Study On The Titanium Distribution Characteristics In Chongqing Typical Soil Profiles And Titanium Biology Validity

There is no certain conclusion about the law of distribution characteristics of titanium in soil profiles till now.К.ИСупругсараяLucar andÐ’.КСупругсараяLucar researched the distribution characteristics of titanium in soil profiles from Russia and White Russia and noted that there was no obvious law of the distribution.But it has the character of enrichment in podzol layer in deeply developed podzol.Yang Jianhong researched the distribution characteristics of titanium in purple soil profiles from Chong Qing and considered that total titanium and amorphous TiO₂ content in plow pan(P layer)and substrate(B layer)are a little higher than that in topsoil in most paddy soil profiles, which means that titanium may leakaged down with water and enriched in close-knit plow pan and substrater.Meanwhile,there are only a few reports on the content and distribution of titanium in plants,and in those reports,the Ti content in same plant were still in a wide range:Xu Xinyu considered that the mean titanium content in aerial part of spring wheat was 2.99 mg·kg^-1,but Xie Huiguang studied the content of titanium in some species of spring wheat and found that the content was in the range of 6.12～85.1 mg·kg^-1.Of corse,this difference has some relation to species of plant,the titanium content in soil and soil.condition,but what is more is lack of a kind of stable and feasible determination with wide applicability of titanium in plant.This paper researched the content and distribution characteristics of titanium in soil profiles which were collected from typical parent materials in Chong Qing,discussed the effect of land use type on distribution characteristics of titanium in soil profiles and the relativity between distribution characteristics of titanium and iron.Simultaneity,we ameliorated the determination method of titanium in plant sample based on method of dry ashing and compared it with two methods that used usually.In addition,biology validity of two different exacting methods of soluble titanium is also studied.The results are as follows:(1)The titanium content in soils of Chongqing area varies from 2.91～19.4(Ti)g·kg^-1.The content and distribution characteristics of titanium vary with soil parent material.Meanwhile,in soil profiles origin from every parent material studied,correlation coefficient of distribution characteristics of titanium and iron are extremely obvious.(2)The distribution characteristics of titanium in soil profiles varies with land use.In dry land profiles,Ti distribution characteristic is A layer＞B layer＞C layer,in paddy field profiles is C layer＞B layer＞A layer,while it's B layer＞C layer＞A layer under the condition of rice/wheat rotation.(3)The results indicate thai:Dry ashing—NaHSO₄ melting method is superior to methods of dry ashing—NaOH and wet ashing HNO₃—HClO₄ in sensitivity,precision,reproducibility and simplicity.(4)In the 3 different grain crop samples that colleted from 4 different areas in China,the titanium content in seed varies from 0.423～38.0(Ti)mg·kg^-1,in stalk varies from 18.3～454(Ti) mg·kg^-1.Rice holds the highest titanium content in three grain crops.Ti content in same grain corps from different area exists remarkable difference.(5)There is no obvious relativity between the titanium amount extracted by DAPM—V_c—HCl method or(NH₄)₂SO4—H₂SO₄ method,and the content of titanium in each part of rice plants.