Energy Use Efficiency and Carbon Footprint of Inorganic Fertilizer and Liquid Animal Manure in Maize Production Under Semi-Arid Conditions

Improving energy efficiency and reducing the carbon footprint of crop production are critical for sustainable agriculture, particularly in semi-arid regions where resource use efficiency is essential. This study evaluated the effects of different fertilization strategies on energy use efficiency and carbon footprint in maize production. A field experiment was conducted during the 2023 growing season in Konya Province, Türkiye, using a randomized block design with three treatments and three replications. The treatments included an unfertilized control (U1), inorganic fertilizer application (U2), and liquid animal manure application (U3). The results showed that the highest grain yield was obtained in the liquid manure treatment, which was 2.08 times higher than the unfertilized treatment and 1.18 times higher than the inorganic fertilizer treatment. The highest total energy input was recorded in the inorganic fertilizer treatment (26,235.12 MJ ha−1), while the highest total energy output was observed in the liquid manure treatment (203,154 MJ ha−1). The liquid manure treatment also showed higher net energy efficiency, output–input ratio, carbon efficiency, and carbon sustainability index, while producing the lowest carbon footprint per unit of product. These findings indicate that liquid animal manure can improve maize productivity while enhancing energy efficiency and reducing carbon emissions in semi-arid agroecosystems.