Supply Chain Management Model at Pumpkin Production Center in East Java Haryono Haryono, Endhang Siswati, Indah Epriliati, Mochammad Muchid, Indra Pratama Putra Salmon Buletin Penelitian Sosial Ekonomi Pertanian Fakultas Pertanian Universitas Haluoleo Vol. 22 No. 2 2021 DOI 10.37149/bpsosek.v22i2.13811