Kajian Kesuburan Tanah pada Lahan Pertanian di Kecamatan Lumban Julu Kabupaten Toba Samosir

Survey of Soil Fertility on Agriculture Land at Subdistrict Lumban Julu, District Toba Samosir

Abstract

The objective of this study was to determine the intensity of soil fertility on farming field at
subdistrict Lumban Julu, District Toba Samosir with land of approximately 9,090 Ha. The research
used Purposive Sampling Method on 8 Land Map Units. The research set off on May to September.
Available P was analyzed with the Bray I method, organic C with Walkley and Black, N-total with
Kjeldahl, pH with H2O NH4OAc 1N pH 7, exchangeable Na with NH4
OAc 1N pH 7, exchangeable
Ca with NH4OAc 1N pH 7, exchangeable Mg with NH4
OAc 1N pH 7 and cation exchange capacity
with extraction of NH4
OAc 1N pH 7. The results showed soil pH was dominantly acid of its
criteria, C-Organic was in a dominant manner very low of its criteria, N-total was prominantly low
of its criteria, available P was noticeably low of its criteria, exchangeable K was dominantly high of
its criteria, exchangeable Na was prominantly low of its criteria, exchangeable Ca was noticeably
low of its criteria, exchangeable Mg was very low to low of its criteria, cation exchange capacity
was in a dominant manner low to medium of its criteria.

Penelitian ini bertujuan untuk mengetahui tingkat kesuburan tanah pada lahan pertanian di Kecamatan Lumban Julu Kabupaten Toba Samosir dengan luas + 9.090 Ha. Metode penelitian yang digunakan adalah metode purposive sampling dengan 8 Satuan Peta Lahan. Penelitian ini dimulai pada Mei 2015. Analisis P tersedia dengan metode Bray I, C-Organic dengan metode Walkley and Black, N-total dengan metode Kjeldahl, pH dengan ekstraksi H 2O NH4 OAc 1N pH 7, Na tukar NH4OAc 1N pH 7, Catukar NH4 OAc 1N pH 7, Mg tukar NH 4 OAc 1N pH 7 and KTK dengan ekstraksi NH 4OAc 1N pH 7. Hasil menunjukkan bahwa pH dominan pada kriteria asam, C-Organic dominan pada kriteria sangat rendah, N-total dominan pada kriteria rendah, P tersedia dominan pada kriteria rendah, K tukar dominan pada kriteria tinggi, Na tukar dominan pada kriteria rendah, Ca tukar dominan pada kriteria rendah, Mg tukar dominan pada kriteria sangat rendah - rendah, KTK dominan pada kriteria rendah - sedang.