ABSTRACT The experiment of the effect of Surplus Kerah concen tration and number mulch to yield soyben (Glycine max (L.) Merril), was carried out at Kedungsari Village, sub Dis- trict ort. Ragelang, Magelang City, from 14 Agustus 1992 Nort until 6 November 1992. The soil type pH 6,7 with an altitude of 380 metres. Latosol, the soil The experiment design used wan Factorial with Randomi zed Com…