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1.
In order to identify soybean cultivars with higher biological N2 fixation capacities, North American and Brazilian soybean [Glycine max (L.) Merrill] cultivars, belonging to maturity groups VI–VIII, were evaluated for nodulation parameters and N2 fixation rates. The symbiotic performance of 152 cultivars was evaluated in pots containing 4 kg soil with an established
population of the three Bradyrhizobium elkanii strains [29w (SEMIA 5019):SEMIA 566 : SEMIA 587, 22%:36%:34%] which are established in most Brazilian soils cultivated with
soybean. Differences were verified among cultivars, with some accumulating up to twice as much nodule dry weight and N in
tissues as others. The variability among cultivars was also confirmed when six of them were used in a field experiment, resulting
in differences in nodulation, yield and total N accumulated in grains. The analysis of nodule occupancy in 12 cultivars grown
either under sterile conditions and receiving a double inoculum and N-free nutrient solution, or in pots containing soil with
an established population of bradyrhizobia, showed the preference of cultivars for specific strains.
Received: 7 December 1998 相似文献
2.
S. P. Palaniappan P. Sudhi Sreedhar P. Loganathan J. Thomas 《Biology and Fertility of Soils》1997,25(3):279-284
Interstrain competitiveness is a key factor affecting the performance of rhizobium inoculant. In the present study five native
strains of Bradyrhizobium japonicum, namely SSF 4, SSF 5, SSF 6, SSF 7 and SSF 8, were assessed for their competitiveness in nodulating soybean using serological
methods. The strains were inoculated individually or with the type strain USDA 110 at a 1:1 ratio. Nodule occupancy determined
by immunofluorescence and dot immunoblot assay revealed that under in vitro conditions SSF 8 is more competitive than USDA 110
whereas the others were less competitive. The competitive ability of these strains was also estimated in pot culture in the
field. In red soil both SSF 8 and USDA 110 were equally competitive whereas in black soil SSF 8 competed better than USDA 110
and produced more nodules. In a black soil field trial using a randomized block design, USDA 110 or SSF 8, when inoculated
alone, occupied the majority of the nodules and enhanced nodule dry weight and shoot biomass. SSF 8 was more competitive when
the strains were co-inoculated.
Received: 1 November 1996 相似文献
3.
P. Houngnandan N. Sanginga P. Woomer B. Vanlauwe O. Van Cleemput 《Biology and Fertility of Soils》2000,30(5-6):558-565
Leguminous cover crops such as Mucuna pruriens (mucuna) have the potential to contribute to soil N and increase the yields of subsequent or associated cereal crops through
symbiotic N fixation. It has often been assumed that mucuna will freely nodulate, fix N2 and therefore contribute to soil N. However, results of recent work have indicated mucuna's failure to nodulate in some farmers'
fields in the derived savanna in Benin. One of the management practices that can help to improve mucuna establishment and
growth is the use of rhizobial inocula to ensure compatibility between the symbiotic partners. Experiments were conducted
in 1995 and 1996 on 15 farmers' fields located in three different villages (Eglimé, Zouzouvou and Tchi) in the derived savanna
in Benin. The aim was to determine the response of mucuna to inoculation and examine the factors affecting it when grown in
relay cropping with maize. The actual amount of N2 fixed by mucuna in the farmers' fields at 20 weeks after planting (WAP) averaged 60 kg N ha–1 (range: 41–76 kg N ha–1) representing 55% (range: 49–58%) of the plant total N. The result suggested that mucuna in these farmers' fields could not
meet its total N demand for growth and seed production only by N2 fixation. It was estimated that after grain removal mucuna led to a net N contribution ranging from –37 to 30 kg N ha–1. Shoot dry weight at 20 WAP varied between 1.5 and 8.7 t ha–1 and N accumulation ranged from 22 to 193 kg N ha–1. Inoculation increased shoot dry matter by an average of 28% above the uninoculated treatments, but the increase depended
on the field, location and year. For the combinations of inoculated treatments and farmers' fields, the response frequency
was higher in Eglimé and Tchi than in Zouzouvou. The response to inoculated treatments was dependent on the field and inversely
related to the numbers of rhizobia in the soil. Soil rhizobial populations ranged from 0 to >188 cells g–1 soil, and response to inoculation often occurred when numbers of indigenous rhizobia were <5 cells g–1 soil. In two farmers' fields at Zouzouvou where extractable P was below 10 μg g–1 soil, mucuna did not respond to rhizobial inoculation despite a higher population of rhizobia. Significant relationships
between mycorrhizal colonization, growth and nodulation of mucuna were observed, and inoculated plants with rhizobia had a
higher rate of colonization by arbuscular mycorrhizal fungi (%AMF) than uninoculated ones. Therefore, it was shown that mucuna
will establish and fix N2 effectively in those fields where farmer's management practices such as good crop rotation and rhizobial inoculation allow
a build up of AMF spores that might lead to a high degree of AMF infection and alleviate P deficiency.
Received: 14 June 1999 相似文献
4.
Bradyrhizobium japonicum strain CB 1809 was recently chosen to replace strain WB 1 in commercial soybean [Glycine max (L.) Merr.] inoculants in South Africa, the selection criterion being N2-fixing effectiveness. Nodulation competitiveness is an additional characteristic required of inoculants and was determined
for CB 1809 and WB 1 as well as two other strains, USDA 110 and a Brazilian strain 965, using the gusA marker gene to identify strains. Initial experiments with plants grown in sterile sand showed that the competitive index
of strain WB 1 was less than that of the other strains. Further comparisons used plants grown in five soils containing established
populations of B. japonicum. When strains were applied in peat inoculum to seed at a rate of 1,000 cells per seed in a soil containing 300 rhizobia g–1, significant differences in nodule occupancy were detected and strains ranked in the order 965>CB 1809>USDA 110>WB 1. The
remaining four soils each contained about 106 rhizobia g–1 and 5×106 cells were applied per seed. Nodule occupancy by inoculant strains ranged from 22% to 81% between soils. In this experiment,
WB 1 was consistently the poorest performer and its competitiveness was significantly less than CB 1809. The competition results
supported the recent decision to replace WB 1 with CB 1809 in commercial inoculants. Although WB 1 had been used in inoculants
over a period of 19 years, this strain was detected in only one soil, where it comprised 8% of isolates. In contrast, a substantial
proportion (32–78%) of isolates from the soils corresponded serologically to a former inoculant strain WB 66, which had been
discontinued in 1966. This illustrates the difficulty of replacing a resident population with an introduced strain. The effect
of naturalized populations on the establishment of CB 1809 in South African soils will need monitoring
Received: 23 November 1999 相似文献
5.
Thirty-five Azospirillum strains (13 strains from plant roots and 22 strains from soils) were isolated from Ishigaki island, Japan, which has a subtropical
climate. These strains were different from each other according to polymerase-chain-reaction band patterns obtained by using
a random primer (OPT-08). Two Azospirillum strains (AZ43 and AZ92-2) were also examined for use in further experiments. Inoculation of lowland rice with these strains
enhanced early growth of rice to various degrees. Inoculation of strains VIII.P1-2, AZ92-2, V.S2-2, and V.P5 in sterilized
soil yielded higher shoot dry weights than the application of 90 μg N g–1 soil without inoculation. Only inoculation with strains AZ92-2 and VIII.P1-2 caused higher N uptake than the application
of 90 μg N g–1 soil. Three strains were selected for the next experiment based on the results of their effect on the early growth of rice.
An investigation was conducted to determine the ability of two indigenous Azospirillum strains (V.S2-2 and VIII.P1-2) and one stock strain (AZ92-2) to promote growth and nutrient-uptake of lowland rice in unsterilized
soil under several levels of N application (0, 80, 160, and 240 mg N pot–1). Inoculation with these strains without N application increased shoot dry weight by 12–15% compared to the uninoculated
treatment. Inoculation with Azospirillum V.S2-2 together with the application of 160 mg N pot–1 resulted in a shoot dry weight as high as that obtained in the treatment with 240 mg N pot–1 without inoculation. Thus, in this former case, the amount of N applied could be reduced by 80 mg pot–1 due to the effect of the microbial inoculum without a significant change in the high, targeted, yield. 相似文献
6.
G. Amanuel R. F. Kühne D. G. Tanner P. L. G. Vlek 《Biology and Fertility of Soils》2000,32(5):353-359
N2 fixation by leguminous crops is a relatively low-cost alternative to N fertilizer for small-holder farmers in developing
countries. N2 fixation in faba bean (Vicia faba L.) as affected by P fertilization (0 and 20 kg P ha–1) and inoculation (uninoculated and inoculated) with Rhizobium leguminosarium biovar viciae (strain S-18) was studied using the 15N isotope dilution method in the southeastern Ethiopian highlands at three sites differing in soil conditions and length of
growing period. Nodulation at the late flowering stage was significantly influenced by P and inoculation only at the location
exhibiting the lowest soil P and pH levels. The percentage of N derived from the atmosphere ranged from 66 to 74%, 58 to 74%
and 62 to 73% with a corresponding total amount of N2 fixed ranging from 169 to 210 kg N ha–1, 139 to 184 kg N ha–1 and 147 to 174 kg N ha–1 at Bekoji, Kulumsa and Asasa, respectively. The total N2 fixed was not significantly affected by P fertilizer or inoculation across all locations, and there was no interaction between
the factors. However, at all three locations, N2 fixation was highly positively correlated with the dry matter production and total N yield of faba bean. Soil N balances
after faba bean were positive (12–58 kg N ha–1) relative to the highly negative N balances (–9–44 kg N ha–1) following wheat (Triticum aestivum L.), highlighting the importance of rotation with faba bean in the cereal-based cropping systems of Ethiopia.
Received: 13 January 2000 相似文献
7.
A 15N isotope dilution technique was applied to quantify the extent of N2 fixation in lentil (Lens culinaris Medik.) cultivars as influenced by Rhizobium leguminosarum bv. viciae strains in a field experiment in Pakistan. The experiment was conducted on a soil with a very small indigenous rhizobial population
and where N was a limiting factor for crop production. Significant variations in number of nodules, dry weight of nodules,
biomass yield, grain yield, total N yield, proportion of plant N derived from N2 fixation (Pfix) and amount of N derived from the atmosphere (Ndfa) were observed among combined treatments of four rhizobial strains and six lentil varieties. In a field previously labelled
with 15N, to which a basal dose of 75 kg P2O5 ha–1 was applied as single super phosphate, Ndfa ranged from 15 to 24 kg N ha–1 when calculated according to rhizobial strain and from 4 to 38 kg N ha–1 when calculated according to lentil variety. Lc 26 was the most effective strain and fixed 243% more N than the indigenous
population in the uninoculated control. In treatments with the lentil variety PL-406, Ndfa was 38 kg N ha–1, which was 850% higher than with the lentil variety Precoz/F6-20-1×M-85. Generally, the varieties with greater Pfix produced a higher dry matter yield.
Received: 26 May 1999 相似文献
8.
M. A. T. Vargas Ieda C. Mendes Mariangela Hungria 《Biology and Fertility of Soils》2000,32(3):228-233
Most soils sown with field beans (Phaseolus vulgaris L.) contain indigenous rhizobia which might interfere with the establishment of inoculated strains. As a consequence, the
benefits of bean inoculation are usually questioned, and the use of N fertilizer is gradually becoming a common practice.
The present study had the objective of evaluating the effectiveness of inoculation and N fertilization in field soil with
(site 1) and without (site 2) a previous bean-cropping history. At site 1, which had a rhizobial population of 7×102 cells g–1 soil, inoculation had no effect on nodulation or yield, whereas at site 2 (<10 cells g–1 soil) inoculation increased nodulation, nodule occupancy by the inoculated strain and grain yield. N fertilizer decreased
nodulation at both sites, but increased grain yield at site 1 but not at site 2, indicating that the response to inoculation
and N fertilization depends on the cropping history. When bean was cultivated for the first time, indigenous populations of
rhizobia were low and high yields were accomplished solely with seed inoculation, with no further response to N fertilizer.
In contrast, previous cultivation of bean increases soil rhizobia, preventing nodule formation by inoculated strains, and
N fertilizer may be necessary for maximum yields. A significant interaction effect between N fertilizer and inoculation was
detected for serogroup distribution only at site 2, with N fertilizer decreasing nodule occupancy by the inoculated strain
and increasing the occurrence of indigenous strains. Consequently, although no benefits were obtained by the combination of
inoculation and N fertilizer, this practice may be feasible with the selection of appropriate N-tolerant strains from the
indigenous rhizobial population.
Received: 26 May 1999 相似文献
9.
R. C. Abaidoo K. E. Dashiell N. Sanginga H. H. Keyser P. W. Singleton 《Biology and Fertility of Soils》1999,30(3):187-192
Soybean cultivars capable of nodulating with indigenous Bradyrhizobium spp. have been developed by the International Institute of Tropical Agriculture (IITA) and national programs in Africa in
order to avoid artificial inoculation by resource-poor farmers in Africa. The current selection procedure for enhanced N2 fixation is based on an assessment of nodule formation which does not directly quantify the proportions of crop N derived
from the atmosphere. We have monitored N accumulation patterns and N2 fixation in nine promiscuous soybean cultivars with different maturity periods, using the 15N dilution technique. Nodule development generally peaked at the early podfill stage for all cultivars except Tgx 1519-1D
and Tgx 1447-2D in which it continued to increase. The proportion of crop N derived from fixation (%NDFA) ranged between 51%
and 67%, 77% and 84%, and 66% and 73% at full bloom, early podfill, and physiological maturity stages, respectively. Total
N accumulation increased in all soybean genotypes with increasing plant age. Significant correlations (P<0.001) were established between nodule weight and %NDFA, even though this did not explain the relationship between nodule
development and N2 fixation in cultivars such as Tgx 1519-1D. Promiscuous soybean cultivars retained between 10% and 19% of total N accumulated
at the final harvest, in belowground biomass. Our results indicated that these soybean cultivars can derive substantial proportions
of plant N from N2 fixation in soils where compatible indigenous bradyrhizobia populations are adequate and effective. Also, we have substantiated
the claims that qualitative nodulation parameters currently used to select varieties with a high N2 fixation capacity need to be validated with other measurements of N2 fixation.
Received: 5 November 1998 相似文献
10.
V. K. Avornyo A. Manu R. Adu-Gyamfi 《Communications in Soil Science and Plant Analysis》2020,51(7):985-996
ABSTRACTSoybean yields in Ghana are low and stagnant in spite of the trio of recommendations: (1) improved seed, (2) rhizobium inoculant and (3) phosphorous fertilizer application being promoted by government to boost productivity. This study evaluates the response of soybean to Pro-soil biostimulant, triple super phosphate (TSP), and rhizobium inoculant in the interior savanna of Ghana. A treatment structure comprising two mainplot factors (biostimulant and conventional), and four subplots factors; TSP, inoculant, TSP+Inoculant and unamended control arranged in a split-plot design was used for this study. Apart from dry matter which increased by 42%, Pro-soil biostimulant as a stand-alone management practice did not significantly increase agronomic parameters measured in this study. Biostimulant did not have a significant effect on grain yield, nodule weight, nodule number, canopy diameter, and plant height. Application of TSP alone, and in combination with inoculant, significantly increased yield, plant dry matter, nodule weight, nodule number, and dry pod weight. Highest soybean yield was obtained from TSP + Inoculant treatment, averaging 3.6 t ha?1 compared to 1.8 t ha?1 for control. Biostimulant, TSP+Inoculant combination resulted in yields as high as 4 t ha?1. Overall, the results indicate that neither PS-Foundation biostimulant nor rhizobia inoculation can be used as stand-alone management practices to increase soybean yield. However, an integrated application of PS-Foundation biostimulant, TSP, and inoculant could double current soybean yields in Ghana. 相似文献
11.
Non-isotopic method for the quantification of biological nitrogen fixation and wheat production under field conditions 总被引:1,自引:0,他引:1
Y. G. M. Galal I. A. El-Ghandour S. S. Aly S. Soliman A. Gadalla 《Biology and Fertility of Soils》2000,32(1):47-51
A field experiment was conducted in the Inshas area (Sharkeia governorate) to study the potential of biofertilizers, when
the quantities of commercial fertilizers were reduced, for optimal wheat production. The different treatments were arranged
in a completely randomized block design with seven replicates. N fertilizer was applied in three treatments with one control,
i.e. zero, full, half and one-fourth rates, in the presence or absence of inocula. Azospirillum brasilense strain Sp245 was used as a biofertilizer. Generally, inoculation increased the accumulation of shoot dry matter and grain
yield by about 35%, relative to the control treatment. Similar trends were observed in the case of N and P uptake by shoots
and grains, as well as the efficient use of both, where inoculation increased the acquisition of the two elements as compared
with the uninoculated plants. The obtained data showed that N2 fixed by shoots and grains ranged from 2 to 10 kg N ha–1 and from 8 to 19 kg N ha–1, respectively. With respect to fixed N2, the best treatment was inoculation combined with the one-fourth dose of N, followed by inoculation combined with half of
the recommended N dose. Most of the fixed N was utilized by grains and the results clearly reflected the negative effect of
high N fertilizer rates on biological N fixation. It is obvious that inoculation, in general, enhanced the N fertilizer utilized
by both shoots and grains of wheat plants. In conclusion, the application of biofertilization technology to a light-textured
soil with low fertility had a positive effect on plant growth, N gained from the air and enhancement of fertilizer N uptake
(apparent recovery fraction).
Received: 22 April 1999 相似文献
12.
AbstractSoybean cultivation in Ethiopia is dominated by smallholder farmers who use little or no inputs, often resulting in low yields. The use of effective rhizobia strains was considered as an ecologically and environmentally sound approach for soybean production. Field experiments were conducted during 2015/16 cropping seasons at two different agro-climatic regions in Ethiopia to investigate the effectiveness of local soybean isolates for improving nodulation, growth, yield and quality of soybean. Ten treatments comprising of seven indigenous rhizobia isolates, one exotic strain, nitrogen fertilized treatment and uninoculated control were arranged in randomized complete block design in three replications. Results of the experiment revealed that nodule number and nodule dry weight significantly increased from nil in the uninoculated control to 14–34 and 110–521?mg plant?1, respectively due to inoculation with different isolates. Furthermore, inoculation significantly increased shoot dry weight by 24–46%, shoot nitrogen concentration by 20–30%, shoot N content by 29–49%, plant height by 14–41%, pods per plant by 12–38%, seeds per pod by 7–19%, thousand seed weight by 15–24%, grain yield by 22–115% and protein content by 7–39% compared with the uninoculated control. Generally, isolates Jm-1-Bo, As-5-Aw, Bk-3-Aw, Cw-6-Aw and MAR 1495 performed better than the others in most yield parameters at both locations of which Jm-1-Bo and As-5-Aw were the local isolates performing best irrespective of location, and were superior to the effective exotic standard strain. Therefore, isolates Jm-1-Bo, As-5-Aw and Bk-3-Aw could be utilized as candidates for inoculant production at large scale in areas with similar agroecology. 相似文献
13.
Mariel Josue Bizarro Adriana Giongo Luciano Kayser Vargas Luiz Fernando Wurdig Roesch Kelsey Annette Gano Enilson Luiz Saccol de Sá Luciane Maria Pereira Passaglia Pedro Alberto Selbach 《Biology and Fertility of Soils》2011,47(3):357-362
Due to their ecologic and economic importance, bradyrhizobia have been extensively studied in recent years. Since 1992, Bradyrhizobium elkanii SEMIA 587 and SEMIA 5019 and Bradyrhizobium japonicum SEMIA 5079 and SEMIA 5080 have been widely used in most Brazilian soybean fields. The objective of this work was to estimate
the genetic variability of bradyrhizobial isolates recovered from soils under rhizobial inoculation and different soil managements.
Only 25% of the isolates demonstrated high similarities to the original strains, and a strong correlation was obtained between
the bradyrhizobial genetic variability and soil management. A high level of genetic diversity was observed both within isolates
(H = 5.46) as well as among the different soil practices. Soil under no-tillage presented a higher bradyrhizobia diversity compared
with bradyrhizobia isolated from soil under conventional tillage. Serological characterization also indicated that B. elkanii strains SEMIA 587 and SEMIA 5019 were more competitive and presented a higher nodular occupancy capacity than strains belonging
to B. japonicum species in Southern Brazilian soils. 相似文献
14.
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
15.
M. Kaleem Abbasi Muhammad Manzoor Majid Mahmood Tahir 《Journal of plant nutrition》2013,36(7):1080-1102
A field experiment was conducted in continuity of our previous study to assess the effect of Rhizobium inoculation (RI) and phosphorus fertilization (P) on growth, yield, nodulation, and P use efficiency of soybean. Different treatments were i) Rhizobium strains (0, S377, S379, and the mixture of S377+S379 i.e. S0, S1, S2, S3); ii) phosphorus fertilizer (0, 50, 100 kg ha?1 i.e. P0, P1, P2). Soybean variety NARC-1 was as used as a testing crop. Results indicated that root and shoot growth increased by RI treatments whether used alone or in combination with P. Rhizobium inoculation increased plant height up to 12% while P did not show significant effect. Increases in soot dry weight, root length and root dry weight due to RI and P was 57 and 22%, 42 and 7%, 55 and 25%, respectively, over the control treatment. Number of nodules increased from 73 in the control to a maximum of 151 in S2 while the number increased from 90 in the control to 147 in P2. Combine application of strains and P increased nodules number from 65 at S0P0 to a maximum of 183 at S2P2. Similar response was also observed for nodules mass. Soybean seed yields ranged between 1710 and 2335 kg ha?1 against 1635 kg ha?1 in the control indicating a maximum of 43% increase over control. Concentration of N and P in plants and their uptake was significantly increased by RI and P. RI also increased the N and protein content of soybean seed. Apparent recovery efficiency (ARE) of applied P was 10?12% and the agronomic, agrophysiological, recovery, utilization efficiencies, and harvest index of P decreased with increasing P rates. Nodule number significantly correlated with the DM yield (r2 = 0.78) and seed yield (r2 = 0.63) while P uptake significantly correlated with root length (r2 = 0.48) and root mass i.e. dry weight (r2 = 0.65). Also a significant correlation existed between N uptake and DM yield (r2 = 0.98) and N uptake and seed yield (r2 = 0.65), P uptake and DM yield (r2 = 0.73), and P uptake and seed yield (r2 = 0.83). The results of present study indicated a substantial growth and yield potential of soybean under the hilly region and increase in yield and N2 fixing potential (nodulation) can be achieved by applying Rhizobium inoculation with P fertilization. 相似文献
16.
Guriqbal Singh Harpreet Kaur Virk Navneet Aggarwal R K Gupta Veena Khanna 《Archives of Agronomy and Soil Science》2019,65(3):411-420
Field experiments evaluated the effects of integrated nutrient management on symbiotic parameters, growth, nutrient accumulation, productivity and profitability of lentil (Lens culinaris Medikus). Application of recommended dose of nutrients (RDN, 12.5 kg N ha?1 + 40 kg P2O5 ha?1) + 25 kg ZnSO4 ha?1 + seed inoculation with biofertilizers [Rhizobium + phosphate solubilizing bacteria (PSB) + plant growth promoting rhizobacteria (PGPR)] + 1.0 g ammonium molybdate kg?1 seed recorded the highest number & dry weight of nodules, leghaemoglobin content, root & shoot dry weight, plant height, number of pods plant?1 and 100-seed weight. The next best treatment was RDN + seed inoculation with biofertilizers + 1.0 g ammonium molybdate kg?1 seed. On the basis of mean of three-year data, the treatment of RDN + 25 kg ZnSO4 ha?1 + seed inoculation with biofertilizers + 1.0 g ammonium molybdate kg?1 seed proved the best in realizing the highest grain yield (34.0%), gross returns (34.0%) and net returns (54.8% higher over control). Nitrogen, phosphorus and potassium in the grains and straw were significantly improved where RDN was applied in combination with seed inoculation, basal application of ZnSO4 and seed treatment with 1 g ammonium molybdate than their single applications. 相似文献
17.
C. Van Nieuwenhove R. Merckx Lieven Van Holm Karel Vlassak 《Biology and Fertility of Soils》2001,33(1):25-32
Azorhizobium caulinodans was directly inoculated onto rice plants in three short-term pot trials. Addition of increasing amounts of sucrose (23, 46,
92 kg ha–1) did not influence the N economy of the A. caulinodans-rice association during the early vegetative growth stage. A. caulinodans inoculation alone and in combination with the highest amount of sucrose had a significantly positive effect on the N balance,
with small but significant N gains in the system. Application of 60 kg urea-N ha–1 had a negative impact on the N economy of the inoculated treatments. N losses increased and the amount of atmospheric N2 fixed and incorporated decreased significantly as compared to the amounts under the 20 kg urea-N ha–1 regime. However, N losses were low – a maximum of 8% – at the early vegetative growth stage under the conditions of the experiments.
C limitation does not seem to be a limiting factor for the incorporation of fixed N2 in this bacteria-plant association. Biological N2 fixation caused by A. caulinodans inoculation was responsible for 14% of the plant N at the vegetative growth stage and under low N conditions.
Received: 30 January 2000 相似文献
18.
Abbas Biabani Lynne Carpenter-Boggs Clarice J. Coyne Lisa Taylor Jeffrey L. Smith Stewart Higgins 《Biology and Fertility of Soils》2011,47(6):679-685
Biological nitrogen fixation (BNF) is a sustainable alternative for nitrogen supply to agriculture worldwide. One approach
to increasing BNF in agriculture is to breed and use legumes with greater BNF capacity. To assess the capacity for BNF in
chickpea (Cicer arietinum) global germplasm, a genetically diverse subset from the USDA global chickpea core collection was assayed for BNF potential.
The greenhouse experiment assayed 39 global accessions and commercial cultivar UC-5, inoculated with Mesorhizobium ciceri. Plant height, branch number, nodule number, shoot weight, root weight, nodule weight, proportion of nitrogen fixed, and total
nitrogen fixation were determined. All characteristics varied significantly among the accessions. Proportion of plant nitrogen
fixed ranged from 47% to 78% and was correlated with shoot weight (r = 0.21, P < 0.01) and total plant weight (r = 0.20, P < 0.01), but not with nodule number or weight. Accession 254549 from Iraq produced the greatest total fixed nitrogen, more
than any other accession and 121% more than that fixed by UC-5. The variation among BNF capacities of the accessions supports
the preservation and use of global germplasm resources and suggests that nitrogen fixation in commercial chickpea varieties
may be improved by introgressing positive alleles from the global chickpea germplasm collections. 相似文献
19.
Summary A field experiment was condutced in a clay loam soil to study the performance of three Bradyrhizobium japonicum strains; USDA 110, USDA 138 and TAL 379, in relation to their N2-fixing potential and competitiveness on two soybean cultivars (Clark and Calland). Inoculation of soybean cultivars with these strains, either singly or in combination, induced significant increases in plant dry weight, N2 fixation and seed yields. However, no significant differences were found between the rhizobial strains and/or their mixtures in N2 fixation and increased seed yield for both cultivars. The two soybean cultivars gave similar responses to inoculation. No significant differences in seed yield were observed between Clark and Calland cultivars. The interaction between inoculant strain and soybean cultivar was not significant. The competition between strains for nodulation was assessed. Strain USDA 110 was the most competitive, followed by USDA 138. Strain TAL 379 was always less competitive on both cultivars. The incidence of double-strain occupancy of nodules varied from 8% to 40%. 相似文献
20.
Shammas K. O'Connell A. M. Grove T. S. McMurtrie R. Damon P. Rance S. J. 《Biology and Fertility of Soils》2003,38(4):228-235
Amounts of nutrients in harvest residues and their contribution to nutrient cycling were quantified following logging of a Eucalyptus globulus plantation in south-western Australia. An estimated 64 t ha–1 of leaf, bark and branch material less than 3 cm in diameter was deposited on the forest floor during harvesting. Leaves contributed about one-third of the residue dry weight but accounted for almost three-quarters of residue-N stores (299 of 428 kg N ha–1) and 36% to 52% of P, K, Ca, and Mg stores. Stores of nutrients in slash were significant in comparison to amounts in surface soil (0–20 cm). Residue-N amounted to 11% of total surface soil N and cations stored in residues were equivalent to 23–114% of surface soil exchangeable cations. Decomposition of the leaf fraction of slash was rapid with more than 90% of dry weight released during the 105-week study. Bark and branch fractions of diameters 0.5, 1 and 2 cm lost 39%, 37%, 32% and 29% of dry weight, respectively, during the same period. Single and double exponential decay models fitted to the data indicated half lives ranging from 20 weeks for leaves and from 3 to 4 years for bark and the branch fractions. During decomposition, K was leached rapidly from all residue fractions, Mg and P were released at similar rates to dry weight, and Ca and N were released more slowly than dry weight. In the 105-week study period, 250 kg ha–1 of N, 20 kg ha–1 of P, 213 kg ha–1 of Ca, 298 kg ha–1 of K, and 63 kg ha–1 of Mg were returned to the soil from decomposing harvest slash. The leaf fraction was the major contributor to nutrient cycling, accounting for almost all of the N and Ca release and from half to three-quarters of the K, Mg and P released. Amounts of nutrients released from residues in the year following logging greatly exceeded quantities likely to be taken up by the newly established tree crop. 相似文献