Sifat Kimia Tanah di Kecamatan Taliwang, Kabupaten Sumbawa Barat pada Penggunaan Lahan Kebun Jati, Ladang, dan Sawah.
Abstract
Fitria Ningsih. Sifat Kimia Tanah di Kecamatan Taliwang, Kabupaten Sumbawa
Barat pada Penggunaan Lahan Kebun Jati, Ladang, dan Sawah. Dibimbing oleh
LILIK TRI INDRIYATI dan SYAIFUL ANWAR
Sifat kimia tanah berperan besar dalam menentukan kesuburan tanah.
Kesuburan tanah secara kimia dinilai dari kandungan nitrogen, fosfor, basa dapat
ditukar (K, Ca, Mg, dan Na), pH tanah, karbon organik, dan kapasitas tukar kation.
Penelitian ini bertujuan mengkaji sifat kimia tanah di Kecamatan Taliwang,
Kabupaten Sumbawa Barat pada tiga penggunaan lahan berbeda yaitu Kebun Jati
(L1), Ladang (L2), dan Sawah (L3). Penelitian ini dilaksanakan pada September
2020 hingga Maret 2021. Contoh tanah diambil pada L1 dan L2 masing-masing
empat lapisan, sedangkan pada L3 tiga lapisan. Analisis kimia tanah dilakukan di
Laboratorium Kimia dan Kesuburan Tanah, IPB University. Hasil penelitian
menunjukkan bahwa pH tanah umumnya berkisar agak masam hingga netral (6,4-
7,3), nilai pH tanah sawah cenderung nertral sedangkan nilai pH tanah kebun jati
dan ladang tergolong agak masam. Kandungan C-organik tergolong rendah hingga
tinggi (0,93% - 4,09%), kandungan N-total tergolong sangat rendah hingga sedang
(0,07%-0,21%). Nilai P-tersedia tergolong sangat rendah pada semua contoh tanah
(0,09 ppm-1,31 ppm). Rendahnya nilai P-tersedia pada lokasi penelitian diduga
karena P diikat menjadi bentuk tidak larut oleh basa-basa seperti Ca dan Mg yang
kandungannya tinggi di dalam tanah yang diamati. Di samping itu karena tanah
yang diamati merupakan tanah yang berkembang dari bahan induk yang miskin
akan unsur P. Nilai KTK tanah berkisar dari 13,9 cmol(+)/kg sampai 30,4 cmol(+)/kg.
Nilai KB tanah yang diamati tergolong sangat tinggi yaitu lebih dari 100% dan
tergolong tinggi sampai sangat tinggi. Kebun jati memiliki kandungan karbon
organik, N-total, P-tersedia, basa dapat ditukar dan KTK lebih tinggi dibandingkan
dengan ladang dan sawah. Kandungan karbon organik, N-total, dan P-tersedia yang
termasuk kategori rendah pada penggunaan lahan kebun jati, ladang, dan sawah
harus menjadi perhatian utama dalam pengelolaan tanah di Kecamatan Taliwang,
Kabupaten Sumbawa Barat. Fitria Ningsih. The Chemical Properties of Soil in Taliwang Distric, West
Sumbawa Regency on Land Use of Teakwood plantation, Dryland, and Paddy soils.
Supervised by LILIK TRI INDRIYATI and SYAIFUL ANWAR.
The soil chemical properties play a major role in determining soil fertility.
Soil fertility is characterized chemically by the nitrogen and phosphorus content,
exchangeable bases (K, Ca, Mg, and Na), soil pH, organic carbon, and cation
exchange capacity (CEC). This research was aimed to examine the chemical
properties of soil in Taliwang District, West Sumbawa Regency on three different
land uses, namely teakwood plantation (L1), dryland (L2), and paddy soil (L3). The
study was conducted from September 2020 to March 2021. Soil samples were taken
at L1 and L2 each from four layers (horizons), while in L3 soil samples were taken
from three layers. Soil chemical properties analysis was conducted at the
Laboratory of Soil Chemistry and Fertility, IPB University. The results showed that
the pH of the soil were generally ranged from slightly acidic to neutral (6.4-7.3),
the pH value of paddy soil is neutral while the pH value of teakwood plantation soil
and dryland soil is relatively slightly acidic. Organic carbon of soil samples of three
landuse observed is relatively low to high (0.93%-4.09%), the total nitrogen content
is classified as very low to moderate (0.07%-0.21%). The available-P value is very
low in all soil samples (0.09 ppm-1.31 ppm). The low value of available-P at the
research site due to the high content of exchangeable bases, phosphorus is fixed by
calcium (Ca) and magnesium (Mg) into undissolved form (Ca-P and Mg-P). In
addition to the observed soil developed from P poor parent material. Soil CEC
values were ranged from 13.9 cmol(+)/kg-30.4 cmol(+)/kg. The Base saturation (BS)
value in all observed soil samples were more than 100% and they were classified
as very high in all observed soil samples. Exchangeable bases content were
classified as high to very high. Teakwood plantation soils have higher organic
carbon, total nitrogen, available-P, exchangeable bases and CEC compared to
dryland and paddy soil. Content of organic carbon, total N, dan available P of three
land use observed were generally low and it should be a major concern in soil
management in Taliwang District, West Sumbawa Regency.