Energy balance in nitrogen and sulfur management strategies for oilseed radish

Abstract

This article analyzes the effects of different rates of nitrogen (0, 30, 60, 90, and 120 kg N ha–1) and sulfur (0, 15, 30 kg S ha–1) fertilizers on energy balance in oilseed radish biomass production. Energy inputs (EI) were determined at 6.8–7.1 GJ ha–1. Nitrogen application increased EI by 34% (30 kg ha–1) and 135% (120 kg ha–1). The energy output of seeds and total biomass peaked after the application of 60 kg N ha–1 + 15 kg S ha–1 and 30 kg N ha–1 + 15 kg S ha–1, respectively. The energy gain from seeds and total biomass peaked in response to 30 kg N ha–1 + 15 kg S ha–1. The energy efficiency ratio (EER) of seeds peaked in response to 15 kg S ha–1 (without N fertilization). The EER of total biomass was highest in the absence of N and S fertilization. Nitrogen decreased the EER of seeds and total biomass by 47% and 56%, respectively. The N-induced decrease in the EER was reduced by 4–8% (seeds) and 4–10% (total biomass) when S was applied.