Analisis Peta Ketersediaan Unsur Hara dan Peta Kebutuhan Unsur Hara Tanaman Padi Ketan Berbasis Metode Deviation Of Optimum Percentage
Abstract
Umumnya pemupukan yang dilakukan sebagian besar petani padi ketan di
Kabupaten Subang belum menggunakan pupuk sesuai kebutuhan tanaman.
Penentuan kebutuhan pupuk padi ketan bisa dilakukan dengan mengetahui
ketersediaan unsur hara tanah dan kebutuhan unsur hara tanaman. Data ketersediaan
unsur hara tanah diketahui dengan melakukan analisis tanah berupa N-Tersedia,
Fosfor (P), dan Kalium (K). Kebutuhan unsur hara tanaman diukur menggunakan
metode DOP (Deviation Of Optimum Percentage). Pembuatan peta ketersediaan
dan kebutuhan unsur hara dilakukan dengan metode interpolasi Kriging. Penelitian
ini bertujuan membuat peta ketersediaan unsur hara, kebutuhan unsur hara tanaman
dan membandingkan kedua peta tersebut. Berdasarkan hasil peta ketersediaan unsur
hara tanah didapatkan persebaran pola unsur hara (N), (P), dan (K) yang bervariasi.
Uji keakuratan model dengan menghitung nilai RMSE (Root-Mean-Square Error)
dan Mean Absolute Error (MAE), dihasilkan nilai RMSE dan MAE paling akurat
pada unsur hara (P) yaitu 6,3 dan 5,2. Berdasarkan indeks DOP, dihasilkan urutan
kebutuhan pemupukan dari yang paling dibutuhkan, seperti perhitungan elevasi
rendah 6,87 – 18,24 mdpl unsur hara (N) lebih dibutuhkan dari pada unsur (K) dan
(P). Berdasarkan hasil perbandingan persentase per hektar peta ketersediaan dan
kebutuhan unsur hara dihasilkan kesesuaian perbandingan pola ketersediaan rendah
= kebutuhan tinggi yaitu 7,0 % (N), 2,6 % (P), dan 0,6 % (K). Sedangkan kategori
tidak sesuai mendominasi pola perbandingan peta ketersediaan dan kebutuhan
unsur hara yaitu 51,4 % (N), 79 % (P), dan 63,4 % (K). In general, most of the glutinous rice farmers in Subang Regency fertilize without
using fertilizer according to the needs of the plants. Determining the need for glutinous
rice fertilizer can be done by knowing the availability of soil nutrients and plant
nutrient requirements. Data on the availability of soil nutrients is known by conducting
soil analysis in the form of Available-N, Phosphorus (P), and Potassium (K). The need
for plant nutrients is measured using the DOP (Deviation Of Optimum Percentage)
method. Making maps of nutrient availability and needs is done by the Kriging
interpolation method. This study to make a map of nutrient availability, plant nutrient
needs and compare the two maps. Based on the results of the soil nutrient availability
map, it was found that the distribution of nutrient patterns (N), (P), and (K) varied.
Test the accuracy of the model by calculating the RMSE (Root-Mean-Square Error)
and Mean Absolute Error (MAE) values, resulting in the most accurate RMSE and
MAE values for nutrients (P), namely 6,3 and 5,2. Based on the DOP index, the
sequence of fertilization needs is generated from the most needed, such as the
calculation of low elevations 6,87 – 18,24 masl nutrients (N) are more needed than
elements (K) and (P). Based on the results of a comparison of the percentage per
hectare map of nutrient availability and requirements, a suitability of the pattern of low
availability = high demand was obtained, namely 7.0% (N), 2.6% (P), and 0.6% (K).
Meanwhile, the unsuitable category dominates the comparison pattern of nutrient
availability and requirement maps, namely 51.4% (N), 79% (P), and 63.4% (K).