Nitrogen release dynamics and carbon sequestration by legume and non-legume cover crops under pure and mixed planting conditions

Abstract

Synchronizing crop residue decomposing and releasing nitrogen with subsequent cash crop needs provides benefits for ecosystems, but it is difficult to carry out. This study aimed to investigate the trend of decomposition of vetch (Vicia sativa), rye (Secale cereale) and mixed (rye + vetch) cover crop residues as well as nitrogen release after incorporating them into the soil during 12 weeks of the potato growth season by using the mesh bag method. Vetch residues decomposed very quickly in the spring and their nitrogen is released due to their higher nitrogen content and consequently a lower Carbon/Nitrogen (C/N) ratio. However, rye residues decomposed at a slower rate compared to mixed treatment, and their nitrogen content was immobilized mainly due to a higher C/N ratio. A better understanding of cover crops residues decomposition dynamics leads to maximizing the cover crop effects and higher nutrient uptake by subsequent main crops. The results of this study showed that the input level of nitrogen fertiliser can be reduced by implementing management strategies in farming potatoes and using cover crops, which will reduce the harmful environmental effects and increase the economic benefit for farmers.