Keragaman Mikroorganisme Di Dalam Tanah Memiliki Peranan Dalam Memperbaiki Struktur Tanah Dan Ketersediaan Hara Bagi Tanaman. Populasi Mikroorganisme Sangat Tinggi Di Daerah Perakaran (Rhizosfer) Dibandingkan Tanah Non Rhizosfer. Mikroorganisme Yang Banyak Dijumpai Di Dalam Tanah Adalah Bakteri. Kelimpahan Dan Keragaman Bakteri Di Dalam Tanah Dipengaruhi Oleh Lingkungan Dan Sumber Nutrisi. Salah Satu Sumber Nutrisi Bagi Bakteri Adalah Ketersediaan Bahan Organik Di Dalam Tanah. Untuk Itu Perlu Dilakukan Upaya Peningkatan Bahan Organik Didalam Tanah. Hal Yang Sering Dilakukan Oleh Petani Di Kota Tarakan Melalui Aplikasi Limbah Udang. Selain Itu, Penambahan Air Kelapa Dalam Budidaya Tanaman Sering Dilakukan Karena Banyak Mengandung Hormon Pertumbuhan Tanaman. Penelitian Ini Bertujuan Untuk : 1) Mengetahui Kelimpahan Dan Keragaman Bakteri Daerah Rhizosfer Tanaman Sawi Dengan Pemberian Limbah Kepala Udang Dan Air Kelapa 2) Mengetahui Aktivitas Fisiologi Bakteri Rhizosfer Tanaman Sawi. Pelaksanaan Penelitian Meliputi Pengambilan Sampel Tanah Yang Berasal Dari Rhizosfer Tanaman Sawi (B1= Tanah Kontrol, B2= Pupuk Kandang, B3= Pupuk Kandang + Pupuk Limbah Udang, B4=Pupuk Kandang + Air Kelapa, B5= Pupuk Kandang + Pupuk Limbah Udang + Air Kelapa), Isolasi, Purifikasi Bakteri, Pengamatan Karakterisasi Fenotip Bakteri, Uji Patogenisitas, Aktivitas Menghidrolisis Protein, Aktivitas Melarutkan Fosfat, Dan Uji Antagonis Isolat Bakteri Terhadap Jamur Patogen Fusarium Oxysporum.
Hasil Penelitian Menunjukkan Kelimpahan Koloni Tertinggi Pada Sampel Tanah B1 Dan Yang Terendah Pada Sampel Tanah B2. Hasil Karakterisasi Fenotip Bakteri Diperoleh Data Keragaman Fenotip Bakteri Dengan Tingkat Keragaman Tertinggi Pada Sampel B3 (Limbah Udang) Dan Keragaman Terendah Pada Sampel B2 (Pupuk Kandang). Pengamatan Aktivitas Fisiologis Bakteri Menunjukkan Sampel Tanah B1 (Kontrol) Diperoleh 3 Isolat Bakteri, B3 (Limbah Udang) Diperoleh 4 Isolat Bakteri, B4 (Air Kelapa) Diperoleh 6 Isolat Bakteri, Dan B5 (Limbah Udang + Air Kelapa) Diperoleh 10 Isolat Bakteri Yang Mampu Menghidrolisis Protein. Hasil Penelitian Menunjukkan Kemampuan Isolat Bakteri Dalam Melarutkan Fosfat B1 (Kontrol) Diperoleh 1 Isolat Dan Sampel Tanah B5 (Limbah+Air Kelapa) Terdapat 1 Isolat Bakteri. Selanjutnya, Pengujian Kemampuan Isolat Bakteri Dalam Menghambat Pertumbuhan Bakteri Menunjukkan Isolat Bakteri Dari Kelima (5) Sampel Tanah Tidak Menunjukkan Zona Hambat Pada Permukaan Media Potato Dextrose Agar (PDA).
Berdasarkan Hasil Penelitian Dapat Disimpulkan Kelimpahan Bakteri Sampel Tanah B1 (Kontrol) 1,94 X 108 Cfu/Ml. Tingkat Keragaman Tertinggi Pada Sampel Tanah B3 (Limbah Udang) Sebesar 18,01%. Sedangkan, Aktivitas Fisiologis Bakteri Menunjukkan Isolat Bakteri B56 Mampu Melarutkan Fosfat Tertinggi Dengan Diameter Zona Bening 1,20 Cm, Dan Kemampuan Menghidrolisis Protein Dengan Diameter Zona Bening Tertinggi Pada Isolat B413 Sebesar 3,5 Cm. Untuk Itu Perlu Dilakukan Penelitian Lanjutan Untuk Mengetahui Potensi Isolat Bakeri Dalam Memacu Pertumbuhan Tanaman Dan Kemampuan Sifat Antagonis Bakteri.

The Diversity Of Microorganisms In The Soil Has A Role In Improving Soil Structure And Nutrient Availability For Plants. The Population Of Microorganisms Is Very High In The Root Area (Rhizosphere) Compared To Non-Rhizosphere. Many Microorganisms Found In The Soil Are Bacteria. Population And Diversity Of Bacteria In The Soil Are Influenced By The Environment And Sources Of Nutrition. Source Of Nutrition For Bacteria Is The Availability Of Organic Matter In The Soil. For This Reason, Efforts Should Be Made To Increase Organic Matter In Soil. There Are Often Done By Farmers In Tarakan City Through Shrimp Waste Applications. The Addition Of Coconut Water In Crop Cultivation Is Often Done Because It Contains A Lot Of Plant Growth Hormones. The Purpose Of This Research Is To Know 1) Population And Diversity Of Bacteria In The Rhizosphere Area Of Mustard Plants By Providing Shrimp Head Waste And Coconut Water 2) Knowing The Physiological Activity Of Mustard Rhizosphere Bacteria. The Implementation Of The Research Includes Taking Soil Samples From The Mustard Plant Rhizosphere (B1 = Control Soil, B2 = Fertilizer Cage, B3 = Manure + Shrimp Waste Fertilizer, B4 = Manure + Coconut Water, B5 = Manure + Shrimp + Water Waste Fertilizer Coconut), Isolation, Bacterial Purification, Observation Of Bacterial Phenotypic Characterization, Pathogenicity Test, Protein Hydrolysis Activity, Phosphate Solubilization Activity, And Antagonism Test Of Bacterial Isolates Against Fusarium Oxysporum Pathogenic Fungi. The Results Showed Population Of Colonies In B1 Soil Samples And The Lowest In B2 (Fertilizer Cage). The Results Of Bacterial Phenotype Characterization With The Highest Level Of Diversity In The Sample B3 (Shrimp Waste) And The Lowest Diversity In The Sample B2 (Fertilizer Cage). Observation Of Bacterial Physiological Activity Showed B1 Soil Samples (Control) Obtained 3 Bacterial Isolates, B3 (Shrimp Waste) Obtained 4 Bacterial Isolates, B4 (Coconut Water) Obtained 6 Bacterial Isolates, And B5 (Shrimp + Coconut Water Waste) Obtained 10 Bacterial Isolates Able To Hydrolyze Proteins. The Results Showed The Ability Of Bacterial Isolates In Dissolving Phosphate B1 (Control) Obtained 1 Isolate And B5 Soil Samples (Waste + Coconut Water) There Was 1 Bacterial Isolate. Furthermore, Testing The Ability Of Bacterial Isolates In Inhibiting Bacterial Growth Showed That Bacterial Isolates From The Five (5) Soil Samples Did Not Show Inhibitory Zones On The Surface Of Potato Dextrose Agar. Based On The Results Of The Reserch It Can Be Concluded That Bacterial Population Of Soil Samples B1 (Control) Is 1.94 X 108 Cfu/Ml. The Highest Level Of Diversity In B3 (Shrimp Waste) Soil Samples Was 18.01%. Meanwhile, Bacterial Physiological Activity Showed That B56 Bacterial Isolates Were Able To Soluble The Highest Phosphate With A Halozone Of 1.20 Cm, And The Ability To Hydrolyze Proteins With The Highest Halozone In Isolates B413 Was 3.5 Cm. For This Reason, Further Research Is Needed To Determine The Potential Of Isolates In Determining Plant Growth And The Ability Of Bacterial Antagonists.