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Penelitian bertujuan mengetahui pengaruh beberapa jenis pembenah tanah dan pupuk NPK terhadap sifat tanah serta produktivitas tanaman kedelai. Penelitian menggunakan Rancangan Petak Terpisah (Split Plot), dengan 3 ulangan. Petak utama: A1= kapur pertanian 1,23 t ha -1 , A2= kapur pertanian 200 kg ha -1 , A3= kapur aktif 200 kg ha -1 , A4= Biochar 2,5 ton ha -1 , dan A5= senyawa humat 20 liter ha -1 . Anak petak: B1 = kontrol, B2 = NPK, B3=3/4 NPK, dan B4 = 3/4 NPK + Tithoganic 2 ton ha -1 . Hasil penelitian menunjukkan bahwa perlakuan kapur aktif tidak efektif dalam meningkatkan pH tanah dan bobot biji kering kedelai. Pemberian kapur pertanian dosis 1,23 t ha -1 (kejenuhan Al 20%) nyata meningkatkan pH, Ca-dd, KB dan menurunkan Al-dd selah panen serta meningkatkan bobot biji kering kedelai dari 0,5 menjadi 0,9 ton ha -1 . Biochar nyata meningkatkan K-potensial, Mg dan K dapat ditukar tetapi tidak nyata meningkatkan bobot biji kering kedelai. Senyawa humat tidak nyata berpengaruh terhadap sifat kimia tanah dan bobot biji kering kedelai. Pemupukan ¾ NPK + Tithoganic 2 t ha -1 nyata meningkatkan hara P dan K potensial, Mg-dd, K-dd, serapan N, P dan K dan menurunkan Al-dd setelah panen, serta meningkatkan bobot biji kering kedelai sebesar 43% dibanding kontrol dan 24% dibandingkan ¾ NPK. Aplikasi pembenah tanah dan pemupukan pada kedelai meningkatkan aktivitas dehidrogenase tanah berkisar 10,39 – 84,40 µg TPF g tanah -1 hari -1 . Perlakuan pemupukan dengan dosis tinggi, memberikan aktivitas dehidrogenase lebih rendah dibandingkan dengan tanpa pupuk . Peningkatan produktivitas kedelai pada Typic Kanhapludults, Lampung Timur memerlukan aplikasi kapur pertanian 1,23 t ha -1 , Tithoganic 2 t ha -1 dan pupuk NPK (50 kg ha -1 Urea, 150 kg ha -1 SP-36 dan 100 kg ha -1 KCl). Abstract. The objectives of this study were to determine the effects of some soil ameliorant and NPK fertilizer on soil properties and soybean productivity. The experimental design was Split Plot, with three replications. As the main plots were A1: Lime 1.23 t ha -1 , A2: Lime 200 kg ha -1 , A3: Active lime 200 kg ha -1 , A4: Biochar 2.5 ton ha -1 and A5: Humate compound 20 l ha -1 . The subplots were B1: Control, B2: NPK; B3: ¾ NPK, and B4: ¾ NPK + Tithoganic 2.5 ton ha -1 . The results showed that active lime dosage of 200 kg ha -1 is not effective to increase the soil pH and dry weight of soybeans. Lime dose of 1.23 t ha -1 (Al saturation 20%) significantly increased the pH, exchangeable Ca, base saturation, decreased exchangeable Al after harvest and increased the weight of dry grain of soybean from 0.5 to 0.9 t ha -1 . Biochar significantly increased K-potential, exchangeable Mg and K, but did not significantly increase the dry weight of soybean. Humic compounds had no significant effect on soil chemical properties and dry weight of soybeans. Fertilization NPK + ¾ Tithoganic 2 t ha -1 significantly increased the potential of P and K, exchangeable Mg, exchangeable K, N, P and K uptake and lowered exchangeable Al after the soybean harvest and increased the dry weight of soybean as high as 43% compared to controls and 24% compared to ¾ NPK. Soil ameliorant and fertilization application on soybean increased the activity of dehydrogenase soil from 10.390 to 84.400 g TPF g soil -1 day -1 . Higher rate of fertilization treatment decreased dehydrogenase activity compared to the without fertilizer. Improvement of soybean productivity on Typic Kanhapludults at the Lampung Timur site needed applications of lime of 1.23 t ha -1 , Tithoganic of 2 t ha -1 and NPK fertilizer (50 kg ha -1 Urea, 150 kg ha -1 SP-36 dan 100 kg ha -1 KCl). |
