Potential and Possibility of Direct Use of Guano as Fertilizer in Indonesia

Guano is a material originally from sea bird or bat excrement. This material is an important source of P fertilizerduring nineteenth century and the early part of twentieth century. The development of artificial fertilizers and the depletion of guano deposits in Peru caused guano negligibled from world fertilizers trading. Recently, guano appeared in fertilizers trading and sciencetific publications again due to the development of organic farming and increasing the price of energy sources for fertilizer manufacture. Based on its origin, guano is classified into sea bird and bat guanos; and based on its composition guano is grouped into nitrogenous dan phosphatic guanos. Moreover, guano deposits are divided into two types: cave guano and insular guano deposits. The main component of guano is N, P, and Ca elements, and the additional elements are K, Mg, and S. Both nitrogenous and phosphatic guanos are important organic fertilizers because the N content of nitrogenous guano and the P content of phosphatic guano are far higher than those of manure, agricultural waste, or muniCipal waste. In Indonesia guano deposits are widely distributed in Sumatera, Java, Kalimantan, Sulawesi, Nusatenggara, and Irian Jaya. The most deposits are cave guano deposits which contain thousands to hundred thousands tons of guano.Consequently, it is highly potential to develop direct use of guano in our country. Futhermore, results of experiments indicated that phosphatic guano has high possibility to be used directly as P fertilizer

APLIKASI PUPUK ANORGANIK DAN ORGANIK HAYATI PADA BUDIDAYA PADI SRI (System of Rice Intensification)

Excessive use of inorganic fertilizers mainly NPK causes soil degradation, environment pollution, decreases production, and reduces soil biological activity. System of rice intensification is one method of rice cultivation. SRI main principles are seed transplanting at young age (7-11 days old), transplanting use single seedling methode, seedlings at wide plant spacing ≥ 25x25 cm, intermittent irrigation and field conditions are not flooded, and reduction of chemical fertilizers and application of organic fertilizer. This research was conducted at Situgede Village, West Bogor District, Bogor. The research design was split plot randomized complete block design with three blocks. Two rice cultivation system as the main plot and five combinations of fertilizer application as sub plot. In the main plot consisted of two rice cultivation which is conventional and SRI while the subplot consisted of five combinations of fertilizer application is no fertilition, 100% inorganic fertilizers (Urea = 250 kg ha-1, SP-36 = 75 kg ha-1 and KCl = 50 kg ha-1), 75% inorganic fertilizers (Urea = 187 kg ha-1, SP-36 = 56.8 kg ha-1 and KCl = 37.5 kg ha-1) + 200 kg of bio-organicfertilizer, 50% inorganic fertilizers (Urea = 125 kg ha-1, SP-36 = 37.5 kg ha-1 and KCl = 25 kg ha-1) + 200 kg of bio-organicfertilizer and 50% inorganic fertilizers (Urea = 125 kg ha-1, SP-36 = 37.5 kg ha-1 and KCl = 25 kg ha-1). The results showed that SRI method produced maximum number of tillers higher that of 25.8 tillers/hill or an increase of 64.33% compared with conventional methods. Wet and dry shoot weight of wet and dry weight of root is greater in successive SRI method of 13.3%, 19.1%, 1.40% and 41.8% compared with the conventional method. The number of productive tillers, grain number/panicle, 1000 grains weight, root wet weight and dry grain at SRI method was higher than those in conventional method respectively 58.6%, 37.0%, 2.50%, 25.1% and 32.6%. The uptake of N and P in the SRI method higher at 72.0% and 100% compared to conventional method. Application 50% inorganic fertilizer + 200 kg bio-organic fertilizer, producing more fresh weight biomass, plant dry weight, wet weight and dry weight, number of productive tillers, 1000 grain weight respectively 13.9%, 42.0%, 49.8%, 74.0%, 10.7% and 2.48% compared with the dosage recommendations dose or 100% inorganic fertilizer. N, P and K uptake at 50% inorganic fertilizer + 200 kg of bio-organic fertilizer treatment higher (55.6%, 66.7% and 46.2%) than the full recommendation dose of inorganic fertilizer. Bio-organic fertilizer can be used as substitute of NPK fertilizer.Keywords : Bio-organic fertilizer, inorganic fertilizer, System of Rice Intensification (SRI

Efektivitas Agronomik Fosfat Alam Diasamkan dengan Asam Sulfat dengan Berbagai Ukuran Butir Pada Tanah-Tanah Masam

Dari tahun ke tahun, kebutuhan pupuk untuk produksi pertanian terus meningkat tidak terkecuali pupuk P. Pupuk P dalam bentuk TSP sudah diproduksi di Indonesia namunsebagian besar bahan baku pembuatan pupuk tersebut masih hams diimpor. Akibatnya harga pupuk P dirasa semakin mahal apalagi jika tanpa subsidi pemerintah. Oleh karena itu penggunaan fosfat alam sebagai salah satu alternatif usaha efisiensi pupuk fosfat tampaknya patut dipelajari lebih lanjut.Salah satu cara meningkatkan efektivitas fosfat alam sebagai pupuk dengan cara meningkatkan sifat kelarutan fosfat alam melalui pengasaman sebagian. Pengasarnan fosfat alam dilakukan dengan mencampur fosfat alam dengan asam baik dalam bentuk asam sulfat, fosfat maupun nitrat dalam jumlah kurang dari yang dibutuhkan untuk pembuatan superfosfat. Penggunaan asam sulfat sebagai bahan pengasam memberikan keuntungan dari segi harga asam yang relatif lebih murah serta perolehan tambahan unsur S dalamcampuran pupuk

PENGARUH PUPUK FOSFAT ALAM PADA TANAH MASAM TERHADAP PERTUMBUHAN JAGUNG SERTA SERAPAN N-ZA DAN N-UREA

Sebuah percobaan pot telah dilakukan di rumah kaca IPB Darmaga, bertujuan untuk mempelajari pengaruh pupuk fosfat alam (FA) pada tanah masam terhadap pertumbuhan tanaman jagung dan serapan N berasal dari ZA (N-Z) dan Urea (N-U). Jenis tanah yang digunakana adalah Typic Dystrudepts yang mempunyaisifat kimia dan fisik antara lain pH rendah dan kandungan pasir cukup tinggi. Tanah ini memiliki daya fiksasi terhadap unsur P yang tinggi sehingga kurang tersedia bagi tanaman. Oleh karena sifat tanah yang masam, maka ketika pupuk fosfat alamdiaplikasikan ke tanah tersebut akan lebih terlarut. Interaksinya dengan pupuk yang lain berpengaruh pada serapan N oleh tanaman. Tanaman percobaan yang digunakan adalah jagung varietas Pioneer. Tiga taraf pemupukan fosfat alam yaitu setara dengan 0, 50, dan 100 kg P2O5/ha dikombinasikan dengan pupuk ZA dan Urea masing-masing tiga taraf yaitu setara dengan 0, 50, dan 100 kg N/ha. ZA dan Urea bertanda 15N dengan atom ekses masing-masing sebesar 9,984 % dan 9,754 % diaplikasikan pada percobaan ini untuk mempelajari serapan N oleh tanaman jagung.Panen dilakukan pada saat pertumbuhan vegetatif maksimum yaitu 40 hari setelah tanam. Parameter yang diamati antara lain pertumbuhan tanaman dinyatakan dalam bobot kering (g), persentase N-total, serapan N-total (mg N/tanaman) serta persentase dan serapan N-berasal dari ZA dan Urea (% N-Z/U, serapan N-Z/U dinyatakan dalam mg N/tanaman). Hasil yang diperoleh menunjukkan bahwa baik pemberian N-ZA (NZ)maupun N-urea (N-U) dan P (FA) secara sendiri-sendiri maupun gabungan dapat mendorong pertumbuhan tanaman (bobot kering, g/tanaman) dan serapan N-total (mg N/tanaman) serta % atom ekses 15N. Dalam hal ini pupuk P (FA) memberikan pengaruh yang lebih dominan dibandingkan dengan pupuk N. Terdapat interaksiyang nyata antara pemberian N (pupuk ZA/Urea) dan P (fosfat alam) sehingga untuk memberikan kedua jenis pupuk tersebut secara bersamaan perlu dipertimbangkan adanya pemberian yang seimbang takarannya agar dapat diperoleh serapan N yangpaling optimal

Teknik Nuklir untuk Penelitian Hubungan Tanah Tanaman : Perhitungan dan Interpretasi Data

iii.130 hal.;21 c

Pengaruh Waktu dan Cara Pemberian N sebagai Pupuk Tambahan terhadap Pertumbuhan dan Hasil Kedelai (Glycine Max (L.) Merr.) pada Budidaya Basah

An experiment was conducted at Muara Experimental Station, Research Institute of Food Crops Biotechnology, Bogor, from October 1996 to January 1997. Split block design was used in this experiment. Factors of experiment consisted of time of fertilizer application (3 week after planting (wap), 3 and 5 wap, and 3, 5, and 7 wap) and method of N fertilizer application (100% fertilizer through soil; 75% through soil, 25% through leaves; 50% through soil, 50% through leaves; 25% through soil, 75% through leaves; and 100% through leaves). Result of experiment showed that N application at 3 and 5 wap with 50% through soils and 50% through leaves increased dry weight to 11.4% if compared to 100% N through foliar application. Time of N application to 7 wap increased empty pod/plant to 31%. Method of N fertilizer application through leaves damaged the soybean leaves.   Key word: Fertilization, Nitrogen, Soybea

NH4+, dan Fe3+ terhadap Ketersediaan K Jerapan dan Pengaruh Na+, NH4+ pada Tanah-tanah yang Didominasi Mineral Liat Smektit

Total content of potassium in smectitic soils is commonly high, however its availability for plant growth is frequently problem because it is fixed at interlayer space of 2:1 type of clay mineral. The research was  aimed to study the sorption and effect of Na+, NH +, and Fe3+  on soil available K at smectitic soils. It  was conducted in Laboratory of Research and Soil Test, Indonesian Soil Research Institute by using four of soil samples taken from Bogor (Typic Hapludalfs), Cilacap (Chromic Endoaquerts), Ngawi (Typic Endoaquerts), and Blora (Typic Haplustalfs). Incubation experiment used Randomized Completely Block Design, 4 treatments, and 5 replications. The treatment consisted of without cation, application of Na+, NH +, and Fe3+ from NaCl, NH Cl, and FeCl respectively at 50% of maximum adsorption level. The results showed that soil sorption, buffering capacity, and maximum sorption of Fe3+ were higher than NH + and Na+, while the variables of NH + were similar with those of Na+. Among the treatments,bond energy constant was in order of  Na+  > Fe3+  > NH +  at Alfisols and it was in order of  Fe3+  > Na+  > NH +  at Vertisols. Among the soils, the soil sorption, buffering capacity, and maximum sorption were in order of Vertisols > Alfisols. The application of Na+ significantly increased soil soluble-K at Chromic Endoaquerts and Typic Endoaquerts; NH + significantly increased soil exchangeable K at Typic Hapludalfs, Chromic Endoaquerts, and Typic Endoaquerts; while Fe3+ significantly increased both variables in all tested soils

Pengaruh Waktu dan Cara Pemberian N sebagai Pupuk Tambahan terhadap Pertumbuhan dan Hasil Kedelai (Glycine Max (L.) Merr.) pada Budidaya Basah

An experiment was conducted at Muara Experimental Station, Research Institute of Food Crops Biotechnology, Bogor, from October 1996 to January 1997. Split block design was used in this experiment. Factors of experiment consisted of time of fertilizer application (3 week after planting (wap), 3 and 5 wap, and 3, 5, and 7 wap) and method of N fertilizer application (100% fertilizer through soil; 75% through soil, 25% through leaves; 50% through soil, 50% through leaves; 25% through soil, 75% through leaves; and 100% through leaves). Result of experiment showed that N application at 3 and 5 wap with 50% through soils and 50% through leaves increased dry weight to 11.4% if compared to 100% N through foliar application. Time of N application to 7 wap increased empty pod/plant to 31%. Method of N fertilizer application through leaves damaged the soybean leaves