Efektivitas Penggunaan Pupuk Rock Phosphate terhadap Pertumbuhan dan Produksi Jagung Manis (Zea mays L.) di Tanah Latosol Dramaga

Abstract

Tanah Latosol pada umumnya bersifat masam dengan ketersediaan fosfor (P) yang rendah akibat tingginya fiksasi oleh ion Al dan Fe, sehingga diperlukan sumber P alternatif seperti pupuk rock phosphate yang kelarutannya meningkat pada kondisi masam. Penelitian ini bertujuan mengkaji efektivitas pupuk rock phosphate sebagai sumber P alternatif pada tanah masam serta responsnya terhadap ketersediaan P tanah, pertumbuhan, dan produksi jagung manis (Zea mays L.) Penelitian dilakukan di Kebun Pendidikan Cikabayan IPB University menggunakan rancangan acak kelompok satu faktor dengan sembilan perlakuan dan empat ulangan, yaitu kontrol, pupuk standar (N+SP-36+K), serta tujuh taraf dosis pupuk rock phosphate (RP 25%, RP 50%, RP 75%, RP 100%, RP 125%, RP 150%, dan RP 200%) dari dosis acuan. Data dianalisis dengan Analysis of Variance (ANOVA) dan Duncan Multiple Range Test (DMRT) serta perhitungan relative agronomic effectiveness (RAE). Hasil penelitian menunjukkan bahwa pemberian pupuk rock phosphate nyata meningkatkan P-tersedia dan menurunkan Al-dd pada 6 minggu setelah tanam, serta nyata meningkatkan tinggi tanaman, bobot tongkol, dan bobot brangkasan dibandingkan perlakuan kontrol, namun antar dosis tidak berbeda nyata. Nilai RAE seluruh perlakuan berada di bawah 100% dengan nilai tertinggi pada dosis rock phosphate 75% (96%) yang mendekati dengan nilai pupuk standar. Dosis rock phosphate 75% dari dosis acuan merupakan dosis paling efektif dan berpotensi menjadi alternatif sumber P yang efisien pada tanah masam.

Latosol soils are generally acidic with low phosphorus (P) availability due to the high fixation of P by Al and Fe ions, so alternative P sources are required, such as rock phosphate fertilizer whose solubility increases under acidic conditions. This study aimed to examine the effectiveness of rock phosphate fertilizer as an alternative P source in acidic soil and its response on soil P availability, growth, and yield of sweet corn (Zea mays L.). The research was conducted at the Cikabayan Educational Farm, IPB University, using a single-factor randomized complete block design with nine treatments and four replications, consisting of a control, standard fertilizer (N+SP-36+K), and seven rates of rock phosphate fertilizer (RP 25%, RP 50%, RP 75%, RP 100%, RP 125%, RP 150%, and RP 200%) of the recommended rate. The data were analyzed using Analysis of Variance (ANOVA), Duncan Multiple Range Test (DMRT), and the calculation of relative agronomic effectiveness (RAE). The results showed that the application of rock phosphate fertilizer significantly increased available P and decreased exchangeable Al at six weeks after planting, and significantly increased plant height, cob weight, and stover weight compared with the treatment without a P source, although the rates did not differ significantly from one another. The RAE values of all treatments were below 100%, with the highest value at the 75% rock phosphate rate (96 %). Rock phosphate at 75% of the recommended rate was the most effective rate and has the potential to become an efficient alternative P source for acidic soils.