Print version ISSN 0006-8705
ZAMBROSI, Fernando César Bachiega. Phosphorus fertilization in sugarcane ratoon and its interaction with magnesium. Bragantia [online]. 2012, vol.71, n.3, pp. 400-405. Epub Oct 04, 2012. ISSN 0006-8705. http://dx.doi.org/10.1590/S0006-87052012005000029.
There are still doubts with regard to the efficiency of P fertilization in the sugarcane ratoon and the interaction between P and other nutrients that could affect the responses to P reapplication. An experiment was set up to evaluate the effects of P rates (45 and 90 kg ha-1 of P2O5) applied either in the absence or presence of Mg fertilizer (50 kg ha-1 of Mg) on the stalk yield, of sugarcane ratoon. P fertilization increased stalk yield in 17% compared to the control treatment (no P fertilizer). However, such response did not depend on Mg fertilization, suggesting that Mg was not critical to the occurrence of P response. The P nutritional status of sugarcane was not also affected by Mg application, being altered exclusively by P fertilization. P content in the leaves varied significantly (p<0.05) from 1.4 g kg-1 in the control to 1.7 g kg-1 and 1.9 g kg-1 in the treatments with application of 45 and 90 kg ha-1 of P2O5, respectively. P fertilization increased in 21% and 16%, the efficiency in the use of N and K fertilizers, respectively, compared to the control. The results suggest that increases in the yield of sugarcane ratoon cultivated in a low-P soil can be obtained with P reapplication, what might be related to the improvements on the P nutritional status of the plants.
Keywords : Saccharum; nutrients accumulation; fertilizer efficiency; nutritional status.