Irrigation amounts different for corn and soybeans.

By Jeff Burbrink
Extension Educator Ag & Natural Resources, Purdue Extension LaGrange County

Jeff Burbrink

LAGRANGE — The latter three weeks of May were dry and warm in our area. The National Weather Service says Fort Wayne experienced the 75th driest month on record, and South Bend was the 23rd driest ever. Temperature wise, South Bend had the 41st warmest May on record, and Fort Wayne recorded the 34th warmest May.

On one hand, the dry weather was beneficial because it allowed people to plant crops and put up hay, but on the other hand, the newly planted crops are now searching for water. We are already seeing irrigation systems running to provide water to our thirsty crops, which is unusual for early June in northern Indiana.

For those who irrigate, monitoring newly emerged crops will be essential. It is important to add enough water to keep roots growing down into the moisture. Irrigation water applied at 0.5 to a 0.75 inch will wet dry soil down to 6 inches. An inch or 1.15 inches of water will wet the soil about 12 inches deep. If the crop roots can be found down to 6 inches deep already, it may be wise to irrigate deeper.

An inch of irrigation will often be needed in a field that has not received rainfall since the cover crop was destroyed. Crop crops have a lot of advantages, but when allowed to grow late into a dry planting season, they can remove a significant amount to water from the soil that the crop desperately needs later.

Lawns and gardens are also being affected by the dry weather. Many bluegrass lawns exposed to direct sunlight have already gone dormant (turned brown). Dormancy does not mean the grass is dead. Dormancy is how the turf protects itself from dry conditions. After three weeks of dormancy, the turf will begin to thin out. In 1988, we saw many lawns thin by as much as 30% when the rain started coming in August. A light irrigation of about one-half inch of water once every three weeks will help the crowns of the grass to stay alive.

If you have an irrigation system for your lawn, apply 1 to 1.5 inches of water in a single dose, and wait to reapply at the first sign of needing water. This is much healthier for the grass than setting the system to run every day. The length of time between sprinkling will vary by temperature and soil type, but can be 3 to 5 days in this type of weather. www.extension.purdue.edu/extmedia/ay/ay-7-w.pdf

For those with vegetable and flower gardens, the rule of thumb is to apply 1 to 1.5 inches of water in a single dose, and wait a few days to make the next application.

If you have a choice, watering in the morning is generally healthier for plants than watering in the evening. Many common plant diseases thrive best when the plants are wet for long periods of time. Watering in the evening often leaves plants wet for 12 hours or more, which encourages disease.