Study Of Variance Characters And Chemic Actions Of Copper In Orchard Soils

Copper are both an essential nutrition element for crops and a heavy metallic element polluting the environment. Copper accumulated in orchards soils for long time used the bactericides containing copper, such as Bordeaux mixture, destroyed the balance of nutrition of soils, depressed the quality and quantity of fruits, and threatened the health of both human and domestic animals. It has been always attached to the pollutions of external copper on the soil-plant surroundings. Route inspection was used to investigate the copper contents in orchard soils of mainly fruit product areas of Shandong province. The form classification and section variance of copper in orchard soils were analyzed to conclude the characters of distribution and transform of external copper in soils. The ability of absorption-desorption and buffering of external copper in orchard soils were researched and respectively fit with the equations of Langmuir or nonlinear damped vibration equation. The geo-statistics was used to study the copper special variance characters in orchard soils and the isolines were painted to nicely reflect the content and special relativity of copper in the soils.1. Characters of copper in orchard soilsThe contents of T-Cu and DTPA-Cu in orchard soils are obviously higher than that of controls. The mean content of T-Cu in orchard top soils is 1.53 times as high as that of controls. And 6.7% of orchard soils are over the national second critical criterions. The contents of DTPA-Cu in top and secondsoils are 6.92 and 3.80 times as high as that of controls respectively. The content differences of DTPA-Cu and T-Cu in top soils between orchards and controls are notability.2. Forms classification of copper in orchard soilsThe content of EX-Cu is the lowest in orchard soils, and less than 2% of T-Cu. Contents of all forms copper are increased compared with controls, especially OC-Cu, which content is 68.79mg·kg－1, 22.07% of T-Cu. That indicates that the copper availabilities in orchard soils are higher than controls. The mainly form of copper in soils is RES-Cu, more than 60% of T-Cu. 3. The section distribution of copper in orchard soilWith the depth adding, the contents of all forms copper in orchard soils decreased, especially T-Cu and DTPA-Cu, which contents in all sections are notably higher than controls. The contents of copper under the second sections don't change great as top soils, which shows that the external copper mainly affects the contents and distribution of copper in orchard surface soils. 4. Absorption-desorption of copper in soilsThe absorption curves of copper in orchard soils were notably fit for Langmuir equation. The ordinal max absorption of soils in test was: aquert >saline-alkali soil > drab soil >burozem. The desorptions were reverse and far smaller than absorption. The desorptions, compared with absorption, showed obvious lag phenomena. And the lag circles had positive correlation with the abilities of absorption. Compared with controls, the max absorption notably decreased, while the desorptions increased.5. The characters of absorption-desorption with timeBoth absorption and disorption were rapidness actions and would extend the balance within 20 min in orchard soils. The desorptions were far smaller than absorption. The time of extended the max in orchard soils was a little earlier than that of controls, and the adsorption in orchard soils was lower than controls.6. The buffering of copper in soilsThe buffering abilities of copper in tested soils were decreased with the content of external copper increased, especially under the condition of high copper content. The order of buffering abilities in tested soil was: aquert > saline soil>drab soil>burozem. The buffering abilities of copper in orchard soils were obviously decreased compared with controls for lots of buffering places were occupied by the copper which accumulated in the orchard soils. The curves of buffering rates changing with time were fit for nonlinear damped vibration eq...