Corn, unlike winter and spring cereals, has not yet experienced drought. Now, however, it will need a lot of water – the plantations sown in April will be entering key development stages.
- Up to 60 percent of corn’s water requirement falls on the period yet to come on plantations.
- Lack of water supply even before flowering will affect the yield.
The water requirement of corn is not that great, but there must be a lot of water in a short time
If water shortages occur in the period before flowering, the growth of both plants and cobs is inhibited. However, if there is a lack of water during flowering, uneven pollination occurs. In the period just after flowering, the assimilates accumulated in the plant will be transferred to the cob to a limited extent. Therefore, the greatest water demand of plants is not only associated with the flowering period, but generally – in the case of corn – concerns the entire period around flowering. Of course, in the case of an earlier drought, losses will also be recorded, but it is just before, during and after flowering that the most severe ones are.
It is estimated that just one corn plant needs at least 30 – 50 liters of water during its vegetation. Theoretically not much, right? However, for example, with a planting density of 80,000 plants/ha, we have 8 plants per square meter. It then turns out that during the vegetation period, between 240 and 400 liters of water should be available at each meter (preferably closer to these upper values). This example shows how important the density of corn sowing is. At a planting density of e.g. 70,000/ha, the water demand for each square meter will range from 210 to 350 l/sq m, while at 90,000 per meter, the plants will have to absorb 270 – 450 liters of water.
From the 10-leaf stage, corn’s increased demand for water begins
While in the period from sowing, emergence to topping out, the water requirement of one plant does not exceed 20 liters, from the time of topping out we are talking about 30 liters for each plant. So 60 percent of corn’s water needs occur around flowering. During this time, the water demand for each meter of corn is 160 – 240 liters per square meter (with a planting density of 80,000 plants/ha). Let us add that this amount of water should appear in a total period of about 6 weeks. We are talking about the time when the corn has already developed 10 leaves, i.e. before flowering begins, during flowering and for about 20 days after flowering ends. This is a crucial period. Good conditions for plant development are important earlier, but now you can forget about them – the coming weeks will be crucial for yielding, when the yield will be shaped. If there is no water, we will lose the crop. At high temperatures and a lack of water, the situation is the worst, because in extreme cases the cob may not even form (the corn is then said to have “cooked”).
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