Mustard Green Manures

Mustard green manures are being used in irrigated regions of eastern Washington to improve soil quality, control wind erosion, and manage soil-borne pests.  Green manures improve soil quality by increasing soil organic matter and also by stimulating the growth of microorganisms.  These microorganisms secrete compounds that bind soil particles together into aggregates.  With improved soil aggregation comes improved water infiltration, aeration, and resistance to wind erosion.  In addition, although all the mechanisms are not well understood, there are several ways that green manures can control soil-borne pests.  They can be divided up into three categories: crop rotation, changes in soil biology (including competitive exclusion, increased predation, and interference of crop-pathogen signals), and allelopathic chemicals (also called Biofumigation with Brassica green manures).

On-farm research has been conducted since 1999 to determine the benefits of these crops and to improve their effectiveness.

WSU Publications

Green Manuring with Mustard: Improving an Old Technology
Green manure summary article in Agrichemical & Environmental News, June 2003.

Mustard Green Manures Replace Fumigant and Improve Infiltration in Potato Cropping System
Published in Plant Management Network; August 2003.

Using Green Manures in Potato Cropping Systems
WSU Extension Bulletin EB1951E.

Mustard Green Manures
WSU Extension Bulletin EB1952E.

Mustard Crop Resources

2008 Partial Budget Analysis for the Replacement of Metam Sodium by a Mustard Green Manure (pdf)
Partial budget for fumigant replacement.

Mustard Types, Seed Sources & Acreage Estimates
Types of mustard for green manures, contacts for WA seed and estimates for mustard acreage by year.

On-Farm Research

Mustard Varieties for Green Manuring
Choosing mustard varieties and on-farm research results on variety biomass measurements and glucosinolate concentrations and production.

Agronomics (pdf)
On-farm research results addressing effects of planting date on mustard biomass; effects of early planting date on mustard emergence and growth; and effects of nitrogen rate on mustard biomass.

Soil Quality (pdf)
On-farm research results addressing infiltration, aggregate stability, and soil penetrometer resistance.

Potato yields after green manure, with and without fumigant (pdf)
On-farm research results addressing potato yields after mustard or sudangrass, with or without metam sodium fumigant.

Gies On-Farm Research
On-farm research system description and research results 1999-2001.

Field Day Materials

2004 Mustard Green Manure Field Day (pdf)
The benefits of mustard green manures and the basics of mustard management.  Handout from 2004 field day.

2003 Mustard Green Manure Field Day (pdf)
Handout from 2003 field day.

Potential to Control Nematodes (Ingham) – 2003 Mustard Green Manure Field Day (pdf)
2003 field day handout.

Potential to Control Nematodes (Riga) – 2003 Mustard Green Manure Field Day (pdf)
2003 field day handout.

Wind Simulation Studies – 2003 Mustard Green Manure Field Day (pdf)
Wind simulation studies handout.

Andy McGuire Agricultural Systems Educator WSU Extension is currently conducting mustard green manure research.  Please contact Andy with questions about this work:, 509-754-2011 Ext. 4313; 1525 E Wheeler Rd Moses Lake, WA 98837