Performance of Different Green Manuring Crops in Bangladesh

An experiment was conducted at Sher-e-bangla Agricultural University during May to July, 2016 to examine the morpho-physical potentiality of eight green manure species and these species are viz. Sesbania aculeata, Sesbania rostrata, Crotalaria juncea, Vigna unguiculata, Vigna mungo, Vigna radiata, Leucaena leucocephala and Mimosa pudica. Leaves number, biomass production and nodulation are an important character of any green manuring crops as these crops are very potential for increasing soil fertility after incorporation. The growth habits of these species were studied from 15 DAS to 45DAS whereas dry matter/plant and nodulation data were taken from 25 DAS to 50DAS. At 45DAS, Sesbania aculeata, Sesbania rostrata and Vigna unguiculata shown 53% to 149% higher plant height compared to Vigna mungo, although C. juncea performed better at 30DAS compared to V. unguiculata. Again, C. juncea along with S. rostrata and S. aculeata gave the highest fresh biomass (24% to 72%), dry biomass (2.6t/ha to 5.25t/ha), dry matter plant-1 (60% to 83%) and nodulation compared to rest green manures at 45DAS whereas V. unguiculata produced higher dry matter plant-1 at 20DAS but later it declined insignificantly at 50DAS.The lowest performance was observed from V. mungo followed by V. radiata and M. pudica. It was shown that S. rostrata, S. aculeata, C. juncea, V. unguiculata and L.leucocephala performed better regarding biomass, dry matter and nodule production. Res. Agric., Livest. Fish.8(1): 25-31, April 2021

PRODUKSI BIOMASSA DAN KANDUNGAN UNSUR HARA PUPUK HIJAU TURI MINI (Sesbania rostrata) PADA JARAK TANAMAN DAN UMUR PANEN YANG BERBEDA

Penelitian ini dilakukan di lapangan untuk mengetahui produksi biomassa dan kandungan unsur hara dari tanaman turi mini (Sesbania rostrata) sebagai pupuk hijau menggunakan jarak tanam dan umur panen yang berbeda. Penelitian dilaksanakan di Dusun Bontouse, Kelurahan Pincengpute, Kecamatan Tanasitolo, Kabupaten Wajo, Provinsi Sulawesi Selatan, Indonesia dari Desember 2018 hingga Juli 2019. Penelitian ini dirancang dengan menggunakan rancangan acak kelompok (RAK) pola faktorial dua faktor. Faktor pertama jarak tanam (J) 3 taraf : 5 cm x 20 cm (J1), 10 cm x 20 cm (J2), 15 cm x 20 cm (J3) dan faktor kedua umur panen pupuk hijau (U) dengan 4 taraf : 15 hari (U1), 30 hari (U2), 45 hari (U3), 60 hari (U4). Setiap unit perlakuan dibuat bedengan 3 m x 2 m dan masing-masing unit perlakuan diulang 3 kali. Hasil penelitian menunjukkan bahwa rata-rata produksi biomassa kering tanaman turi mini terberat 569 g m-2 atau 5,69 ton ha-1 pada jarak tanam 5 cm × 20 cm (j1) dan berbeda nyata dengan jarak tanam 10 cm × 20 cm (j2) serta jarak tanam 15 cm × 20 cm (j3). Untuk umur panen tanaman 60 hari (u4) diperoleh rata-rata biomassa kering terberat 1.133 g m-2 atau 11,33 ton ha-1 dan berbeda nyata dengan umur panen tanaman 15 hari (u1), 30 hari (u2) dan 45 hari (u3). Sedang kandungan unsur hara Sesbania rostrata dengan penggunaan berbagai jarak tanam tidak berbeda nyata; jarak 10 cm × 20 cm (j1) kandungan nitrogen (N) (4,56 %), produksi posfor (P) tertinggi (0,24 %). Untuk umur panen 45 hari (u3) menghasilkan rata-rata kandungan nitrogen tertinggi (5,1 %), rata-rata kandungan posfor tertinggi (0,26 %), dan umur panen 15 hari (U1) rata-rata kandungan kalium tertinggi (6,54 %).

Glutaredoxins Play an Important Role in the Redox Homeostasis and Symbiotic Capacity of Azorhizobium caulinodans ORS571

Glutaredoxin (GRX) plays an essential role in the control of the cellular redox state and related pathways in many organisms. There is limited information on GRXs from the model nitrogen (N2)-fixing bacterium Azorhizobium caulinodans. In the present work, we identified and performed functional analyses of monothiol and dithiol GRXs in A. caulinodans in the free-living state and during symbiosis with Sesbania rostrata. Our data show that monothiol GRXs may be very important for bacterial growth under normal conditions and in response to oxidative stress due to imbalance of the redox state in grx mutants of A. caulinodans. Functional redundancies were also observed within monothiol and dithiol GRXs in terms of different physiological functions. The changes in catalase activity and iron content in grx mutants were assumed to favor the maintenance of bacterial resistance against oxidants, nodulation, and N2 fixation efficiency in this bacterium. Furthermore, the monothiol GRX12 and dithiol GRX34 play a collective role in symbiotic associations between A. caulinodans and Sesbania rostrata. Our study provided systematic evidence that further investigations are required to understand the importance of glutaredoxins in A. caulinodans and other rhizobia.

POTENSI PUPUK HIJAU TURI MINI (Sesbania rostrata Brem) DALAM BIDANG PERTANIAN

Penggunaan pupuk anorganik yang terus menerus menyebabkan kerusakan tanah dan pencemaran lingkungan akibat residu yang ditinggalkannya. Penggunaan pupuk organik dapat mengatasinya dengan cara meningkatkan kesuburan fisik, kimia dan biologis tanah. Salah satu diantaranya adalah pupuk hijau yang sekaligus mengatasi masalah keterbatasan pupuk organik yang berasal dari pupuk kandang. Pupuk hijau yang potensial untuk dikembangkan adalah turi mini (Sesbania rostrata) dari kelompok legum yang mempunyai beberapa kelebihan dibandingkan legum lainnya. Turi mini mempunyai nodula pada batang yang sangat banyak, selain pada akarnya, yang bekerjasama dengan bakteri Azorhizobium caulinodans untuk menambat N2 udara. Jumlah nodul itu bisa 5 sampai 10 kali lipat daripada legum lainnya, sehingga dapat memfiksasi N2 udara mencapai 5 sampai 10 kali lipat yaitu 270 kg ha-1. Turi mini dapat meningkatkan efisiensi penyerapan N sampai 25%, meningkatkan kandungan N tanah dan meningkatkan penyerapan P. Kelebihan dari legum lain adalah mampu hidup pada kondisi tergenang seperti di rawa-rawa atau pada lahan sawah, tahan terhadap tingkat salinitas tinggi, tahan terhadap kekeringan. Hasil penelitian yang telah dibuktikan beberapa peneliti adalah meningkatkan hasil gabah padi, meningkatkan bobot tongkol jagung dan mengurangi penggunaan pupuk anorganik urea

CheY1 and CheY2 of Azorhizobium caulinodans ORS571 Regulate Chemotaxis and Competitive Colonization with the Host Plant

ABSTRACT The genome of Azorhizobium caulinodans ORS571 encodes two chemotaxis response regulators: CheY1 and CheY2. cheY1 is located in a chemotaxis cluster (cheAWY1BR), while cheY2 is located 37 kb upstream of the cheAWY1BR cluster. To determine the contributions of CheY1 and CheY2, we compared the wild type (WT) and mutants in the free-living state and in symbiosis with the host Sesbania rostrata. Swim plate tests and capillary assays revealed that both CheY1 and CheY2 play roles in chemotaxis, with CheY2 having a more prominent role than CheY1. In an analysis of the swimming paths of free-swimming cells, the ΔcheY1 mutant exhibited decreased frequency of direction reversal, whereas the ΔcheY2 mutant appeared to change direction much more frequently than the WT. Exopolysaccharide (EPS) production in the ΔcheY1 and ΔcheY2 mutants was lower than that in the WT, but the ΔcheY2 mutant had more obvious EPS defects that were similar to those of the ΔcheY1 ΔcheY2 and Δeps1 mutants. During symbiosis, the levels of competitiveness for root colonization and nodule occupation of ΔcheY1 and ΔcheY2 mutants were impaired compared to those of the WT. Moreover, the competitive colonization ability of the ΔcheY2 mutant was severely impaired compared to that of the ΔcheY1 mutant. Taken together, the ΔcheY2 phenotypes are more severe than the ΔcheY1 phenotype in free-living and symbiotic states, and that of the double mutant resembles the ΔcheY2 single-mutant phenotype. These defects of ΔcheY1 and ΔcheY2 mutants were restored to the WT phenotype by complementation. These results suggest that there are different regulatory mechanisms of CheY1 and CheY2 and that CheY2 is a key chemotaxis regulator under free-living and symbiosis conditions. IMPORTANCE Azorhizobium caulinodans ORS571 is a motile soil bacterium that has the dual capacity to fix nitrogen both under free-living conditions and in symbiosis with Sesbania rostrata, forming nitrogen-fixing root and stem nodules. Bacterial chemotaxis to chemoattractants derived from host roots promotes infection and subsequent nodule formation by directing rhizobia to appropriate sites of infection. In this work, we identified and demonstrated that CheY2, a chemotactic response regulator encoded by a gene outside the chemotaxis cluster, is required for chemotaxis and multiple other cell phenotypes. CheY1, encoded by a gene in the chemotaxis cluster, also plays a role in chemotaxis. Two response regulators mediate bacterial chemotaxis and motility in different ways. This work extends the understanding of the role of multiple response regulators in Gram-negative bacteria.

Pengurangan Penggunaan Pupuk Urea Melalui Pemanfaatan Tanaman Turi Mini (Sesbania rostrata) pada Budidaya Jagung Manis

The use of inorganic fertilizer in agriculture as well as on sweet corn cultivation is quite high. Inorganic fertilizer recommended for sweet corn is 35 kg urea ha-1, 150 kg TSP ha-1 and 150 kg KCl ha-1. Besides high prices, its difficult to find when needed. To overcome this, an experiment was carried out by utilizing TM plants for reducing urea input. This research was carried out in Air Kuti Village, South Lubuklinggau District I, Lubuklinggau City, South Sumatera Province with an altitude of 110 meters above sea level (ASL), from April to June 2017. The experiment was arranged out in a randomized completely block design (RCBD) factorial 4 x 3 and repeated three times. The first factor was treatment combination of inorganic N fertilizer (urea) and TM plants consisted 4 kinds i.e: 75% urea and 1 TM plant, 50% urea and 2 TM plants, 25% urea and 3 TM plants, and 0% urea and 4 TM plants. The second factor was a frequency of urea application consisted of 3 levels i.e: 1-time application 15 days after planted (15 DAP), 2 times application (15 and 30 DAP), and 3 times application (15, 30 and 45 DAP). The results showed that application of urea fertilizer dosage of 25% recommended (108,75 kg urea ha-1) combinated with 3 stem of TM plants produced the best growth and yield of sweet corn. The frequency of urea application 3 times produced the best growth and yield of sweet corn.

Influence of Green Manuring Crops on Dry Matter Production and Soil Health Improvement

The field experiment was conducted at the Agronomy farm of Sher-e-Bangla Agricultural University to evaluate the impact of different kind of green manures on soil nutrient balance through adding biomass and N,P and K accumulation. Green manuring crops were incorporated after in situ cultivation and results showed that, the biomass incorporation increased the N production in soil. The biomass from Sesbania rostrata, Sesbania aculeata and Crotalaria juncea gave the higher dry matter and nutrient status. Incorporation of Sesbania rostrata and Sesbania aculeata added more organic matter and nitrogen to the soil after green manure incorporation than the prior soil. However, the improved soil quality was recorded with S. rostrata and S. aculeata followed by C. juncea and V. unguiculata incorporation as compared to control (no green manure) and other green manuring crops. The nutrient balance of soil after incorporation of different green manuring crops specially S. rostrata, S. aculeata and C. juncea showed positive balance of nutrients than other green manures. Bangladesh Agron. J. 2019, 22(1): 39-45