Potassium Fertilization of Upland and Pima Cotton (1991-1995, a five year project review)

Abstract

In an effort to provide information on the agronomic necessity of potassium (K) fertilization in Arizona cotton (Gossypium spp.) production, a five-year study was initiated in 1991 with a single field study located near Gila Bend. Subsequent study sites selected ranged from western (Yuma) to eastern (Safford) Arizona, which totaled 11 site years. Both Upland (G. hirsutum L.) and American Pima (G. barbadense L.) cotton were cultivated, using soil and foliar applications of K. In 1992, study sites included the Safford Ag. Center (SAC), Maricopa Ag. Center (MAC), and a Cooperator site at Coolidge. In 1993, the experiment stations sites were maintained (SAC and MAC) and Yuma Valley was added. The 1994 study sites included only the two experiment stations (SAC and MAC). In 1995, SAC and MAC were maintained, and a third location was a farmer cooperator site at Buckeye. The results from all studies (12) indicated no lint yield increases due to K fertilization at any of the locations with either Upland or Pima cotton. However, in 1995, at the Buckeye location, the result revealed a significant yield reduction due to the K foliar treatments. There were, however, no significant differences among soil as well as the soil-plus-foliar treated plots in the 1995 study at Buckeye.