Judul: Comparison of Methods for Assessing Soil Fertility Status  on Toposequence Transect in Sandai Subdistrict, Ketapang District, West  Kalimantan
Abstrak: Penilaian status kesuburan tanah penting dalam pengembangan pertanian terutama untuk menghadapi tantangan krisis pangan dan potensi degradasi lahan. Penelitian ini mengkaji status kesuburan tanah pada transek toposekuen di Kecamatan Sandai, Kabupaten Ketapang, Kalimantan Barat. Contoh tanah yang diambil dari kedalaman 0-30 dan 30-60 cm pada tujuh titik pengamatan (TP1, TP2, TP3, TK1, TK2, TK3, dan TK4) kemudian dianalisis kapasitas tukar kation (KTK), kejenuhan basa (KB), P2O5 ekstrak HCl 25%, K2O ekstrak HCl 25%, dan karbon organik (C-organik) serta basa-basa dapat ditukar (Ca, Mg, dan K). Analisis ini didukung dengan Principal Component Analysis (PCA) melalui perangkat lunak statistik R Studio. Penilaian kesuburan tanah didasarkan pada kriteria Five Major Soil Chemical Properties (FMSCP), Basic Cation Saturation Ratio (BCSR) dan Sufficiency Level of Available Nutrients (SLAN). Status kesuburan tanah berdasarkan metode FMSCP berkisar antara sangat rendah (SR) hingga rendah (R). Terdapat variasi yang tinggi pada status kesuburan tanah (defisiensi hingga berlebih) berdasarkan kriteria BCSR dan SLAN, yang memiliki hubungan erat dengan keragaman bahan induk tanah dan kemiringan lereng. Tanah-tanah pada titik pengamatan TP1, TP2, dan TP3 berstatus defisiensi hingga seimbang, sedangkan TK1, TK2, TK3, dan TK4 didominasi oleh status seimbang hingga berlebih pada metode BCSR. Kriteria SLAN nasional mengindikasikan Ca, Mg, dan K tanah berstatus defisiensi. Status defisiensi juga terdapat hanya pada unsur K berdasarkan kriteria SLAN internasional. Hasil penelitian ini merekomendasikan implementasi dari metode penilaian status kesuburan tanah berbasis kriteria FMSCP pada tanah-tanah tropis di Indonesia., Assessment of soil fertility status is important in agricultural development, especially to face the challenges of the food crisis and potential land degradation. This research examines the status of soil fertility on topose sequence transects in Sandai Subdistrict, Ketapang District, West Kalimantan. Soil samples taken from depths of 0-30 and 30-60 cm at seven observation points (TP1, TP2, TP3, TK1, TK2, TK3, and TK4) were then analyzed for cation exchange capacity (CEC), base saturation (BS), P2O5 extract HCl 25%, K2O extract HCl 25%, and organic carbon (C-organics) as well as exchangeable bases (Ca, Mg, and K). This analysis was supported by Principal Component Analysis (PCA) via R Studio statistical software. Soil fertility assessment is based on the Five Major Soil Chemical Properties (FMSCP), Basic Cation Saturation Ratio (BCSR) and Sufficiency Level of Available Nutrients (SLAN) criteria. Soil fertility status based on the FMSCP method ranges from very low (VL) to low (L). There is high variation in soil fertility status (deficient to excessive) based on the BCSR and SLAN criteria, which is closely related to the diversity of soil parent materials and slope. The soils at observation points TP1, TP2, and TP3 have deficiency to balance status, while TK1, TK2, TK3, and TK4 are dominated by balance to excess status using the BCSR method. National SLAN criteria indicate soil Ca, Mg and K have deficiency status. Deficiency status also exists only for element K based on international SLAN criteria. The results of this research recommend the implementation of a soil fertility status assessment method based on FMSCP criteria on tropical soils in Indonesia.
Keyword: BCSR, FMSCP, SLAN, soil fertility, toposequence