Aplikasi Formula Pupuk Granul N-slow release Berpelindung Polimer terhadap Sifat Kimia Inseptisols dan Pertumbuhan Bawang Merah Bauji

Nitrogen is an essential nutrient for plants, but its existence is easily moved out due to washing and evaporation factors. Therefore, an effort is needed to reduce nitrogen-loss through the formulation of slow available urea making, which it purposes to improve the N efficiency. This research aims to determine: (i) the effect of four formulae on slow release urea toward several chemical properties of rice fields Inceptisols; (ii) the effect of four formulae on slow release area toward the growth of Bauji variety shallot plants. The research was conducted in rice field which located in Purwosari Village, Baturraden, Banyumas, Central Java and Soil Laboratory of the Agriculture Faculty. It was done from December 2019 until August 2020. This research was an experiment which executed in rice field by using non-factorial RAKL with 5 treatment levels and repeated 5 times. The formulae on each treatment were: F0 = N-P-K (Urea, SP-36, dan KCl), F1 = 70% Urea + 6% chitosan + 24% humate, F2 = 70% Urea + 10% Azolla microphylla + 10% gum rosin + 10% humate, F3 = 60% Urea + 10% Azolla microphylla + 10% gum rosin + 10% humate + 10% montmorillonite and F4 = 56% Urea + 24% zeolit + 3% humate + 11% tapioca flour + 6% gum rosin. The variables observed were height of the plants, number of leaves, number of tillers, the weight of fresh plants, and the weight of fresh bulbs, pH H2O, electrical conductivity, and N-Total of soil. The results showed that the F3 formula increased the weight of plant fresh by 29,29% and the weight of fresh bulbs by 29,68% compared to the control.  In the F4 formula, the release of urea is not really stable, so, the supply of N nutrients for plants is not optimal.Nitrogen merupakan unsur hara esensial bagi tanaman, namun keberadaannya mudah hilang karena pencucian dan penguapan. Oleh karena itu usaha untuk mengurangi kehilangan nitrogen melalui pembuatan formulasi pupuk lepas lambat untuk meningkatkan efisiensi N. Penelitian ini bertujuan untuk mengetahui: (i) pengaruh empat formula pada pupuk N lepas lambat terhadap beberapa sifat kimia Inseptisols sawah; (ii) pengaruh empat formula pupuk N lepas lambat terhadap pertumbuhan dan hasil tanaman bawang merah varietas Bauji. Penelitian ini dilaksanakan pada bulan Desember 2019 hingga Agustus 2020 di lahan sawah yang bertempat di Desa Purwosari, Kecamatan Baturraden, Banyumas, Jawa Tengah serta di Laboratorium Tanah Fakultas Pertanian. Penelitian berupa percobaan di lahan sawah dengan RAKL non-faktorial dengan lima perlakuan yang diulang sebanyak lima kali. Formula pada masing-masing perlakuan meliputi: F0 = N-P-K (Urea, TSP, dan KCl) , F1 = 70% Urea + 6% kitosan + 24% bahan humat, F2 = 70% Urea + 10% Azolla microphylla + 10% gondorukem + 10% bahan humat, F3 = 60% Urea + 10% Azolla microphylla + 10% gondorukem + 10% bahan humat + 10% montmorilonit, dan F4 = 56% Urea + 24% zeolit + 3% bahan humat + 11% tepung tapioka + 6% gondorukem. Variabel yang diamati antara lain tinggi tanaman, jumlah daun, jumlah anakan, bobot tanaman segar, dan bobot umbi segar, pH H2O, daya hantar listrik (DHL), dan N-Total tanah. Hasil penelitian menunjukan bahwa formula F3 dapat meningkatkan bobot tanaman segar sebesar 29,29% dan bobot umbi segar sebesar 29,68% dibanding kontrol. Perlakuan formula F4 memiliki pelepasan pupuk yang kurang stabil sehingga penyediaan unsur hara N untuk tanaman kurang optimal