Will drought reduce corn yield?

We are experiencing drought in many regions of the country. Will it affect yields?
How serious is water deficiency in corn?

Drought at a crucial moment

Drought affects most of the country, although the intensity of water shortages varies. However, any water deficit at this point is dangerous, among others: for corn. This one is at a key stage of its development, and now the fate of the crop is being decided.

In the period around flowering, corn's sensitivity to drought is greatest. At this stage, the highest water demand of plants is recorded. Up to 60 percent water demand occurs for a period of approximately 6 weeks (before, during and just after flowering). Generally, one corn plant needs 30 – 50 liters of water during the growing season. Most of which is used during flowering. If we take into account that the number of plants per square meter is, for example, 8, then the plants need up to 400 liters of water per square meter, most of which is during and around the flowering period.

Corn flowering is a key period for yield

Of course, corn will benefit from water reserves in the soil, if any. But things are different here, because this buffer was minimal in many locations. Below we present the climatic water balance for June, where significant deficits are noticeable in large parts of the country.

Climatic water balance for June. Source – IMGW.png

The next graphic shows the water balance for July. Deficiencies in the same area are also noticeable.

Climatic water balance for July – source IMGW.png

The corn will use up the supply, if there was one

In some locations, rainfall was low in May, as was the case in June and July. Unfortunately, in this weather pattern, a reduction in yield is certain. Corn did not have a supply of water to use during the crucial period of its development. Plantations may look much better where, despite low rainfall in July and the second half of June, there was a certain supply of water from May. There, the plants could use the water buffer. But this is also limited, and at some point such plantations also feel the effects of drought.

The lack of rainfall at this point will therefore reduce the yield, although the degree will vary. Some plantations are just starting to experience shortages, others already have a problem with a deep water deficit. Here again, the earliness of the variety and the sowing date are important. There is also an agrotechnical issue. Plants, e.g., fertilized with phosphorus, developed the root system faster in the initial stages. There are also varieties that manage water slightly better. There are more of these factors, but the availability of water will always be key.

However, the factor that has deepened the drought stress in recent days has been the heat, which may also disturb the flowering process.

Rain is needed now, and in significant amounts. However, if the plants have already experienced drought, a reduction in yield will be likely, although obviously lower. In most plantations, rainfall may still save the situation, although yield potential has already been reduced, especially on light soils and in locations where there was no water buffer before flowering began.