Category Archives: Nutrient Management

Growing degree day update

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Growing degree days (GDD) are commonly used to schedule the beginning of spring nitrogen fertilizer applications in grass seed crops. Typically, 200 GDD (base 0 C) from January 1st is used as the opening date of spring nitrogen fertilizer applications.  This number of GDD marks the beginning of the period that the average daily temperature reaches 5 C (41 F) and as a result, grass seed crops resume growth after winter quiescence.

The current (February 13th) GDD  is 197 GDD at Hyslop Farm near Corvallis.  At the current rate of GDD accumulation, 200 GDD should be attained on the 14th.  The long-term average date for attaining 200 GDD is February 14th.

Yellow mustard seed production and nitrogen management

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Thomas G. Chastain

Here’s an article just published by our seed production team on nitrogen’s effect on seed yield and other seed production characteristics in yellow mustard.  Trials were conducted on this crop over a 3-year period at OSU’s Hyslop Farm by Alyssa DuVal, a former graduate student and current instructor in the department.  Yellow mustard is a potential seed crop for the high rainfall areas of western Oregon and unlike many other Brassica family crops, there is no threat of crossing of yellow mustard with the region’s vegetable seed crops.

Yellow mustard crop pods prior to harvest. (Photo by T.G. Chastain)

This article was published in Agronomy Journal and can be found at the link below:

Duval, A.S., T.G. Chastain, C.J. Garbacik, and D.J. Wysocki.  2017.  Nitrogen affects seed production characteristics in yellow mustard (Sinapis alba L.).  Agron. J. 109:995-1004.

Key findings of the article:

  • Applied N increased seed and oil yield in yellow mustard in a high rainfall environment.
  • Seeds m–2 was the most influential factor in determining seed yield in yellow mustard.
  • Applied N increased height, biomass, tissue N content, leaf area index, and crop growth rate.

Spring nitrogen and seed yield in winter canola

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Thomas G. Chastain

Here’s a new article from our seed production research and extension team on spring nitrogen and seed yield in winter canola.  Field trials were conducted in the Willamette Valley over a 3-year period at OSU’s Hyslop Farm.  This work was led by Brock Ferguson and is the first study to be published on winter canola in the seasonally wet environment of western Oregon.

Winter canola flowers and buds (TG Chastain photo)
Winter canola flowers and buds (TG Chastain photo)

This article appears in the most recent issue of Agronomy Journal and can be found at the link below:

Ferguson, B.T., T.G. Chastain, C.J. Garbacik, B.T. Chastain, and D.J. Wysocki. 2016. Spring nitrogen and cultivar affect seed production in winter canola (Brassica napus L.). Agron. J. 108:1124-1131.

Key findings of the article:

  • Spring nitrogen increased seed and oil yield in winter canola except when the crop was lodged as a result of high spring rainfall.
  • Seeds m-2 was the most influential factor in determining seed yield in winter canola.
  • Seed oil content was high but was inversely related to the rate of spring N applied.
  • Seed yield and oil yield were maximized at 100 lbs N/acre while minimizing lodging losses.

 

Advances in Pasture Seed Production

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Here’s a video of a presentation that I made at the Pasture Seed Conference in Tasmania:

Presentation Video

The presentation concentrated on some of the advances that have been made in seed production of cool-season grass seed crops.

The slides from the presentation can be accessed here:

Advances in Pasture Seed Production

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New OSU Tall Fescue Seed Crop Nutrient Management Guide

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A new nutrient management guide for tall fescue seed crops has been published by OSU’s seed production research and extension team.  The 42-page publication (EM 9099) is a product of many years of  field work in tall fescue seed crops by the members of the research and extension team.

Tall fescue cover

The nutrient management guide covers the impacts of application of nutrients on seed yield, seed yield components, crop growth and development, plant growth regulator use, pests, and others.  Extensive use of tables, figures, and appendices supplement this comprehensive guide to tall fescue seed crop nutrient management.

The publication can be accessed at the link below:

Tall Fescue Grown for Seed: A Nutrient Management Guide for Western Oregon, EM 9099

Spring-Applied Nitrogen and Trinexapac-ethyl Effects on Seed Yield in Perennial Ryegrass and Tall Fescue

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Here’s a new article from our research group on the impacts of spring applied nitrogen and trinexapac-ethyl plant growth regulator (PGR) effects in perennial ryegrass and tall fescue seed crops.  This article is in the current issue of Agronomy Journal and is a part of our series on PGR in grass and legume seed production.  The product is marketed as Palisade, Moddus, and several generic products for lodging control in grass seed crops and legume seed crops.

Effect of spring-applied N (160 lbs/acre - left) and no spring-applied N (right) on lodging and canopy structure in perennial ryegrass seed crops (T.G. Chastain photo).
Effect of spring-applied N (160 lbs/acre – left) and no spring-applied N (right) on lodging and canopy structure in perennial ryegrass seed crops (T.G. Chastain photo).

Key findings of the article:

  • Identifies an interaction of spring-applied N and PGR application on seed yield and other seed production characteristics in perennial ryegrass and tall fescue.
  • Is the first peer-reviewed publication to document the effect of trinexapac-ethyl PGR on increasing seed yield in tall fescue.
  • Seed yield was only increased in perennial ryegrass and tall fescue by the PGR when recommended rates of applied rates of spring N were made.
  • Although seed weight was increased by spring N, most of the effect of the combination of spring-applied N and PGR on increasing seed yield was attributable to increases in seed number.

The article can be found at the link below:

Chastain, T.G., C.J. Garbacik, and W.C. Young III.  2014.  Spring-applied nitrogen and trinexapac-ethyl effects on seed yield in perennial ryegrass and tall fescue.  Agron J. 106:628-633.