Questions often arise among no-tillers concerning the best height at which to leave small grain stubble. At the Semiarid Prairie Agricultural Research Centre at Swift Current, Saskatchewan, Canada, researchers set out to find answers by no-tilling four spring crops into three residue combinations.

Four Crops, Four Stubbles

They no-tilled spring wheat, lentils, field peas and chickpeas into cultivated stubble, 6- to 7-inch spring wheat stubble and 10- to 16-inch-tall spring wheat stubble. The plots were left in place over the winter to equalize snow trapping effects.

“Standing stubble changed the microclimate near the soil surface by reducing soil temperatures, solar radiation, wind speed and potential evapotranspiration,” says researcher Brian McConkey. “Standing stubble effects on microclimate continued well beyond the time when taller crops grew above the stubble. These effects were more pronounced for tall vs. short stubble.”

The researchers found the four crops grew 2 to 3 inches higher with the tall stubble. Even the lowest pod height was still as much as 3 inches higher with the tall stubble than with the cultivated stubble.

McConkey says crop water-use efficiency increases as stubble height rises. The only exception was with chickpeas where both yield and crop water usage appeared to decline in tall stubble. This may be due to shading effects on the relatively small chickpea canopy that never grew past the height of the tall stubble.

Compared with cultivated stubble, yield results were as follows:

• Spring wheat—6 percent higher for short stubble and 12 percent more for tall…