The beneficial effect of K on productivity of sugarcane
cultivated in a harvest system without elimination of
residues by fire is reported in the literature. Rossetto et al.
(2004) reported significant effects of K in seven out of ten
evaluations in which K was applied to ratoon sugarcane
plants, since K is the nutrient more extracted by the crop,
mainly by ratoon (Korndörfer and Oliveira, 2005). In
most of their results productivity increased linearly with
K2O doses only in second or third ratoon. Uchôa et al.
(2009) reported quadratic adjustments between K2O doses
and stalk productivity. According to these authors, K2O
dose with maximum economic effect was between 94 and
165 kg ha-1. It is important to remember that the optimum
economical yield depends of changing economic factors
(prices of products and inputs), therefore they may change
year to year.