On Farm: Exploring the Impact of Low vs High Stubble Heights

Term: 2 years
Status: Ongoing
Researcher(s): Kayla Slind, WARC; Danny Petty, IHARF
SaskOilseeds Investment: $6,720.00
Total Project Cost: $13,440.00
Funding Partners: Sask Wheat

Objective

To evaluate the effects of different stubble heights on various factors, with a primary focus on snow catch, soil moisture, and soil temperature.

1. Measure snow catch and water retention at different stubble heights, particularly in regions where snow accumulation is an important moisture source.

2. Quantify soil moisture levels and assess whether taller stubble leads to improved moisture conservation through better residue cover and reduced evaporation.

3. Examine the effect of different stubble heights on soil erosion (wind and water) and assess whether taller stubble provides better soil protection through improved soil armor and reduced wind erosion.

Project Description

A study by Schlegel, conducted from 2006 to 2020 at Kansas State University, investigated the impact of wheat stubble height on the yields of corn and grain sorghum, as well as soil water, crop water use, and precipitation storage efficiency in a wheat-corn/sorghum-fallow system. The results revealed that high and stripper-harvested wheat stubble provided a 9%–10% yield advantage for corn and a 5% advantage for sorghum compared to low cut stubble, with enhanced water productivity observed in the higher stubble treatments. The study concluded that low cut wheat stubble reduced crop yields, with high cut stubble offering the most significant benefits for both crops in terms of water availability and yield.

In a similar vein, a 2021 study by Schillinger, conducted over four years in a dry Mediterranean climate, assessed the effects of wheat stubble height on overwinter precipitation capture and soil water retention during 13-month fallow periods. Tall (75 cm) and medium (25 cm) stubble captured more overwinter precipitation and retained more soil water compared to short (8 cm) stubble, with the largest differences occurring during winters with drifting snow. The study concluded that medium-height stubble was most effective for precipitation capture and soil water retention, making it the best fallow option for wheat farmers in the US Pacific Northwest drylands.

In 2015, Hu examined how row spacing and stubble height impacted soil water content, water use, yield, and water use efficiency in canola and wheat in the drier regions of the Canadian prairies. While wider row spacing and taller stubble generally increased surface soil water content, the study found minimal effects on water use for both crops, with no significant interactions between row spacing and stubble height for water use, yield, or water use efficiency. However, 30-cm row spacing and 30-cm stubble typically improved surface soil water content, yield, and water use efficiency across most crop types and locations.

A 1993 study conducted by the Chinook Applied Research Association south of Acadia Valley, Alberta, compared tall stubble, short stubble, and alternate height trap strips on snow accumulation, soil moisture conservation, and crop yield in a durum wheat-fallow rotation. The results indicated that tall stubble was most effective for snow trapping and soil moisture conservation, while short stubble, although less effective at trapping snow, conserved moisture through a mulch effect. The study concluded that residue management practices like direct combining and evenly spread chopped straw effectively conserve moisture in the brown soil zone, with trap strips being useful under specific conditions, such as lodging, and early results from a new treatment suggested that straw removal could reduce moisture conservation.

Field-scale research by crop consultant Mike Palmier in Saskatchewan, reported by Grainews, demonstrated that even small increases in stubble height could significantly improve crop yield in dry conditions. For example, taller stubble trapped more snow, leading to increased soil moisture and higher yields of canola—about 6 to 8 bushels per acre more compared to crops grown on shorter stubble. Palmier’s trials showed that increasing stubble height by just 2-3 inches can notably enhance moisture retention and crop vigor, particularly when combined with effective residue management, offering a valuable strategy for managing water during dry growing seasons.