<p>Cropping systems may affect root decomposition and our objective was to evaluate chemical characteristics and root decomposition in signal grass ‘Basilisk’ [<i>Urochloa decumbens</i> (Stapf) R.D. Webster] pastures under different cropping systems. A split-split plot scheme, with four cropping systems (0, 50, 100&#xa0;kg·ha⁻¹ of N, and intercropping with calopo (<i>Calopogonium mucunoides</i> Desv.) in the plots (paddocks), two experimental periods (2019/2020 and 2020/2021) in the split-plots, and nine incubation times (4, 8, 16, 32, 64, 128, 256, and 512 days) in the split-split plots, in a randomized block design with two replications was used. Root biomass was not affected (<i>p</i> &gt; 0.05) by cropping systems (7.4 t ha⁻¹ on average). Before incubation, ADIN-TN (acid detergent insoluble nitrogen in total nitrogen) concentration was affected by cropping systems and C concentration was affected by interaction cropping systems x period. The remaining biomass had a loss total of 28% (1st ) and 30% (2nd ) after 512 d. N concentration was higher in the 1st period, resulting in a lower carbon: nitrogen ratio. Higher lignin concentration was observed for 0&#xa0;kg·ha⁻¹ of N (1st ) and 50&#xa0;kg·ha⁻¹ of N (2nd ). The ADIN concentration was higher in 100&#xa0;kg·ha⁻¹ of N than others systems. The lignin: N and lignin: ADIN ratios decreased over time. Although the root litter decomposition was not affected by the cropping systems, a potential average input of 18.6&#xa0;kg·ha⁻¹ of N was observed after 512 days.</p>