Direct Seed Crop Rotations for Intermediate Rainfall Zones

Monsanto Center of Excellence


Sheldon Blank-Research Agronomist; Barry Beaudoin, Dean Brown, Joe Dahmen, Bryan Kliewer, Frank Orey,
Kevin Zander-Local Marketing Managers; Dion McBay-Plains Conservation Tillage Specialist

Conservation tillage (CT) systems across the nation have often met barriers to adoption, partly due to unanswered agronomic questions. In dryland agriculture throughout the Plains States, the concept of intensive crop rotations using no or reduced tillage has considerable grower interest. The lack of local data and exposure to these systems has hindered CT adoption.

As an element of Monsanto’s National Conservation Tillage Direction, each region in the Plains has dedicated time and funding to Centers of Excellence (COE) research and demonstration sites to address grower questions about CT. The concept of the COE is to establish an on-farm site in cooperation with progressive growers and retailers in order to jointly explore agronomic issues surrounding local crop production practices. These centers are designed to be sustained locations over 5 or more years in order to show long-term effects of conservation tillage and crop rotations. They are working partnerships among local growers, Monsanto and other CT related entities in the agricultural community. Trials at the COE’s are designed to focus on various elements of CT systems including crop rotations, fertility placement, seeding techniques, residue management, moisture conservation, soil structure and organic matter content. In addition, the Centers will highlight current and future technologies such as herbicide tolerant crops, biotechnology, hybrids and alternative crops.

Monsanto’s COE location in the Pacific Northwest is in eastern Washington on the Dan and Steve Moore farm. The site is 5 miles west of Dusty, WA at the intersection of highway 12 and the Zaring Cutoff Road. This dryland site is in a 13-15 inch rainfall zone characterized by a wheat-fallow rotation and considered to be a marginal recrop area.

The objective of this COE site in the Pacific Northwest is to demonstrate the agronomic and economic feasibility of direct seeding annual crops and to evaluate the ability to intensify and diversify cropping practices in a traditional wheat-fallow region through utilization of direct seeding techniques. Thirty acres were leased with individual plots being 1.65 acres in size to facilitate planting, spraying and harvest with commercial, grower equipment.

Five cropping rotations are represented at this COE site:

  1. Continuous hard red spring wheat
  2. Winter wheat/spring barley/fallow (chemical fallow)
  3. Winter wheat/spring wheat/mustard
  4. Spring wheat/winter wheat/corn/dry peas
  5. winter wheat/fallow (traditional rotation for the region, but fallow is chemical fallow with no tillage)

Each component of each rotation is represented each year, thus thirteen 1.65 acre plots comprise the test plot site. All plots, except corn, were direct seeded with a John Deere 750 off-set disc drill which deep banded fertilizer at planting. Starter fertilizer was also applied with the seed at planting.

The attached spreadsheet gives a breakdown of revenue, expenditures and net-income for each plot in 1997 and 1998 as a component of a particular rotation. When the project was started the spring of 1997, spring wheat was seeded in plots where winter wheat was a component of the rotation and should have been seeded the fall of 1996. The site received approximately 21 inches of moisture during the 1996-97 season (6-7 inches above normal) and about 14 inches (near normal) during the 1997-98 season. The spring seasons of 1997 and 1998 were both relatively wet and ideal for spring cropping.

A summary table of per acre profitability by rotation is as follows:

Net $$ Income/Acre
 Crop Rotation  1997  1998  Sum '97+'98
 Winter wheat/chem fallow  19.54  36.24  55.78
 Spring wheat/mustard/winter wheat  75.24  47.04  122.28
 Continuous DNS wheat  53.31  19.39  72.70
 Winter wheat/spring barley/chem fallow  22.44  34.67  57.11
 Winter wheat/corn/peas/spring wheat  18.92  10.01  28.93

The inclusion of fallow in a 2 or 3-year rotation substantially reduced the profitability of these rotations.. Both continuous cropping rotations of spring wheat/mustard/winter wheat or continuous DNS wheat provided greater net income per acre than rotations practicing fallow. The DNS wheat did not make protein in either cropping year.

Growing dryland corn presented formidable agronomic challenges in both 1997 and 1998, as witnessed by the sizable loss in income for this crop. Dry peas in this continuous cropping rotation also reduced profitability, and it appears peas may have a marginal fit in this transitional zone.

It is imperative that this COE site be maintained in order to determine long-term profitability and sustainability of various crop rotations in a direct seed environment. Data generated to date suggest that direct seeded, annual cropping rotations in a transitional 13-15 inch moisture zone may be sufficiently profitable and sustainable to reduce or eliminate the need for fallow.