Effects of sowing date and nitrogen applications on the energy efficiency of facultative wheat ( Triticum aestivum L.) in a Pannonian environment

Abstract

Energy efficiency analysis provides a deeper understanding of non-renewable energy dependent cropping systems. In this study, we examined the crop yield and energy efficiency of facultative rainfed wheat (W _W – winter wheat, W _S – spring wheat) and mineral nitrogen (N) fertilization (0, 50, 100, 150, and 200 kg N ha ⁻¹) in two growing seasons 2019/20 and 2020/21 in Central Europe. W _W out performed W _S significantly overall (2019/20: +30.3 to +47.9 %; 2020/21: +18.9 to +37.3 %) in terms of energy efficiency indicators. The impact of N fertilization on energy efficiency was minimal, largely due to one dose application of mineral N fertilizer. The highest estimated net-energy output (NEO) was observed at 160.2 kg N ha ⁻¹, which may not sustainable for this pedo-climatic region due to potential N emissions risks. Zero N fertilization showed best performance in terms of energy use efficiency (EUE), energy intensity (EI), and energy productivity (EP). The ERG z-score, which combines NEO and EUE into a single bi-dimensional indicator, indicated an optimal N fertilization level of 72.0 kg N ha ⁻¹.

Highlights

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  Mineral N fertilization and facultative wheat were evaluated under Pannonian conditions.

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  Winter wheat is more energy efficient than spring wheat.

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  Mineral N fertilization (0–200 kg N ha ⁻¹) has a low effect on energy efficiency.

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  Optimization of N fertilization was estimated with 72 kg N ha ⁻¹.

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  Crop yield determines mainly the energy efficiency indicators.