Do Contemporary Cotton Cultivars Respond Differently to Potassium Fertilization?

摘要

Contemporary upland cotton cultivars may differ in their potassium (K) nutrition requirements to achieve optimum yields. Researchers have offered several possible explanations for varietal differences in yield response to K, including differences in earliness of maturity and in partitioning of the products of photosynthesis within the plant. This article summarizes some Tennessee research in progress to investigate these relationships.Earliness of maturity is important to the adaptation of cultivars to different parts of the U.S. cotton belt, especially where season length is marginal for cotton, as in the North Mississippi River Delta. Earliness is enhanced when a greater proportion of new photosynthate is partitioned to bolls instead of more vegetative growth. This reduces the number of new fruiting sites, thus limiting the number of late-set bolls. By contrast, cultivars that continue to grow vegetatively during boll filling are said to be physiologically indeterminate. Production of new fruiting sites and foliage late in the season delays their maturity and harvest.