Agronomy Library > Soil Conservation

Saving Spring Soil Moisture - Making the Most of Standing Stubble
Author: Rick Taillieu, Reduced Tillage LINKAGES
Date Created: July 24, 2002
Last Reviewed: February 21, 2007

Key things a farmer needs to know about saving spring soil moisture:

- Every tillage pass contributes to losses in soil moisture. 
- Unprotected soil is more susceptible to moisture losses caused by combinations of warm air temperatures, radiant heat and wind speed at the soil surface. 
- Undisturbed land has dramatically greater water infiltration rates and is therefore better able to take advantage of spring rains and save the moisture.
 
The relationship between standing stubble and saving spring soil moisture 
- Last year’s anchored stubble acts a series of “shelterbelts” and significantly reduces the wind speed at the soil surface. This not only protects soil moisture before seeding, but also reduces seedbed drying after direct seeding. 
- Standing stubble provides a shading effect on the soil surface, which can further protect soil moisture from evaporation caused by direct sunlight. 
- Below the surface, anchored stubble has undisturbed infiltration pathways created by the decomposition of the plant roots. These small channels allow the soil profile to better absorb water after a significant spring rainfall event. 
- After crop emergence, standing stubble protects new seedlings from the wind, which may help to further reduce moisture losses from evapotranspiration in addition to providing protection from blowing soil. 
- Standing stubble significantly reduces the risk associated with pre-emergent rolling which is a major cause of spring soil erosion resulting in soil moisture losses. 

How to Save your Stubble in the Spring 
- Reduce your tillage operations. Remember every pass destroys stubble and costs you moisture. If possible, fertilize and seed in a single pass. If fertilizer application requires a separate operation, consider a narrow opener to minimize soil disturbance. 
- Reduce your tillage intensity. Using smaller openers and/or wider row spacing will reduce your Seed Bed Utilization (SBU). The less of the seedbed you disturb, the more stubble you will leave anchored and standing. 
- Use on-row packing. This will help ensure a good seedbed and eliminate the need to harrow after seeding. A harrowing operation will dislodge and knock down stubble thus reducing its effectiveness in reducing wind speed. 
- Fine tune your seeding system. Seeding in the same direction as last years stubble rows generally saves the stubble and is easier to seed through. If you are able to “seed between the rows”, you will realize the greatest benefits from your stubble. Seeding perpendicular to the prevailing winds will help ensure that next year’s stubble is best able to protect your land. 

So the point is?
The more you reduce soil disturbance – the more standing stubble you save. The combination of these will help conserve spring soil moisture, both before and after seeding. The challenge for all direct seeders is to maximize the benefits of the stubble from last year’s crops to help ensure the following crop’s success, starting with germination.