Pakistan has been constantly deficient in its oil seed production and it is very difficult to meet the edible oil requirement of its ever-increasing population. A field experiment was conducted at the Agronomy Research Farm, The University of Agriculture Peshawar, Northern Pakistan during winter (2013–14). Five sulphur levels (15, 30, 45, 60 and 75 kg·ha-1) and times of application (at seedling, bolting and flowering stages) were used for the canola variety Abasin-95. The experiment was laid out in a randomized complete block design replicated four times on a 5 m × 3.2 m plot size. The results showed that the sulphur-applied plots gave the highest seed yield, biological yield, glucosinolate, erucic acid, oil content, protein content, oleic acid and linoleic acid compared to the control plots. Sulphur applied at the rate of 60 kg·ha-1 and applied at the bolting stage increased seed yield, biological yield, oil content, and protein content.
Canola is an important oil seed crop of Cruciferae (Holmes,
The average yield of canola in Pakistan is very low (922 kg·ha-1) and its average yield in northern Pakistan is 452 kg·ha-1 (MNFS&R,
Fertilizers always play an important role in increasing many crop yields as a result of sufficient nutrition availability to the crops. Sulphur has prime importance in the synthesis of chlorophyll and oil in canola. It plays an important role in chemical composition as well as seed oil content (Hassan
Keeping in mind the importance of sulphur both for improving the seed production and oil quality of canola, the present research was aimed to assess the effects of sulphur nutrition levels and sulphur application timing on the yield and oil quality of canola in the calcareous soils of northern Pakistan.
In order to study the effect of sulphur nutrition levels and time of application on seed yield and oil quality of canola, an experiment was undertaken at the Agronomy Research Farm, The University of Agriculture Peshawar (2013–2014). The experiment consisted of five sulphur levels (S1= 15, S2 = 30, S3 = 45, S4 = 60, S5 = 75; kg·ha-1) and three different application times (AT1 = application at seedling growth stage, AT2 = application at bolting growth stage and AT3 = application at flowering growth stage). In addition, a control was maintained with each of the replicated treatments (no sulphur application was made). A randomized complete block design was used and replicated four times. Ammonium sulphate (NH4SO4) from the Fuji fertilizer private Ltd, Lahore, Pakistan was used as the source of sulphur. Canola seeds (Abasin-95) were provided by the Nuclear Institute for Food and Agriculture, Pakistan and sown in winter. 5 m × 3.2 m plots were made and replicated, consisting of 8 rows with 0.4 m row-to-row distance. Phosphorus (50 kg·ha-1) was applied during sowing in the form of single super phosphate, and nitrogen (75 kg·ha-1) was applied in the form of urea (half dose during sowing time and half dose during flowering stage) after subtracting the amount of nitrogen supplied through ammonium sulphate. After complete emergence, hand thinning was done at the four leaf stage, maintaining 50 plants per row. All other cultural practices, including irrigation, weeding and hoeing etc. were carried out uniformly in all the plots. An average soil analyses of the experimental site showed a sandy loam texture, pH (7.4), EC (0.204 dS·m-1), bulk density (1.52 g·cm-3), moisture (7.8%), organic matter (0.50 mg·kg-1), phosphorous (0.45 mg·kg-1) and low sulphur (0.035 mg·kg-1) at 0–15 cm depth. Mean maximum, minimum temperature (oC), humidity (%) and rainfall (mm) for the growing period of the canola crop are presented in
Mean minimum, maximum temperature (oC), humidity (%) and rainfall (mm) for the growing period of canola (2013–14).
Biological yield (kg·ha-1) was calculated after harvesting the four central rows in each of the replicated plots at harvest maturity of the canola crop, dried under sun light, weighed and converted in kg·ha-1.
To determine the glucosinolate (μ mol g-1), erucic acid (%), oil content (%), protein content (%), oliec acid (%) and linoliec acid (%) in the canola seed, a five (5) gram sample obtained from each treatment plot was analyzed by a Near Infra-red Reflectance Spectroscopy System, (TR-3657-C Model 6500) as described by Ahmad
The recorded data was statistically analyzed according to the analysis of variance techniques used for randomized complete block design and least significant difference (LSD) was applied at a 5% level of significance (P ≤ 0.05) upon significant F-test through the procedure described by Jan
During the growing season the temperature ranged from 11.8 ºC minimum to 25.8 ºC maximum (
Seed is the ultimate output of a crop which determines the profitability of the crop production enterprise. Sulphur levels and time of sulphur application had significant effects on the seed yield of canola and their interaction was found to be non significant (
Seed yield (kg·ha-1) and biological yield (kg·ha-1) of canola as affected by sulphur levels and application times
Application times (AT) | Seed yield (kg·ha-1) |
Biological yield (kg·ha-1) |
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---|---|---|---|---|---|---|---|---|---|---|---|---|
Sulphur (kg·ha-1) |
Sulphur (kg·ha-1) |
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15 | 30 | 45 | 60 | 75 | Mean | 15 | 30 | 45 | 60 | 75 | Mean | |
Seedling | 1318 | 1540 | 1979 | 2421 | 2278 | 1907b | 9363 | 9121 | 10600 | 11548 | 10788 | 10284 |
Bolting | 1469 | 1630 | 2023 | 2526 | 2342 | 1998a | 10198 | 10863 | 10025 | 11513 | 11850 | 10890 |
Flowering | 1340 | 1581 | 1974 | 2408 | 2306 | 1922b | 9796 | 10125 | 10713 | 11325 | 10788 | 10549 |
1376e | 1584d | 1992c | 2452a | 2309b | 9785b | 10036b | 10446ab | 11462a | 11142a | |||
Control | 1134 | Lsd | Sulphur | AT | SxAT | Control | 8469 | Lsd | Sulphur | AT | SxAT | |
Fertilized | 1942 | 0.05 | 35.67 | 27.63 | ns | Fertilized | 10574 | 0.05 | 1033 | ns | ns |
S=Sulphur, AT= Application times, SxAT= Sulphur x Application times, ns=non significant, Lsd=Least significant difference test
The data revealed that sulphur levels have a significant effect on the biological yield of canola (
The glucosinolate content of canola as influenced by various sulphur levels and application times is presented in
Glucosinolate (μmol·g-1) and erucic acid (%) of canola as affected by sulphur levels and application times
Application times (AT) | Glucosinolate (μmol·g-1) |
Erucic acid (%) |
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---|---|---|---|---|---|---|---|---|---|---|---|---|
Sulphur (kg·ha-1) |
Sulphur (kg·ha-1) |
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15 | 30 | 45 | 60 | 75 | Mean | 15 | 30 | 45 | 60 | 75 | Mean | |
Seedling | 19.7 | 23.6 | 25.5 | 25.5 | 29.8 | 24.8 | 1.3 | 1.4 | 1.5 | 1.7 | 2.1 | 1.6 |
Bolting | 20.0 | 23.8 | 23.8 | 25.5 | 31.3 | 24.9 | 1.3 | 1.5 | 1.5 | 1.6 | 2.1 | 1.6 |
Flowering | 19.5 | 23.4 | 23.3 | 24.2 | 32.4 | 24.6 | 1.4 | 1.5 | 1.6 | 1.6 | 2.1 | 1.6 |
19.7c | 23.6b | 24.2b | 25.1b | 31.2a | 1.3d | 1.4cd | 1.5bc | 1.6b | 2.1a | |||
Control | 18.9 | Lsd | Sulphur | AT | SxAT | Control | 1.2 | Lsd | Sulphur | AT | SxAT | |
Fertilized | 24.7 | 0.05 | 1.68 | ns | ns | Fertilized | 1.6 | 0.05 | 0.11 | ns | ns |
S=Sulphur, AT= Application times, SxAT= Sulphur x Application times, ns=non significant, Lsd=Least significant difference test
Means of same category followed by different alphabets reveal significant differences among mean values (P < 0.05) using least significant difference test.
Oil content (%) and protein content (%) of canola as affected by sulphur levels and application times
Application times (AT) | Oil content (%) |
Protein content (%) |
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---|---|---|---|---|---|---|---|---|---|---|---|---|
Sulphur (kg·ha-1) |
Sulphur (kg·ha-1) |
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15 | 30 | 45 | 60 | 75 | Mean | 15 | 30 | 45 | 60 | 75 | Mean | |
Seedling | 43.6 | 43.4 | 45.6 | 45.9 | 44.2 | 1907 b | 22.6 | 23.5 | 23.3 | 24.9 | 23.5 | 23.5 |
Bolting | 41.6 | 43.5 | 45.0 | 44.8 | 43.8 | 1998 a | 22.6 | 22.4 | 23.7 | 24.6 | 23.3 | 23.3 |
Flowering | 43.3 | 43.5 | 44.0 | 45.0 | 44.2 | 1922 b | 22.0 | 22.4 | 23.3 | 24.9 | 24.1 | 23.3 |
42.8c | 43.5bc | 44.8ab | 45.2a | 44.0abc | 22.4c | 22.8bc | 23.4bc | 24.8a | 23.6ab | |||
Control | 41.1 | Lsd | Sulphur | AT | SxAT | Control | 20.6 | Lsd | Sulphur | AT | SxAT | |
Fertilized | 44.1 | 0.05 | 1.45 | ns | ns | Fertilized | 23.4 | 0.05 | 1.22 | ns | ns |
S=Sulphur, AT= Application times, SxAT= Sulphur x Application times, ns=non significant, Lsd=Least significant difference test
The mean values for the data showed that sulphur application enhanced erucic acid (1.6%) compared to the control (1.2%). Significantly higher erucic acid (2.1%) was recorded for 75 kg sulphur·ha-1 (
The sulphur levels significantly affected the oil content in canola seeds (
The seed protein content (%) of canola is the basic parameter with respect to the quality. The statistical analysis of the data indicated that sulphur levels showed a positive influence on protein content (%) (
The data on the oleic acid (%) of canola as affected by sulphur levels, application timings and their interaction are given in
Oleic acid (%) and linoleic acid (%) of canola as affected by sulphur levels and application times
Application tmes (AT) | Oleic acid (%) |
Linoleic acid (%) |
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---|---|---|---|---|---|---|---|---|---|---|---|---|
Sulphur (kg·ha-1) |
Sulphur (kg·ha-1) |
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15 | 30 | 45 | 60 | 75 | Mean | 15 | 30 | 45 | 60 | 75 | Mean | |
Seedling | 54.33 | 56.40 | 55.63 | 55.05 | 56.20 | 55.52 | 10.7 | 10.6 | 10.4 | 10.5 | 10.4 | 10.5 |
Bolting | 55.90 | 55.40 | 56.08 | 56.38 | 56.78 | 56.11 | 10.3 | 10.5 | 10.6 | 10.9 | 10.5 | 10.5 |
Flowering | 55.48 | 54.85 | 56.38 | 56.98 | 55.55 | 55.85 | 9.9 | 10.1 | 10.8 | 10.9 | 10.3 | 10.4 |
55.23 | 55.55 | 56.03 | 56.13 | 56.18 | 10.3 | 10.4 | 10.6 | 10.8 | 10.4 | |||
Control | 52.65 | Lsd | Sulphur | AT | SxAT | Control | 9.5 | Lsd | Sulphur | AT | SxAT | |
Fertilized | 55.82 | 0.05 | ns | ns | ns | Fertilized | 10.5 | 0.05 | ns | ns | ns |
S=Sulphur, AT= Application times, SxAT= Sulphur x Application times, ns=non significant, Lsd=Least significant difference test
Means of same category followed by different alphabets reveal significant differences among mean values (P < 0.05) using least significant difference test.
Analysis of variance for seed yield (kg·ha-1), biological yield (kg·ha-1), glucosinolate (μmol·g-1), erucic acid (%), oil content (%), protein content (%), oleic acid (%), and linolec acid (%) of canola as affected by sulphur levels and application times
Source of variance | D.F. | Seed yield (kg·ha-1) | Biological yield (kg·ha-1) | Glucosinolate (μmol·g-1) | Erucic acid (%) | Oil content (%) | Protein content (%) | Oleic acid (%) | linoleic acid (%) |
---|---|---|---|---|---|---|---|---|---|
Rep | 3 | 1078.52 | 1745287.04 | 4.19 | 0.01 | 6.04 | 2.44 | 2.39 | 0.08 |
Treatments (T) | 15 | 847831.51 |
3518813.50 |
64.92 |
0.33 |
6.50 |
5.07 |
4.54 |
0.52 |
Control Vs Fertilized | (1) | 2450235.16 |
16611081.67 |
128.12 |
0.54 |
33.71 |
28.53 |
37.76 |
3.58 |
Sulphur Levels (S) | (4) | 2537405.12 |
6112988.54 |
204.12 |
1.06 |
11.46 |
10.29 |
2.05 |
0.42 |
Application timings (AT) | (2) | 47777.06 |
1843977.92 |
0.46 ns | 0.01 |
3.33 |
0.37 |
1.72 |
0.13 |
Sulphur x Application time | (8) | 2757.86 |
1003901.35 |
3.53 |
0.01 |
1.42 | 0.71 | 2.34 |
0.28 |
Error | 45 | 1881.54 | 1578991.76 | 4.20 | 0.02 | 3.11 | 2.20 | 1.84 | 0.25 |
Total | 63 |
= Significant at 5% level of probability
= Significant at 1% level of probability
= non significant, all parameter presents their sum of squares
Co-efficient of variance (C.V) for seed yield (kg·ha-1), biological yield (kg·ha-1), glucosinolate (μmol·g-1), erucic acid (%), oil content (%), protein content (%), oleic acid (%), and linoleic acid (%) of canola as affected by sulphur levels and application times
Parameters | Seed yield | Biological yield | Glucosinolate | Erucic acid | Oil content | Protein content | Oleic acid | Linoleic acid |
---|---|---|---|---|---|---|---|---|
2.29 | 12.03 | 8.40 | 8.65 | 2.44 | 6.38 | 2.44 | 4.83 |
Sulphur levels, time of application and their interaction have no significant effects on the linoliec acid of canola (
The application of sulphur at the rate of 60 kg·ha-1 produced higher yield and better oil quality in canola seeds. Sulphur application at the bolting stage produced a higher yield and oil components in canola seeds. It is recommended that sulphur be applied at the rate of 60 kg·ha-1 in the bolting stage to enhance the yield and oil quality of canola.
The research team are thankful to the Farm Director, The University of Agriculture Peshawar, for providing seeds and harvesting of the canola crop. The authors wish to thank the Nuclear Institute for Food & Agriculture, Peshawar for conducting the analyses.