Influence of nitrogen sources and foliar silicon fertilization on agronomic characteristics and differential profit from sugarcane stalk production

Abstract

Appropriate nitrogen (N) availability ensures sugarcane crop longevity and yield, and foliar application of silicon (Si) can maintain or increase crop yields by inducing resistance to biotic and abiotic stresses. This study evaluated the influence of N sources and doses of foliar Si application on the agronomic characteristics of and differential profit from sugarcane stalk production. A field experiment was conducted with the second ratoon of sugarcane variety CTC-04 (2021/2022 harvest). The experimental design was arranged in randomized blocks with a 2 × 5 × 3 factorial scheme: two N sources [urea or calcium ammonium nitrate (CAN) plus the nitrification inhibitor 3,4-dimethylpyrazole succinic – DMPSA]; five Si doses of 0, 450, 900, 1350, or 1,800 g ha−1, divided into three sprays during the crop cycle; and three sampling times of 150, 240, or 305 days after cut (DAC). At each sampling time, biometric parameters, leaf nutrient content, pigment concentrations, technological quality, sugar yield, and stalk yield were evaluated, and differential profit was analyzed. Of the Si doses, foliar Si application at 900 g ha−1 resulted in the highest sugarcane biometric parameters, chlorophyll index, and leaf nutrient content in second ratoon. Ammonium and calcium nitrate associated with the nitrification inhibitor DMPSA increased sugarcane stalk yield by 12.14% and sugar yield by 14.30% compared with urea. In addition, foliar Si application was found to be an economically viable option. Foliar application of 900 g Si ha−1 increased the maximum profit by US$ 1,480.49 ha−1 for sugar yield and US$ 812 ha−1 for stalk yield when combined with ammonium and calcium nitrate associated with the nitrification inhibitor DMPSA as the N source.