Study On The Manganese In Soils And Its Transfer Characteristics From The Soils To Vegetables

The content and availability of Mn in the agricultural soils in Fujian Province, the factors influencing the accumulation and the availability of Mn in the soils, and the transfer characteristics of Mn from the soils to the edible parts of various vegetables were studied based on an investigation carried out over 9 counties in Fujian province.220 vegetable samples including 21 species of 10 groups of vegetables and the corresponding surface soil samples were collected for this study. The main results were as follows:The total Mn contents of the surface soils ranged between 107.53 and 2319.69 mg.kg-1 with an average of 457.49mg.kg-1.The DTPA-extractable Mn Mn of the soils varied from 2.48 to 391.21 mg.kg-1 with a mean of 54.85mg.kg-1.The available degree (DTPA-extracble Mn/total Mn) of the soil Mn varied from 2.03% to 48.94% with a mean of 11.97%. The soils showed a good capability to provide Mn to pants.The Mn contents (fresh weight basis) of the various kinds of vegetables ranged between 5.10 and 274.87 mg.kg-1 with an average of 55.30 mg.kg-1.As a whole, the vegetables produced in these regions were safe for cosumption.The Mn concentrations in the edible parts of most of the vegetables species did not significantly correlated with both the soil total and available Mn, which may be attributed to the effects of the factors other than the soil Mn status, such as gricultural managements, climate, afertilization and gowth characteristics. Soil-to-plant transfer factors of Mn (total Mn based or available Mn based) decreased with the increase of soil total Mn and available Mn, most of which can be best described by exponential equation (y=axb)According to the ranges of the total and available Mn of the soils studied, the representative Mn accumulation index of each vegetable were estimated based on the regression equations between the transfer factors and the soil total Mn or available Mn at the concentrations of 450 mg.kg-1(total Mn) and 50 mg.kg-1 (available Mn), respectively. All the vegetable species studied were put in order according to their difference in the transfer factor based on available Mn at 50 mg.kg-1 of available Mn:water spinach>spinach>celery>lettuce>pakchoi>wild rice stem> cowpea>leaf mustard>kidney bean>garlic>bottle gourd>rape>Chinese cabbage>vase vegetables>cabbage>towel gourd>eggplant>tomato>hexagon melon>cauliflower>radish。...