The classification, characteristics, and assessment of soil profile fertility on Coffea arabica productivity in North Sumatra

Posma Marbun, Zulkifli Nasution, Hamidah Hanum and Abubakar Karim

Abstract: There is a problem with low yield of Coffea Arabica in North Sumatra that is supposed to be caused by the low of soil fertility. The research was aimed to classification, characteristic, and assessment fertility of soil profile from the epipedon subgroup on Coffea arabica in North Sumatra Province. The investigation was conducted in Lintong Nihuta Subdistrict, Humbang Hasundutan District from July 2014 until June 2017 using the descriptive analytic method. The experiment began with collecting climate data, than making an overlay map, soil classification, soil characteristic and assessment fertility of the soil profile. The results were demonstrated in thirteen soil map units (SMU) in Lintong Nihuta Subdistrict, Humbang Hasundutan District – the widest result was found in SMU 6 of 37.55%. Soil classification showed that the first profile consisted of SMU 1, 2, 3, 4, 13 with the horizon Ap-A-B-C, the second profile- MU 5, 9 with the horizon Ap-A-B-C, the third profile-SMU 6, 10, 11, 12 with the horizon Ap-Ah1-Ah2-C, the fourth profile-SMU 7 with the horizon Ap-Bt-C, and the fifth profile-SMU 8 with the horizon A-B-C. Soil classification resulted in three soil orders, including inceptisol found in the first, second, and fifth profile with 37.55%, entisol in the third profile with 54.08%, and ultisol in the fourth profile with 8.37%. The soil chemical characteristics of entisol and inceptisol were higher compared to ultisol. The soil physical characteristics showed granular and angular blocky structure that was very soft till hard consistency – from 1.04 to 1.42 g.cm-3 bulk density and four types of texture including sandy loam, loamy sand, sandy clay loam, and sandy. Soil fertility based on cation exchange capacity, C-organic, P-total, and K-total showed entisol was higher compared to inceptisol and ultisol. A linear relationship with the highest productivity of Coffea Arabica found in entisol of 865.28 kg.ha-1.year-1, followed by inceptisol and ultisol of 834.56 and 747.52 kg.ha-1.year-1, respectively.

Keywords: Coffea arabica; overlay; soil classification; soil fertility; soil map unit; soil profile

Date published: 2020-06-29