Maintaining the optimum plant population and competition in field crops right from germination to harvesting is one of the important tasks for efficient utilization of resources and to get highest economical yield. To know the about the inter and intra plant competition and its ultimate response on plant density dynamics, review was done on the topic managing plant population and competition on field crops. It was found that the optimum plant population is highly dependent on the various factors like crop inputs, environmental condition and managerial factors and the competition within and between the crop plants. The optimum plant population for any crop in given locality is usually determined by trial and error method. Managing the input level and environmental condition as well as many agronomical approaches can maintain the plant population to a desired level. Proper method of sowing, using good quality seed and right seed rate, optimum sowing depth, sowing seed in good quality soil, plant size and architecture, proper fertilization and irrigation, gap filling and reseeding, over-seeding and thinning, double transplanting and use of tolerance variety can be used to obtain optimum plant population.