**5. Conclusions**

The presence of mineral fertilization improved the results of all studied cultivation systems (single sorghum, sorghum grown in *Leucaena* alleys and sorghum grown in *Gliricidia* alleys) when compared to the absence of fertilization. Nevertheless, the cultivation in alleys was not significantly di fferent when considering the influence of mineral fertilization on plant height, panicle length, leaf dry mass, leaf stem ratio and the leaf content of K in both experimental periods. *Leucaena* alleys outperformed *Gliricidia* alleys considering plant height, panicle diameter and panicle length. At least one of the alley cropping systems was larger than the single sorghum for the dry mass of the morphological components, total yield of green mass, and dry and root mass.

The contents of leaf N and P were not related to mineral fertilization. The alleys were able to positively influence the contents of these nutrients in the plant. The cultivation in *Leucaena* alleys increased the content of P when compared to single sorghum in the crop. The cultivation of sorghum in the alley cropping system also contributed to a higher leaf content of K when compared to the single crop in the double crop. The leguminous plants could have competed with sorghum for Ca and Mg, resulting in lower levels of these elements when compared to the single crop.

Mineral fertilization increased sorghum productivity regardless of the studied cultivation system. *Gliricidia* and *Leucaena* alleys showed clear potential to increase sorghum productivity, especially for sorghum cultivated in the double crop. However, in the crop with the presence of mineral fertilization, the cultivation in alleys did not overcome single sorghum cultivation regarding productivity.

**Author Contributions:** Conceptualization, R.d.C.L. (Robson da Costa Leite) and A.C.d.S.; methodology, R.d.C.L. (Robson da Costa Leite), R.d.C.L. (Rubson da Costa Leite) and A.C.d.S.; software, R.d.C.L. (Robson da Costa Leite), L.F.S. and L.F.R.; validation, A.C.d.S., J.G.D.d.S. and L.F.S.; data curation, R.d.C.L. (Robson da Costa Leite), G.O.d.S.S., J.S.d.S.C. and R.d.C.L. (Rubson da Costa Leite); writing—original draft preparation, R.d.C.L. (Robson da Costa Leite); writing—review and editing, R.d.C.L. (Robson da Costa Leite) and J.G.D.d.S.; supervision; A.C.d.S.

**Funding:** This study was carried out with the support of the Coordination of Improvement of Higher Education Personnel-Brazil (CAPES)-Financing Code 001.

**Conflicts of Interest:** The authors declare no conflict of interest.
