Effect of Thiobacillus,sulfur, and phosphorus on the yield and nutrient uptake of canola and the chemical properties of calcareous soils in Iran

This factorial experiment consists of four levels of sulfur+Thiobacillus and three levels of triple superphosphate arranged in a completely randomized block design in three regions. With an increased sulfur+Thiobacillus and phosphorus (P), grain yield, phosphorus, iron (Fe), and zinc (Zn) uptake of canola increased in Qom and Mazandaran. Combined treatments of S₂₀₀₀T₄₀ and P_100% showed these properties most. In Safiabad, S₁₀₀₀T₂₀ resulted in a significant increase of P, Fe, and Zn uptake of canola, and no significant effect was found on the grain yield. The highest Fe and Zn concentrations in Qom soil was measured in S₂₀₀₀T₄₀. In Safiabad, maximum Fe concentration in soil was registered by S₁₀₀₀T₂₀ and P_65%. The minimum soil pH of Qom and Mazandaran was recorded by S₁₀₀₀T₂₀ and S₂₀₀₀T₄₀, respectively. The effect of sulfur and Thiobacillus on nutrients uptake and canola yield was good and indicates its potential for alleviating the impacts of calcareous soils.     

Role of Mycorrhiza in a Wheat–Flax versus Canola–Flax Rotation: A Case Study

Early-season growth of flax (Linum usitatissimum L.) was reduced in the field following canola (Brassica napus L.) compared to rotation with wheat (Triticum aestivum L.). This effect was associated with reduced formation of arbuscular mycorrhizae in flax caused by rotation with canola. Greater uptake of copper (Cu), phosphorus (P), and zinc (Zn) was seen for flax after wheat. Mycorrhizal stimulation of uptake of these elements likely relates to their immobility in soil. The ratio of biomass of flax after wheat to flax after canola was 1.6. Corresponding ratios of nutrient uptake were 1.5 to 1.8 for Cu, P, and Zn but were between 1.2 and 1.4 for macronutrients other than P. These data illustrate the importance of consideration of a range of nutrients for concentration, uptake, and ratios of uptake among treatments to evaluate the impact of arbuscular mycorrhizae. Rotation of flax after canola should be avoided.     

Bacterial inoculants for rice: effects on nutrient uptake and growth promotion

Beneficial soil bacteria are able to colonize plant root systems promoting plant growth and increasing crop yield and nutrient uptake through a variety of mechanisms. These bacteria can be an alternative to chemical fertilizers without productivity loss. The objectives of this study were to test bacterial inoculants for their ability to promote nutrient uptake and/or plant growth of rice plants subjected to different rates of chemical fertilizer, and to determine whether inoculants could be an alternative to nitrogen fertilizers. To test the interaction between putatively beneficial bacteria and rice plants, field experiments were conducted with two isolates: AC32 (Herbaspirillum sp.) and UR51 (Rhizobium sp.), and different nitrogen fertilization conditions (0%, 50%, and 100% of urea). Satisfactory results were obtained in relation to the nutrient uptake by plants inoculated with both isolates, principally when the recommended amount of nitrogen fertilizer was 50% reduced. These bacterial strains were unable to increase plant growth and grain yield when plants were subjected to the high level of fertilization. This study indicated that the tested inoculant formulations can provide essential nutrients to plants, especially when the levels of nitrogen fertilizers are reduced.     

有机肥施用模式对蔬菜产量、土壤化学性质及微生物的影响

在广州市蔬菜集约化种植区连续进行了6茬菜心试验,探讨有机肥施用模式[施无机肥(CK)、无机肥配施国产生物有机肥(BM)、无机肥配施腐殖酸(HA)、无机肥配合淋施复合芽孢杆菌剂(BSP)、无机肥配施腐殖酸并淋施复合芽孢杆菌剂(HA+BSP)、无机肥配施水沤腐熟鸡粪并淋施复合芽孢杆菌剂(CM+BSP)、无机肥配施复合芽孢杆菌剂堆沤腐熟鸡粪(BSPCM)]对蔬菜产量、土壤化学性质及微生物的影响。结果表明,不同茬别菜心产量差别较大。连续6茬试验中,CM+BSP处理菜心产量均为最高且显著高于CK处理,BSPCM处理菜心产量仅次于CM+BSP处理。BM、CM+BSP、BSPCM处理能提高土壤pH,降低连作土壤的酸化风险。随着种植茬数的增加,CM+BSP处理土壤细菌、真菌和微生物总数持续增加,显著高于原始土壤和其他施肥处理,BSPCM处理次之。CK处理土壤中细菌、真菌及微生物总量均比原始土壤下降。在连作菜地蔬菜生产中,在施用无机肥基础上配施适量水沤腐熟鸡粪,并在蔬菜生长过程中淋施复合芽孢杆菌剂,不但可提高蔬菜产量,而且具有培肥、活化和改良土壤生物质量的作用,有利于减轻蔬菜连作障碍,实现集约化蔬菜种植的可持续发展。     

Influence of phosphorus application on growth,yield and oil quality of linola

Influence of different phosphorus (P) sources on growth, yield and oil quality of linola was evaluated when randomized in complete block design using three replications. Treatments were control (No P), hydropriming, soil phosphorus (50 kg ha^?1), seed inoculation with phosphate solubilizing bacteria (PSB, Bacillus spp.) and seed priming with single super phosphate (2%) alone and combined with reduced soil phosphorus (25 kg P ha^?1). Among treatments, hydropriming and seed inoculation reduced seedling 50% and mean emergence time with highest emergence index, seedling fresh and dry weights and chlorophyll contents. Seed inoculation with soil P (25 kg ha^?1) produced highest seeds per capsule, 100-seed weight, seed and biological yield, harvest index. Maximum oil percentage, low protein contents and high cost benefit ratio with net economic returns were also found for seed inoculation combined with soil phosphorus. Nonetheless, soil phosphorus application can be reduced when seed inoculation with PSB is employed.     

Phosphate-solubilization activity of bacterial strains in soil and their effect on soybean growth under greenhouse conditions

The efficiency of 13 phosphate-solubilizing bacteria (PSB; four Burkholderia sp., five Enterobacter sp., and four Bradyrhizobium sp.) was assessed in a soil plate assay by evaluating soil phosphorus (P) availability. A commercial argentine strain, Pseudomonas fluorescens, was used for comparing solubilizing activity. Burkholderia sp. PER2F, Enterobacter sp. PER3G, and Bradyrhizobium sp. PER2H strains solubilized the largest quantities of P in the soil plate assay after 60 days as compared with the other strains, including the commercial one. The effect of PSB inoculation on growth and nutrient uptake of soybean plants was also studied under greenhouse conditions. Plants inoculated with Burkholderia sp. PER2F had the highest aerial height and showed an appropriate N/P ratio. However, none of the PSB increased P uptake by plants. This suggests that PSB inoculation does not necessarily improve P nutrition in soybean, nor was there any relationship between P availability in the soil plate assay and P content in the soybean shoot in the greenhouse. We concluded that the selection of efficient PSB strains as possible inoculation tools for P-deficient soils should focus on the integral interpretation of soil assays, greenhouse experiments, and field trials.     

Effects on yield and nutrition of mycorrhizal and nodulated Pueraria phaseoloides exerted by P-solubilizing rhizobacteria

We studied the effect of bacteria involved in rock phosphate (four isolates), iron phosphate (two isolates), and aluminium phosphate (two isolates) solubilization, and two phytate-mineralizing bacteria in terms of their interaction with two Glomus spp. on Pueraria phaseoloides growth and nutrition. The plant —Rhizobium sp. — mucorrhiza symbiosis system may increase in yield and nutrition in association with specific rhizosphere bacteria that solubilize calcium, iron, and aluminium phosphates. No benefit from phytate-mineralizing bacteria was found under these experimental conditions. P. phaseloides growth responses were influenced in different ways by specific combinations of the selected bacteria and arbuscular mycorrhizal fungi. Considerable stimulation of nutrient uptake was observed with fungus-bacteria combinations of Azospirillum sp. 1, Bacillus sp. 1 or Enterobacter (spp. 1 or 2) associated with G. mosseae. The fact that Bacillus sp. 1, a calcium-phosphate solubilizing isolate, positively interacted with G. mosseae and negatively with G. fasciculatum is an indication of specific functional compatibility between the biotic components integrated in the system. From our results, the interactions between bacterial groups able to solubilize specific phosphate and mycorrhizal fungi cannot be interpreted as occurring only via P solubilization mechanisms since no generalized effect was obtained. Iron-phosphate solubilizing microorganisms were more active alone than in dual associations with Glomus sp., but the aluminium-phosphate dissolving isolates positively interacted in mycorrhizal plants. Further work is needed in this area in order to elucidate the mechanisms that affect rhizosphere microorganism interactions. G. mosseae was more effective but less infective than G. fasciculatum in most of the combined treatments.     

Organic By-Product Effects on Soil Chemical Properties And Microbial Communities

Soil management practices that contribute to increased soil productivity and longterm sustainable agricultural production have been neglected over the last four decades. The need to increase soil productivity led to the evaluation of a system of disposing of large quantities of organic by-products and poultry litter on agricultural land. Our objectives were to evaluate the effects of applying noncomposted municipal solid waste (MSW), amended with either poultry litter (PL) or NH₄NO₃ to adjust C:N ratios in the soil surface in either the spring or fall. Changes in soil chemical properties, bacteria population shifts, changes in species richness and evenness of indigenous soil bacteria, and response by cotton (Gossypium hirsutum L.) were evaluated. Soil P, K, Ca, and Mg were increased in the surface 0–15 cm by a factor of three or four times by application of organic by-products. After two annual applications, soil Cu increased slightly, Zn doubled, Co and Cr decreased, while Pb increased by a factor of two. Soil organic matter content increased on average by 89 percent for treatments containing newsprint, yard trimmings, and cotton gin trash. Newsprint plus NH₄NO₃ resulted in a shift to more Gram positive bacteria, while newsprint plus poultry litter resulted in a shift to more Gram negative bacteria. Both N sources resulted in a reduction in Bacillus sp. Shifts in the bacterial populations and changes in species richness (number of species detected) and evenness (relative abundance of each species) were induced by organic by-product additions. These shifts appear to be the result of increased substrate for C mineralization rather than any properties of biological control. Shifts in the microbial community structure towards Gram negative organisms may benefit plant growth and may be useful as an indicator of soil quality.     

Improved Nutrient Uptake and Growth of Maize in Response to Inoculation with Thiobacillus and Mycorrhiza on an Alkaline Soil

Most plant nutrients are optimally available when soil pH is close to neutral. In this experiment the effects of Thiobacillus and Mycorrhiza on nutrient uptake and grain yield of maize were studied on an alkaline soil as a factorial experiment with randomized complete blocks design. Treatments consisted of Mycorrhiza fungi (M): inoculated (m₁) and noninoculated (m₀), Thiobacillus (T): inoculated (t₁) and noninoculated (t₀), and sulfur (S) (S₀, S₁: 250, and S₂: 500 kg ha^?1). Inoculation of Mycorrhiza, Thiobacillus, and S application decreased soil pH and increased grain yield and seed oil content. The lowest soil pH and the greatest S content were obtained from the combination of Thiobacillus and 500 kg ha^?1 S. Inoculation of Thiobacillus and S application significantly decreased root colonization. The greatest iron (Fe) content was in the combination of Mycorrhiza inoculation and 500 kg ha^?1 S. Grain P content significantly increased with Mycorrhiza inoculation and S application. The greatest grain yield obtained from combination of Thiobacillus with 500 kg ha^?1 S.     

Phosphorus Efficiency of Winter Canola Cultivars and Rhizosphere Properties in Rhizobox Technique

Production of oilseed crops requires balanced fertilization, while environmental problems of applied fertilizers must be considered. We evaluated seven winter canola cultivars (Brassica napus L.) for their relative efficiency to use or acquire phosphorus (P) under deficient and sufficient conditions. Average root mean diameter (RMD), total root length (RL) and root surface area (RA), of plants were measured as well as rhizosphere properties in rhizobox technique. Water-soluble P (WSP) and phosphatase activity of treatments containing plant were higher than control. WSP increased by 2.86 mg kg^?1 soil in Gabriela and 2.63 mg kg^?1 soil in Elvis at P deficient condition, compared to the control soil. The Olsen extractable P of the treatments decreased compared to control. Variations in total dry weights of cultivars were mainly explained by the differences in P solubilizing bacteria (PSB) population, pH, and phosphatase activity. The responsible mechanism for the P efficient (PE) cultivars can be higher P uptake through larger root and changes in rhizosphere properties.     

Maize grain production,plant nutrient concentration and soil chemical properties in response to different residue levels from two previous crops

ABSTRACT

The incorporation of previous crop residues in agricultural management benefits soil fertility, crop production, and environment. However, there is no enough information about maximum residue application level without negative effect over next crop yield. To evaluate maize (Zea mays L.) yield under short-time conservation management with incorporation and/or importation of different residue levels, a biannual rotation experiment was conducted in ash volcanic soil in south-central Chile. The experiment consisted of two previous crops, canola (Brassica napus L.) and bean (Phaseolus vulgaris L.), and four levels of residue incorporation (0%, 50%, 100%, and 200% of generated residue; from 0 to 21.4?Mg?ha^?1 for canola and from 0 to 19.0?Mg?ha^?1 for bean). Previous crop species and residue level affected some nutrients concentrations in grain and plant and some soil chemical properties, without effect in maize yield, which averaged 16.6?Mg?ha^?1. Bean residue increased Ca and reduced S in maize plant, increasing soil P, Ca, Mg and K (P?<?0.05). Maize grain Ca content was positively and proportionally affected by canola residue level and negatively and proportionally affected by bean residue level. All canola residue levels increased soil pH and Mg, but the highest level reduced soil S; soil P concentration increased proportionally with bean residue level. The highest bean residue level increased soil S. Different crop and levels of residue did not affect maize yield but did some plant nutrient concentration, and also affected some soil chemical properties.     

Inoculating wheat seedlings with exopolysaccharide-producing bacteria restricts sodium uptake and stimulates plant growth under salt stress

A pot experiment was conducted to elucidate the effects of inoculating five exopolysaccharide- (EPS-) producing bacterial strains on the dry matter yield and the uptake of K⁺, Na⁺, and Ca²⁺ by wheat seedlings grown in a moderately saline soil. The bacteria were isolated from the rhizosphere soil (RS) of wheat grown in a salt-affected soil and included Aeromonas hydrophila/caviae (strain MAS-765), Bacillus insolitus (strain MAS17), and Bacillus sp. (strains MAS617, MAS620 and MAS820). The inoculation substantially increased the dry matter yield of roots (149–527% increase) and shoots (85–281% increase), and the mass of RS (176–790% increase). All the strains, except MAS617, also increased the RS mass/root mass ratio as well as the population density of EPS bacteria on the rhizoplane, and both these parameters were significantly correlated with the content of water-insoluble saccharides in the RS. Inoculation restricted Na⁺ uptake by roots, which was not attributable to the binding of Na⁺ by the RS, or to the ameliorative effects of Ca²⁺ under salinity. The decreased Na⁺ uptake by roots of inoculated than uninoculated plants was probably caused by a reduced passive (apoplasmic) flow of Na⁺ into the stele due to the higher proportion of the root zones covered with soil sheaths in inoculated treatments. Among the strains tested, MAS820 was the most efficient in all respects, whereas MAS617 was the least effective. Results suggested that inoculating selected EPS-producing bacteria could serve as a useful tool for alleviating salinity stress in salt-sensitive plants.     

接种食细菌线虫对小麦生长和N、P吸收的影响

A 40-day gnotobiotic microcosm experiment was carried out to quantify the effect of bacterial-feeding nematode on plant growth and nutrient absorption. The results showed that inoculation of bacterial-feeding nematode Protorhabditis sp. stimulated the growth of wheat (Triticum aestivum) and the uptake of N. By the end of the 40-day incubation wheat biomass and N uptake in the treatment with nematode and bacteria (Pseudomonas sp.) increased by 6.5% and 5.9%, respectively, compared with bacteria alone treatment. The presence of nematode mainly accelerated the growth of aboveground of wheat, while it slightly inhibited the root development. There was little difference in plant tissue N concentration between treatments. P concentration and uptake of wheat, however, were generally reduced by nematode. It appears that the enhancement of plant growth and nitrogen uptake is attributed to the enhancement of nitrogen mineralization induced by nematode feeding on bacteria, and the reduction of phosphorous uptake is the result of weak root status and competition by bacteria immobilization.     

Influence of Spent Mushroom Compost (SMC) as an Organic Fertilizer on Nutrient,Growth, Yield,and Essential Oil Composition of German Chamomile (Matricaria Recutita L.)

To investigate the effect of Spent Mushroom Compost (SMC) as an organic fertilizer on German chamomile (Matricaria recutita L.) nutrient, growth, yield, essential oil and osmolytes a greenhouse experiment was conducted through a randomized complete design in six replications. A mixture of sandy loam soil with 5, 10 and 15% volume rates of spent mushroom compost was used as the partial substrate for German chamomile pot culture. Finding of results revealed that usage of SMC in the growing media increased significantly plant growth, flower yield, essential macro nutrient uptake, sodium concentration, proline and soluble sugars content as well as essential oil percentages in compared to control. Comparison between the treatments indicated that addition of 10% SMC to the plant soil substrate cause to higher growth and addition of higher rates of SMC (10% and 15%) led to better yield. The obtained results showed that absorption of K and Na enhanced significantly by increasing of SMC percentage in growing media but there was no significant difference in N and P uptake in SMC treatments. The results of GC and GC-MS analysis presented that the main compositions of essential oil extracted from German chamomile flowers accounted for 83.99–99.84% of total essential oil in SMC treatments. Regarding important role of SMC on the essential oil yield, we can consider SMC could be a suitable substitute for chemical fertilizers as environmentally friendly material in cultivation medicinal plant German chamomile.     

Root-associated bacteria containing 1-aminocyclopropane-1-carboxylate deaminase improve growth and nutrient uptake by pea genotypes cultivated in cadmium supplemented soil

The effect of inoculation with Pseudomonas brassicacearum Am3, Pseudomonas marginalis Dp1 and Rhodococcus sp. Fp2 containing 1-aminocyclopropane-1-carboxylate deaminase (ACCD) on growth and uptake of N, P, K, Ca, S, Fe and Cd in shoots of pea (Pisum sativum) genotypes VIR188, VIR1658, VIR3429 and VIR4488 was studied in pot experiment with non-polluted and Cd-supplemented (10 mg Cd kg⁻¹) sod-podzolic soil. The growth-promoting effect of bacteria depended on plant genotype and bacterial strain. Only Rhodococcus sp. Fp2 had no ACCD activity in vitro in the presence of Cd and did not stimulate pea growth in Cd-supplemented soil. Inoculation with bacteria counteracted the Cd-induced inhibition of nutrient uptake by plants probably through stimulation of root growth and enhancement of nutrient uptake processes. Nutritional effects of the bacteria were specific with respect to the nutrient.     

Improving of seed quality of black seed (Nigella sativa L.) by increasing seed phosphorus content in a calcareous soil

Phosphorus (P) sufficiency during seed formation and development can affect the quality of seeds production. For increasing P content of black seed (Nigella sativa) in a calcareous soil, series of experiments were conducted in completely randomized factorial design with 4 replications at the Faculty of Agriculture, Ferdowsi University of Mashhad, Iran, in 2012 and 2013. The combinations of vermicompost (V), sulfur (S), and Thiobacillus bacteria (T) were mixed with a calcareous soil fertilized with 0, 30 and 60 kg P ha^?1 in pots and incubated for 63 days. At the end of incubation period, black seeds were sown in the pots and plants were grown to maturity. Results showed that S+T and V treatments were significantly increased soil available P, emergence, plant P content, seed yield and vigor of the seeds production. There were positive relationship between soil and plant P concentration with the quality of seeds production.     

Effect of Vermicompost and Chemical Fertilizer on Growth,Herb, Oil Yield,Nutrient Uptake,Soil Fertility,and Oil Quality of Rosemary

Essential oil of rosemary (Rosmarinus officinalis L.) possesses good olfactory properties and is suitable for use in perfumes, soaps, and fragrances. Field experiments were conducted for 2 years (2003?2005) in an area experiencing a semi-arid tropical climate to study the influence of vermicompost and chemical fertilizer on growth, herb, oil yield, nutrient uptake, soil fertility, and oil quality of rosemary. Results from the experiment revealed that among the seven treatments, the application of vermicompost (8 t ha^?1) + fertilizer nitrogen (N)?phosphorus (P)??potassium (K) (150:25:25 kg ha^?1) produced optimum herbage and oil yield of rosemary compared with control (no fertilizer) and was found to be on par with application of fertilizer NPK 300:50:50 kg ha^?1. Content and quality of oil were not influenced by vermicompost and chemical fertilizers. Furthermore, it was noticed that available N and P were greater in postharvest soils that received vermicompost alone or in combination with inorganic fertilizers than control (no fertilizer) and inorganic fertilizer?treated soil. This study indicates that combined application of vermicompost and chemical fertilizer helps to increase crop productivity and sustain the soil fertility.     

Effects of soil compaction and arbuscular mycorrhiza on corn (Zea mays L.) nutrient uptake

Soil compaction is of great importance, due to its adverse effects on plant growth and the environment. Mechanical methods to control soil compaction may not be economically and environmentally friendly. Hence, we designed experiments to test the hypothesis that use of plant symbiotic fungi, arbuscular mycorrhiza (AM) may alleviate the stressful effects of soil compaction on corn (Zea mays L.) growth through enhancing nutrient uptake. AM continuously interact with other soil microorganisms and its original diversity may also be important in determining the ability of the fungi to cope with the stresses. Hence, the objectives were: (1) to determine the effects of soil compaction on corn nutrient uptake in unsterilized (S1) and sterilized (S2) soils, and (2) to determine if inoculation of corn with different species of AM with different origins can enhance corn nutrient uptake in a compacted soil. Using 2 kg weights, soils (from the field topsoil) of 10 kg pots were compacted at three and four levels (C1, C2, C3 and C4) (C1 = non-compacted control) in the first and second experiment, respectively. Corn (cv. 704) seeds were planted in each pot and were inoculated with different AM treatments including control (M1), Iranian Glomus mosseae (M2), Iranian G. etunicatum (M3), and Canadian G. mosseae, received from GINCO (Glomales In Vitro Collection), Canada (M4). Corn leaf nutrient uptake of N, P, K, Fe, Mn, Zn and Cu were determined. Higher levels of compaction reduced corn nutrient uptake, however different species of AM and soil sterilization significantly increased it. The highest increase in nutrient uptake was related to P (60%) and Fe (58%) due to treatment M4S2C3. Although it seems that M3 and M4 may be the most effective species on corn nutrient uptake in a compacted soil, M2 increased nutrient uptake under conditions (C3 and C4 in unsterilized soil) where the other species did not. Through increasing nutrient uptake AM can alleviate the stressful effects of soil compaction on corn growth.     

Trophic interactions between rhizosphere bacteria and bacterial feeders influenced by phosphate and aphids in barley

The aim was to study the effects of P fertilization and leaf aphid attack on the trophic interactions of bacteria and bacterial feeders in the rhizospheres of barley plants. The density of protozoa peaked in the rhizospheres of plants fertilized with N and P, whereas nematodes peaked in the rhizospheres of plants to which only N had been added. Fingerprinting of bacterial communities by length heterogeneity polymerase chain reaction revealed differences in community structure between NP rhizospheres and N rhizospheres as well as aphid-related differences within N rhizospheres. Specifically, α-proteobacteria increased with P addition. To evaluate if differences in bacteria in terms of their quality as food could partly explain the observed differences in protozoan and nematode abundances, growth of the flagellate Cercomonas sp. was assessed with 935 bacteria isolated from the different treatments. This assay indicated that bacterial isolates were of higher food quality to Cercomonas sp. in NP than in N rhizospheres when plants were subjected to aphid attack. Bacteria of high and low food quality for Cercomonas sp., respectively, were fed to the nematode Caenorhabditis elegans and larval production examined. α-Proteobacteria supported the growth of Cercomonas sp. well, whereas Actinobacteria did not. In contrast, C. elegans reproduced poorly on most α-proteobacteria but were able to reproduce well on some Actinobacteria. These results suggest that the different response of protozoa and nematodes to P addition could be mediated through a food quality-related change in community composition of bacteria and that leaf aphid attack may interfere with nutrient effects on bacterial assemblages of rhizospheres.     

Uptake and nutrient balance of nitrogen,sulfur, and boron for optimal canola production in eastern Canada

Balanced plant nutrition is essential to achieve high yields of canola (Brassica napus L.) and get the best economic return from applied fertilizers. A field study was conducted at nine site‐years across eastern Canada to investigate the effects of nitrogen (N), sulfur (S) and boron (B) fertilization on canola nutrient uptake, nutrient balance, and their relationship to canola yields. The factorial experiment consisted of four N rates of 0 (N0), 50 (N50), 100 (N100), and 150 (N150) kg ha^?1, two S rates of 0 (S0) and 20 (S20) kg ha^?1, and three B treatments of 0 (B0), 2 kg ha^?1 at preplant (B2.0P), and 0.5 kg B ha^?1 foliar‐applied at early flowering stage (B0.5F). Each site‐year used the same experimental design and assigned treatments in a randomized complete block design with four replications. Fertilizer S application greatly improved seed yields at six out of nine site‐years, and the highest N use efficiency was in the N150+S20 treatment. Sulfur application generally increased seed S concentration, seed S removal, and plant total S uptake, while B fertilization mainly elevated straw B concentration and content, with minimal effect on seed yields. At the early flowering stage, plant tissue S ranged from 2.2 to 6.6 mg S g^?1, but the N : S ratio was over or close to the critical value of 12 in the N150+S0 combination at five site‐years. On average across nine site‐years, canola reached a plateau yield of 3580 kg ha^?1 when plants contained 197 kg N ha^?1, 33 kg S ha^?1 and 200 g B ha^?1, with a seed B content of 60 g B ha^?1. The critical N, S, and B values identified in this work and their potential for a posteriori nutrient diagnosis of canola should be useful to validate fertilizer requirements for canola production in eastern Canada.