The two-week rainy period in early May, without a doubt, caused nitrogen
losses. The million dollar question is: just how much nitrogen was lost, and how much needs to be added through side-dressing, to ensure proper vegetable crop growth and development?
It is critical to ensure that short season crops such a spinach,
lettuce etc. have adequate supplies of nitrogen in the early stages of
growth. In addition, crops with high fertility requirements such a cole
crops (cauliflower, broccoli, cabbage), and any fruiting crops fertilized and planted prior to rainy period, may need additional nitrogen to make up for the losses.
I am estimating that 25-40 kg of nitrogen per hectare may have been lost
from fields which received 80-100 kg of nitrogen prior to the wet period.
Growers should carefully observe crops and adjust side-dress rates to
make up for earlier nitrogen losses.
If you have any questions, please contact me.
Viliam
