Jurnal Ilmu Tanah dan Lingkungan
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Functional Microbial Population on Oil Palm Rhizosphere in Riau Peatlands: Populasi Mikrob Fungsional pada Rhizosfer Kelapa Sawit di Lahan Gambut Riau
No full textOil palm growth in peatland may influence the presence of microbial populations. Root exudate is one of the organic compounds that is released by oil palm roots in the rhizosphere area where it can be used as a nutrient for microbes to survive in peatland. The study was conducted to study functional microbial population in the rhizosphere area of oil palm plantation aged <6, 9−15, and >15 years in Riau peatlands. The highest microbial populations were found in oil palm plantation aged <6 years at peat thicknesses of <3 and >3 m, which was respectively 10.3 x 106 and 5.7 x 106 CFU g-1. The highest cellulolytic microbial population was found in oil palm plantation aged <6 years at peat thicknesses of <3 and >3m, which was respectively 17.4 x 104 and 11.4 x 104 CFU g-1. The highest Azotobacter population was found in oil palm plantation aged >15 years at peat thicknesses of <3 and >3m, which was respectively 9.4 x 105 and 12.5 x 105 CFU g-1. The highest phosphate solubilizing microbial population was found in oil palm plantation aged <6 years at peat thicknesses of <3 and >3m, which was respectively 11.4 x 104 and 13.2 x 104 CFU g-1. The highest fungal population was found in oil palm plantation aged <6 years at peat thicknesses of <3 m and >3 m, which was respectively 11.4 x 104 CFU g-1 and 17.3 x 104 CFU g-1. The highest white-rot fungal population was found in oil palm plantation aged 9−15 years at peat thicknesses of <3 m and >3 m, which was respectively 8.7 x 103 CFU g-1 and 9.4 x 103 CFU g-1. In conclusion, the highest microbial population was dominantly found in oil palm plantation aged <6 years.
Keywords: Microbial populations, oil palm plantation, peat thickness, rhizosphere areaPertumbuhan kelapa sawit di lahan gambut dapat mempengaruhi keberadaan populasi mikrob. Eksudat merupakan salah satu senyawa organik yang dihasilkan oleh akar sawit di rhizosfer, yang digunakan sebagai nutrisi bagi mikrob untuk bertahan hidup di lahan gambut. Penelitian ini dilakukan untuk mempelajari populasi mikrob fungsional pada rhizosfer kelapa sawit berumur <6, 9−15, dan >15 tahun di lahan gambut. Populasi total mikrob tertinggi pada ketebalan gambut <3 dan >3m ditemukan pada umur kelapa sawit <6 tahun masing-masing sebesar 10.3 x 106 dan 5.7 x 106 CFU g-1. Populasi mikrob selulolitik pada ketebalan gambut <3 dan >3 m 17.4 x 104 dan 11.4 x 104 CFU g-1 ditemukan pada kelapa sawit <6 tahun. Populasi Azotobacter tertinggi 9.4 x 105 dan 12.5 x 105 CFU g-1 ditemukan pada umur kelapa sawit >15 tahun pada kedua ketebalan gambut. Populasi mikrob pelarut fosfat pada ketebalan gambut <3 dan >3m tertinggi pada umur kelapa sawit <6 tahun, masing-masing 11.4 x 104 dan 13.2 x 104 CFU -1. Populasi jamur tertinggi pada kedua ketebalan gambut (<3 dan >3m) adalah 11.4 x 104 CFU g-1 dan 17.3 x 104 CFU g-1 terdapat pada kelapa sawit <6 tahun. Populasi White-rot fungi 8.7 x 103 CFU g-1 terdapat pada kelapa sawit 9-15 tahun dan 9.4 x 103 CFU g-1 pada kelapa sawit >15 tahun. Populasi mikrob tertinggi dominan pada kelapa sawit <6 tahun.
Kata kunci: Populasi mikrob, kebun kelapa sawit, ketebalan gambut, rhizosfe
The Relationship of Dissolved Organic Carbon with Soil Properties on Toposequence in the Bukit Duabelas National Park: Hubungan Karbon Organik Terlarut dengan Sifat Tanah pada Toposekuen di Taman Nasional Bukit Duabelas
No full textBahan organik dalam ekosistem hutan yang berkontribusi pada horizon organik dalam profil tanah terdekomposisi menjadi CO2. DOC (karbon organik terlarut) yang tercuci melalui horison tanah mineral dapat didekomposisi, larut sebagai DOC atau diserap ke permukaan mineral. Pengaruh sifat-sifat tanah terhadap dinamika DOC belum sepenuhnya dipahami karena data yang terbatas. Tujuan dari penelitian ini adalah untuk mengkaji pengaruh dari toposekuen terhadap sifat tanah dan DOC. Enam profil tanah dibuat dengan perbedaan posisi lereng dalam toposekuan. Lisimeter dipasang horisontal (di horison AO, AB, dan B di setiap profil tanah) dan dihubungkan dengan botol kolektor yang diletakkan di bawah profil tanah. Sampel tanah dikumpulkan dari setiap profil tanah pada awal penelitian, sedangkan larutan tanah dikumpulkan secara periodik. Hasil penelitian menunjukkan bahwa hasil uji beda rata-rata fluks DOC pada toposekuen menunjukkan bahwa fluks DOC di profil tanah lereng bawah dengan fluks DOC di profil tanah lereng atas dan tengah berbeda. Konsentrasi, jumlah, dan fluks DOC di profil tanah lereng bawah lebih tinggi dibandingkan di profil tanah lereng atas dan lereng tengah. Hasil uji beda rata-rata fluks DOC antar horison tanah menunjukkan fluks DOC di horison AO dengan fluks DOC di horison AB dan B berbeda. Konsentrasi, jumlah, dan fluks DOC di horison AO lebih tinggi dibandingkan di horison AB dan horison B. Hasil korelasi Pearson menunjukkan bahnwa fluks DOC berkorelasi positif dengan C-organik, total-N, dan kapasitas tukar kation (KTK), tetapi berkorelasi negatif dengan bobot isi, pH, dan kandungan Fe dithionite-citrate-bicarbonate (Fed). Penelitian menghasilkan bahwa profil tanah pada lereng yang lebih rendah secara toposekuen memiliki jumlah DOC yang lebih tinggi dibandingkan dengan profil tanah di atasnya. Horison tanah AO memiliki jumlah DOC yang lebih tinggi dibandingkan horison AB dan B. Peningkatan C-organik, N-total, dan KTK meningkatkan jumlah DOC. Di sisi lain peningkatan bobot isi tanah, pH dan Fed menurunkan jumlah DOC.
Kata kunci: DOC, horison, bahan organik tanah, toposekuenThe organic matter in the forest ecosystem that contributes to the organic horizon of soil profile decomposes to CO2. The DOC (dissolved organic carbon) leached to the mineral soil horizons could be decomposed, leached or adsorbed onto mineral surfaces. The effect of soil properties on the DOC dynamic has not been fully understood because of limited data. The objective of this research was to characterize the DOC in Bukit Duabelas National Park and reveal the effect of soil profile position in toposequence and soil properties to the DOC. Six soil profiles were made with different positions in toposequence (two soil profiles on each upper, middle, and lower slope). Lysimeters were installed horizontally (in AO, AB and B horizons and in each soil profile) and connected to a bottle collector that placed on the bottom of the soil profile. The soil samples were collected from each of the soil profiles, at the beginning of the research, while soil solutions were collected periodically. The results showed that the independent sample t-test revealed that fluxes of DOC of soil profile on the lower slope were different from that of soil profiles on the upper and middle slopes. The concentration, amount, and fluxes of DOC in soil profile on the lower slope were higher than those of soil profiles on the upper and the middle slopes. The independent sample t-test also revealed that fluxes of DOC of AO horizons were different from those of AB and B horizons. The concentration, amount, and fluxes of DOC of AO horizon were higher than those of AB and B horizons. The result of Pearson correlation showed positive correlations between DOC fluxes with organic-C, total-N, and Cation Exchange Capacity (CEC), but negative correlation with soil bulk density, pH, and Fe dithionite-citrate-bicarbonate (Fed) content. The results suggested that soil profile on the lower slopes on toposequence had a higher amount of DOC than that on other soil profiles above it. Horizon AO had a higher amount of DOC than that of AB and B horizons. The increase of organic-C, total N and CEC increased DOC. On the other hand the increase of soil bulk density, pH and Fed decreased DOC.
Keywords: DOC, horizon, soil organic matter, toposequenc
Test of Phytopathogenicity, Hemolysis and Microbial Ability in Solubilizing Phosphate and Potassium: Uji Fitopatogenitas, Hemolisis serta Kemampuan Mikrob dalam Melarutkan Fosfat dan Kalium
Get PDFMikrob tanah memiliki peran pentingdalam daur unsur organik, seperti daur fosfat dan kalium. Oleh karena itu diperlukan mikrob multifungsional yaitu satu mikrob memiliki dua fungsi atau lebih.Uji patogenitas sangat penting dilakukan terlebih dahulu sebelum melakukan pengujian mikrob multifungsional, sehingga aman untuk diaplikasikan kedepannya. Tujuan dari penelitian ini adalah mempelajari sifat fitopatogenitas dan kemampuan mikrob dalam melarutkan fosfat dan kalium. Prosedur penelitian terdiri dari, uji fitopatogenitas, uji hemolisis, uji kemampuan melarutkan fosfat pada media Pikovskaya padat dan kalium pada media Alexandrov padat. Berdasarkan hasil uji fitopatogenitas pada bakteri dan fungi, semua isolat bersifat non fitopatogen. Dari uji hemolisis isolat bakteri BPK 2, BPK 6 dan BPK 7 menyebabkan hemolisis total. Berdasarkan uji hemolisis pada fungi isolat SSIO 6 menyebabkan hemolisis total, FPF E1 dan JK 6 menyebabkan hemolisis sebagian. Isolat BPK 5 memiliki indeks tertinggi dalam melarutkan kalium (1.375), sedangkan isolat BPF 9 memiliki indeks tertinggi dalam melarutkan fosfat (1.533).
Kata kunci: Mikrob, multifungsional, patogenitas, pelarut fosfat, pelarut kaliumSoil microbes have an important role in the cycle of phosphorus and potassium. Therefore, a multifunctional microbe is required to have two or more functions. Before a multifunctional test is performed, the microbes must be tested and confirmed, they are not pathogenic. The purpose of this research was to study phytopathogenicity, hemolysis and microbial ability in solubilizing phosphate and phosphate. The research procedure consisted of phytopathogenicity test, hemolysis test, the test of phosphate solubilizing ability on Pikovskaya solid medium and potassium solubilizing ability on Alexandrov solid medium. Based on the results of phytopatgonecity tests on bacteria and fungi, all isolates are non-phytopathogenic. From the hemolysis test of bacterial isolate BPK 2, BPK 6 and BPK 7 caused total hemolysis. Based on the hemolysis test of fungi isolate SSIO 6 caused total hemolysis, FPF E1 and JK 6 caused partial hemolysis. Isolate BPK 5 has the highest index in solubilizing potassium (1.375), while isolate BPF 9 has the highest index in solubilizing phosphate (1.533).
Keywords: Microbe, multifunctional, pathogenicity, phosphate solubilizing, potassium solubilizin
Comparison of Three Models for Predicting The Spatial Distribution of Soil Organic Carbon in Boalemo Regency, Sulawesi: Comparison of Three Models for Predicting The Spatial Distribution of Soil Organic Carbon in Boalemo Regency, Sulawesi
No full textInformation on the spatial distribution of soil organic carbon content is required for sustainable land management. But, creating this map is time-consuming and costly. Digital soil mapping methodology makes use of legacy soil data to create provisional soil organic carbon map. This map helps soil surveyors in allocating the next soil observation. This study aimed: (i) to develop predictive statistical soil organic carbon models for Sulawesi, and (ii) to evaluate the best model between the three obtained models. Boalemo Regency in Gorontalo Province (Sulawesi) was selected as a studying area due to abundant legacy soil data. The study covered dataset preparation, model development, and model comparison. Dataset of soil organic carbon at 6 different depths as the target was established from 176 soil profiles and 7 terrain parameters were selected as predictors. Soil-landscape models for each soil depth were created using a regression tree, conditional inference tree, and multiple linear regression techniques. The result showed that model performance differed among 3 modeling techniques and soil depths. The tree models were better than the multiple linear regression model as they have the lowest RMSE index. The best model in the mountainous area seems to be the regression tree model, whereas in the plains it may be the conditional inference tree. In creating the provisional map, several models should be developed and the median of the predicted value is used as a provisional map.
Keywords: Digital soil mapping, multiple linear regression, regression tree, soil-landscape model, soil organic carbon mapInformation on the spatial distribution of soil organic carbon content is required for sustainable land management. But, creating this map is time-consuming and costly. Digital soil mapping methodology makes use of legacy soil data to create provisional soil organic carbon map. This map helps soil surveyors in allocating the next soil observation. This study aimed: (i) to develop predictive statistical soil organic carbon models for Sulawesi, and (ii) to evaluate the best model between the three obtained models. Boalemo Regency in Gorontalo Province (Sulawesi) was selected as a studying area due to abundant legacy soil data. The study covered dataset preparation, model development, and model comparison. Dataset of soil organic carbon at 6 different depths as the target was established from 176 soil profiles and 7 terrain parameters were selected as predictors. Soil-landscape models for each soil depth were created using a regression tree, conditional inference tree, and multiple linear regression techniques. The result showed that model performance differed among 3 modeling techniques and soil depths. The tree models were better than the multiple linear regression model as they have the lowest RMSE index. The best model in the mountainous area seems to be the regression tree model, whereas in the plains it may be the conditional inference tree. In creating the provisional map, several models should be developed and the median of the predicted value is used as a provisional map.
Keywords: Digital soil mapping, multiple linear regression, regression tree, soil-landscape model, soil organic carbon ma
Studi Peran Subsektor Perikanan dalam Pengembangan Wilayah di Kota Sibolga: Study of Fisheries Subsector in Supporting Regional Development in Sibolga
Get PDFSubsektor perikanan diharapkan bisa menjadi sektor strategis bagi pengembangan wilayah Kota Sibolga di masa depan, karena sektor ini merupakan sumber daya fundamental dan termasuk sumberdaya terbarukan. Tujuan penelitian ini adalah untuk: (1) mengidentifikasi pengembangan subsektor perikanan di Sibolga, (2) menganalisis keterkaitan ke belakang dan ke depan (backward and forward linkages) dari ekonomi subsektor perikanan di Sibolga, (3) menggali persepsi pemangku kepentingan tentang pengembangan subsektor perikanan di Sibolga, dan (4) merumuskan arah prioritas pengembangan subsektor perikanan di Sibolga. Analisis data yang digunakan adalah analisis deskriptif, Hierarcy Analytical Process (AHP), dan Input-Output (I-O). Hasilnya menunjukkan bahwa subsektor perikanan menyumbang produk domestik regional bruto tertinggi hingga 22.86% dan memberikan kontribusi terhadap total output hingga 17.70%. Perikanan di Sibolga masih memiliki potensi untuk dieksplorasi mencapai 123.63 ribu ton di zona WPP-572, belum termasuk eksploitasi di luar zona ekonomi eksklusif. Keramba Jaring Apung (KJA) masih memiliki ruang seluas 1,276.97 ha untuk dimanfaatkan, terletak di Kecamatan Sibolga Utara dan Kota Sibolga. Subsektor perikanan secara total masih memiliki keterkaitan ke belakang dan ke depan (backward and forward linkages) yang kecil. Rendahnya hubungan subsektor perikanan memberikan dampak yang rendah terhadap peningkatan output sektor lain baik secara langsung maupun tidak langsung terhadap sektor lainnya. Persepsi pemangku kepentingan mengatakan bahwa sumber daya manusia dari kegiatan penangkapan ikan merupakan prioritas utama dalam pengembangan subsektor perikanan, namun dari analisis sumber daya manusia, perikanan budidaya harus menjadi prioritas pengembangan di subsektor perikanan di Sibolga.
Kata kunci: Subsektor perikanan, keterkaitan, pembangunan daerah, SibolgaFisheries subsector is expected to be a strategic sector for future regional development in Sibolga, because this sector is a fundamental resource and has renewable character. The purposes of the study are to (1) identify the fisheries subsector development in Sibolga, (2) analyze the backward and forward linkages of the fisheries subsector economy in Sibolga, (3) explore the perceptions of stakeholders about fisheries subsector development in Sibolga, and (4) formulate the direction of fisheries subsector development priorities in Sibolga. The data analysis used is descriptive analysis, Analytical Hierarchy Process (AHP), and Input-Output (I-O). The results show that the fisheries subsector contributes to the highest gross regional domestic product up to 22.86% and contributes to the total output up to 17.70%. Fisheries still have the potential to explore 123.63 thousand tons in WPP-572 zones, in addition to the exploitation outside the exclusive economic zone. The aquaculture activities (KJA) still have space 1, 276.97 ha to be utilized, located in the district of North Sibolga and Sibolga City. Fisheries subsector in total still has small backward and forward linkage. The low linkages fisheries subsectors provide a low impact on increasing the output of other sectors either direct and indirect linkages to other sectors. The perception of all stakeholders says human resources from fishing activities is a top priority in developing the fisheries subsector, but from the analysis, human resource aquaculture should be apriority development in fisheries subsector in Sibolga.
Keywords: Fisheries subsector, linkages, regional development, Sibolg
Binary Logistic Regression and Normalization for Landslide Hazard Analysis in Cianjur District, West Java
Get PDFSepanjang tahun 2002-2007 Cianjur telah mengalami 33 kali kejadian longsor. Tujuan penelitian ini adalah: (i) mengidentifikasi faktor yang paling berpengaruh terhadap bahaya tanah longsor di Kabupaten Cianjur, dan (ii) menganalisis bahaya tanah longsor di Kabupaten Cianjur. Metode yang digunakan untuk mengidentifikasi faktor yang paling berpengaruh terhadap bahaya longsor di Kabupaten Cianjur adalah analisis regresi logistik biner dan analisis rasional. Berdasarkan hasil analisis regresi logistik biner dan rasional, curah hujan merupakan faktor yang paling berpengaruh terhadap terjadinya longsor di daerah penelitian. Hal ini ditunjukkan oleh nilai koefisien parameter curah hujan yang tertinggi pada ketiga persamaan (0.542 pada hasil menggunakan SPSS, 0.920 pada hasil menggunakan Idrisi, dan 0.29 pada hasil analisis rasional). Kejadian longsor dipengaruhi terutama oleh kelas curah hujan yang tinggi. Ketiga peta bahaya longsor menghasilkan lokasi-lokasi untuk kelas bahaya sedang sampai tinggi. Pada peta bahaya longsor hasil regresi logistik biner menggunakan SPSS, kelas bahaya sedang sampai tinggi terdapat di bagian barat laut dan tenggara Cianjur. Pada peta hasil analisis menggunakan Idrisi, kelas tersebut di bagian tengah dan bagian utara Kabupaten Cianjur. Peta bahaya longsor hasil rasional, kelas bahaya longsor sedang dominan dan menyebar di seluruh kecamatan di Kabupaten Cianjur. Peta bahaya longsor hasil regresi logistik biner menggunakan Idrisi lebih baik dibandingkan dua peta bahaya lainnya, karena mempunyai nilai koefisien determinan terbesar yaitu 0.980.
Kata kunci: Regresi logistik biner, bahaya, tanah longsor, rasionalCianjur had 33 times occurrence landslides during 2002-2007. The objectives of this study were: (i) to identify the main cause of landslide hazard; and (ii) to analyze the landslide hazard areas in Cianjur. Analysis methods to identify the main cause of landslide hazards were based on binary logistic regression and normalization. Based on binary logistic regression and normalization result, rainfall is the main cause of landslide hazard in this study area. This was shown by the highest coefficient value of rainfall at the 3 equation (0.542 by using SPSS, 0.920 by using Idrisi, and 0.29 by using normalization). Positive coefficient value means that the occurrence of landslide mainly influenced by the highest class of rainfall. The three landslide hazard maps resulted from different methods showed different locations with moderate to very high-level hazards. A hazard map of binary logistic regression using SPSS showed that the moderate to very high-level hazard was found in the northwest and southeast part of Cianjur. Hazard map using binary logistic regression on Idrisi showed that the moderate to very high-level hazard was found in middle and north part of Cianjur. Hazard map using the normalization method showed the domination of moderate level hazard which was spread through all subdistricts in Cianjur. The landslide hazard map of binary logistic regression on Idrisi was better than two other maps, indicated by the highest determinant coefficient value which is 0.980.
Keywords: Binary logistic regression, hazard, landslide, normalizatio
Acacia auriculiformis dan Eragrostis chariis: Vegetasi Potensial dari Lahan Bekas Tambang Timah Pulau Bangka Sebagai Fitoremediator Pb dan Sn: Acacia auriculiformis and Eragrostis chariis: Potential Vegetations from Tin-Mined Lands in Bangka Island as Pb and Sn Phytoremediator
Get PDFTimbal (Pb) dan Timah (Sn) merupakan logam berat yang paling umum ditemukan di lahan bekas tambang timah, Pulau Bangka. Pemulihan tanah tercemar logam berat dapat dilakukan dengan teknologi fitoremediasi. Penelitian ini bertujuan menganalisis komposisi dan struktur vegetasi di lahan bekas tambang timah, mengevaluasi akumulasi Pb dan Sn di dalam tanah dan jaringan vegetasi dominan, serta menentukan vegetasi potensial untuk dimanfaatkan sebagai fitoremediator Pb dan Sn. Pengamatan dilakukan di lahan bekas tambang timah yang sudah direklamasi (LBTR), lahan bekas tambang timah yang belum direklamasi (LBTB), dan lahan hutan sekunder sebagai kontrol. Vegetasi dominan ditentukan berdasarkan kurva spesies area dan analisis vegetasi dengan metode Kuadrat. Akumulasi Pb dan Sn dalam tanah dan jaringan vegetasi dominan masing-masing ditetapkan menggunakan pengekstrak Morgan dan toxicity characteristic leaching procedure (TCLP). Hasil penelitian menunjukkan bahwa Sn-tanah tidak terdeteksi. Kadar total Pb-tanah di LBTR dan LBTB melebihi baku mutu. Kadar total Pb-tanah tertinggi terukur di LBTR. Kadar Pb dan Sn pada jaringan vegetasi dominan tidak melebihi batas normal. Acacia auriculiformis di lahan hutan sekunder dan Eragrostis chariis di LBTB berpotensi sebagai fitoremediator Pb dan Sn.
Kata kunci: Acacia auriculiformis, Eragrostis chariis, Pb, fitoremediator, SnLead (Pb) and Tin (Sn) are heavy metals most commonly found in tin-mined lands, Bangka Island. Heavy metal contaminated soil can be remediated by applying phytoremediation technology. This research was aimed to analyze vegetation composition and structure in tin-mined lands, to evaluate Pb and Sn accumulation in soils and tissues of the dominant vegetations, and to determine potential vegetations to be utilized as Pb and Sn phytoremediator. The observation was conducted at reclaimed tin-mined lands (LBTR), unreclaimed tin-mined lands (LBTB), and secondary forest lands as the control. Dominant vegetation was determined by the species-area curve and vegetation analysis using the Square method. Accumulation of Pb and Sn in soil and tissue of the dominant vegetation were respectively determined using Morgan extractant and toxicity characteristic leaching procedure (TCLP). The results showed that soil-Sn was undetected. The total soil-Pb in LBTR and LBTB exceeded its quality standard. The highest level of total soil-Pb was found in LBTR. The content of tissue-Pb and -Sn in the dominant vegetation did not exceed them each normal limits. Acacia auriculiformis in secondary forest and Eragrostis chariis in LBTB were found potential to be utilized as Pb and Sn phytoremediator.
Keywords: Acacia auriculiformis, Eragrostis chariis, Pb, phytoremediator, S
Phosporus Sufficiency for Growth and Production of Soybean under Saturated Soil Culture in Mineral and Peaty Soils: Kecukupan Hara Fosfor pada Pertumbuhan dan Produksi Kedelai dengan Budidaya Jenuh Air di Tanah Mineral dan Bergambut
No full textTujuan penelitian adalah menentukan dosis dan pemberian pupuk P pada varietas kedelai di tanah bergambut dan mineral dengan budidaya jenuh air di lahan pasang surut. Penelitian ini dilaksanakan di tanah bergambut dan mineral lahan pasang surut tipe B dan C di Kecamatan Tanjung Lago Kabupaten Banyuasin Provinsi Sumatera Selatan dari April hingga Agustus 2014. Penelitian menggunakan rancangan petak-petak terpisah. Petak utama adalah varietas (Willis dan Tanggamus), anak petak adalah waktu aplikasi (0, 0 dan 4 MST), dan anak-anak petak adalah dosis pupuk (0, 36, 72, 108 kg P2O5 ha-1). Hasil percobaan menunjukkan bahwa produktivitas kedelai di tanah mineral bergambut lebih rendah daripada di tanah mineral. Di tanah mineral bergambut waktu aplikasi fosfor pada 0 dan 4 MST lebih meningkatkan pertumbuhan dan produktivitas, sedangkan waktu aplikasi fosfor di tanah mineral lebih baik pada umur pada 0 dan 4 MST. Dosis pupuk 108 kg P2O5 ha-1 meningkatkan produktivitas tanaman kedelai di tanah mineral bergambut sedangkan dosis 72 kg P2O5 ha-1 lebih baik untuk tanah mineral. Pada tanah mineral bergambut, interaksi (Tanggamus, waktu aplikasi 0 dan 4 MST serta dosis 72 kg P2O5 ha-1), menghasilkan produktivitas tanaman kedelai tertinggi (2.83 ton ha-1). Sementara itu interaksi (Tanggamus, waktu aplikasi 0 dan 4 MST serta dosis 72 kg P2O5 ha-1) menghasilkan produktivitas tanaman kedelai tertinggi 3.8 ton ha-1 di tanah mineral dengan teknik budidaya jenuh air di lahan pasang surut.
Kata kunci : Dosis pupuk, Glycine max (L) Merr., fosfor, kemasaman tanah, varietasThe research objective is to determine the dosage and frequency of given of P fertilizer on soybean varieties in soil mineral and peaty mineral under saturated soil culture in tidal land. The research was conducted in mineral and peaty mineral soil of tidal area types B and C in the District of Tanjung Lago, Banyuasin Regency, Province of South Sumatra from April to August 2014. This study used split plots. Willis and Tanggamus varieties were main plots, application time (0, 0 and 4 MST) were on subplot, and fertilizer dose (0, 36, 72, 108 kg P2O5 ha-1) was on sub-sub plot. Experiment results showed that soybean productivity in peaty mineral soil was lower than mineral soil. In peaty mineral soil, the application time of phosphorus at 0 and 4 MST was able to increase growth and productivity of soybean, while phosphorus application time on mineral soils was better at 0 and 4 MST of planting time on mineral soils. The dose of 108 kg P2O5 ha-1 increased the productivity of soybean in peaty mineral soils, while a dose of 72 kg P2O5 ha-1 was better in mineral soil. In peaty mineral soil, interaction (Tanggamus, application at 0 and 4 MST as well as 72 kg P2O5 ha-1), showed the highest productivity of soybean (2.83 ton ha-1). Meanwhile, interaction (Tanggamus, application at 0 and 4 MST as well as 72 kg P2O5 ha-1) showed the highest productivity of soybean (3.8 ton ha-1), respectively in mineral soil under saturated soil culture techniques in tidal land.
Keywords: Dose of fertilizer, Glycine max (L) Merr., phosphorus, soil acidity, variet