Nutrient extraction by mombaga grass submitted to sources and doses of nitrogen

Abstract

The extraction of nutrients from the soil by plants depends on soil fertility, plant management and plant production. The objective of this study was to evaluate the effect of the application of sources and doses of nitrogen on macronutrient extraction by Panicum maximum cv. Mombaça. The experiment was conducted from 1 October 2011 to 14 April 2012 in the Federal Institute of Espírito Santo, Santa Teresa Campus. The experimental design was a randomised block design with three repetitions in a 3 × 6 factorial scheme, with three nitrogen fertilisers (urea, ammonium sulphate and calcium nitrate) and six nitrogen doses (0, 120, 240, 360, 480 and 600 kg ha -1 ). The established nitrogen doses were divided equally and applied every 28 days after the mombaça grass was cut, resulting in a total of seven applications during the 196-day experimental period. It was observed than nutrient extraction depends on forage plant production and was highest with the higher doses of nitrogen because of the greater dry matter production. The application of high doses of nitrogen in the form of calcium nitrate caused a reduced absorption of magnesium. Nitrogen fertilisation in pastures should be accompanied by the management of other nutrients to avoid nutritional imbalances or the depletion of soil fertility.Key words: Panicum maximum, nitrogen fertilisers, macronutrient absorption, interaction between ions. RESUMEN