Spring Barley Production Guide - College of Agricultural and Life ...

Crop Residue
Management
Roger J. Veseth and Bradford D. Brown
Spring barley health and production potential can be
influenced by crop residue management practices used
with the preceding crop, particularly a large residue-producing
crop such as winter wheat. Likewise, management
of spring barley residue can affect the following crop.
Residue management must begin with the combine at
harvest.
High concentrations of residue in combine straw and
chaff rows can seriously interfere with the subsequent
tillage and planting operations and can create a poor environment
for plant growth. Uniform distribution of straw
and chaff from the combine is worthwile in any farming
system. It is especially important for no-till or minimum
Figure 29. Poor combine residue distribution
contributes to many problems, including the creation of
a favorable disease environment, termed the ”green
bridge.”
IDAHO SPRING BARLEY PRODUCTION GUIDE
46
tillage seeding because more of the residue remains on
or near the soil surface (Fig. 29). The adverse effects of
heavy straw and chaff rows also have been observed
under conventional tillage systems, even moldboard plowing.
For more information about residue management in
cereal production, refer to PNW 297, Uniform Combine
Residue Distribution for Successful No-till and Minimum
Tillage Systems.
The potential for problems with combine residue distribution
has increased over the past few decades for several
reasons. Combine header widths have increased from
about 12 feet in 1950 to 20 to 30 feet today. Most standard
factory-run combines are not adequately equipped
to uniformly spread the large volumes of residue produced
at these header widths. The introduction of new high-yielding
wheat and barley varieties has also increased residue
volume. Chaff, in particular, has become an increasingly
larger component of this residue with increasing yields.
Furthermore, improved fertility management has increased
grain production potential and the volume of residue
at harvest.
Combine Straw and Chaff
Rows
Many production problems can be associated with high
concentrations of straw and chaff behind the combine.
Some of these are:
• Poor drill performance Drills plug, straw “tucks” in
the seed row, seeding depth is uneven, seed-soil contact
is poor, and seedlings emerge unevenly.
• Slower growth Less solar energy leads to cooler
and wetter soils.
• Reduced nutrient availability Nitrogen, sulfur, and
other soil and applied fertilizer nutrients are temporarily
immobilized by microbial decomposition of residue.
• Favorable disease environment Pythium and Rhizoctonia
root rots are favored by the abundant food source;
cool, moist environment; and dense weed and volunteer
populations. Disease inoculum carryover increases with
slower rates of residue decomposition.
• Reduced herbicide e fectiveness Residues intercept
and absorb herbicide, germination of weeds and volunteer
seeds is delayed, and high weed and volunteer populations
are more difficult to control.
• Increased crop competition High concentrations of
weeds and volunteers limit the availability of nutrients,
moisture, and light to the crop.
• Increased rodent damage The abundant food source
and cover for protection from predators draw rodents.