Showing 4 results for Calcareous Soil.
T. Rahimi, A. Ronaghi,
Volume 16, Issue 59 (4-2012)
Abstract
Contamination of agricultural soils by heavy metals is a serious threat from both agricultural and environmental standpoints. Among heavy metals, cadmium (Cd) toxicity for humans and plants is of great concern due to its high mobility and phytoavailability in soil even at low concentrations. Opposite to Cd, Phosphorus (P) is an essential nutrient for plant growth. A greenhouse experiment was carried out in a completely randomized design to examine the influence of Cd, P and their interaction on the growth and chemical composition of spinach grown on a calcareous soil. Treatments consisted of four Cd levels (5, 10, 20 and 40 mg/kg soil as cadmium sulfate) and four P levels (0, 20, 40 and 80 mg/kg soil as mono-calcium phosphate) in three replicates. The results indicated that 40 mg Cd significantly decreased spinach dry weight by 47% but P application decreased detrimental effect of Cd on spinach dry weight. Also, phosphorus application significantly decreased Cd concentration in spinach aerial parts by 78%. Increasing Cd levels increased concentration of this element in spinach shoots. Addition of 40 mg Cd decreased P concentration by 21.5% in aerial parts. Zinc (Zn), manganese (Mn), calcium (Ca), and nitrogen (N) concentration significantly decreased with P application but increased concentration of sodium (Na). Cadmium application decreased Zn concentration but increased Ca, Na and N concentrations in spinach. Our tentative conclusion is that P application in P-deficient soils is probably effective in decreasing Cd concentration and the detrimental effect of Cd on spinach growth, indicating a negative interaction between these elements. Prior to any fertilizer recommendation, the results of this experiment should be verified under field conditions
E. Chavoshi, M. Afyuni, M. A. Hajabbasi,
Volume 19, Issue 72 (8-2015)
Abstract
Transport of fluoride and consumption of groundwater with excess fluoride concentrations poses a health threat to millions of people around the world. The objective of this study was to simulate transport of fluoride (F) using HYDRUS-1D model. The study was conducted in lysimeters at Lavark research station site in Isfahan. The treatments consisted of two concentrations of F (157 and 315 mg kg-1). The duration of the study was 125 days. Some of soil physical and chemical properties, soluble F and total F concentration were determined during the study. The results showed the transport of F in calcareous soil profiles. This may be due to the high pH and desorption of F ion as a result of repulsion by the more negatively charged soil surfaces. The highest concentration of total F and water soluble F were observed in the 10 cm surface soil layer. The concentration of F decreased with increased soil depth. The correlation coefficient was significant between the water soluble fluoride and the total fluoride (1% level). Also, the difference between the observed t- value and a critical value on the t distribution is statistically insignificant. It showed that the model simulated successfully water soluble F concentration in the soil profile.
M. Zolfi Bavariani, A. Ronaghi, N. Karimian, R. Ghasemi, J. Yasrebi,
Volume 20, Issue 75 (5-2016)
Abstract
This study was conducted to investigate the effects of poultry manure (PM) and its derived biochars on chemical properties of a sample calcareous soil. Poultry manure and its derived biochars at 200(B200), 300(B300) and 400(B400)°C were incorporated with 400 g of soil at 2% level (w/w) and incubated for 150 days. Some chemical properties of soil and bio-availability of some nutritional ingredients such as phosphorous, potassium, iron, manganese, zinc and copper were determined at different times of incubation. Soil nutrients availability, organic carbon (OC), electrical conductivity (EC) and cation exchange capacity (CEC) increased by addition of all these organic substances. Biochars prepared at higher temperatures were more effective in increasing soil OC and its durability. Addition of PM and B200 decreased soil pH, whereas B400 increased it. Although highest soil EC was observed in B300 and B400 treated samples in the early stages of incubation, the rate of increasing in soil EC was higher at PM and B200 treated samples. In general, it was concluded that biochar prepared at 300°C had the highest effect on availability of nutrients and their durability in the soil.
M. Hosseini, E. Adhami, H. R Owliaie,
Volume 22, Issue 1 (6-2018)
Abstract
Cadmium (Cd) is of special importance among heavy metals because its toxicity to the plant is 20 times higher than other heavy metals. The present study was conducted to evaluate the trend of available soil Cd changes over time and its relationship with soil properties. Treatments consisted of 13 soil samples and two Cd rates (12.5 and 25 mg kg-1) as a factorial in a complete randomized design with two replications. DTPA extractable Cd was measured upon 5, 10, 20, 30, 60 and 90 days after adding Cd rates to the soils. The results showed that DTPA extractable Cd was increased as Cd application rates was raised in all soils. DTPA extractable Cd was decreased over time; however, at the end of the experiment, much of the added cadmium to the soil remained in use. Among the soil properties, calcium carbonate showed a significant negative correlation with DTPA extractable Cd in most of the incubation times in both Cd rates. DTPA extractable Cd also showed a significant negative correlation with pH and soil sand and a significant positive correlation with OC. Also, the results of the fitting of cadmium adsorption data with the kinetic equations showed that the exponential function equation was the most suitable kinetics descriptive equation for variations in cadmium adsorption in the studied soils.
