The late summer and early fall period has long been thought to be critical for regrowth of the perennial ryegrass and tall fescue seed crops after harvest and for the following year’s seed yield. Extremely dry conditions during this period in the Willamette Valley can reduce stands and crop regrowth in both seed crops. There is good evidence from our research that irrigation improves the appearance of the stand (number of tillers and stand cover) going into the winter. But what about the impact of fall irrigation on seed yield in perennial ryegrass and tall fescue?
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)
Oregon State University has recently released the 31st annual Seed Production Research Report in both hard copy and an online version. This publication has long been a forum for reports from a variety of seed production researchers, not only from OSU but also from affiliated institutions and agencies. For much of the Report’s existence, the publication has been edited and produced by Bill Young – now retired professor and extension agronomist in seed production. This year’s installment was edited by OSU Extension staff members Andrew Hulting, Nicole Anderson, Darren Walenta, and Michael Flowers.
The report is home to articles on a wide range of topics concerning the production of seed from species found in Oregon. Topics in this year’s edition include weed, insect and disease management; plant growth regulators; irrigation management; and seed testing. Here’s a link to the online version of the Seed Production Research Report:
Crop fields are generally not uniform and the harvested yield can vary across the field. Perennial ryegrass seed production fields are also not very uniform but some farmers use yield monitors on their combines to estimate seed yield and the spatial variability in seed yield across their fields.
This variability can be mapped for the fields where yield monitors are used and these maps can serve as the basis for making crop management decisions. But the reliability of these yield monitor-based estimates was not known for perennial ryegrass seed crops.
A recent paper by co-authored by extension agronomist in seed production Bill Young and others at OSU finds that there is considerable variability in seed yield in an otherwise uniform perennial ryegrass seed field and that a yield monitor can reliably capture this variability in seed yield.
This spring has seen alternating very dry and warm periods and cool, wet periods in the Willamette Valley. While the effect of these varying conditions on seed yield remains to be determined, grass seed harvest will soon be under way. To maximize harvest efficiency, identifying the best 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.
Range of maturity in perennial ryegrass spikes taken from one field (Tom Silberstein photo)Continue reading →
Under certain conditions, the tiller cannot support the weight of the developing inflorescence and seed. The tiller lodges or falls to the ground, especially when there are high levels of nitrogen fertilizer and soil moisture present (Fig. 1). Both conditions are common in Oregon’s commercial grass seed production fields in the spring. But will that be the case in spring 2013?
The winter months of January through March 2013 have been the 2nd driest winter period on record at Corvallis with only 6.28 inches recorded. Can we expect more of the same dry weather during spring? No one can say for sure, but an examination of weather records for the past 124 years reveals that when precipitation is very low (50% or less of the 16.02 inch normal) in January through March, the following April through June period averages 5.78 inches or near normal rainfall (normal is 5.83 inches).
Despite the very dry weather that has been recorded to date, there may still be enough rainfall present in coming months to make lodging a problem for local seed growers.
Figure 1. Lodging in ryegrass. (T.G Chastain photo)
