Energy use in cropping systems: A regional long-term exploratory analysis of energy allocation and efficiency in the Inland Pampa (Argentina)

As agricultural system comprises natural processes that are ruled by thermodynamics, the energy utilization is well suited for assessing the sustainability in the management of natural resources. The goals of this paper are 1) to assess the energy use efficiency of the main crops during the 1992–2005 period in Inland Pampa (Argentina); 2) to evaluate the database structure in terms of energy allocation; 3) to assess the changes in technical efficiency using frontier analysis and 4) to identify the best explanatory variables for energy efficiency variability. Results showed an upward trend in productivity per unit area in the crops analyzed (excluding sunflower). Summer soybean and sunflower showed higher energy efficiency values by the end of time series. The main shift in the energy use pattern was the reduction of the energy allocated to tillage. The overall performance of the wheat and soybean crops in the study area appears to be closer to the energy usage pattern shown by the top 5% energy use efficiency crop fields. The exploratory analysis using classification and regression trees (CART) revealed that the energy allocation to tillage; and the crop specie were the attributes that mainly explained the energy efficiency changes.

► Energy use efficiency (EUE) of main Pampean crops (Argentina) in the 1992–2005 period was analyzed.
► An upward trend in productivity per unit area was observed with the exception of sunflower crop.
► Summer soybean and sunflower showed higher energetic efficiencies by the end of the time series analyzed.
► Average wheat and soybean EUE were closer to the energy usage pattern of the top 5% EUE crop fields.
► Tillage energy and crop specie were the attributes that most strongly explain the EUE changes.