The effects of sugar cane molasses on calcareous soil chemical characteristics

Molassesa by-product of sugar cane industry is an organic compound containing high amount of carbohydrates with proteins, gum, wax and pectin that in this research the possibility of using cane molasses as amendment for calcareous soils has been investigated. The soil samples were collected from the 0-30 cm depth of a cane field in Haft tappeh and a region of Lowshan in Khoozestan and Guilan provinces, respectively. Treatments with regards to the soil bulk densities and 0-30 cm depth were 0, 2.5, 5, 10, 20 and 40 ton/ha of molasses, 10 ton/ha of molasses with 10 ton/ha of elemental sulfur and 10 ton/ha of molasses with 40 ton/ha of cane bagass. The molasses (mixture with water) was added to 500 gr soil in plastic pots. Soil moisture content was adjusted to near field capacity and changes pH, EC, total nitrogen, organic matter and available phosphorus and potassium were determined at 1, 30 and 60 days. Results indicated that the molasses decreased soil pH in all molasses treatments to some extent compare to blank. Elemental sulfur significantly decreased soil pH, but bagass no influenced it. Molasses increased EC that this was considerable in 40 ton/ha treatment. Molasses increased total nitrogen, but decreased available phosphorus. Total nitrogen and available phosphorus increased in some treatments and decreased in other treatments during the time incubation. The amount of increase in available potassium was proportional to the amount of molasses used. Elemental S had not considerable effect on total N and available P and K, but the bagass had significant effect on available P and K. Results indicates the molasses can be used as a soil amendment in calcareous soils. It is suggested that the effect of molasses on plant growth and chemical characteristics of calcareous soils be studied under greenhouse and field conditions. Key words: Molasses, Soil amendment, Calcareous soil, pH, Soil electerical conductivity