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1.
Summary Nitrogen fixation in seven groundnut genotypes was measured by 15N-isotope dilution using a non-nodulating cultivar of groundnut as the nonfixing reference plant. Nitrogen fixation varied between 100 kg N ha–1 in genotype J-11 and 153 kg N ha–1 in Robut 33-1. The amount of plant-available soil N was small, so that 86%–92% of plant nitrogen was derived from N2-fixation. Thus differences in N2-fixation between genotypes closely reflected differences in their total N accumulation.ICRISAT Journal Article no. 600  相似文献   

2.
We studied the effect of the soil physical properties on soybean nodulation and N2 fixation in the heavy soil of an upland field (UF) and an upland field converted from a paddy field (UCPF) in the Hachirougata polder, Japan. Seeds of the soybean cultivar Ryuho were sown in each field with or without inoculation of Bradyrhizobium japonicum A1017. The soybean plants were sampled at 35 (V3) and 65 (Rl) d after sowing (DAS), and then nodulation and the percentage of N derived from N2 fixation in the xylem sap were determined. The soil physical properties were different between UF and UCPF, especially the air permeability and soil water regime. Nodule growth was restricted in UCPF irrespective of rhizobial inoculation, though rhizobial infection was not inhibited by the unfavorable soil physical conditions. Soybean plant growth was closely related to the nodule mass and N2 fixation activity, and the inoculation of a superior rhizobium strain was effective only at 35 DAS. These results indicate that soybean nodulation and N2 fixation was considerably affected by the physical properties of heavy soil, and that it is important to maintain the N2 fixation activity and inoculate the soybean plants with a superior rhizobium strain at a later growth stage in order to increase soybean production in heavy soil fields.  相似文献   

3.
Summary Field experiments were carried out to determine the effects of single and mixed inoculations with Rhizobium and vesicular-arbuscular mycorrhiza (VAM) on nodulation, symbiotic N2 fixation and yield of soybeans in six Taiwan subtropical-tropical sites. Inoculation with Rhizobium alone significantly increased nodulation, nodule weight and nitrogenase activity of nodules in three out of six experimental fields, and affected soybean yields in the range –13% to + 134%. Inoculation with VAM fungi alone did not have a significant effect on nodulation and nitrogenase activity. Mycorrhiza inoculation affected soybean yields in the range –13% to + 65%, but only the yield increases at one out of six sites with N application were statistically significant. Mixed inoculation with Rhizobium and mycorrhiza affected yields in the range –8% to + 145% A synergistic effect from mixed inoculation of Rhizobium-mycorrhiza on soybean yields was found in one out of six experimental fields. The yield response to N application (40 kg N ha–1) in these six paddy-field trials was not significant. These results suggest that single or mixed inoculation of rhizobia can greatly assist soybean grain yields and can replace N fertilizers.  相似文献   

4.
ABSTRACT

Co-inoculation of nitrogen-fixing bacteria with plant growth-promoting bacteria has become more popular than single inoculation of rhizobia or plant-growth-promoting bacteria because of the synergy of these bacteria in increasing soybean yield and nitrogen fixation. This study was conducted to investigate the effects of Bradyrhizobium japonicum SAY3-7 and Streptomyces griseoflavus P4 co-inoculation on plant growth, nodulation, nitrogen fixation, nutrient uptake, and seed yield of the ‘Yezin-6’ soybean cultivar. Nitrogen fixation was measured using the acetylene reduction assay and ureide methods. Uptake of major nutrients [nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg)] was also measured. This study showed that single inoculation of SAY3-7 significantly increased shoot biomass; nodulation; Relative Ureide Index (RUI %), percent nitrogen derived from N fixation (% Ndfa); N, P, K, Ca, and Mg uptakes; during the later growth stages (R3.5 and R5.5), compared with control. These observations indicate that SAY3-7 is an effective N-fixing bacterium for the plant growth, nodulation, and nitrogen fixation with an ability to compete with native bradyrhizobia. Co-inoculation of SAY3-7 and P4 significantly improved nodule number; nodule dry weight; shoot and root biomass; N fixation; N, P, K, Ca, and Mg uptake; at various growth stages and seed yield in ‘Yezin-6’ soybean cultivar compared with the control, but not the single inoculation treatments. Significant differences in plant growth, nodulation, N fixation, nutrient uptake, and yield between co-inoculation and control, not between single inoculation and control, suggest that there is a synergetic effect due to co-inoculation of SAY3-7 and P4. Therefore, we conclude that Myanmar Bradyrhizobium strain SAY3-7 and P4 will be useful as effective inoculants in biofertilizer production in the future.  相似文献   

5.
Summary The influence of three inoculum rates on the performance of three chickpea (Cicer arietinum L.) Rhizobium strains was examined in the field on a Mollisol soil. Increasing amounts of inoculum improved the performance of the strains. A normal dose (104 cells per seed) applied at different intervals gave non-significant increases in nodulation, nitrogenase activity (acetylene reduction assay), nitrogen uptake and grain yield. A ten-fold increase in inoculum increased nodule number, shoot dry weight, nitrogenase activity (ARA) and grain yield, but increases over the control were significant only for nodule dry weight and nitrogen uptake by shoot and grain. The highest level of inoculum (100 × normal) significantly increased nodule dry weight, grain yield, total nitrogenase activity (ARA) and nitrogen uptake by shoot and grain. Strain TAL 620 was more effective than the other two. Combined nitrogen (60 kg N ha–1) suppressed nodulation and nitrogenase activity (ARA).Research paper No. 4345 from the Experiment Station, G. B. P. U. A. & T., Pantnagar, Nainital, U. P.  相似文献   

6.
Co-inoculation of selected nitrogen-fixing bacteria with plant growth-promoting bacteria is the promising way for the improvement of soybean production through enhancing plant growth, nodulation, and N2 fixation. Therefore, this experiment was conducted to study the effects of co-inoculation of Bradyrhizobium elkanii BLY3-8 with Streptomyces griseoflavus P4 on plant growth, nodulation, N2 fixation, N uptake, and seed yield of Rj4 soybean varieties. Two experiments with completely randomized design and three replicates were done in this study. N2-fixation ability of soybean was evaluated by acetylene reduction activity (ARA) and relative ureide method. In the first experiment, synergetic effect in N2 fixation and nodulation was occurred in co-inoculation treatment (BLY3-8 + P4) in Yezin-3 and Fukuyutaka. Based on these results, co-inoculation effect of BLY3-8 and P4 was assessed on Yezin-3 and Fukuyutaka varieties at three different growth stages, using Futsukaichi soil under natural environmental conditions. This study shows that co-inoculation of BLY3-8 and P4 significantly increased N2 fixation at V6 stage; plant growth, nodulation, N2 fixation, and N uptake at R3.5 stage; and shoot growth, N uptake, and seed yield at R8 stage, in Rj4 soybean varieties compared with the control. Significant difference in plant growth, nodulation, N2 fixation, N uptake, and yield between co-inoculation and control, not between single inoculation and control, suggests that there is a synergetic effect due to co-inoculation of BLY3-8 and P4.  相似文献   

7.
Abstract

The effect of P deficiency on nodulation, nodule P content, nodule O2 permeability and N fixation rates in Phaseolus vulgaris–rhizobia symbiosis was studied under glasshouse conditions. Four recombinant inbred lines (L34, L83, L115 and L147) and one variety cultivated in Morocco (Concesa) were inoculated with Rhizobium tropici CIAT 899 in hydroaeroponic culture. Two P levels i.e. 75 (deficient level) and 250 µmol plant?1 week?1 P (sufficient level) were applied and the trial was assessed 42 days after transplanting that coincide with plant flowering stage. Under P-deficiency, decrease of plant growth (18%) and nodule biomass (19%) was detected and significantly pronounced in the sensitive line L147 compared with the remaining genotypes. Additionally, under P-deficiency, the efficiency in use of rhizobial symbiosis, estimated by the slope of the regression model of shoot biomass as a function of nodule biomass, was significantly increased in the four lines. This constraint did not significantly influence nodule P content in Concesa, but it was 24 and 41% lower in the tolerant and in the sensitive lines, respectively. Nodule P content was positively correlated to nodule biomass, r=0.75, and shoot N, r=0.92. These genotypic variations were associated with variability in nodule O2 permeability that was significantly affected by the P level-bean genotype interaction. Under P-deficiency, nodule O2 permeability was significantly reduced in the tested genotypes and accompanied with a decrease in shoot N content, especially in the sensitive lines (35%). Moreover, the ratios plant N fixed: nodule P content and plant N fixed:nodule dry weight were affected under P-deficiency in four lines with an exception observed in Concesa. Depending on the observed data we concluded that N2 fixation efficiency could be influenced by nodulation and level of nodule P requirement which depend on both bean genotypes and P level.  相似文献   

8.
N2 fixation, photosynthesis of whole plants and yield increases in soybeans inoculated with mixed cultures of Bradyrhizobium japonicum 110 and Pseudomonas fluorescens 20 or P. fluorescens 21 as well as Glomus mosseae were found in pot experiments in gray forest soil carried out in a growth chamber. The effects of pseudomonads and vesicular-arbuscular (VA) mycorrhizal fungus on these parameters were found to be the same. Dual inoculation of soybeans with mixed cultures of microorganisms stimulated nodulation, nitrogenase activity of nodules and enhanced the amount of biological nitrogen in plants as determined by the 15N dilution method in comparison to soybeans inoculated with nodule bacteria alone. An increased leaf area in dually infected soybeans was estimated to be the major factor increasing photosynthesis. P. fluorescens and G. mosseae stimulated plant growth, photosynthesis and nodulation probably due to the production of plant growth-promoting substances. Increasing phosphorus fertilizer rates within the range of 5–40 mg P 100 g-1 1:1 (v/v) soil: sand in a greenhouse experiment led to a subsequent improvement in nodulation, and an enhancement of N2 fixation and yield in soybeans dually inoculated with B. japonicum 110 and P. fluorescens 21. These indexes were considerably higher in P-treated plants inoculated with mixed bacterial culture than in plants inoculated with nodule bacteria alone.  相似文献   

9.
The rose of an isolate of the arbuscular mycorrhizal (AM) fungusGlomus mosseae in the protection ofMedicago sativa (+Rhizobium meliloti) against salt stress induced by the addition of increasing levels of soluble salts was studied. The interactions between soluble P in soil (four levels), mycorrhizal inoculum and degree of salinity in relation to plant growth, nutrition and infective parameters were evaluated. Salt stress was induced by sequential irrigation with saline water having four concentrations of three salts (NaCl, CaCl2, and MgCl2).15N-labelled ammonium sulphate was added to provide a quantitative estimate of N2 fixation under moderate to high salinity levels. N and P concentration and nodule formation increased with the amount of plant-available P or mycorrhizal inoculum in the soil and generally declined as the salinity in the solution culture increased from a moderate to a high level. The mycorrhizal inoculation protected the plants from salt stress more efficiently than any amount of plant-available P in soil, particularly at the highest salinity level applied (43.5 dS m–1). Mycorrhizal inoculation matched the effect on dry matter and nutrition of the addition in the soil of 150 mg P kg–1. Nevertheless the highest saline solution assayed (43.5 dS m–1) affected more severely plants supplemented with phosphorus than those with the addition of mycorrhizal inoculum. Such a saline-depressing effect was 1.5 (biomass), 1.4 (N) and 1.5 (P) times higher in plants supplied with soluble phosphate than with AM inoculum. Mechanisms beyond those mediated by P must be involved in the AM-protectioe effect against salinity. The15N methodology used allowed the determination of N2 fixation as influenced by different P applications compared to mycorrhizal inoculation. A lack of correlation between nodule formation and function (N2 fixation) was evidenced in mycorrhizal-inoculated plants. In spite of the reduced activity per nodule in mycorrhizal-inoculated In spite of the reduced activity per nodule in mycorrhizal-inoculated plants, the N contents determined indicated the highest acquisition of N occurred in plants with the symbiotic status. Moreover, N and P uptake increased while Ca and Mg decreased in AM-inoculated plants. Thus P/Ca ratios and cation/anion balance in general were altered in mycorrhizal treatments. This study therefore confirms previous findings that AM-colonized plants have optional and alternative mechanisms available to satisfy their nutritive requirements and to maintain their physiological status in stress situations and in disturbed ecosystems.  相似文献   

10.
Few studies of the inoculation of cereal crops with N2-fixing bacteria have included more than one or two plant genotypes. In a recent study performed in Argentina using 12 different maize genotypes, it was found in 2 consecutive field experiments that several of them responded consistently, either negatively or positively, to inoculation with a mixture of strains of Azospirillum spp. The present study in post was performed to investigate the effect of inoculation of individual strains (and a mixture) of Azospirillum spp., and their nitrate reductase negative (NR-) mutants, on the growth of four of these maize genotypes. Two of these genotypes were grown in 15N-labelled soil with the aim of quantifying any contributions of biological N2 fixation. Two genotypes (Morgan 318 and Dekalb 4D-70) produced similar increases in grain yield when they were inoculated with a mixture of Azospirillum spp. strains or fertilized with the equivalent of 100 kg N ha-1. The other genotypes (Dekalb 2F-11 and CMS 22) showed little response to inoculation or N fertilization. The Morgan 318 and Dekalb 4D-70 genotypes showed a large increase in total N accumulation, suggesting that the response was due to increased N acquisition, but not due to bacterial nitrate reductase as the NR- mutants generally caused plant responses similar to those of the parent strains. Despite problems with the stabilization of the 15N enrichment in the soil, the 15N isotope dilution results indicated that there were very significant biological nitrogen fixation (BNF) contributions to the Dekalb 4D-70 and CMS 22 maize genotypes.Dedicated to Professor J.C.G. Ottow on the occasion of his 60th birthday  相似文献   

11.
Summary The legume Medicago sativa (+Rhizobium melilott) was grown under controlled conditions to study the interactions between soluble P in soil (four levels), or a mycorrhizal inoculum, and the degree of water potential (four levels) in relation to plant development and N2 fixation. 15N-labelled ammonium sulphate was added to each pot for a qualitative estimate of N2 fixation, in order to rank the effects of the different treatments.Dry-matter yield, nutrient content and nodulation increased with the amount of plant-available P in the soil, and decreased as the water stress increased, for each P-level. The mycorrhizal effect on dry matter, N yield, and on nodulation was little affected by the water potential. Since P uptake was affected by the water content in mycorrhizal plants, additional mechanisms, other than those mediated by P, must be involved in the mycorrhizal activity.There was a positive correlation between N yield and nodulation for the different P levels and the mycorrhizal treatment at all water levels. A high correlation between plant unlabelled N content and atom% 15N excess was also found for all levels of P. In mycorrhizal plants, however, the correlation between unlabelled N yield and 15N was lower. This suggests that mycorrhiza supply plants with other N sources in addition to those derived from the improvement on N2 fixation.  相似文献   

12.
The influence of three sulphur application rates in combination with two nitrogen application rates on N2 fixation and growth of different legumes was investigated. N was applied as N-labelled 15NH4 15NO3. The 15N isotope dilution technique was used to estimate N2 fixation. At both N increments dry matter yield was highest with high S supply. Independently of the N supply, the high S application rate resulted in a significantly higher N accumulation, which was mainly caused by a higher N2 fixation rate. With the grain legumes the weight of nodules was increased by the high S application rate. The higher number of nodules per pot with optimum S supply was the result of a better root growth. Rates of acetylene reduction correlated significantly with S supply.  相似文献   

13.
An experiment was conducted under greenhouse conditions to test the symbiotic performance and plant nutrient uptake of the twelve nationally registered chickpea cultivars (‘Çak?r’, ‘I??k-05’, ‘Can?tez-87’, ‘Hisar’, ‘Ya?a-05’, ‘Azkan’, ‘Küsmen-99’, ‘Gökçe’, ‘Damla-89’, ‘Diyar-95’, ‘Aziziye-94’, and ‘?zmir-92’) in Turkey. Inoculation with Mesorhizobium ciceri increased the average nodule number by 687%, nodule weight by 257%, plant height by 6%, shoot dry weight by 12%, root dry weight by 21%, chlorophyll content by 4.2%, nitogen (N)% by 7.9%, and total N by 22.7%. Averaged across chickpea cultivars, inoculation also significantly increased sulfur (S) by 14.4%, phosphorus (P) by 1.9%, magnesium (Mg) by 13.8%, potassium (K) by 6.2%, calcium (Ca) by 17.4%, copper (Cu) by 4.5%, iron (Fe) by 16.5%, manganese (Mn) by 10.9% and zinc (Zn) uptake by 9.4%. The macro- and micronutrient uptake of cultivars significantly correlated with their nitrogen content and the magnitude of response to inoculation in relation to nodulation, plant growth, nitrogen fixation, and nutrient uptake significantly varied among cultivars. Based on the amount of fixed N and plant nutrient uptake, ‘Azkan’, ‘Aziziye-94’, ‘Küsmen-99’, ‘Diyar-95’, and ‘Hisar’ were the genotypes with the most positive response to inoculation. Our data showed that nodulation, nitrogen fixation, plant dry matter production, and macro- and micronutrient uptake of the inoculated chickpea can be improved by selecting the best compatible cultivar.  相似文献   

14.
Plant growth performance, the P content in root and nodule tissues, and nodulation and N2-fixing ability were studied in four provenances of Acacia mangium from Papua New Guinea following different levels of P fertilizer application. A. mangium did not seem to need high levels of P for growth and N2 fixation. The response by this leguminous tree to the P supply varied significantly according to provenance and to P concentrations in the culture solution. The provenances of A. mangium were classified into three types according to their P response: (1) Growth performance, nodulation, and N2 fixation of plants were stimulated as concentrations of P increased (provenance PH 482); (2) the maximal effect of P on plant growth was found only at P concentrations higher than 500 M (provenance PH 484); and (3) the plant response to P fertilization was low, even with nutrient solutions containing P concentratins higher than 500 M (provenances PH 483 and PH 485). Provenance PH 483 was distinguished by its low nodulating ability. However, this provenance grew well, probably because of its high N2 fixation efficiency as expressed by specific acetylene reduction activity and its high P content in nodule tissues. Therefore, in certain cases, these two parameters may be useful criteria in selecting leguminous plants for field use. Statistical analyses of the study results showed that the effect of the factor P supply on N2 fixation efficiency and nodule development was only significant at P concentrations lower than 250 M whereas the effect of the factor plant provenance was significant regardless of the P concentration used. This observation emphasizes the value of provenance screening in the identification of plants for use in a wide range of soil types.  相似文献   

15.
Summary A spontaneous mutant ofAzospirillum lipoferum, resistant to streptomycin and rifampicin, was inoculated into the soil immediately before and 10 days after transplanting of rice (Oryza sativa L.). Two rice varieties with high and low nitrogen-fixing supporting traits, Hua-chou-chi-mo-mor (Hua) and OS4, were used for the plant bacterial interaction study. The effect of inoculation on growth and grain and dry matter yields was evaluated in relation to nitrogen fixation, by in situ acetylene reduction assay,15N2 feeding and15N dilution techniques. A survey of the population of marker bacteria at maximum tillering, booting and heading revealed poor effectivety. The population of nativeAzospirillum followed no definite pattern. Acetylene-reducing activity (ARA) did not differ due to inoculation at two early stages but decreased in the inoculated plants at heading. In contrast, inoculation increased tiller number, plant height of Hua and early reproductive growth of both varieties. Grain yield of both varieties significantly increased along with the dry matter. Total N also increased in inoculated plants, which was less compared with dry matter increase.15N2 feeding of OS4 at heading showed more15N2 incorporation in the control than in the inoculated plants. The ARA,15N and N balance studies did not provide clear evidence that the promotion of growth and nitrogen uptake was due to higher N2 fixation.  相似文献   

16.
Summary Following screening, selection, characterization, and symbiotic N2 fixation with 12,5, 25.0, and 40.0 mg N kg–1 in normal and saline-sodic soils, only two Phaseolus vulgaris genotypes (HUR 137 and VL 63) and two Rhizobium spp. strains (ND 1 and ND 2) produced maximum nodulation, nitrogenase activity, plant N contents, and grain yields in saline-sodic soil, with 12.5 mg N kg–1, compared with the other strains. However, interactions between strains (USDA 2689, USDA 2674, and ND 5) and genotypes (PDR 14, HUR 15, and HUR 138) were significant and resulted in more nodulation, and greater plant N contents, nitrogenase activity, and grain yields in normal soils with 12.5 mg N kg–1 compared with salt-tolerant strains. Higher levels of N inhibited nodulation and nitrogenase activity without affecting grain yields. To achieve high crop yields from saline-sodic and normal soils in the plains area, simultaneous selection of favourably interacting symbionts is necessary for N economy, so that bean yields can be increased by the application of an active symbiotic system.  相似文献   

17.
Legume plants are an essential component of sustainable farming systems. Phosphorus (P) deficiency is a significant constraint for legume production, especially in nutrient-poor soils of arid and semi-arid regions. In the present study, we conducted a pot experiment to evaluate the effects of a phosphorus-mobilizing plant-growth promoting rhizobacterial strain Bacillus cereus GS6, either alone or combined with phosphate-enriched compost (PEC) on the symbiotic (nodulation-N2 fixation) performance of soybean (Glycine max (L.) Merr.) on an Aridisol. The PEC was produced by composting food waste with addition of single super phosphate. The bacterial strain B. cereus GS6 showed considerable potential for P solubilization and mobilization by releasing carboxylates in insoluble P (rock phosphate)-enriched medium. Inoculation of B. cereus GS6 in combination with PEC application significantly improved nodulation and nodule N2 fixation efficiency. Compared to the control (without B. cereus GS6 and PEC), the combined application of B. cereus GS6 with PEC resulted in significantly higher accumulation of nitrogen (N), P, and potassium (K) in grain, shoot, and nodule. The N:P and P:K ratios in nodules were significantly altered by the application of PEC and B. cereus GS6, which reflected the important roles of P and K in symbiotic performance of soybean. The combined application of PEC and B. cereus GS6 also significantly increased the soil dehydrogenase and phosphomonoesterase activities, as well as the soil available N, P, and K contents. Significant positive relationships were found between soil organic carbon (C) content, dehydrogenase and phosphomonoesterase activities, and available N, P, and K contents. This study suggests that inoculation of P-mobilizing rhizobacteria, such as B. cereus GS6, in combination with PEC application might enhance legume productivity by improving nodulation and nodule N2 fixation efficiency.  相似文献   

18.
Abstract

The response of peanut (Arachis hypogaea L.) to inoculation with vesicular-arbuscular mycorrhizal (VAM) fungi (Glomus etunicatum) and Bradyrhizobiurn sp. was studied in pots by the acetylene reduction activity (ARA) and ‘A-value’ methods. The soil used was a Light-coloured Andosol and the treatments consisted of the inoculation of VAM fungi only, inoculation of Bradyrhizobium only, dual inoculation of VAM fungi and Bradyrhizobium and control, under non-sterilized and sterilized soil conditions.

In the non-sterilized soil the ARA and nitrogen fixation determined by the ‘A-value’ method increased significantly only by dual inoculation of VAM fungi and Bradyrhizobium at 100 days after planting (DAP), but no significant difference was observed at 70 DAP. In the case of dual inoculation, 75% of the nitrogen of the plant was derived from fixation whereas the plants inoculated only with Bradyrhizobium derived 68% of their nitrogen from fixation and the control plants, 64%. Amount of P in plant increased significantly only by dual inoculation with VAM fungi and Bradyrhizobium.

In the sterilized soil a highly significant increase in the ARA was observed of the dual inoculation at all the sampling times. Nitrogen fixation determined by the A-value technique and N and P contents in plant also increased significantly by dual inoculation. Results obtained by the A-value method showed that plants with dual inoculation derived 68% of their nitrogen from fixation while the plants inoculated only with Bradyrhizobium, 38%.

From our this study we conclude that nitrogen fixation as well as N and P contents in peanut increased significantly only by dual inoculation with VAM fungi and Bradyrhizobium.  相似文献   

19.
Summary In three field trials conducted during the summer season of 1986, 1987 and 1989 in an alkaline soil, 17 accessions of annual Sesbania spp. were evaluated for nodulation, N2 fixation (acetylene reduction assay), dry weight of roots and shoots, woody biomass production, and nutrient uptake. At 50 days after sowing all the accessions were effectively nodulated (average 36.4 root nodules plant-1) with a high nodule score (3.4). There was a lot of variation in nodule volume and mass and in acetylene reduction activity but not in N content (5.2%). N uptake in shoots, roots and nodules averaged 639, 31, and 13 mg plant-1, respectively, and much of the fixed N remained in shoots. Accessions of S. cannabina complex performed better than others. S. rostrata had poor root nodulation but exhibited excellent stem nodulation (300 nodules plant-1) even though not inoculated with Azorhizobium sp. Average concentrations of N, P, K, S, Ca, and Mg in the shoots were high, at 3.2, 0.28, 1.5, 0.28, 1.5, and 0.4% respectively, and Na was low (0.15%), reflecting the usefulness of Sesbania spp. as an integrated biofertilizer source. Green matter production was 26.0 Mg ha-1 (5.9 Mg dry matter) and N uptake was 158 kg ha-1, 54 days after sowing. Average woody biomass of six accessions at maturity, 200 days after sowing, was high (19.9 Mg ha-1), showing its potential for shortterm firewood production. Total nutrient uptake for production of woody biomass (200 days of growth) was no more demanding than growing the plant to the green-manuring stage of 50–60 days' growth.  相似文献   

20.
Summary N2(C2H2) fixation by Ulex gallii Planchon (dwarf or autumn flowering gorse/furze) seedlings was determined following 8 months of growth (December-August) in the glasshouse in a very acid, N- and P-deficient forest soil. Application of Na2HPO4·12H2O or North African ground rock phosphate fertilizer was essential for growth, nodulation and C2H2 reduction activity. Overall, both the sodium phosphate and the rock phosphate were equally effective P sources and the maximum acetylene reduction by intact roots was measured as 4.09 and 4.69 mol C2H4g-1 fresh weight nodule h-1, respectively. Applied NH4Cl severely inhibited nodulation and restricted acetylene reduction activity but not seedling growth. The results are discussed in relation to the spread of U. gallii in the south of Ireland and its potential as a leguminous nurse crop for Sitka spruce on the very impoverished forest soils of the region.  相似文献   

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