Search

The study on the soil arsenic (As) accumulation under different types of agricultural use in Shouguang of Shandong Province showed that farmland soils had an average As content of 9. 63 mg x kg(-1) , with the highest being 15. 15 mg x kg(-1) . Compared with the local background value (9. 3 mg As x kg(-1)) , 53. 1% of soil samples was detected as As enrichment. The soil As content was high in the west, east and north parts of Shouguang, relatively lower in the middle part, and the lowest in the south part. Different agricultural use had an obvious effect on the soil As content, which was decreased in the order of wheat/maize land > cotton field > protected vegetable land > uncovered vegetable land. Such a difference in soil As content was mainly affected by agricultural activities. With the increasing year of vegetable planting, soil As content had an increasing trend, because the As input from pig dung and chicken feces was the main source of soil As in protected vegetable land. Soil As enrichment could be reduced to some degree by applying soybean cake fertiliz-

Cadmium (Cd) accumulation in vegetable plantation land soils under a greenhouse was investigated in Shouguang County, Shandong Province, China. A total of 128 soil samples were collected from different agricultural fields. Soil samples were digested with the mixture of hydrogen peroxide (H2O2) and nitric acid (HNO3), and Cd content in the digested solution was detected with inductively coupled plasma-mass spectrometry (ICP-MS). The results indicated that the concentration of Cd in the greenhouse vegetable field was significantly more than that in open vegetable field, cotton field, wheat/maize field, and uncultivated soils. Cadmium concentration increased with the cultivation age, and the related accumulation rate was 0.0289 mg Cd kg-1y-1 in a greenhouse vegetable field. Organic fertilizer such as livestock manure was the major source for Cd accumulation in the greenhouse vegetable field with the average input amount of 70.7 g Cd ha-1 y-1 from organic manure. Thus, a decrease of Cd input from organic fertilizer into greenhouse soils is necessary. [ABSTRACT FROM AUTHOR]