Dry matter accumulation and macronutrient uptake in sugarcane varieties

Abstract

The increase of the area cultivated with sugarcane has demanded information about the culture, mainly in relation to its nutritional needs. There are few studies that report the nutrient uptake in sugarcane, in addition, there are no reports of studies focused on the different periods of sugarcane growth and development. In view of the above, the objective of this research was to determine the macronutrient uptake and dry matter production in the shoots of two sugarcane varieties. The experiment was carried out in Vicentina, Mato Grosso do Sul, Brazil, during the 2017/2018 harvest, using two varieties of sugarcane (RB92579 and SP832847). The experimental design was in randomized blocks with two sugarcane varieties, nine collecting times (90, 120, 150, 180, 210, 240, 270, 300 and 330 days after planting (DAP) and 4 replications. Samples were collected from the shoots of 10 plants, which were divided into leaves, sheaths and stalks, then dried and weighed, and finally the samples were submitted to laboratory analysis to determine the nutrient concentrations in each organ. The accumulation of macronutrients in the shoots of both varieties followed the order: K > N > Ca > S>Mg > P. The export by the stalk followed the order K > N > Ca > S > P > Mg for RB92579 and K > N > Ca = P > S > Mg for SP832847. Maximum accumulation of nutrients and the maximum dry matter production occurred in the interval between 240 and 300 DAP. The variety SP832847 accumulated higher amounts of nutrients and dry matter in relation to RB92579, as well as the time required for the maximum accumulation was shorter.