Nitrogen (N) is easily
leached from the soil. If this happens, money is wasted and ground water may be
contaminated. Nitrogen applications should be timed to meet crop demands. Large
pre-plant broadcast N applications should be avoided. If needed, additional N
can be applied by topdressing, side-dressing or injection into a trickle
irrigation system.
Leafy greens, fruiting
vegetables and cole crops require larger amount of nutrients and in
general require additional Nitrogen to be applied. Heavy rainfall events may
cause leaching and on sandy soils 20-40 kg/N per hectare can be lost.
Nitrogen deficiency in collards
It is recommended that tissue samples be taken and sent for analysis to determine nutrient levels in the
plant tissue, so an adequate fertilizer regime can be established.
