No abstract

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).

<p>Rate of NPK fertilization on rice using NPK compound fertilizer needs to consider soil nutrient status and plant nutrient requirement. The research was aimed to determine the optimum rate of compound fertilizer and the effect of enriched S nutrient of NPKS compound (15-15-15-5S) and NPK compound fertilizer (15-15-15) on the growth and yield of rice. The experiments were conducted at two sites in Galuga, Ciampea Bogor, West Java from April to September 2013, using randomised complete block design with 3 replications. Experiment at site I consisted of 9 treatments: six levels of fertilizers NPKS i.e. 0; 150; 300; 450; 600; and 750 kg/ha, standard fertilizer, NPK compound fertilizer equivalent to standard, and standard fertilizer plus S. Rate of urea, SP-36, and KCl for standard fertilizer treatment was respectively 250, 75, and 50 kg/ha. At site II the treatments consisted of 6 levels of NPK compound fertilizer i.e. 0; 150; 300; 450; 600; and 750 kg/ha and the standard fertilizer with rate of 250 kg/ha of urea, 50 kg/ha SP-36, and 75 kg/ha KCl. Plot size was 4 m x 5 m planted with Ciherang variety. Data collection included chemical properties of soil before and after the experiment, plant height, number of tillers, straw weight, and dry grain weight and the nutrient uptake. The effectiveness of fertilizer was calculated by RAE (Relative Agronomic Effectiveness). Results showed that fertilizer NPKS (15-15-15-5S) at 600 kg/ha effectively increased dry grain weight from 3.63 t/ha to 4.67 t/ha, but was not significantly different from a standard fertilizer treatment. It increased dry grain weight by 29% compared to control. NPK fertilizer (15-15-15) effectively promoted growth and dry grain weight equivalent to standard fertilizer at rate of 300-750 kgha. The optimum rate of NPK compound fertilizer (15-15-15) was 440 kg/ha as was shown with the production performance of 4.12 t/ha with RAE by 58%. NPKS compound fertilizer with rate of 750 kg/ha showed the highest uptake of N, P, and K nutrients and significantly increased the available P in the soil. Whereas NPK compound fertilizer with a rate of 600 kg/ha indicated the highest P nutrient uptake. Fertilizer enrichment with sulfur on NPKS fertilizer (15-15-15-5S) did not significant affect on grain dry weight.</p>

<p>The purpose of this study was to determine the effect of inorganic fertilizer and leucite mineral residues on K uptake and maize yields. This research had been conducted from October 2016 to September 2017 in the experimental field of Neglasari, Dramaga, Bogor. The soil was analyzed in the Soil Chemistry and Fertility Laboratory of Sebelas Maret University, Surakarta. The study was arranged in a completely randomized block design using 11 treatments with three replications. The result showed that the NPK 150 kg ha^-1 residues gave a better effect on corn yields whereas there was no significant effect of employing the standard NPK with RAE value of 123%. The study found that the residual treatment of inorganic fertilizers and leucite minerals had a significant impact on maize yields but not on K uptake.</p>

Mexican sunflower (Tithonia diversifolia) is a invansive weed but it can be used as continuous and on-farm source of nutrient for organic farming system. The objective of this study was to investigate growth and biomass production of T. diversifolia with different rates of chicken manure and plant spacings. The experiment was conducted at Cikarawang, Bogor, on Inceptisol soil type, from October 2011 until January 2012. The experiment was arranged in a randomized block design with 2 factors and 3 replications. The rates of chicken manure were  0, 2.5, 5 and 10 ton ha-1, while the plant spacings were 50 cm x 50 cm and 75 cm x 75 cm. The interaction effect between manure rates and plant spacing was significant on nett assimilation rate at 4-8 weeks after planting, but it was not significant on biomass production. The highest dry weight of biomass (1,129.1 kg ha-1) was obtained from the addition of 10 ton chicken manure ha-1 with the potential contribution as much as 55.47 kg N, 4.54 kg P, 88.54 kg K per hectare. The highest dry weight of biomass produced with planting distance 50 cm x 50 cm (897 kg ha-1). Referring to the results, it can be recommended that the cultivation of T. diversifolia at the first planting needs 10 ton chicken manure ha-1 and the planting distance of 50 cm x 50 cm.<br />Keywords: biomass production, Mexican sun flower, nett assimilation ratio, nutrient contributio, weed

Upaya pengendalian pelepasan Urea secara perlahan dapat dilakukan dengan memformulasi pupuk Urea dengan Zeolit dan penyalutan Kitosan sehingga dapat menyediakan hara N secara lambat, dan meningkatkan efisiensi pemupukan, produktivitas tanah dan tanaman. Tujuan penelitian ini adalah memformulasi dan mempelajari kelarutan N dari formula pupuk Urea dan Zeolit yang berukuran submikron dan yang disalut dengan Kitosan. Penelitian dilaksanakan di Laboratorium dengan rancangan percobaan Rancangan Acak Lengkap dengan 3 ulangan. Perlakuan yang dicobakan adalah 1) Kontrol lengkap (tanpa pupuk), 2) Urea prill (pupuk standar), 3) Formula Urea + Zeolit, dan 4) Formula Urea + Zeolit + Kitosan. Pengamatan yang dilakukan yaitu kelarutan N-total, N-NH4 dan N-NO3 selama inkubasi 2, 4, 6, 8, 10, dan 12 minggu. Hasil penelitian menunjukkan bahwa formula pupuk Urea + Zeolit dengan perbandingan 3:2 yang disalut Kitosan memberikan kelarutan N-total sebesar 25,43% pada inkubasi 12 minggu dibandingkan Urea prill sebesar 43,43%. Selama inkubasi perlakuan kontrol memberikan kelarutan N-total paling rendah, karena kadar N tanah awal rendah. Formula pupuk Urea + Zeolit yang disalut Kitosan dapat meningkatkan efisiensi pemupukan melalui kelarutan N yang slow release sehingga mampu mengurangi penguapan dan pencucian pupuk Urea.

The decline in agricultural land productivity due to climate change and excessive use of inorganic fertilizers requires us to implement an environmentally friendly cultivation system, by reducing the application rate of inorganic fertilizers and combining them with organic fertilizers. Liquid organic fertilizer (LOF) is one type of fertilizer that is expected to increase plant growth and yield and reduce the dose of inorganic fertilizers. The objective of this study was to examine the effect of LOF on growth, the yield of sweet corn, nutrient uptake, and the fertilizer use-efficiency of inorganic fertilizers. This Research has conducted at Inceptisol Galuga Bogor, with a randomized block design as an experimental design. The treatments consisted of a control, five doses of LOF and 2 doses of NPK fertilizer. The results showed LOF fertilizer at a dose of 0.75 - 3.0 l ha−1 combined with 100% NPK and 75% NPK increased the yield of fresh cobs by 15% - 19% compared to NPK without LOF. The weight of fresh cobs fertilized with LOF with 100% NPK was (14.63 - 16.68 t ha−1) with RAE= 130 - 205%, which is higher than without LOF (13.73 t ha−1). The combination of LOF with 75% NPK gave the weight of fresh cobs (11.88-15.12 t ha−1) with RAE = 115-507 %, which is higher than without LOF (11.75 t ha−1). LOF can contribute to NPK fertilizer efficiency by 25% of the dose. Nutrient use-efficiency for N is well-managed but lower for P and K.

Formula pupuk N lepas lambat diperlukan untuk meningkatkan efisiensi N. Tujuan penelitian adalah mempelajari pengaruh beberapa jenis pupuk N terhadap pembibitan kelapa sawit menggunakan tanah Inceptisols Bogor. Penelitian dilaksanakan di Rumah Kaca dan Laboratorium Balai Penelitian Tanah, Bogor. Rancangan percobaan yang digunakan Rancangan Acak Lengkap dengan 5 ulangan. Perlakuan yang dicobakan adalah (1) Kontrol lengkap, (2) Kontrol tanpa Urea, (3) Urea pril (standar), (4) N + Zeolit 50%, (5) N + Zeolit 75%, (6) N + Zeolit 100%, (7) N+ Zeolit + Kitosan 50%, (8) N + Zeolit + Kitosan 75%, (9) N + Zeolit + Kitosan 100%, (10) N + Zeolit + Humat 50%, (11) N + Zeolit + Humat 75%, (12) N + Zeolit + Humat 100%, (13) N-Humat 50%, dan (14) N-Humat 100%. Analisis tanah dilakukan sebelum tanam dan sesudah panen biomas dengan parameter: N-total (metode Kjeldahl), P-tersedia (Bray I), Kation dapat ditukar (Ca, Mg, K) dan kapasitas tukar kation (KTK) (ekstrak NH4Ac pH 7), kejenuhan basa (KB). Pengamatan agronomis tinggi tanaman umur 1, 2, 4, 6, 8 dan 9 bulan, bobot biomas basah dan kering, serapan hara N, P dan K. Hasil penelitian menunjukkan bahwa perlakuan N + Zeolit + Kitosan 75% nyata meningkatkan tinggi tanaman kelapa sawit umur 9 bulan sebesar 146,7 cm, bobot biomas kering sebesar 701,2 g pot -1 dengan nilai RAE 140% dan serapan hara N, P, dan K masing-masing sebesar 2,82; 0,25 dan 2,17 g pot -1 . Peningkatan bobot biomas kering sebesar 22% dibanding Urea standar. Formulasi pupuk N dengan Zeolit dan penyalutan dengan Kitosan mampu mengefisienkan pupuk Urea hingga 25%.