Weeds Weeds compete with canola for moisture and nutrients. Applied nitrogen fertilizer may stimulate the growth of wild oat seedlings almost as much as it does that of canola, so be prepared to control wild oats. The higher rates of nitrogen recommended will usually not be profitable when weed competition is severe. Placing the fertilizer with the seed where only small amounts are required, or in a band near the seed, or in deep-bands, makes it less accessible to weeds during the early growing season. The maximum response to nitrogen fertilizer cannot be obtained when other essential nutrients are not in good supply.
Nutrient balance is extremely important to canola.
This has been observed in the relationships between nitrogen and phosphorus and also between nitrogen and sulphur. For example, in the case of soils deficient in both nitrogen and sulphur, application of nitrogen only may actually cause a reduction in yield as a result of nutrient imbalances within the plant. Excessive quantities of nitrogen, under some conditions, prolong the growing period and delay crop maturity. This effect can be partly overcome by applying sufficient phosphorus and potassium. Lodging Lodging usually is caused by a combination of excess nitrogen fertilizer or available nitrogen in the soil and excess soil moisture.