A study with eight cover crops types was developed: pearl millet ( Pennisetum americanum [ Pennisetum glaucum] syn. tiphoydes), brachiaria grass ( Brachiaria brizantha [ Urochloa brizantha]), sorghum ( Sorghum bicolor), pigeonpea ( Cajanus cajan), sunn hemp ( Crotalarea juncea) and black oat ( Avena strigosa [ Avena nuda]), fallow land and conventional culture (control) in the experimental area of CEFET-Uberaba-MG, in a cerrado area to evaluate K accumulation and release. The dry mass production, crop residue decomposition in litter bags and K release were evaluated. A mathematical model was used to describe residue decomposition and K release, which calculates the decomposition constant (k) and half-time life. Pearl millet, sorghum and the sunn hemp were the cover crops that produced most dry matter while K accumulation was highest in the grasses. K release was highest in pearl millet, oats, brachiaria grass and sunn hemp in the first 42 days after handling. Brachiaria grass had the shortest half-time life and the highest K release rate.
