Effects of Parthenium hysterophorus L. residue on early sugarcane growth in organic and mineral soils

Parthenium hysterophorus is an aggressive annual weed of tropical and subtropical environments commonly associated with noncrop areas in the sugarcane production region of Florida but is now encroaching into cultivated fields. Greenhouse studies were conducted to evaluate the potential phytotoxic effect of P. hysterophorus residue on germination and early growth of sugarcane on organic and minerals soils of Florida. P. hysterophorus dry residue was mixed with both soils at 0, 132, 264, 527, 1054, 2108, 4216, and 8432 g of P. hysterophorus dry residue per m−3 of soil. The weight of P. hysterophorus was based on the dry biomass of average current field infestation of 32 plants m−2 in fallow sugarcane fields, and the volume of the planting media was based on an area of a field disked at a depth of 15 cm. These rates were equivalent to 0×, 0.25×, 0.5×, 1×, 2×, 4×, 8×, and 16× the amount of P. hysterophorus dry biomass present at field infestation levels in Florida based on an area of a field disked at a depth of 15 cm. Results showed that on mineral soil, sugarcane germination, height, aboveground and belowground biomass decreased <5% in response to P. hysterophorus residue at the current infestation level in Florida. In contrast, P. hysterophorus residue had no effect on sugarcane germination, height, aboveground and belowground biomass on organic soil. These results show that there is no potential adverse effect of P. hysterophorus residue on sugarcane grown on mineral and organic soils in Florida at the current infestation level in cultivated fields.