Liana, Devi, Heni Purnamawati, Maya Melati, and Yudiwanti Wahyu. 2019. “Determination of the Optimum Rate of N Fertilizers With Addition of Goat Manure for Production of Cowpea (Vigna Unguiculata [L.] Walp)”. Journal of Tropical Crop Science 6 (02):121-28. https://doi.org/10.29244/jtcs.6.02.121-128.