Snail survival as bioindicator of cadmium contaminated soils under semi-realistic field conditions

Juvenile brown garden snails (Helix aspersa Müller) were exposed to Cd-contaminated soils for 60 days under semi-realistic field conditions. The soils were contaminated with increasing concentrations of cadmium chloride (0–2900 mg kg-1 Cd2+/solution CdCl2). The snails were housed in terrariums and were fed exclusively with nettle leaves. The experiments were carried out in Timisoara on 1000 snails.The survival rates differed significantly for different Cd treatments. Only higher cadmium concentrations (> 1000 mg kg-1 Cd2+/solution CdCl2) had a significant influence on survival curves of snails exposed to Cd-contaminated soils. The maximal death rate reached 81.00±9.9% for snails exposed to soils contaminated with 2900 mg kg1 Cd /solution CdCl2. We found dose-dependent survival rates, whereas the half maximal effective concentration was 1365 mg kg-1 Cd2+/solution CdCl2. Our results suggested that longer-term studies are required for assessing the real potential of snail survival rate as bioindicator of Cd-contaminated soils in field conditions

Change in time of agrochemical soil parameters after tomato mineral fertilization

The paper presents the results regarding the effect of different NPK fertilization doses on change, during three years of agrochemical soil parameters after tomato mineral fertilization. The following agrochemical indicators were analyzed: pH, humus, total nitrogen, mobile phosphorus and mobile potassium content. The experience was done in a cambric cernosium soil, with low acidity reaction, very good content in nitrogen, phosphorus and potassium and the high natural fertility potential favorable vegetables cultivation in Romanian Western Plain area. The experimental field is located in temperate climatic area, characterized by Koppen classification in the formula Cfbx. The study was performed on control soil samples (without fertilizers) and soil samples after differentiated NPK fertilization in variable dozes: N30P30K30, N45P45K45, N60P60K60 and N120P60K60. Tomato fertilization with mineral fertilizer determines, in time, significant modifications of agrochemical soil parameters. To preserve the soil quality must find the optimum dose of NPK fertilizer in tomato crop fertilization