Recovery of field-grown canola from sulfur deficiency

1996 ◽  
Vol 36 (1) ◽  
pp. 79 ◽  
Author(s):  
PJ Hocking ◽  
A Pinkerton ◽  
A Good

Sulfate-sulfur was applied to sulfur (S)-deficient canola at several growth stages in a field experiment at Cargo near Orange, New South Wales. Applications of 0, 10 or 40 kg S/ha (S0, S10 and S40) as mixtures of potassium sulfate and potassium chloride were made at sowing, the 5-6 leaf rosette stage, flower buds visible, stem elongation and first flowering. The plots received either 80 or 160 kg nitrogen (N)/ha at sowing. Plants from the S0 plots showed symptoms of severe S deficiency during rapid stem elongation, and had a 52% reduction in seed yield and a 21% reduction in seed oil concentration compared with the S40 plants. Application of S10 at sowing, or topdressing S-deficient plants with this rate of S, was inadequate because, although seed oil concentrations were normal (39-42%), seed yields were 25% lower than those from plots that received S40. Topdressing S-deficient plants with S40 at either the 5-6 leaf rosette stage, flower buds visible or stem elongation resulted in the same seed yields and seed oil concentrations as obtained when S40 was applied at sowing. However, there was a 15% reduction in seed yield but no reduction in seed oil concentration when the S40 topdressing was delayed until flowering. Although S10 was inadequate to correct the S deficiency, there was no reduction in either seed yield or seed oil concentration when S10 was topdressed as late as flowering, when compared with this rate of S applied at sowing. Seed meal protein levels were increased by the S40 topdressings. Concentrations of S in seed from the S0 and S10 plants were below the critical value of 0.36% for canola. Seed N:S concentration ratios of S-deficient plants were greater than 10, but 7.5 for plants which received adequate S. Total glucosinolates in seed were increased by the application of S, but the levels were still well below the limit set for the canola standard.

2004 ◽  
Vol 84 (3) ◽  
pp. 791-793 ◽  
Author(s):  
H. T. Kunelius ◽  
K. B. McRae ◽  
G. H. Dürr ◽  
S. A. E. Fillmore

Seed production, plant characteristics and herbage regrowth of three cultivars of Westerwolds ryegrass (Lolium multiflorum Lam.) were determined during 3 production years. Ryegrass was fertilized with nitrogen at 60, 90 and 120 kg ha-1 applied either all at the two- to three-leaf stage or split (3:2) between the two- to three-leaf stage and stem elongation. Seed yield of three cultivars ranged from 742 to 1440 kg ha-1. Nitrogen fertilizer at 90 kg ha-1 resulted in near maximum seed yields. Single and split applications of nitrogen resulted in similar seed yields. Density of fertile tillers ranged from 541 to 911 m-2 among the cultivars and responded linearly to applied N. A positive relationship was detected between the density of fertile tillers and seed yield. Herbage in aftermath averaged 2280 kg ha-1 dry matter, 125 g kg-1 crude protein, 597 g kg-1 neutral detergent fibre and 344 g kg-1 acid detergent fibre. Key words: Lolium multiflorum, Westerwolds ryegrass, nitrogen fertilizer, seed, tiller, spikelet, herbage, herbage composition


1972 ◽  
Vol 78 (2) ◽  
pp. 179-182 ◽  
Author(s):  
S. Abu-Shakra ◽  
A. Bassiri

SUMMARYSoya beans grown on land planted the previous year with inoculated soya beans produced more nodules, lodging, seed yield, 1000 seed weight, and protein content and less seed oil concentration as compared to those grown on land that was planted with non-inoculated soya beans. Nitrogen fertilization (120kg N/ha) reduced the total number of nodules per plant. Increasing inoculation rates of the seed increased the dry weight of nodules per plant. Location, nitrogen fertilization, and inoculation increased or decreased the levels of certain amino acids but had no significant effect on the sulphur amino acids, cystine and methionine.


1995 ◽  
Vol 35 (6) ◽  
pp. 725 ◽  
Author(s):  
A Wallace ◽  
PM Evans ◽  
D Bowran

The ability of 2,2-dichloropropionic acid (2,2-DPA) to control annual grasses was examined in a 4-year-old medic (Medicago polymorpha var. brevispina cv. Circle Valley) pasture. Six rates of 2,2-DPA with and without spray adjuvants (1% spray oil + 0.25% wetting agent) were used: 0.37, 0.56, 0.74, 1.11, 1.48, 2.22 kg a.i./ha. The pasture was sprayed in July at the 4-true-leaf stage of the medic, after identifying and counting grasses and medics. Plants were counted again after spraying and grass seed heads were counted in spring. At the end of the season, medic seed yields were obtained. Nine annual pasture legumes were later evaluated for their tolerance to 2.22 kg 2,2-DPA/ha at 3 growth stages [post plant, pre-emergence (PPPE); 3-5-true-leaf stage; flowering] under weed-free conditions. A rate of 1.11 kg 2,2-DPAJha was found to reduce barley grass density by 85%. Efficacy was improved, however, with higher rates and/or the addition of spray adjuvants. Because of low silvergrass (Vulpia spp.) and ryegrass (Lolium rigidurn) plant numbers, it was not possible to assess whether 2,2-DPA controlled these species effectively. There was no effect of herbicide on medic seed yields, seed weight, seed number per pod, or seed germination. Medic seed yields were well correlated with plant density of medic but not with herbicide rates. There was a wide variation in biomass production of the 9 pasture legumes in the evaluation of tolerance, when assessed by visual rating and seed yield, with significant biomass and yield reductions at all timings of application of 2,2-DPA. Subterranean clover (Trifoliurn subterraneum L.) was the most severely affected. Generally, medic species tolerated 2,2-DPA well. Serena was the most susceptible medic cultivar at any treatment time, with seed yield reductions at the first 2 times of application. The results suggest that 2,2-DPA could be used safely on annual medics for the control of barley grass, and possibly other annual grasses.


1973 ◽  
Vol 53 (4) ◽  
pp. 811-815 ◽  
Author(s):  
G. S. SANDHA ◽  
B. E. TWAMLEY

Birdsfoot trefoil (Lotus corniculatus L.), cult Leo, was used as a base population for a recurrent selection program for seed yield. Objectives were: (1) improvement of seed yield, and (2) comparison of a genotypic and a geno-phenotypic method of selection. Two cycles were completed and evaluated. Seed yields for the genotypic and geno-phenotypic methods were 132 and 158%, respectively, of Leo after two cycles of selection. The geno-phenotypic method proved superior to the genotypic after each cycle. The broad sense heritability (61% for cycles 1 and 2), genotypic standard deviation, and genotypic coefficient of variability estimates (16.9 and 15.0% for cycles 1 and 2) indicated no reduction in genotypic variability with the geno-phenotypic method. However, the variability was practically exhausted with the genotypic method after cycle 2. Thus, further improvement with additional cycles of selection should be possible with the geno-phenotypic method but not with the genotypic method.


1978 ◽  
Vol 29 (4) ◽  
pp. 789
Author(s):  
WJ Collins

Swards of three strains of subterranean clover (Seaton Park, Yarloop, Midland B) were subjected to a range of defoliation treatments. In all strains, cutting at weekly intervals at a height of 1.5–2 cm from 1 month after sowing until the onset of flowering led to a slight delay in flower initiation but the time of flowering was little affected. The rate of inflorescence production, however, was always increased, as was the total number of inflorescences produced by the end of flowering. In particular, seed yields were increased by at least 30% compared with uncut controls. This effect was attributable partly to increased inflorescence numbers and partly to increases in other yield components as a consequence of the burial of a large proportion of burrs. Cutting increased the initial level of hard-seededness in Seaton Park and Yarloop; in addition the rate of breakdown of hard-seededness in all strains was slower in seed from the defoliated swards. When cutting was continued until midway through flowering (with the cutting height progressively raised) the seed yield in Yarloop and especially in Midland B was much lower than that obtained when cutting was stopped at the beginning of flowering; but in Seaton Park there was no reduction. With further cutting-until the end of flowering-seed yields were less than when cutting was stopped midway through flowering. Extending cutting into the flowering period (compared with cutting only until the onset of flowering) resulted in a decline in the initial level of hard-seededness and an increase in the rate of breakdown of hard-seededness in Midland B but had little effect in Yarloop or Seaton Park.


2018 ◽  
Vol 69 (12) ◽  
pp. 1251
Author(s):  
Fei Ni ◽  
Jiahuan Liu ◽  
Jing Zhang ◽  
Mohammad Nauman Khan ◽  
Tao Luo ◽  
...  

Soluble sugar content in silique wall and seeds of rapeseed (Brassica napus L.) has significant effects on seed oil formation and accumulation. We studied the relationship between soluble sugar content in B. napus seeds and silique wall and oil concentration under field conditions in two cropping seasons, and examined changes in soluble sugar content in seeds and silique wall under different nitrogen (N) levels. Two commercialised Chinese rapeseed varieties, HZ9 and HZ62, with high seed yield and different N responses were used. Our results indicated that carbon (C):N ratio and soluble sugar content in silique wall had the greater effect on seed oil concentration. When C:N ratio and soluble sugar content in silique wall were within 5–15% and 10–25%, respectively, plants had relatively well coordinated C and N metabolism, facilitating oil accumulation. During 25–35 days of silique development, when C:N ratio and soluble sugar content in silique wall were within 10–15 and 15–25%, respectively, oil synthesis was fastest; the highest accumulation rate was 3.8% per day. When they were each <5%, seeds tended to mature, and oil synthesis gradually decreased, ceased or degraded. During the early stage of silique development, if C:N ratio and soluble sugar content in silique wall were >15% and 30%, there was no apparent tendency for oil accumulation, probably because of adverse environmental conditions. When N application increased from 0 to 270kg ha–1, final oil concentration in seeds decreased by 0.024%. In summary, C:N ratio and soluble sugar content in silique wall are important in regulating seed oil concentration, whereas excessive N application significantly reduced seed oil concentration. Therefore, appropriate reduction of N application would save resources, provide environment benefits and increase rapeseed oil production with no substantial reduction in seed yield, through coordinated seed yield and oil concentration.


2003 ◽  
Vol 83 (4) ◽  
pp. 681-688 ◽  
Author(s):  
G. Lafond ◽  
C. Grant ◽  
A. Johnston ◽  
D. McAndrew ◽  
W. May

The major flax-growing areas of Canada coincide with areas where large shifts towards conservation tillage have occurred. These shifts have also brought about major changes in the way fertilizer is applied. The objective of this study was to determine the combination of nitrogen fertilizer form and N and P fertilizer placement methods that can increase N and P uptake, seed yield and seed oil concentration and composition in flax. The study was conducted at four locations covering the flax-growing areas over a 3-yr period. Three fertilizer forms, ammonium nitrate (AN), ammonium sulphate (AS) and urea were compared using different placement methods, pre-plant band (Pp) or side-band (Sb) in combination with monoammonium phosphate in either a Pp, Sb or seed-placed (Sp) position. Plant uptake of N and P was measured at 7, 14, 21 and 28 d after crop emergence and at the start of flowering. Other variables collected included crop establishment, crop yield and seed oil concentration and composition. AS resulted in the highest N uptake followed by AN then urea. As well, AS in the Sb showed higher N uptake than when applied Pp. The largest uptake of P was observed on days 7, 14 and 21 when AS and P were placed together in an Sb position. Crop establishment was adversely affected by urea and least by AN and AS, indicating that adequate seed-fertilizer separation between urea and flax seed is critical to minimizing reductions in plant stands. N form and placement, and P placement had no effect on seed oil concentration and composition in this study. Seed yield was improved marginally, overall, with the addition of P, while changes in N and P placement had no overall yield benefits. Treatments that resulted in improved N and P uptake in the first 21 d after crop emergence did not result in improved seed yields. When site × year interactions were investigated, 2 of 12 site years showed better yields when N and P were placed together in the Sb position. Based on the results of this study, we conclude that flax growers have many agronomically acceptable N and P management options available. Key words: Linum usitatissimum L., fertilizer placement, fertilizer form, nutrient uptake, seed yield, seed quality, oil quantity, urease inhibitor, Agrotain™


1978 ◽  
Vol 29 (4) ◽  
pp. 789
Author(s):  
WJ Collins

Swards of three strains of subterranean clover (Seaton Park, Yarloop, Midland B) were subjected to a range of defoliation treatments. In all strains, cutting at weekly intervals at a height of 1.5–2 cm from 1 month after sowing until the onset of flowering led to a slight delay in flower initiation but the time of flowering was little affected. The rate of inflorescence production, however, was always increased, as was the total number of inflorescences produced by the end of flowering. In particular, seed yields were increased by at least 30% compared with uncut controls. This effect was attributable partly to increased inflorescence numbers and partly to increases in other yield components as a consequence of the burial of a large proportion of burrs. Cutting increased the initial level of hard-seededness in Seaton Park and Yarloop; in addition the rate of breakdown of hard-seededness in all strains was slower in seed from the defoliated swards. When cutting was continued until midway through flowering (with the cutting height progressively raised) the seed yield in Yarloop and especially in Midland B was much lower than that obtained when cutting was stopped at the beginning of flowering; but in Seaton Park there was no reduction. With further cutting-until the end of flowering-seed yields were less than when cutting was stopped midway through flowering. Extending cutting into the flowering period (compared with cutting only until the onset of flowering) resulted in a decline in the initial level of hard-seededness and an increase in the rate of breakdown of hard-seededness in Midland B but had little effect in Yarloop or Seaton Park.


Sign in / Sign up

Export Citation Format

Share Document