichment characteristics, geomorphological characteristics and soil-forming process, the total amount and available distribution of various nutrients in the same rock type area are also different. This difference is the key factor that leads to the difference in fruit yield and quality under the same natural conditions such as topography and geographical location and the same agronomic management measures. The relationship between 1:200000 geochemical data and available forms of soil has been discussed, and the content of available forms is bound to be high in most parts with high total content of elements (geochemical results). The sampling density and data of1:200,000 geochemical data in the same area are unmatched by any soil survey and special study of soil and fertilizer. From the perspective of regional research and regional agricultural planning, exploring the relationship between fruit quality and nutritional elements is the most adequate data source.

1. Relationship between phosphorus geochemistry and fruit quality

The content of P (P2O5, the same below) in Nanzigou and Beizigou of high-quality sour pomegranate producing areas in Yuanshi County is more than 500× 10-6, and that in Hu Jiazhuang and Sandaopo of high-quality sweet pomegranate producing areas is more than 1000× 10-6, and the available phosphorus is as high as 50× 65438+. However, the P content in Beizheng Township is only between (300 ~ 400) × 10-6, and the quality of pomegranate is relatively poor. There is an enrichment area of P in the northwest of Heishui River, which is inconsistent with the distribution area of high-quality persimmon trees, but highly consistent with the distribution area of high-quality pomegranate. The P content in the distribution area of high-quality jujube trees in Zanhuang County is more than 600× 10-6, and the enrichment area coincides with the distribution area of high-quality jujube trees. The distribution of high-quality walnuts is inconsistent with that of phosphorus-rich areas. In terms of regional distribution, the P content of Pingshan, Lingshou and Xingtang is generally higher than that of Yuanshi County and Zanhuang. The phosphorus content of jujube trees in Xingtang County is above 1000× 10-6. In Lianglingkou, Kugou and other high-quality jujube producing areas, the P content is more than 2000× 10-6. Lingshou Nanying is a high-quality walnut producing area and a P-enriched area, which is generally greater than 2000× 10-6, with the highest value of 2437× 10-6. The P content of Wuqikou and Yangjiatai in high-quality walnut producing areas is generally 1600× 10-6, which is the high-quality walnut of Lini River in Pingshan. The P content in walnut producing areas around Yushuping is also around 1000× 10-6. Several pepper producing areas are in areas with relatively low phosphorus content.

2. The relationship between copper geochemistry and fruit quality.

The background value of copper is generally higher than the national average, but the enrichment degree is low, which is reflected in the small difference between various rock types and the relatively uniform distribution within the same rock type, which has relatively little restriction on the fruit quality of various fruit trees. The effective state is basically at the normal to rich level. In the south, the area with relatively high copper content is distributed in the volcanic lava area of shallow metamorphic Gantaohe Group, which is consistent with the distribution area of walnut and chestnut. Generally, it is more than 40× 10-6, and the maximum is 80× 10-6. The copper content in Zanhuang high-quality jujube distribution area is in the range of (25 ~ 32) × 10-6, and there is no obvious enrichment characteristic. In the high-quality pomegranate producing area of Yuanshi County, the copper content is generally between (25 ~ 32) × 10-6, and the available copper is in the range from rich to normal. The copper content in the distribution area of high-quality persimmon trees is relatively low, generally between (20 ~ 25) × 10-6. The copper content in the areas of Xingtang, Lingshou and Pingshan is generally higher than that in Zanhuang and Yuanshi counties in the south. In the anomaly area of 10-6, which is more than 40×10, the distribution area of high-quality jujube in Tang Dynasty coincides with the maximum anomaly area, with the highest value of 65× 10-6. The high-quality walnut producing areas in Pingshan and Lingshou are mostly abnormal areas of copper, and the content is above 40× 10-6. The copper content in Pingshan high-quality pepper producing area is relatively low, generally lower than 32× 10-6. There are some differences in copper content in Lingshou chestnut distribution area. Some of them are distributed in the abnormal area larger than 40× 10-6, and chestnuts are also distributed in the area smaller than 40× 10-6. The quality difference between them has not been further studied. Persimmon producing areas in Pingshan County are all low copper areas.

3. The relationship between boron geochemistry and fruit quality.

Boron varies greatly in the region, and is negatively correlated with copper and phosphorus in spatial distribution, which is higher in hilly areas, relatively higher in middle and low mountainous areas and relatively lower in phosphorus-rich and copper-rich areas. Boron content in pomegranate high-quality areas and persimmon high-quality distribution areas in Yuanshi County is relatively low, generally less than 50× 10-6. However, the boron content in Zanhuang high-quality jujube distribution area is mostly less than 40× 10-6, while the boron content in Zanhuang walnut and chestnut distribution area is generally greater than 50× 10-6, with the highest value of 200× 10-6. The boron content in the distribution area of high-quality jujube in Xingtang is less than 40× 10-6, which is basically consistent with the distribution area of Zanhuang jujube. The boron content in Nilihe area of Pingshan high-quality walnut production area is more than 50× 10-6, while the boron content in other high-quality walnut production areas is lower, the boron content in Yingli area is less than 30× 10-6, and the boron content in Lingshou Nanying area is less than 25× 10-6. It can be seen that walnut is not highly dependent on boron. The boron content in Pingshan high-quality walnut producing area is also lower than 32× 10-6. The content of B in Lingshou high-quality chestnut producing area is relatively rich, which is generally (40 ~ 50) × 10-6. According to the research, the increase of B content can reduce the empty bud rate of chestnut, and the high B content in Zanhuang and Lingshou chestnut producing areas is a very favorable factor.

4. The relationship between zinc geochemistry and fruit quality.

In Zanhuang County and Yuanshi County, the distribution of zinc is low in the east and high in the west. In the mountain slopes of high-quality pomegranate producing areas in Hu Jiazhuang and Yuanshi County, the zinc content is rich, generally above 80× 10-6, and the highest available zinc content is 125× 10-6. However, the producing areas of high-quality sour pomegranate in Nanzigou and Shandaopo areas are relatively low, generally (63 ~ 80) × 10-6, which is basically consistent with the Zn content in Heishuihe area where high-quality persimmon trees are distributed. The zinc content in the distribution area of high-quality jujube in Zanhuang County is not obvious, but slightly increases to the west. The distribution area of high-quality walnuts is relatively rich in zinc, which is generally greater than 100× 10-6. The general trend of zinc distribution in Pingshan, Lingshou and Xingtang areas is high in the northwest and low in the southeast, showing a strip distribution from northeast to southwest. In the distribution area of high-quality jujube in Xingtang, the total zinc content and available zinc content are both enriched, with the total zinc content generally greater than 80× 10-6 and the available zinc generally greater than 0.4× 10-6. The zinc content in Pingshan and Lingshou high-quality walnut producing areas is relatively high, generally greater than 100× 10-6, and there is no obvious enrichment trend in pepper distribution areas. The zinc content in Pingshan persimmon production area is low, generally (50 ~ 32) × 10-6, which is one of the lower areas in the area.

5. The relationship between manganese geochemistry and fruit quality.

There is little difference in the distribution of manganese between Yuanshi County and Zanhuang County, which is mostly (600 ~ 700) × 10-6, and the highest value is only 800× 10-6. Available manganese is generally high, and there is little difference between high-quality fruit trees and non-high-quality fruit trees. The characteristics of Pingshan, Lingshou and Xingtang areas are basically similar to those in the south. There is no significant difference in manganese content between high-quality areas and non-high-quality areas in Xingtang County. Manganese content in Pingshan and Lingshou high-quality walnut producing areas increased slightly, generally around 800× 10-6. The manganese content in chestnut producing areas in Lingshou County is generally around 800× 10-6, which is higher than that in jujube trees and other fruit trees. In Zanhuang County, only a small area to the west of Huzhaikou and the area near the barrier rock have a manganese content greater than 800× 10-6, which is the distribution area of chestnut. It shows that manganese has certain guiding significance to the high-quality growth area of chestnut in the study area, and there is little difference between high-quality and non-high-quality areas of other fruit trees, so it is not suitable as a symbol of the division of dominant areas.

6. Relationship between magnesium geochemistry and fruit quality

Magnesium is one of the components of chlorophyll; It plays a regulatory role in plant life activities and also participates in the reflection of some enzymes. It is one of the essential trace elements for plants. Compared with the two regions, the magnesium content in Zanhuang and Yuanshi counties in the south is lower than that in Pingshan, Lingshou and Xingtang counties in the north. The highest value in the south is 4.5%, and the highest value in the north can reach 10.8%. The magnesium content in the northwest of Heishui River in Yuanshi County is higher than 2.5%, and the highest is 3.5%, which is consistent with the distribution area of high-quality pomegranate and the high magnesium content in pomegranate. The content of Heishui River and Nanzuo is low, generally 2.2% ~ 1.67%. Mg is not enriched in the distribution area of high quality persimmon trees. There is little difference in magnesium content between high-quality jujube and non-high-quality jujube in Zanhuang County. The distribution areas of high-quality walnuts and chestnuts are areas with high magnesium content, which is generally greater than 2.5%. In Pingshan, Lingshou and Xingtang areas, the high magnesium content areas are mainly concentrated in the northwest of Xiakou-Shanglianzhuang line, and there is little difference between the high-quality and non-high-quality distribution areas of Xingtang jujube. High-quality walnut producing areas in Pingshan and Lingshou are both areas with high magnesium content, generally greater than 4%. It can be used as one of the signs of high-quality walnut development zone. Compared with the surrounding areas, the content of Mg in the high-yield area of Zanthoxylum bungeanum in Pingshan County is relatively low, generally 2.4% ~ 2.9%. The distribution of magnesium in Lingshou chestnut production area is very stable, generally 2% ~ 3.2%, with no obvious enrichment characteristics.

7. The relationship between iron geochemistry and fruit quality.

Sandaopo and Hu Jiazhuang, the producing areas of high-quality sweet pomegranate in Yuanshi County, overlap with Fe2O3 enrichment areas, generally above 6.3%, and the available iron content is (50 ~ 100) × 10-6, which is also a high-content area. The sour pomegranate producing areas in Nanzigou and Beizigou are generally more than 5.0%, with the highest value of 6.05%. However, the content of Fe2O3 in high-quality persimmon producing areas around Heishui River is not high. There is little difference in Fe2O3 content between high-quality jujube and non-high-quality jujube in Zanhuang County, which is generally between 5.0% and 6.3%, and the highest is 8.0% in the southeast of Hua Mu. The distribution area of high-quality walnuts and chestnuts in Zanhuang County is a high Fe2O3 content area with two abnormal areas. The Fe2O3 enrichment area in Huzhaikou area is nearly north-south, generally between 8.0% and 9.7%. The fe2o 3-enriched area in Bailu-Zhangbei 'ao is distributed in the northeast direction, generally 8.0% ~ 1.0%, and the highest value is near the barrier rock (1 1.7%). There is little difference in Fe2O3 content between high-quality jujube and non-high-quality jujube in Xingtang County. The content of Fe2O3 in Lianglingkou and Kugou areas is generally higher than 5.6%, while that in Koukou and Shangyanzhuang areas is relatively low, generally 4.5% ~ 5%. The high-quality walnut producing areas in Pingshan and Lingshou are high-value areas, and the content of Fe2O3 in persimmon trees in Pingshan is relatively low, generally 5.0% ~ 6.3. The content of Fe2O3 in chestnut distribution area of Lingshou is relatively stable, generally around 7. 1%.

8. The relationship between potassium geochemistry and fruit quality.

There is little difference in the distribution of potassium oxide in Yuanshi county, and there is no obvious enrichment area and low content area, most of which are around 2.5%. The K2O content of Nanzigou, Beizigou, Hu Jiazhuang and Sandaopo in high-quality pomegranate distribution areas is more than 0.3% higher than that of Heishuihe, Nanzuo and Zhangxie, while the K2O content of high-quality persimmon distribution areas is relatively low. In Zanhuang County, the K2O content in the north is relatively stable, with little difference. The content of high-quality jujube trees in the distribution area is basically around 2.5%. The distribution in the south is quite different, and there are obvious relative enrichment areas. In Huzhaikou-Barrier Rock Area, the K2O content around Zhangbei Depression is relatively low (generally 1.7% ~ 2.0%), while the content in other areas is relatively high. Up to 3.5%, which is consistent with the distribution area of high-quality walnuts and chestnuts. In the north, there is little difference in K2O content between high-quality and non-high-quality red dates, walnuts, chestnuts and peppers in Xingtang County, which is generally around 2.5%. The K2O content in Pingshan persimmon tree distribution area is slightly higher than that in other fruit tree areas, generally 2.5% ~ 2.8%. From the distribution characteristics of K2O, the content of K2O in soil has little change, indicating that the supply of potassium for fruit trees mainly depends on the slow-acting potassium of layered potassium-bearing minerals in rock differentiation layer.

9. Relationship between calcium geochemistry and fruit quality

There is no significant difference in calcium oxide content between high-quality jujube and non-high-quality jujube in Xingtang County. In the high-quality walnut producing areas of Pingshan County and Lingshou County, the CaO content in Nilihe, Yushuping and Wangjiawan is obviously higher, and the highest content in Nilihe area is 8.89%, generally greater than 5%. The highest value in Wangjiawan and its vicinity is 9.35%. Nanying area of Wuqikou, a high-quality walnut producing area in Lingshou, is slightly lower than Pingshan, generally 4% ~ 5%, but higher than other areas in Lingshou. The CaO content in the main producing areas of Zanthoxylum bungeanum in Pingshan is generally 2.5% ~ 3.2%, and there is no obvious enrichment. The Ca content in the main persimmon producing areas in Pingshan county is lower than that in other fruit producing areas, generally 3.2% ~ 4%, which is equivalent to that in Yuanshi county.

In the high-quality pomegranate producing areas of Yuanshi County, the CaO content in Nanzigou, Beizigou, Hu Jiazhuang and Sandaopo areas is low, which is about 65,438 0% lower than that in other areas. The CaO content in Heishuihe area where high-quality persimmon trees are distributed is high, which is generally 3.2% ~ 4.69%. There is no obvious difference in CaO content in Zanhuang jujube tree distribution area, which is generally 2.5% ~ 3.2% (similar to the jujube tree distribution area in Xingtang County). However, the higher CaO distribution area in the east (4.0% ~ 4.7%) is non-jujube distribution area. The CaO content of high-quality walnuts in Zanhuang county has no relatively high trend, generally 2.5% ~ 3.0%, far lower than Pingshan county. According to the research (Shu Huairui, 1993), when the pH value is less than 7, the calcium content absorbed by plants increases with the increase of pH value; When the pH value is greater than 7, it will affect the absorption of calcium; When the pH value is 6-6.5, the available forms of calcium are the most. Secondly, Shear( 1982) also thinks that when the water content in the root zone is sufficient, it can ensure the continuous movement of Ca to roots, xylem and even fruits. Although the CaO content in Zanhuang high-quality walnut production area is not as high as that in Pingshan high-quality walnut production area, the soil pH value in this area is 5.5 ~ 6.8, and the soil water content is high, which is beneficial to the absorption of calcium, thus meeting the demand of walnut growth for Ca.

10. the relationship between molybdenum geochemistry and fruit quality

The distribution characteristics of molybdenum are closely related to the distribution of rock types, with the lowest content in metamorphic glutenite, relatively high content in gneiss and the highest content in granite, generally (0.5 ~ 0.8) × 10-6, and the highest molybdenum content in Lingshou granite is 8.8× 10-6. Molybdenum content in pomegranate producing areas and persimmon producing areas in Yuanshi County is lower than 0.5× 10-6, and that in jujube distributing areas in Zanhuang County is also lower than 0.5× 10-6. The high molybdenum area in Shijialan, south of Hua Mu [(0.63 ~1.0 )×10-]. Xingtang jujube is also distributed in the low value area less than 0.5× 10-6. There is no obvious difference between high-quality areas and non-high-quality areas. The molybdenum content of persimmon trees in Pingshan county is relatively high, mostly (0.8 ~ 0.9) × 10-6. The producing areas of Pingshan high-quality walnuts are all areas with relatively low molybdenum content, and the general content is in the range of (0.5 ~ 0.63) × 10-6. The molybdenum content in Lingshou Yingli walnut production area is the highest, which is obviously affected by granite. The range of molybdenum content in Zanthoxylum bungeanum in Pingshan is (0.63 ~ 0.8) × 10-6. From the macroscopic distribution characteristics of molybdenum, there is no direct corresponding relationship with the quality of fruit trees, especially pomegranate and jujube.

1 1. the relationship between the geochemistry of silicon and fruit quality.

People pay more and more attention to the nutritional value of silicon to crops. Silicon dioxide is the most abundant in the earth's crust, but it can be absorbed by crops in the form of ions or complexes. The content of SiO _ 2 in high-quality sour pomegranate producing areas in Yuanshi County is above 63%, generally below 60% in Hu Jiazhuang and Sandaopo areas, and generally between 60% and 63% in high-quality persimmon producing areas in Heishui River. The content of silica in jujube distribution areas in Zanhuang county and Xingtang county is 60% ~ 63%, and there is little difference between high-quality areas and non-high-quality areas. The content of silicon dioxide in Zanhuang walnut producing area is lower than that in other areas, generally 60% ~ 53.37%. The high-quality walnut producing areas in Pingshan and Lingshou are all low-value areas of SiO2 _ 2, generally 56% ~ 47%. There is a certain spatial relationship between the total amount of silica and the distribution of fruit trees, but this relationship depends more on the distribution of rock types.

12. Relationship between geochemical characteristics of aluminum and fruit quality

Both high-quality sweet pomegranate and sour pomegranate in Yuanshi County are in the relatively high value area of Al (Al2O3, the same below) (13% ~ 13.7%), and the Al of high-quality persimmon trees in Heishui River area is 12% ~ 13%. The aluminum content of high-quality jujube production area in Zanhuang County is about 12%, and there is no obvious enrichment phenomenon. The distribution area of Zanhuang walnut and chestnut has high aluminum content (13.5 ~ 15.07). Al in the distribution area of Xingtang jujube is generally 13% ~ 14%, and there is no obvious difference between high-quality area and non-high-quality area. The aluminum content in Pingshan and Lingshou high-quality walnut distribution areas is less than 65438 02%. The Al content in the distribution areas of Zanthoxylum bungeanum and persimmon trees is generally 13% ~ 14%, which is higher than that in walnut producing areas. Whether aluminum can promote plant growth has not been reported. The difference of spatial distribution more accurately reflects the relationship with rock types, and the opinion confirms the correlation between rock types and fruit quality.

Relationship between sodium geochemistry and fruit quality

In Yuanshi County, the Na content in high-quality sweet pomegranate producing areas in Hu Jiazhuang and Sandaopo is relatively high (2.0% ~ 2. 18%), while the Na content in high-quality sour pomegranate producing areas is relatively low, generally, it is 1.6% ~ 1.8%. The Na content in the high-quality persimmon tree area of Heishui River is 1.8% ~ 2.0%. The Na content in Zanhuang jujube distribution area is generally 1.8% ~ 2.2%, and the Na content in high-quality walnut and chestnut distribution area is higher, generally 2.2% ~ 2.5%. The Na content in high-quality jujube distribution areas in Xingtang County is generally higher than that in non-high-quality jujube distribution areas, the former is more than 65438 0.8%, and the highest value is more than 2.0%. The Na content of the latter is generally less than 1.8%. In the high-quality walnut producing area of Pingshan County, the Nili River and Elm are low-sodium distribution areas, and the area around Wujikou in Lingshou high-quality walnut producing area is also low-sodium (1.65% ~ 2.0%). The physiological effects of sodium on plants have not been reported, but the relationship between jujube trees and sodium has been shown in some high-quality jujube producing areas. Cangzhou Jinsixiaozao contains Na (87 ~ 100) × 10-6, K (700 ~ 800) × 10-6, and Xingtang jujube contains Na 65438+. The Na content of the former is much higher than that of the latter, and the soil of the former is close to saline-alkali land, and its Na content is obviously higher. Jujube trees grow well in many coastal saline-alkali land such as Hebei and Shandong. Yuan Keneng's research (1983) holds that under certain conditions, some elements replace the role of another essential element to some extent, or are insufficient, so Na and K have complementary functions. We think that the high Na content in the high-quality area of jujube trees in Tang Dynasty is also a sign.

14. the relationship between strontium geochemistry and fruit trees

Strontium content in Yuanshi County and Sandaopo of Hu Jiazhuang in sweet pomegranate producing areas is relatively high, generally above 200× 10-6, while that in Nanzigou and Beizigou in sour pomegranate producing areas is relatively low, less than 200× 10-6. The Sr content of Heishui River in the distribution area of high-quality persimmons is generally around 160× 10-6, and some points are lower than 160× 10-6. The distribution area of high-quality jujube trees in Zanhuang County is obviously high, generally at (200 ~ 250) × 10-6 (up to 320× 10-6), and the distribution area of high-quality walnuts is relatively high, generally at (200 ~ 213 )× 6544.

There is obvious difference in strontium content between high-quality jujube and non-high-quality jujube in Xingtang County. The former is generally greater than 200× 10-6, while the latter is mostly (160 ~ 200 )× 10-6. In Pingshan County, a high-quality walnut producing area, the strontium content in Lini River is relatively low (less than 160× 10-6), while the strontium content in Wujikou area of Lingshou County (200× 10-6) is higher than that in Pingshan Lini River. The strontium content in the main persimmon producing areas in Pingshan County belongs to the low-value area, which is (200 ~ 160) × 10-6. The main producing area of Zanthoxylum bungeanum is generally around 200× 10-6, and there is no obvious enrichment phenomenon. From the spatial distribution characteristics of Sr, it is closely related to jujube trees. The analysis of 24 trace elements in Xingtang jujube shows that the content of strontium is the highest (2.56× 10-6), which is equivalent to that of copper (2.56× 10-6) and higher than that of molybdenum (0.05). The physiological effects of strontium on jujube trees have not been reported. Lerman pointed out that strontium, like calcium, potassium, magnesium, boron, zinc and molybdenum, is a highly bioaccumulative element. Yuan Keneng (1983) thinks that strontium can supplement or replace the calcium needed for plant growth. We believe that strontium can be used as a tracer element for high-quality jujube trees in the study area.

15. the relationship between rare earth elements and fruit quality of fruit trees

The correlation between rock types and fruit quality has pointed out that the high content of rare earth elements in biotite plagioclase gneiss is closely related to the quality of jujube trees. In order to further confirm this relationship, the contents of rare earth elements in the soil of high quality, good and poor areas of jujube distribution in Xingtang County were analyzed and compared. The results show that:

Total amount and characteristics of (1) rare earth elements

The total amount of rare earth elements in jujube in three different quality areas has obvious changes. The total amount of rare earth elements in the area with the best quality is higher than that in the other two areas, which is three times higher than that in the area with poor quality. There is the same rule among LREE, but the HREE is different, and its content change is not very significant. It shows that all geological bodies are enriched with light rare earth elements during their formation or weathering, especially in the high-quality areas of jujube (Table 2-2- 1).

Table 2-2- 1 characteristic parameters of rare earth elements in Tangxian county (unit: 10-6)

(2) Distribution patterns and characteristics of rare earth elements.

According to the characteristics of three jujube regions, the REE fractionation pattern diagram of samples standardized by chondrites (Figure 2-2- 1) has the following characteristics: ① The distribution curve of each sample is a wide and gentle curve, with high left and low right, steep LREE and slow hree, indicating that the fractionation degree between them is different. The fractionation degree of light rare earth elements is higher than that of heavy rare earth elements. La/Yb reflects the enrichment degree of light rare earth elements and heavy rare earth elements in the sample. It can be seen from the figure that the three different regions of jujube quality are rich in light rare earth elements, and the fractionation degree of light rare earth elements is higher than that of specific rare earth elements, but the optimal region is more obvious. ② The loss of Eu in the best area is obvious and the degree of loss is high; The loss of the EU in the better regions is low, but there is basically no loss in the worse regions. δEu is less than 1.

Fig. 2-2- 1 Distribution Pattern of Rare Earth Elements

16. the relationship between the geochemistry of chromium and nickel and the quality of jujube fruit.

The analysis of the contents of chromium and nickel in the soil of different quality jujube production areas in Xingtang county shows that the contents of chromium and nickel in the soil of different quality areas change obviously, which shows that the contents of chromium and nickel in rocks and soil have a very important influence on the quality of jujube. The average content of chromium is 17.56× 10-6 in the best quality area,181.38×10-6 in the better quality area and 258.99×16 in the worse quality area. The content of poor area is 1.5 times higher than that of good area and about 15 times higher than that of best area. Chromium is recognized as a toxic element, and its toxicity depends on its oxidation stage and the easily available form of chromate. According to the plant effect of Cr element, the soil with high Cr content is toxic to plants, that is, high Cr can reduce almost all nutrients in the top of the tree and the contents of K, P, Fe and Mg in the roots.

The average content of nickel in jujube is 13.66× 10-6 for high quality, 39.24× 10-6 for high quality and 3010-6 for poor quality. The content of poor area is about 8 times higher than that of good area and 22 times higher than that of best area. The absorption of Ni2+ by plants can promote their growth and development to a certain extent, while the absorption of Ni2+ by plants from soil is influenced by external environmental conditions, mainly the content of replaceable Ni and the pH value of soil. However, excessive nickel can poison plants and cause yellowing. Under the action of nickel, plants have the metabolic function of absorbing nutrients and preventing root development. Before the obvious symptoms of poisoning appeared, the content of Ni in plant tissues had been proposed for photosynthesis and transpiration. Therefore, in poor areas, the high content of Ni element should be an influencing factor.

conclusion

1) The calcium content in high-quality persimmon producing areas in Yuanshi County is significantly higher than that in other persimmon producing areas, ranging from 3.2% to 4.69%, which can be used as an indicator element. Most of the other elements did not show the characteristics of enrichment, which may be due to the thick soil layer in Heishuihe area of Yuanshi County, which was lost after long-distance transportation. Although various nutrients are not obviously enriched, the deep soil can meet the needs of persimmon growth as a whole; Moreover, persimmon trees in Heishui River are mostly intercropped with food crops on the edge of terraced fields, and nitrogen, phosphorus and potassium fertilizers are added every year.

2) In high-quality pomegranate producing areas, P, Cu, Zn, mg, Fe and K tend to be enriched and can be used as indicator elements (P > 500× 10-6, Cu > 25× 10-6, Zn > 80× 10-6.

3) Zanhuang high-quality jujube area P > 600× 10-6, Xingtang high-quality jujube area P > P > 2000×10-6, general area > 1000× 10-6, and the Sr content is greater than 2000×/0-6. In addition, high content of rare earth elements and low content of chromium and nickel are also important factors to improve the quality of jujube.

4) copper (> 40× 10-6), zinc (> 100× 10-6), magnesium (> 2.5%), iron (> 5.0%), calcium (> 4.0%) and calcium.

5) Chestnut has the highest distribution consistency with Cu (> 40× 10-6), Mn (> 80× 10-6) and B (> 40× 10-6), which can be used as indicator elements.

6) The enrichment degree of most elements in Zanthoxylum bungeanum production area is not high, and there are no particularly significant indicator elements.