WITH THE CLIMATE becoming warmer, no-tillers are in a much better position to turn limited amounts of rainfall into higher yields than neighbors who are still using intensive tillage. By keeping the soil covered with crop residue and with the additional benefits of cover crops, no-tillers are retaining much more water in their fields.

Organic Matter Benefits 

Jim Hoorman points out that the amount of water your soils can hold is highly dependent on both soil organic matter and soil texture, both of which improve with no-till. 

The owner of Hoorman Soil Health Services in Jenera, Ohio, says the improvement in bulk density that growers normally see in no-tilled soils dramatically increases water storage, especially since about 50% of the volume in an ideal soil consists of pore space where water is stored. Under an intensive tillage situation, pore space in a compacted soil may decrease by 20-30% and hold much less water. With serious hard pan issues in tilled fields, plant roots may not be able to access most of the available water in a soil.

“Increasing the amount of soil organic matter such as is the case with no-till improves the soil structure to allow more water to be stored and accessed by plant roots,” says Hoorman. “Increasing the soil organic matter in your fields comes from growing live roots year-round, as is the case with no-till and cover crops. Simply seeding a cover crop may take out as much as 1 foot of soil compaction per year and add up to 0.25% soil organic matter per year.”

Soil Temp vs. Water Needs

To produce 200-bushel corn yields, Elwyn Taylor says you need 19-23 inches of water during the growing season. The Iowa State University ag weather expert says a corn plant’s water needs double for every 10 degrees F increase in soil temperature during the growing season. 

At a soil temperature of 75 degrees F, corn needs one-acre inch of water per week, which increases to 4 inches per week once the soil temperature reaches 95 degrees F. These high soil temperatures often occur in tilled fields when soils have no protective cover, resulting in a negative impact on water needs, microbial populations and even nutrient cycling.

Covering the ground with residue and creating a good crop canopy dramatically reduces soil temperatures. Along with better soil structure, finding ways to store more water in our no-tilled soils is going to be critical as we tackle climate change concerns.