Study of zeolite and humic acid impacts on cadmium absorption by Lactuca sativa var. Crispa

Nowadays, the potential dangers and risks of toxic heavy metals existing in water, soil and their entrance to the food chain of human beings and animals upon human , plants and animals is well known. In order to study the rate of Cadmium absorption by Lactuca sativavar. Crispa, a research was executed in the form of a factorial test and based on a completely randomized plan of 6 treatments. The treatments of this test include zeolite clinoptilolite in the three levels zero ,2000, 4000 kg per hectare and humic acid (from trade resource of American Humax) in the three levels zero,20 and 40 liters per hectare. For cadmium contamination in soil, un amount of 3 mg per kilo of pure cadmium from cadmium nitrate source was added to the soil of the treatments under experiment in an equal range. At the end of experiment, the absorption ratio of cadmium, zinc and nitrogen and also dry weight of aerial organ and root were measured. The results showed that the second level of Zeolite and third level of Humic acid had the minimum cadmium absorption in the plant compared to the control. The maximum rate of nitrogen absorption was seen at the third levels of Zeolite and Humic acid. About the ratio of dry weight of aerial organ and root, the maximum amount of root and leaf dry material was seen at the second treatments of Zeolite and Humic acid. The findings of the research illustrated that application of Zeolite and Humic acid can reduce absorption of the heavy metal of cadmium in lettuce plant and insist on further application of these two elements to improve plants’growth.

Keywords:

Cadmium , Humic acid , Lettuce , Zeolite