Abstract: The experiment show that the most suitable temperature for crabgrass(Digitaria ciliaris)germination is 25℃-35℃, with germination rate up to 81% - 86%. Lighting is an inevitable condition. The crabgrass seed has wide adaptability to the solution pH from 2 to 10 and the solution potential,from -0.2 to -0.8 MPa which have no obvious impact on the crabgrass seed. The increase of nitrogen concentration between 0.01% - 0.18% speeds up the crabgrass seed germination than in deionized water. The main soil depth for seed emergence is 0 - 2 cm due to the undisturbed soil crop system. Some strategies for controlling the crabgrass can be made according to its germination and emergence characteristics.

Key words: Illex argentinus, stock assessment and management, Schaefer model, Southwest Atlantic Ocean.