Dry conditions are normal for the Willamette Valley in July and August. This is an important period for flowering and seed development in red clover seed crops. While much of the region’s red clover seed crop is not irrigated, would the crop benefit from additional water during this dry period? That is one of the questions that the seed production research and extension team has addressed.
Research conducted at Hyslop Farm has shown that spring irrigation in tall fescue and perennial ryegrass can increase seed yield. The soil at Hyslop Farm is a medium textured soil (Woodburn silt loam) that is typical of many places in the valley where tall fescue and perennial ryegrass seed crops are grown. This soil is deep and has good water holding capacity.
Tall fescue seed yield responses to spring irrigation varied among the cultivars tested. Increased number of seed in tall fescue was most responsible for the seed yield improvement observed with spring irrigation. Strategic timing of spring irrigation to support seed filling was more important for increasing seed yield than season-long irrigation. Spring irrigation increased seed yield up to 39%. First years stands of stands of tall fescue averaged 28% increase in seed yield with spring irrigation while second year stands averaged 11% increased yield. Continue reading →
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?
Here’s a new article on spring irrigation of tall fescue seed crops published in Field Crops Research. This work was led by Krista Huettig, a former graduate student and member of my research team.
The study reports several important findings and was the first study to demonstrate that spring irrigation increases seed yield in tall fescue. Tall fescue seed yield responses to spring irrigation varied among the cultivars tested. Increased number of seed in tall fescue was most responsible for the seed yield improvement observed with spring irrigation. Strategic timing of spring irrigation to support seed filling was more important for increasing seed yield than season-long irrigation.
The Willamette Valley has experienced very dry late summer and early fall conditions to date and long-range projections are for more of the same coming in the middle and late parts of fall. How dry has it been? Rainfall for the July through September period has been 0.87 inches at Hyslop Farm or 37% of the normal 2.35 inches for the period. Only 10 years in the past 123 years have been this dry or drier in the Willamette Valley. In these dry years, rainfall in October has averaged 2.11 inches or 66% of normal. When it gets this dry in July through September, dry Octobers typically follow. Thus, no relief from the dry conditions in the near term can be expected given either the forecasts or the historical records observed in past drought periods. Continue reading →
For more information
Thomas G. Chastain, Ph.D.
Department of Crop and Soil Science
351C Crop Science Building
Oregon State University
Corvallis, Oregon 97331-3002