The Productivity and Income of Corn Farming Business through the Application of Biological Fertilizers - Karman, Joni; Suparwoto, Suparwoto; Hutapea, Yanter (SOCA: Jurnal Sosial Ekonomi Pertanian; Vol 14 No 3 (2020): Vol.14, No.3, 2020DO - 10.24843/SOCA.2020.v14.i03.p05, 2020)