Factors Study And Abundance Evaluation Of Soil Available Trace Elements In Arable Layer Soil Of Xi’an

Trace elements are very important for people, animals and plants. For more than one hundred years, both at home and abroad the study of trace elements has a continuous development. On the one hand,from the perspective of biology to explain the mechanism and effects on the growth and nutrition of plants and animals as well as human health,seek breakthrough from the basis of the physiological and biochemical studies progress. On the other hand, from the perspective of geochemical and geological to study the time and space distribution characteristics of trace elements. In order to easily guide agricultural production, many researchers will focus on the trace element abundance and deficiency index system what is formulate scientific and reasonableWe use the data from work of formula fertilization by soil testing from 2007 to 2011 to analyse the available trace element in arable layer soil of Xi’an from different aspects. Providing the reference and laying a good foundation for later developing xian soil trace element abundance and deficiency index system. The results show that:(1) We evaluate the available trace elements in Xi’an arable layer soil by referring the available trace elements trace element abundance and deficiency index system of the national agricultural systems(1985).The available iron reached medium on the high side level, the available manganese content is in the medium to low level, available copper content and available zinc content is rich, water soluble boron content is in medium high level. Compared with the 80 s, the soil organic matter, available iron,available manganes, available copper,available zinc, available boron content in arable layer soil of Xi’an of all had varying degrees of increase. Among them, the available zinc content had the most obvious increase, average content is 4.1 times that of the 80 s.(2) The available trace element content in different types of soil had obvious differences. In 17 representative soils of different subcategories in Xi’an, The average content of the available iron in gley paddy soil was the the highest,reached 25.468mg/kg,it was rich. Because gley paddy soil was long-term flooded and the lack of oxygen soil oxygen promoted the reduction of iron, increase the efficiency of iron; The average content of the available iron in cumulated irrigated soils was the lowest, was just 3.021 mg/kg, it was closely related with high pH values of cumulated irrigated soils.The average content of the available manganese in typical red clay and calcareous purple soil was relatively high,reached rich level, might be related to their soil parent material. he average content of the available manganese in leached drab soil was the 6.227 mg/kg,the lowest,it was affected by very strong eluviation. On the whole,there was manganese deficiency of different levels phenomenon in soils of different subcategories in Xi’an.The average content of the available copper in loessial soil was the highest,reached 2.612 mg/kg.What in leached drab soil was the lowest.,just was 0.690 mg/kg.The average content of the available zinc in lou soil was the highest, reached 4.018 mg/kg. What in white slurrying brown soil was the lowest,just was 1.102 mg/kg. On the whole,the average content of zinc in all subcategories of soil reached above rich level.(3)Significant difference was found in seven texture available about soil trace element content. The average content of available iron,available manganes, available copper in sandy soil was higher, and the average content of available zinc in clay soil was higher.(4) As an example, the difference of available trace element content in soil of different plants in the same was not obvious. Plants had the less influence than other factors on available trace element in the soil.(5) The correlation coefficients between pH with available iron,available manganes,availablecopper,available zinc respectively was-0.561,-0.358,-0.133,-0.299, there was a very significant negative correlation. There was a very significant negative correlation between organic matter with available iron and available copper,but the correlation coefficients was very small; There was a very significant positive correlation between organic matter with available manganes,there was no significant correlation between organic matter with available zinc.(6) There was significant difference about available trace element content in soils in different areas.As for available iron:Changan > Huxian > Lantian > Weiyang > Yanliang > Baqiao > Lintong > Gaoling.As for available manganes: Baqiao> Huxian> Yanliang> Changan> Lantian> Weiyang> Gaoling>Lintong. As for available copper: Weiyang> Baqiao> Yanliang> Huxian> Gaoling> Changan Lantian> Lintong. As for available zinc: Yanliang> Baqiao> Huxian> Weiyang> Lintong> Gaoling >Changan> Lantian.(7) The available trace element distribution in Xi’an is characterized by a certain zonality. Available iron content presented the obvious trend that from west to east, from south to north first decreased after increased. The change trend of available manganese, available copperwas relatively flat. Available zinc content in northeast is much higher than other areas in Xi’an.