Mohammad Golam kibria
Professor
Department of Soil Science, University of Chittagong, Chittagong 4331, Bangladesh,
lead (Pb), Amaranthus, Shoot, Root, Concentration, Amount.
Chittagong University
Crop-Soil-Water Management
Soil Characteristics: Pot experiment with sandy clay loam soil was conducted to study the effect of various levels of lead in soil on the growth performance and Pb uptake by amaranthus (Amaranthus tricolor L.). Soil samples were dried in the air after collection from a depth of about 0-15 cm from agricultural land of Chittagong University campus. After air drying, larger and massive aggregates were broken down by gentle crushing with wooden pluck. Dry roots, grasses and other particulate materials were discarded from the soil sample. A portion of the soil sample was passed through 2.00mm sieve for laboratory analyses. The soil contained 57, 22 and 23% of sand, silt and clay, respectively as determined by the method of Day (1965). The pH of the soil was 5.5 (soil to water ratio of 1: 2.5) measured with the help of glass electrode pH meter. The content of organic carbon (Jackson, 1973) and total nitrogen (Jackson, 1973) were 0.83% and 0.09%, respectively. The soil contained aqua regia digestible (Jackson, 1973) phosphorus, potassium, iron, lead, zinc and manganese of 0.029%, 0.24%, 0.736%, 7.8 µgg-1, 58.96µgg-1 and 190.20 µgg-1 respectively. The aqua regia digestible Cd was below detection limit determined by Atomic Absorption Spectrophotometer (Varian spectra AA-220).
Pot Experiment: Earthen pots were filled with soil @ 8 kg pot. Nitrogen, phosphorus, and potassium at the rate of 90, 25 and 30 kg ha-1 in the form of Urea, Triple Super Phosphate, and Murate of Potash, respectively were applied to the soil as recommended by BARC (1997). All phosphorus & potassium and one half nitrogen were applied and incorporated with soil during preparation of the pot. Remaining N was applied in two equal installments at 10 and 25 days after sowing (DAS). Seeds of amaranthus ( Amaranthus tricolor L.) were sown in the pot. At 15 days after sowing, plants were thinned to 10 plants in each pot and lead was added in solution form to the pot as lead nitrate, Pb(NO3)2 at the rate of 0, 10, 20, 30, 40 and 50 mg Pb kg-1 soil . Each treatment was replicated three times. The pots were arranged according to a randomized complete block design. Five plants were harvested from each pot at 30 days after sowing (DAS) and the remaining 5 plants were harvested at 45 days after sowing (DAS). At both the stages of harvesting, the heights of plants were measured. The shoots and roots were collected separately. The roots were collected carefully and washed thoroughly to remove adhering soil particles. Plant samples were dried at 650 C for 72 hours, weighed ground and stored for chemical analyses.
Plant Analysis: Plant samples were digested with tri acid mixture ( Imamul Huq and Alam, 2005) and lead content of the digest was determined by Atomic Absorption Spectrophotometer.
Statistical Analysis: The experimental data were statistically evaluated. Analysis of variance (ANOVA) was done. The test of significance of different treatment means was computed by Duncan’s Multiple Range Test (DMRT).
Hamdard Medicus, Vol.52,No.3, Page 82-87, 2009
Journal