The Impact of Maize Legume Intercropping on Energy Indices and GHG Emissions as a Result of Climate Change

Abstract

Multicropping can solve energy use and GHG balance problems, but the emergence, development, and productivity of such mixed crops are at risk due to the uneven distribution of precipitation. For this reason, investigations were performed at the Experimental Station of Vytautas Magnus University, Lithuania. Single maize crops were compared with Crimson/red clover, Persian clover, and alfalfa intercropped maize. The objective of this study was to evaluate the main energy indices and GHG balance of legume intercropped maize cultivated in humid and arid vegetative conditions. The results showed that, under arid conditions, the quantity of intercrop biomass was about four times lower than that under humid conditions. Humid conditions were less suitable for maize and resulted in about 3–5 t ha−1 less dried biomass from intercrops and about 6 t ha−1 less biomass in single crops than in arid conditions. Due to the higher yield of maize biomass in the arid season, better energy indicators of crops were obtained in arid than humid conditions. The difference between net energy was about 122–123 MJ ha−1 in all treatments, except for the maize crop with intercropped alfalfa, where the difference was 62 MJ ha−1. All tested technologies were environmentally friendly; the CO2 equivalent varied between treatments from 804 to 884 kg ha−1. The uneven distribution of precipitation during the vegetative season provides insight into the improvement of intercropping technologies. Sowing intercrops at the same time as maize could improve their germination but increase the problem of weed spread.