Sesbania Cannabina Research Articles

Ensifer psoraleae sp. nov. and Ensifer sesbaniae sp. nov., isolated from the root nodules of Psoralea corylifolia, Sesbania cannabina and other legumes

In a survey of rhizobia associated with the native legumes in Yunnan Province, China, seven and nine strains isolated from the root nodules of Psoralea corylifolia, Sesbania cannabina and Medicago lupulina were respectively classified into the novel genomic species group I and group II in the genus Ensifer (former Sinorhizobium) based on the sequence analyses of the 16S rRNA gene. Analyses of concatenated housekeeping genes (atpD, recA and glnII) further revealed that they were distinct lineages in the genus Ensifer, and group I was most similar to Ensifer terangae and Ensifer garamanticus (both with 94.2% similarity), while group II was most similar to Ensifer adhaerens (94.0%). These groups could be distinguished from closely related species by DNA–DNA relatedness, MALID-TOF MS, cellular fatty acid profiles and a series of phenotypic characters. Therefore, two novel groups were proposed: Ensifer psoraleae sp. nov. (seven strains, type strain CCBAU 65732T=LMG 26835T=HAMBI 3286T) and Ensifer sesbaniae sp. nov. (nine strains, type strain CCBAU 65729T=LMG 26833T=HAMBI 3287T). They had a DNA G+C mol% (Tm) of 58.9 and 60.4, respectively. The type strains both formed effective nodules on common bean (Phaseolus vulgaris) and their hosts of origin.

Effect of different plants on azo-dye wastewater bio-decolorization

Two salt-tolerant plants (Medicago sativa L. and Sesbania cannabina Pers) as well as a kind of salt-tolerant azo-dye decolorization bacteria GTY (Gracilibacillus sp.GTY) were selected to treat acid red B or acid scarlet GR contaminated water. Results showed that Medicago sativa L. was more tolerant to the azo dyes and more helpful in promoting the azo-dye wastewater bio-decoloration than Sesbania cannabina Pers, but GTY density was higher in the root exudates of Sesbania cannabina Pers than that of Medicago sativa L. This indicated that the increase of GTY density only partially presented the azo-dye decolorization promoted by plants.

Rhizodegradation of petroleum hydrocarbons by Sesbania cannabina in bioaugmented soil with free and immobilized consortium

The present study reports the effect of bioaugmentation by free and immobilized bacterial culture on the rhizodegradation of petroleum-polluted soil using Sesbania cannabina plant. Total petroleum hydrocarbon (TPH), hydrocarbon-degrading bacterial counts, microbial activity and root morphology were assessed during 120 days of plant growth. TPH concentration analyzed by GC–MS showed that bioaugmentation did not improve the TPH degradation. TPH concentration decreased from 2541mgkg−1 to 673mgkg−1 and 867mgkg−1 in the rhizosphere of free (FR) and immobilized bacterial inoculated (IR) soil, respectively at the 120th day while in the rhizosphere of uninoculated soil (CR) concentration decreased to 679mgkg−1 only at the 90th day, showing higher and rapid rhizodegradation with indigenous bacteria than bioaugmented bacterial cultures. Various predominant bacterial groups responsible for higher TPH degradation in the rhizosphere of S. cannabina were identified by PCR–DGGE analysis. It is concluded that natural plant-microbe interaction in the rhizosphere of S. cannabina was efficient enough to degrade TPH and plant rhizosphere keeps bacterial community in its surrounding therefore immobilized culture had no obvious effect on petroleum degradation.

Kinetics of Ammonium, Nitrate and Phosphate Uptake by Candidate Plants Used in Constructed Wetlands

Abstract The constructed/artificial wetland system is a new sewage technique with low cost and less energy consumption for removal of nitrogen and phosphorus in wastewater, and the wetland plants have the important functions in the system. In wastewater purification, plants can absorb and utilize the nutrients (nitrogen and phosphorus) directly, and enhance nutrient transformation processes such as nitrification, denitrification, adsorption and desorption. In this study, a series of experiments for investigating the kinetics of ammonium, nitrate and phosphate uptake by 8 candidate wetland plants, such as Carex taliensis Franch, Dracaena sanderiana Virens, Impatiens balsamina, rush (Juncus effusus L.), mulberry (Morus indica L.), wetland rice (Oriza Sativa L.), Salvia plebeia R. Br., and Sesbania cannabina Poir, were carried out under controlled conditions (temperature 25-28, illumination 3000Lux, relative°C humidity 60-70%). The results indicated that the kinetic characteristics of ammonium, nitrate and phosphate uptake by the selected plants could be well illustrated with the Michaelis-Menten equation, and the kinetic parameters (maximum rate and Km value of absorption) could also be calculated using the regression equations. The orders of maximum uptake rate were as follows: Morus indica L. > Carex taliensis Franch > Oriza Sativa L. > Impatiens balsamina > Juncus effusus L. > Sesbania cannabina Poir > Salvia plebeia R. Br. > Dracaena sanderiana for ammonium; Carex taliensis Franch > Oriza Sativa L. > Sesbania cannabina Poir > Juncus effusus L. > Impatiens balsamina > Morus indica L. > Salvia plebeia R. Br. > Dracaena sanderiana for nitrate; Oriza Sativa L. > Juncus effusus L. > Salvia plebeia R. Br. > Dracaena sanderiana > Impatiens balsamina > Morus indica L. Sesbania cannabina Poir > Carex taliensis Franch for phosphate. Sesbania cannabina Poir., Dracaena sanderiana Virens and Salvia plebeia R. Br. had the smallest Km value for ammonium uptake, and Impatiens balsamina, Dracaena sanderiana Virens and Salvia plebeia R. Br. had the smallest Km value for nitrate uptake, Sesbania cannabina Poir., mulberry and Dracaena sanderiana Virens had the smallest Km value for phosphate uptake. According to the kinetic characteristics of N and P uptake, we suggested that plant species with higher maximum uptake rates could be used in the first section for cleaning up wastewater with high nutrient concentrations, and plant species with lower Km values could be used in subsequent sections for cleaning up wastewater with lower nutrient concentrations.

Genome damage and microsporogenesis inhibition in Sesbania cannabina (Retz.) Pors. (Fabaceae) through impact of lead

Heavy metals are one of the important classes of environmental hazards. They become toxic, when they are not metabolized by the body and accumulate in the soft tissues. Heavy metals may enter the human body through food, water, air, or absorption through the skin when they come in contact with humans in agriculture and in manufacturing, pharmaceutical, industrial, or residential settings. As many heavy metals are mutagenic and clastogenic, they cause teratogenic or carcinogenic effects. Dhaincha (Sesbania cannabina (Rets.) Pors., Fabaceae) is a multipurpose legume crop and is adaptable to adverse climatic conditions such as water logging, drought etc. and is widely used as green manure crop. Effects of lead on germination percentage, survival percentage, pollen fertility and meiotic divisions of S. cannabina were studied. For this purpose soaked seeds of S. cannabina were treated with different concentrations of lead nitrate solution i. e. 25, 50, 100 and 200 ppm for 3 h and treated seeds were sown to raise the population. There was dose dependent effect of the mutagenic treatments on chromosomal aberrations and pollen fertility. Increase in various types of meiotic aberrations and reduction in pollen fertility percentage were observed at all the doses of treatment. Higher frequency of chromosomal anomalies was observed at maximum dose of treatment.

Phytosequestration of Metals in Selected Plants Growing on a Contaminated Okhla Industrial Areas, Okhla, New Delhi, India

Contamination of metal ions in soil and water represents more pressing threats to resources as well as human health. The present research was carried out to screen the phytosequester plants growing in industrial waste- and wastewater-affected industrial areas of Okhla, New Delhi, India. Accumulation trend of metal Fe, Zn, Cu, Cr, Pb, Cd, Hg, and As from soil and wastewater by plants were collected for study. Among aquatic plants Hydrilla verticillata, Marsilea quadrifolia, and Ipomea aquatica were found to be highest metals accumulator, Eclipta alba and Sesbania cannabina among terrestrial plant were highest accumulator of metals. Among the algal spp. Spirulina platensis and Phormidium papyraceum were the most efficient in accumulating Cd and Hg. The maximum bioconcentration factor (BCF) was recorded in Hygroryza aristata for the metals (Hg, Cd) in M. quadrifolia (Cd, Cr), in E. alba (Cr, Cu), and in S. platensis (Hg, Pb). However, the translocation factor (TF) of metals was found more in M. quadrifolia followed by I. aquatica than other plants. Among all the plants, H. verticillata showed high TF and low BCF values for toxic metals (Pb, Cr) and was suitable for phytostabilization of these metals. Our study showed that native plant species growing on contaminated sites may have a potential of phytosequestration of these metals.

Abstracts of Nippon Dojo-Hiryogaku Zasshi

Abstracts of Nippon Dojo-Hiryogaku Zasshi

Nodulation of Sesbania species by Rhizobium (Agrobacterium) strain IRBG74 and other rhizobia

SummaryConcatenated sequence analysis with 16S rRNA, rpoB and fusA genes identified a bacterial strain (IRBG74) isolated from root nodules of the aquatic legume Sesbania cannabina as a close relative of the plant pathogen Rhizobium radiobacter (syn. Agrobacterium tumefaciens). However, DNA:DNA hybridization with R. radiobacter, R. rubi, R. vitis and R. huautlense gave only 44%, 5%, 8% and 8% similarity respectively, suggesting that IRBG74 is potentially a new species. Additionally, it contained no vir genes and lacked tumour‐forming ability, but harboured a sym‐plasmid containing nifH and nodA genes similar to those in other Sesbania symbionts. Indeed, IRBG74 effectively nodulated S. cannabina and seven other Sesbania spp. that nodulate with Ensifer (Sinorhizobium)/Rhizobium strains with similar nodA genes to IRBG74, but not species that nodulate with Azorhizobium or Mesorhizobium. Light and electron microscopy revealed that IRBG74 infected Sesbania spp. via lateral root junctions under flooded conditions, but via root hairs under non‐flooded conditions. Thus, IRBG74 is the first confirmed legume‐nodulating symbiont from the Rhizobium (Agrobacterium) clade. Cross‐inoculation studies with various Sesbania symbionts showed that S. cannabina could form fully effective symbioses with strains in the genera Rhizobium and Ensifer, only ineffective ones with Azorhizobium strains, and either partially effective (Mesorhizobium huakii) or ineffective (Mesorhizobium plurifarium) symbioses with Mesorhizobium. These data are discussed in terms of the molecular phylogeny of Sesbania and its symbionts.

Effect of soil moisture content on the deformation behaviour of root-reinforced soils subjected to shear

This paper presents an experimental study on how soil moisture content affects the deformation behaviour within root-reinforced soils subjected to shear. In-situ shear tests were carried out in this research. The plant used in the shear tests was Prickly Sesban (Sesbania cannabina Merr.). The shear deformation within the root-reinforced soil after shear was measured. The effect of soil moisture content and the root area ratio on the development of the shear zone was investigated. The experimental results showed that the deformed shape within the soil for root-reinforced soils subjected to shear correlated well with the exponential decay function. The width of the shear zone of root-reinforced soils increases with increasing soil moisture content. Additionally, the width of the shear zone increases with increasing root area ratio. Widths of the shear zone developed in front of and beside the root structure are greater than those behind the root structure. Finally, the mechanism between the shear strength increase provided by roots and the development of the shear zone width are discussed in this paper.

Role of roots in the shear strength of root-reinforced soils with high moisture content

This paper presents an experimental study on the effect of soil moisture content on the shear strength of root-reinforced soils by conducting in situ shear tests. The plant used in the shear tests was Prickly Sesban ( Sesbania cannabina Merr.). Performance of plants in stabilizing slopes against shallow landslides in a rainfall event is closely relevant to the variation of the shear strength of root-reinforced soils with changes in the moisture content, which may take place due to seasonal effects (e.g. rainfall and temperature changes) as well as the influence of vegetation. The shear strength of soils may decrease noticeably with increasing soil moisture content. The role of roots in providing the shear strength to root-reinforced soils turns out to be important if soils are subjected to an increase in the moisture content. The experimental results show that root efficiency, defined as the ratio of the additional shear strength provided by roots over the shear strength of soils, may reach more than 1.0 if soils are at a high degree of saturation. In addition, an approximately linear relationship between the additional shear strength (Δ S) provided by roots and the tensile strength of roots per unit area of soils ( t R) was obtained in this study, and the ratios of Δ S/ t R are about 0.39 and 0.42 in terms of the peak and the residual shear strength, respectively. These results are considerably less than the theoretic value (=1.2), based on a simple force equilibrium model derived by Wu et al. [Wu, T.H., McKinell, W.P., Swanston, D.N., 1979. Strength of tree roots and landslides on Prince of Wales Island, Alaska. Can. Geotech. J. 16 (1), 19–33].

Increase of multi-metal tolerance of three leguminous plants by arbuscular mycorrhizal fungi colonization

A greenhouse pot experiment was conducted to investigate the effects of the colonization of arbuscular mycorrhizal fungus (AMF) Glomus mosseae on the growth and metal uptake of three leguminous plants (Sesbania rostrata, Sesbania cannabina, Medicago sativa) grown in multi-metal contaminated soil. AMF colonization increased the growth of the legumes, indicating that AMF colonization increased the plant's resistance to heavy metals. It also significantly stimulated the formation of root nodules and increased the N and P uptake of all of the tested leguminous plants, which might be one of the tolerance mechanisms conferred by AMF. Compared with the control, colonization by G. mosseae decreased the concentration of metals, such as Cu, in the shoots of the three legumes, indicating that the decreased heavy metals uptake and growth dilution were induced by AMF treatment, thereby reducing the heavy metal toxicity to the plants. The root/shoot ratios of Cu in the three legumes and Zn in M. sativa were significantly increased (P<0.05) with AMF colonization, indicating that heavy metals were immobilized by the mycorrhiza and the heavy metal translocations to the shoot were decreased.

Long‐Term Effects of Organic Inputs on Yield and Soil Fertility in the Rice–Wheat Rotation

The sustainability of the rice (Oryza sativa L.)–wheat (Triticum aestivum L.) rotation is important to Asia's food security. Intensive cropping with no return of crop residues and other organic inputs result in the loss of soil organic matter (SOM) and nutrient supply, and is assumed to be nonsustainable. We evaluated seven treatments comprised of various combinations of green manure (GM; Sesbania cannabina L.); wheat straw (WS), farmyard manure (FYM), and urea on yields and yield trends; P and K balance; and soil fertility in a rice–wheat experiment (1988–2000) on a loamy sand in Punjab, India. Rice yields were comparable with GM + urea, WS + GM + urea, and urea alone, but yields were reduced when FYM was supplemented with N. Except during 1 yr, integrated use of FYM and GM produced equal or higher rice yields than other GM based treatments. Wheat straw incorporation reduced average rice yields by 7% compared with WS removal. After 5 yr of continuous application, FYM and WS were at par in increasing rice yields. Organic materials applied to rice had no residual effect on wheat yields except FYM, which increased yield by about 6% compared with urea alone. Rice yield declined by 0.02 to 0.13 Mg ha−1 yr−1 but wheat yields remained unchanged. Soil C increased with the application of WS and FYM. Potassium balance was highly negative. Although the causes of yield decline are unknown, inadequate K applications and changes in the climatic parameters are possible reasons.

Effects of Residue Decomposition on Productivity and Soil Fertility in Rice–Wheat Rotation

Rice (Oryza sativa L.)–wheat (Triticum aestivum L.) farmers in India burn or remove residues to facilitate seedbed preparation. Incorporation of residues before planting of the next crop generally decreases yields due to N immobilization. Since a window of about 40 d is available between rice harvest and wheat planting, the effect of time of incorporation on rice residue decomposition and N mineralization–immobilization was studied in 1992–1993. The mass loss of residue was 25% for a 10‐d, 35% for a 20‐d, and 51% for a 40‐d decomposition period before wheat planting. Nitrogen release from residue ranged from 6 to 9 kg ha−1 during the wheat season. The immobilization of urea N decreased when residue was allowed to decompose for 10‐d or longer. Based on these studies, a long‐term (1993–2000) experiment was conducted on a sandy loam soil to examine the effect of time of residue incorporation before sowing wheat when compared with burning or removal of residue on yields, N‐use efficiency, and soil fertility. The effect of wheat residue incorporation with green manure (GM, Sesbania cannabina L.) on subsequent rice yields was also determined. Residue incorporation for 10 to 40 d had no effect on wheat yields. Rice yields increased (0.18–0.39 Mg ha−1) when wheat residue was incorporated with GM. Starter N applied at residue incorporation did not influence wheat yields but decreased N recovery efficiency. Physiological efficiency was higher when rice straw was incorporated in wheat and when wheat straw plus GM were incorporated in rice than when rice straw was incorporated for 10 d or when the straw was burned. The long‐term application of rice residue increased C accumulation in soil.

Yield and Soil Nutrient Changes in a Long-Term Rice-Wheat Rotation in India

Major improvements in the productivity of rice (Oryza sativa L.) and wheat (Triticum aestivum L.) have occurred in South Asia since 1965–1966 when the Green Revolution began. However, after the 1980s, yield stagnated or declined. We analyzed grain yield trends, soil C, N, P, and K status, and P and K balances in a 14-yr rice–wheat experiment conducted at Punjab, India with 11 treatments comprised of various combinations of inorganic and organic sources of nutrients. Recommended levels of N, P, and K were supplemented with N through farmyard manure (FYM), wheat chopped straw (WCS), or sesbania (Sesbania cannabina Linn. & Merrill). Soil parameters were analyzed in archived soil samples collected periodically from 1988 to 1999. Rice yield declines ranged from 0.07 to 0.13 Mg ha−1 yr−1 dependent on treatment. Wheat yields declined by 0.04 Mg ha−1 yr−1 with applications of 75 and 100% N-P-K fertilizer but were maintained over the 14-yr period in the other treatments. Total soil N and available P and K declined in all the treatments except with FYM, in which total N was maintained and available P increased. Total soil C was either maintained or increased with time. Nitrogen and K depletion may have collectively contributed to the yield decline. Stable wheat yields may have been because of continuing variety improvement, resulting in higher harvest index (HI). Results show that current fertilizer recommendations are inadequate for maintaining yields. This cropping system may not be sustainable without increased K input to maintain soil K above sufficiency levels.

Yield and Soil Nutrient Changes in a Long‐Term Rice‐Wheat Rotation in India

Major improvements in the productivity of rice (Oryza sativa L.) and wheat (Triticum aestivum L.) have occurred in South Asia since 1965–1966 when the Green Revolution began. However, after the 1980s, yield stagnated or declined. We analyzed grain yield trends, soil C, N, P, and K status, and P and K balances in a 14‐yr rice–wheat experiment conducted at Punjab, India with 11 treatments comprised of various combinations of inorganic and organic sources of nutrients. Recommended levels of N, P, and K were supplemented with N through farmyard manure (FYM), wheat chopped straw (WCS), or sesbania (Sesbania cannabina Linn. &amp; Merrill). Soil parameters were analyzed in archived soil samples collected periodically from 1988 to 1999. Rice yield declines ranged from 0.07 to 0.13 Mg ha−1 yr−1 dependent on treatment. Wheat yields declined by 0.04 Mg ha−1 yr−1 with applications of 75 and 100% N‐P‐K fertilizer but were maintained over the 14‐yr period in the other treatments. Total soil N and available P and K declined in all the treatments except with FYM, in which total N was maintained and available P increased. Total soil C was either maintained or increased with time. Nitrogen and K depletion may have collectively contributed to the yield decline. Stable wheat yields may have been because of continuing variety improvement, resulting in higher harvest index (HI). Results show that current fertilizer recommendations are inadequate for maintaining yields. This cropping system may not be sustainable without increased K input to maintain soil K above sufficiency levels.

Productivity and economics of rice (Oryza sativa)-wheat (Triticum aestivum) cropping system under integrated nutrient-supply system in recently reclaimed sodic soil

A field experiment was conducted during the rainy and winter seasons of 2001-04 to study the influence of integrated nutrient-supply system, comprising inorganic fertilizers and organic manures on the soil-fertility status, productivity and economics of rice (Oryza sativa L.)-wheat (Triticum aestivum L. emend. Fiori &amp; Paol.) cropping system. Three organic manures @ 10 tonneslha, viz. farmyard manure (FYM), Sesbania canabina (Retz.) Pers. (dhaincha) and cut rice straw were added at 50 and 100% of the recommended doses of NPK fertilizers. The green-manure dhaincha [Sesbania cannabina (Retz.) Pers. syn, S. aculeata] applied with 100% of recommended dose of NPK fertilizers gave the maximum yield of rice as well as wheat crop. This treatment also gave the highest net return and benefit : cost ratio and produced significantly higher biomass in terms of rice- equivalent yield. The total uptake of N, P, K and Zn by both the crops increased significantly with the application of fertilizers or their combined use with organic manures. Among the organic manures the overall performance of green-manure was the best, followed by farmyard manure and cut rice straw. Application of farmyard manure and cut rice straw as well as green-manuring in rice and wheat significantly improved the available N, P, K and Zn status of the soil.

Diversification of rice (Oryza sativa)-based cropping system in new alluvial zone of West Bengal

In a field experiment with rice (Oryza sativa L.)-based crop sequences, viz. rice-rice-dhaincha [Sesbania cannabina (Retz.) Pers.], rice-rice, rice-mustard [Brassica juncea (L.) Czernj. &amp; Cossonl-okra (Hisbiscus esculentus ), rice-potato (Solanum tuberosum L.)-sesame (Sesamum indicum L.), rice-potato-groundnut (Ara- chis hypogaea L.), rice-potato-rice, rice-wheat (Triticum aestivum L. emend. Fiori &amp; Paol.)-jute (Corchorus olitorius L.), rice-cabbage [Brassica oleracea L. convar. capitata (L.) Alef. var capitatal-rice and rice-mustard, were tested for their performances over 4 years during 1997-2000 at Kalyani, West Bengal. Rice-potato- groundnut gave the highest gross return, net return and benefjt,: cost ratio (Rs 105,117, Rs 68,0191halyear and 1.833 respectively), followed by rice-cabbage-rice, rice-potato-rice and rice-potato-sesame. Maximum amount of energy was harvested (196,980 MJIhalyear) from rice-potato-groundnut, followed by rice-potato- rice and rice-cabbage-rice. Rice-equivalent yield, production efficiency, land-use efficiency and energy-use ef- ficiency were highest in rice-potato-groundnut sequence. The yield of subsequent rainy-season rice in pooled analysis was also higher in rice-potato-groundnut sequence indicating that this sequence has good effect on subsequent rice crop.

Influence of long-term organic nutrient management on soil quality and crop productivity in rice (Oryza sativa)potato (Solanum tuberosum)okra (Abelmoschus esculentus) cropping system under irrigated condition

A long-term field experiment was conducted during 200607 to 201415 on organic nutrient management in rice (Oryza sativa L.)potato (Solanum tuberosum L.)okra (Abelmoschus esculentus L.) cropping system under irrigated conditions in the coastal alluvial sandy loam soil having pH 5.8 and organic carbon 0.62% at Bhubaneswar, Odisha. Eight treatments comprising of five organic, two integrated and one inorganic of nutrient management were tested with three replications in randomized block design. Organic sources of nutrient supply reduced the system yield by 7.6 to 9.7% over the inorganic source in the first year. However, the mean system yield of conversion period (first three cropping system cycles) with organic nutrient management comprising of supply of one-third N each through farm yard manure (FYM), green manuring of dhaincha (Sesbania cannabina) or vermicompost and neem (Azadirachta indica) oilcake + Azospirillum or Azotobacter + phosphate solubilizing bacteria (PSB) was on par with inorganic approach. The mean system yield from fourth to ninth cropping system cycles (after conversion period) with organic sources of nutrient supply, i.e. FYM + green manuring or vermicompost + neem oilcake + Azospirillum or Azotobacter + PSB was significantly higher (11.1%) than that of with inorganic source of nutrient supply i.e., 100% NPK + ZnSO @ 25 kg/ha to rice and 100% NPK + gypsum @ 4 110 kg/ha + borax @ 10 kg/ha + ammonium molybdate @ 0.8 kg/ha to both potato and okra. The organic nutrient management package increased the soil organic carbon and available N, P and K at the end of ninth cropping system cycle over the initial and the build-up was maximum in the soil applied with one third N each through FYM, dhaincha/vermicompost and neem oilcake + Azospirillum/Azotobacter + PSB. The microbial population in terms of colony forming units increased in a higher rate in soils with organic nutrient supply system (bacteria 36.5 to 39.4%, fungi 33.0 to 38.2% and actinomycetes 36.0 to 37.3%) compared to the inorganic source of nutrient supply system (bacteria 5.6%, fungi 10.3% and actinomycetes 12.7%) after ninth cropping system cycle over initial status. The microbial biomass carbon of the soils with organic sources of nutrient supply was enhanced considerably (57.7% to 66.8%) over the initial level (98.7 to 107.4 ?g C/g). Application of one-third N each through FYM, green manur- ing of dhaincha and neem oilcake + Azospirillum + PSB to rice followed by similar combination of FYM, vermicompost, neem oilcake + Azotobacter + PSB to both potato and okra was the best organic nutrient manage- ment practice for ricepotatookra cropping system for improving soil health and productivity. However, this sys- tem can be profitable under organic farming only when on-farm generated organic manures are used.

Effect of combined use of green-manure crop and nitrogen on productivity of-rice (Oiyza sativa)-wheat (Eticum aestivum) system under lowland rice

A field experiment was conducted during 1992-93 to 1993-94 to study the effect of green-manuring crop in relation to nitrogen use on productivity of rice (Oryza sativa L.)-wheat (Triticum aestivum L. emend. Fiori &amp; Paol.) system. The treatments comprised 3 green-manuring crops, viz. dhaincha [Sesbania cannabina (retz.) Pers.] as green-manure, greengram (Phaseolus radiatus L.) as dual purpose and cowpea [Vigna unguiculata (L.) Walp.] as fodder crop, taken as pre-rainy season (kharif), apart from clean fallow in 4 main plots and 3 N rates (control, 50% and 100% of recommended dose in both crops) in subplots. Rice yield significantly responded to green-manuring, whereas succeeding wheat to the residual effect of green-manuring was only a marginal. Dhaincha and greengram showed superiority to rest of the treatments. Cowpea ranked second in position. More or less same trend was observed for economics. N level linearly responded up to 100% level in all respects. Green-manuring also improved the organic cabon of the soil irrespective of soil depth.

Productivity and profitability of seed dhaincha (Sesbania cannabina) + relay yard long bean (Vigna unguiculata subsp. sesquipedalis) under different date of planting and row spacing

A field experiment was conducted at Bhubaneswar, Odisha, during the rainy (kharif) 2019 and winter (rabi) season 201920, to study the effect of date of planting and row spacing on the performance of seed dhaincha [Sesbania cannabina (Retz.) Pers.] and relay yard long bean [Vigna unguiculata subsp. Sequipedalis (L.) Verdc.]. The treatments comprising 5 dates of planting of dhaincha, viz. onset of monsoon (13 June), and one (20 June), two (27 June), three (4 July) and four (11 July) week(s) after onset of the monsoon, and 3 row spacing, viz. 80, 120 and 160 cm, giving rise to 15 treatment combinations, were tried in split-plot design with 3 replications. The dates of planting and row spacings were allocated to the main and the sub plots, respectively. Yard long bean (bodi) was planted as relay crop after the first picking and before final harvesting of dhaincha. Planting dhaincha on 13 June at row spacing of 80 cm resulted in the maximum seed yield of 1.27 t/ha, while planting on 13 June at row spacing of 120 cm and planting on 20 June at row spacing of 80 and 120 cm recorded statistically similar seed yield. Planting of yard long bean on 5 October at row spacing of 80 cm gave the maximum fresh pod yield of 2.83 t/ha and planting on 5 October at row spacing of 120 cm and planting on 12 October at row spacing of 80 and 120 cm exhibited statistically similar fresh pod yield. Planting dhaincha on 13 June and relay yard long bean on 5 October at the closest row spacing of 80 cm resulted in the maximum system productivity (dhaincha seed-equivalent yield) of 3.06 t/ha, the maximum gross return of 192.68 103 `/ha and the maximum net return of 96.17 103`/ha. All combinations of 2 earliest date of planting (13 and 20 June) and the closest and the moderate row spacing (80 cm and 120 cm) remained at par for these productivity and profitability indices