**3. Results and discussion**

#### **3.1 Effect of seed-row placed ammonium sulfate on brassicae emergence and early season biomass**

Generally, there was no significant difference in percent emergence up to 20-30 kg S ha -1 when ammonium sulfate was applied alone with the exception of *Camelina sativa. Camelina sativa* appeared more sensitive to AS placed in the seed-row than the *Brassica* crops (Table 3). At rates of 30 kg S ha-1, only *Invigor 5440* and *B. Juncea Dahinda* showed inhibition effect. When application rate approached 40 kg S ha-1, the majority of cultivars were affected. The cultivars *HEAR, 5525 Clearfield* and *74P00LL* were the least sensitive to seed-row placement of AS, possibly reflecting greater seed vigor. In general, percentage emergence that dropped below 80% was observed in some *Brassica* cultivars at rates of 30 kg S ha-1, and more so at the rates of 40 kg S ha-1 and above (Table 3).

High oleic, low linolenic (HOLL) (*v1037*; *v1040*) were also less sensitive to seed-row placement of AS; however, they were not as resistant as high erucic acid rapeseed (H.E.A.R). The number of days to first seedling emergence increased with increasing S rate. Time to seedling emergence from seeding was approximately 5-7 d. Emergence was generally 1 to 2 d longer in the high S rate treatments. There was a close relationship between seed size and seed coat color and a decrease in percent emergence, with the yellow-seeded and small seeded cultivars slightly more prone to reduced emergence with seed-placed AS. In most cases, the larger the seed size, the better the vigour. The more vigour, the better the seed/seedling is able to cope with early stresses and survive (Canada Canola Council 2005). High rates of AS reduced the seedling emergence, early seedling growth and increased the time to maximum emergence of seeds. There was an increase in the number of abnormal seedlings observed in the higher S treatments due to seedling injury, which can be attributed to the salt effect of the fertilizer playing a major role in this case (Follett et al., 1981).

Seedling biomass yield (mg / pot) at 14 days of growth was not significantly affected up to rates of 20 – 30 kg S ha-1 (Table 4). At higher rates in which significant emergence reduction was observed, seedling biomass was also reduced. As Hall (2007) indicated, canola is much more sensitive to seed-place fertilizer than corn or cereals.

#### **3.2 Effect of combinations of ammonium sulfate and monoammonium phosphate on emergence and early season biomass**

Addition of 15 to 30 kg P2O5 ha-1 along with the S application led to more injury represented by reduced seed germination/emergence and early growth of seedlings, than S alone at corresponding rates. Canola usually shows injury response to MAP alone at rates of 30 kg P2O5 ha-1 and higher (Qian and Schoenau 2010). However, decreases from addition of the


Numbers in a column followed by the same letter are not significantly different at P<0.05.

Table 3. Mean germination (percentage of unfertilized control) of *Brassica* species with seed-row applied AS and MAP.

Effect of Seed-Placed Ammonium Sulfate and Monoammonium Phosphate

on Germination, Emergence and Early Plant Biomass Production of Brassicae Oilseed Crops 59

Numbers in a column followed by the same letter are not significantly different at P<0.05.

and MAP.

Table 4. Mean plant tissue biomass (mg) of 12 oilseed cultivars with seed-row applied AS

Numbers in a column followed by the same letter are not significantly different at P<0.05.

seed-row applied AS and MAP.

Table 3. Mean germination (percentage of unfertilized control) of *Brassica* species with


Numbers in a column followed by the same letter are not significantly different at P<0.05.

Table 4. Mean plant tissue biomass (mg) of 12 oilseed cultivars with seed-row applied AS and MAP.

Effect of Seed-Placed Ammonium Sulfate and Monoammonium Phosphate

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Follett, R. H., Murphy, L. S., and Donahue, R. L. 1981. Fertilizers and soil amendments.

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Hall, B. 2007. Starter Fertilizers with Canola – Too Much of a Good Thing? Ontario Ministry

Harapiak, J. 2006. Maximizing seed and seed-row fertilizer benefits. Top Crop Manager (on-

http://www.topcropmanager.com/index.php?option=com\_content&task\_content

Jackson, G.D. 2000. Effects of N and S on canola yield and nutrient uptake. Agron. J. 92: 644-

Janzen, H. H., and Bettany, J. R. 1984. Sulfur nutrition of rapeseed: I. Influence of fertilizer

Karamanos, R. E., Goh, T. B., and Poisson, D. P. 2005. Nitrogen, phosphorous and sulfur

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Lauzon, J. D. and Miller, M. H. 1997. Comparative response of corn and soybean to seed-

Malhi, S.S., Gan, Y., and Rancey, J.P. 2007. Yield, Seed Quality, and Sulfur Uptake of Brassica Oilseed crops in Response to Sulfur Fertilization. Agron. J. 99:570-577. Miller, M.H., Bates, T. E., Singh, D., and Baweja, A. J.. 1971. Response of corn to small

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Efficiency Phosphorus Fertilizers on Canola Emergence, Yield, Maturity, and

MAP were typically smaller with the *B. napus* and *B. carinata*. The *B. rapa* and *B. juncea cv. Dahinda* appeared more sensitive to the addition of the P along with S. Among these, the *B. rapa cv. ACS- C7* was particular sensitive to P addition for both rates (15 and 30 kg P2O5 ha-1). When AS alone was used, the injury in this cultivar was observed at AS rate of 40 kg S ha-1; but the reduction of emergence with both rates of P addition was observed at AS rate of 10 kg S ha-1 (Table 3). For the two cultivars of *B. juncea*, the *Dahinda* cultivar was less tolerant to AS with MAP than *Xceed 8571* (Table 3). The seed sample from which the *Dahinda* was taken was two years old, which may have affected seed vigour and reduced germination. Seeds with lower vigour result in greater reduction in emergence (Canada Canola Council 2005).

Overall, while the high rate (30 kg P2O5 ha-1) sometimes reduced emergence and biomass production compared to the low rate (15 kg P2O5 ha-1), often the reductions were not large (Table 3) for most cultivars tested. This agrees with earlier findings that the adverse effect of MAP-P on seed germination and biomass of canola became pronounced at rates over 30 kg P2O5 ha-1 (Qian and Schoenau, 2010).
