Evaluation of carbon sequestration potential in corn fields with different management systems

Carbon sequestration could be an effective way to reduce atmospheric carbon dioxide which is the most important greenhouse gas. Two field experiments were conducted at Agricultural Research Station of Ferdowsi University of Mashhad, Iran, during growing seasons of 2008-2009 and 2009-2010. Four treatments including two low input management systems based on application of cow manure or compost municipal made from house-hold waste, a medium input system and a high input system were applied. In low input system 30 t ha−1 cow manure or 30 t ha−1 compost municipal made from house-hold-waste was applied and twice hand weeding were carried out. In medium input system, 15 t ha−1 compost, 150 kg ha−1 urea, disking and ploughing, 1.5 l ha−1 2,4-D applied at five leaf stage with only one hand weeding. In high input system, management practices included twice disking, twice ploughing, 2 l ha−1 Paraquat applied after planting and 1.5 l ha−1 2,4-D applied at five leaf stage. Results showed that the maximum carbon and nitrogen yields in corn residues observed in high input system (0.8 and 0.02 kg m−2) and its minimum were in low input system with using compost (0.5 and 0.01 kg m−2). The highest and lowest labile and recalcitrant carbon rates were observed in low input system with manure (0.92 and 1.05%) and high input system (0.06 and 0.004%), respectively. The maximum sequestered carbon obtained in low input management system with using cow manure (4.1 t ha−1) and the minimum sequestered carbon were in high input management system (0.01 t ha−1). In low input system due to slow releasing nutrients, long term crop growth and hence higher recalcitrant carbon content of the soil were enhanced which could be an indication of its potential for carbon sequestration in low input management system.