"More sown" refers to the act of scattering or planting more seeds. The antonyms of "more sown" would be words that indicate the opposite, such as reducing, decreasing, or cutting back on sowing seeds. These antonyms could be used, for example, to describe a farmer who has decided to plant fewer crops, or a gardener who is cutting back on the number of seeds he plants. In general, antonyms for "more sown" would convey a sense of restraint and economy, as opposed to the abundance and growth suggested by the original word.