Thomas G. Chastain

In order to maximize harvest efficiency and seed yield, using the appropriate timing for harvest is essential. Seed moisture content is the most reliable indicator of seed maturity and harvest timing in grass seed crops.

Since pollination and seed maturation are not uniform processes in grass seed crops, a range of seed maturity can be found in a single field. Harvesting within the correct range of seed moisture contents will maximize seed yield and minimize losses of seed during harvest. Seed moisture content is also an important factor in the storage of harvested seed. High seed moisture content reduces longevity of seed in storage and reduces seed quality.

To optimize the timing to swath grass seed crops and to maximize the quantity of seed harvested, seed growers must balance cutting late-maturing seeds too early with cutting early-maturing seeds too late. Cutting too early at high seed moisture content shortens the seed fill period leading to immature seed and reduced seed size or weight. Cutting too late at low seed moisture content can reduce yield as a result of seed shattering losses.

The table below shows the seed moisture content range recommended for swathing of grass seed crops:

Crop

Recommended seed moisture for swathing (%)

Moisture loss per day (%)

Annual ryegrass

43-48

2.0-3.0

Orchardgrass

42-46

1.0

Tall Fescue (forage)

40-43

2.5-3.0

Tall Fescue (turf)

35-45

2.5-3.0

Perennial ryegrass

35-43

3.0

Chewings fescue

30

5.0

Creeping red fescue

25-35

4.0

Kentucky bluegrass

24-28

3.0-4.0

Illustrated instructions on how to conduct a seed moisture test in grass seed crops and guidelines for seed moisture contents for best harvest efficiency can be found in OSU’s publication EM 9012. Here’s a link to the publication:

Using Seed Moisture as a Harvest Management Tool

A video showing step by step instructions on collecting seed and methods to test moisture content of seed is linked below:

Seed moisture and harvest video

Thomas G. Chastain

In order to maximize harvest efficiency and seed yield, using the appropriate timing for harvest is essential. Seed moisture content is the most reliable indicator of seed maturity and harvest timing in grass seed crops.

Since pollination and seed maturation are not uniform processes in grass seed crops, a range of seed maturity can be found in a single field. Harvesting within the correct range of seed moisture contents will maximize seed yield and minimize losses of seed during harvest. Seed moisture content is also an important factor in the storage of harvested seed. High seed moisture content reduces longevity of seed in storage and reduces seed quality. Continue reading

Thomas G. Chastain

Our work on grass seed crop residue management suggests that the answer to this question depends on the grass crop species.  On-farm trials over 60 site-years and in 6 seed crops species across Oregon were used to compare baling straw with and without flailing of the crop stubble.  In several of our grass seed crops including perennial ryegrass, tall fescue, orchardgrass and Chewings fescue, the differences in seed yield for baling and post-bale flail chopping of a field were negligible and were not statistically significant.  Thus, there was no requirement for flailing of these crops after baling of the straw in order to harvest good seed yields.

Stack of straw bales in grass seed field (T.G. Chastain photo)
Stack of straw bales in grass seed field (T.G. Chastain photo)

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Thomas G. Chastain

Grass seed harvest has begun here in the Willamette Valley.  In order to maximize harvest efficiency and seed yield, using the appropriate timing for harvest is essential.  Seed moisture content has been found to be the most reliable indicator of seed maturity and harvest timing in grass seed crops.

Since pollination and seed maturation are not uniform processes in grass seed crops, a range of seed maturity can be found in a single field.  Harvesting within the correct range of seed moisture contents will maximize seed yield and minimize losses of seed during harvest. Seed moisture content is also an important factor in the storage of harvested seed.  High seed moisture content reduces longevity of seed in storage and reduces seed quality. Continue reading

Thomas G. Chastain

Grass seed crop acreages in Oregon’s Willamette Valley have varied over time.  One interesting aspect of the rise and fall of grass seed crop acreages in the region is their relationship with wheat acreages in the Willamette Valley.  A rise in grass seed crop acreage is mirrored by a simultaneous fall in wheat acreage and vice versa, and these trends are evident in the graphic below.

Grass seed and wheat trends Continue reading

Thomas G. Chastain

The stubble and straw remaining in grass seed fields after harvesting seed is known as residue.  Post-harvest residue burning has been justified on the basis of pest control and stimulation of seed yield.  Public concern over air quality and the potential for adverse health impacts on the region’s residents has necessitated the identification of alternative residue management practices.  Oregon legislation (SB 528) has, in effect, ended the practice of field burning in the western part of the state for most species except for the fine fescues.

Smoke plume from open-field burning in Oregon’s Willamette Valley. (T.G. Chastain photo)

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