The cotton industry spends about $8M on P fertilizers and about $5M of K fertilizers. This indicates the extent of recognised P and K deficiency. It is envisaged that many cotton-growing soils are nearing deficient status, as continual cotton cropping quickly depletes these nutrients. Identification of these soils through soil and plant testing and formulation of improved fertilizer management practices will avoid nutrient deficiencies that reduce the productivity and profitability of cotton cropping.

Inadequate P and K nutrition are responsible for substantial losses of yield and profitability in cotton farming. Deficencies of both nutrients have been linked with the premature senescence syndrome, although confusion arises between the importance and the interactions of these two nutrients.

Previous research has indicated levels of available soil P at which response to P fertilizer is expected and P fertilizer recommendations for maintaining levels of soil P to adequate crop P nutrition. Similarly, research has been conducted on the association between K nutrition and premature. However, the influence of soil sodicity on the P and K nutrition of cotton has now been recognised and a significant effort is required to determine its importance and economic relevance to production.