2001 Table of Contents

2001 STEEP III Progress Report

RESEARCH PROJECT TITLE: Rotation designs for direct seed cropping systems

INVESTIGATORS: David Huggins, Research Agronomist, USDA-ARS, Pullman, WA.; Eric Gallandt, Weed Ecologist, formerly with Dept. of Crop and Soil Sci., WSU, Pullman, WA; Roger Veseth, Conservation Tillage Specialist, PSES, Univ. of Idaho, Moscow, ID and Dept. of Crop and Soil Sci. WSU, Pullman, WA; Timothy Fiez, former Soil Fertility Specialist, Dept. of Crop and Soil Sci. WSU, Pullman, WA; Claudio Stockle, Crop modeler, Biological Systems Eng. Dept., WSU, Pullman, WA; Joe Yenish, Weed Scientist, Dept. of Crop and Soil Sci. WSU, Pullman, WA; Javier Marcos, former Ph.D. candidate (completed degree) and Derek Appel, M.S. candidate, Dept. of Crop and Soil Sci, WSU, Pullman, WA.

PROJECT OBJECTIVES:

1. Identify potential crop rotation designs suitable for direct seed systems.
   
2. Establish on-farm and research center field trials to develop crop models and evaluate winter and spring crop performance in direct seed and tilled systems.
   
3. Initiate evaluation of beneficial or detrimental effects of crop rotation diversity under direct seed conditions and formulate recommendations to address growers= most critical soil and crop management questions (i.e. potential pest problems, moisture use, temperature requirements, soil erosion control, nutrient use efficiency).

KEY WORDS: alternative crops, no-till, water use efficiency, crop rotations

STATEMENT OF PROBLEM: Crop rotation designs for direct seed systems have not been extensively developed for the annual cropping region of the Pacific Northwest. Changes in environmental conditions notably soil water storage under direct seed may increase the feasibility of alternative crops and rotations. Development of crops and rotations suited to the direct-seed environment may lead to greater economic viability and adoption of direct seed farming systems.

AGRONOMIC ZONE OF INTEREST: Field studies will focus on the high rainfall, annual cropping region and modeling efforts will be applicable to the high, intermediate and low rainfall areas.

ABSTRACT OF RESEARCH FINDINGS: Eight spring crops (canola, yellow mustard, hard red spring wheat, proso millet, safflower, linola, pea, and corn) were successfully modeled using Cropsyst and crop characteristics including yield, yield stability, water use efficiency, and thermal time requirements were simulated and mapped for the dryland cropping regions of OR, WA and ID. Calibrated model was used for prediction purposes to evaluate many different scenarios including: forecasting yield under different weather scenarios, evaluating date of planting effects on yield, risk of not completing crop maturity, the regional productivity and suitability of alternative crops, and potential crop rotation designs. No-till (NT) and conventionally (CT) established winter and spring crops (spring and winter canola, yellow mustard, hard red spring wheat, winter wheat, proso millet, pinto beans, safflower, soybean, linola, winter and spring pea, and winter and spring lentil) were evaluated following winter wheat as well as no-till establishment methods using different no-till drill and broadcast (canola and mustard) treatments. In general winter crops emerged more rapidly under NT but final stands were greater for CT. Spring crop emergence and stand establishment were favored by CT. Under NT, spring crop stands were improved with a hoe-type opener (Anderson) as compared to double-disk and inverted-T (cross-slot) opener types. Slight changes in seed-zone environment significantly affected crop establishment in wheat stubble. Yields of alternative crops were not consistently affected by tillage system. Field scale direct-seed cropping systems research was initiated at the Palouse Conservation Field Station and at the Cunningham Agronomy Farm to further evaluate rotation design and crop performance.

RESULTS AND INTERPRETATION: In 1998, two field studies were initiated at the Palouse Conservation Field Station near Pullman, WA to evaluate winter and spring crop performance following winter wheat under no-till conditions. The crop modeling study consisted of 10 different spring crops: canola (Sunrise), yellow mustard (Tilney), hard red spring wheat (WB 926R), peas (Columbia), corn (Pioneer 3970), proso millet (WSUEAAC2), dry beans (Bill Z pinto), soybeans (Monsanto Roundup Ready), safflower (S-208) and linola (989) on 50 by 30 foot plots. A no-till double disk drill (Fabro, Inc.) with an offset, leading disk, starter and deep band fertilizer capabilities (all 7.5 inch spacing), and a cone seeder was used to no-till seed into standing Madsen winter wheat stubble (grain yield of about 85 bu/ac) in 1998. In 1999 and 2000, the Cross-slot drill (notched coulter, inverted T slot, 8 inch spacing, banded fertilizer) was used to seed all spring and winter crops. Data for parameterizing, corroborating and assessing the Cropsyst model were collected throughout 1998 and 1999 including detailed measurement of water, temperature, light, and crop growth and development.

The second study consisted of seven spring crops in 1998 and 14 winter and spring crops in 1998-1999 and 1999-2000. The crops were: spring and winter canola, yellow mustard, hard red spring wheat, winter wheat, proso millet, pinto beans, safflower, soybean, linola, winter pea (Granger) and spring pea, and winter lentil (WA8649041) and spring lentil seeded both no-till and conventionally (fall moldboard plow, spring disk), following winter wheat (Madsen). The fabro drill was used in the spring and fall of 1998 and the cross-slot drill in 1999 and 2000. Agronomics used in the tillage comparison studies for 1999-00 are in Table 1.

Treatments for the seeding method study initiated in 1999 were four crops (winter and spring pea and winter and spring canola) and five seeding methods (three drill types for all four crops and two broadcast treatments for the winter and spring canola). Drill types tested were inverted T (Cross-slot), double disc (Great Plains) and hoe-type (Anderson opener).

Table 1. Agronomics of alternative crops used in tillage studies (1999-2000).

Crop modeling results including detailed agronomic performance across the dryland regions of WA, ID and OR were reported last year. We concluded that the overall performance of the model and the accuracy of the parameterization were adequate for region-wide assessment of crop performance. Briefly, predicted yields, stability of yields and water relationships were used to analyze crop adaptation in the PNW. Economical aspects were treated in a very simplified approach as little regional information exists on the economics of alternative crops, such as prices and costs. The adaptation of these new crops in the PNW were assessed according to the following criteria:

1. thermal time supply: determining the probability of the crop to complete its growth cycle and establishing the location and length of the crop cycle in the growing season.
2. average yields as a measure of the total productivity of each crop in each of six defined agroclimatic zones.
3. coefficient of variation as a measure of the production stability of each crop in each of the agroclimatic zones.
4. water use efficiency (WUE) (g m-2 mm-1), defined as: Y/Ws where Y is the grain yield of the crop (g m-2) and Supply (Ws) is the total amount of water that the environment is potentially able to supply to the crop. It is calculated as the sum of the total amount of water stored in the soil (mm) at planting and the rain during the growing season (mm). This efficiency is a measure of how the crop uses water supplied by the environment to produce grain yield in each of the agronomic zones.
   
5. Evapotranspiration efficiency (WUEET) defined as: ET/Ws where ET is the actual evapotranspiration (mm). This term measures how efficiently the crop is using water from the total environmental water supply. This efficiency also indicates how the crop satisfies its water requirement given a certain environmental supply under dryland conditions.
6. actual evapotranspiration (ET) (mm). Average ET of each crop in each climatic zone. The amount of water that the crop used for evapotranspiration is an indication of the water requirement of the crop. This information can be used to estimate crop rotation possibilities in terms of the water needed by the crop and the soil water conditions remaining for the subsequent crop.
7. wheat break-even alternative crop price (W-ACP). This is defined as the price the alternative crop must attain in order to match the gross revenue of hard red spring wheat in each climatic zone. This price was calculated in each climatic zone according to the average yield of hard red spring wheat and the average yield of the given alternative crop. This approach was used because of the uncertainty in the alternative crop prices since there is no production or market history for this particular region as there is for more traditional crops such as wheat. Price and production levels of spring wheat are fairly well known for different areas in the region. Therefore, comparing alternative crop performance to spring wheat is a reasonable method to evaluate a general economic convenience of the alternative crop. Actual alternative crop prices for yellow mustard, spring canola, safflower, linola, wheat, millet and corn were obtained from the 1999 and 1998 Summary of Agricultural Prices of the National Agricultural Statistics Service. Price for pea was obtained from the Dry Pea and Lentil Commission (Pullman, WA). In addition to the W-ACP, the ratio of the W-ACP to actual alternative crop price was calculated. This ratio evaluates how far the actual price of the alternative crop is from the W-ACP.

These analyses showed that most alternative crops could not compete economically with hard red spring wheat unless prices increased considerably. Their value as rotation crops, however, could be significant and is under continuing research.

Data comparing crop yields (established in 100 bu/ac wheat straw) under NT and CT (1999-2000) are presented in Table 2. These data show few crops with statistically significant differences in yield between the two tillage treatments and no consistent trend was found across all three cropping years. Rodent damage was quite evident in winter grain legumes and contributed to low yields. Soybean established and grew well but did not reach maturity in any of three seasons tested. Low crop emergence occurred for many small-seeded crops, similar to low values obtained in previous years. These crops are very sensitive to slight differences in seeding depth and seed-zone conditions of water and temperature.

INTERACTION WITH OTHER SCIENTISTS CONDUCTING RELATED ACTIVITY:
Interaction of scientists on this study has been excellent with frequent exchanges of ideas, expertise, equipment.

PUBLICATIONS AND PRESENTATIONS:
Crop modeling results were presented at the American Society of Agronomy meetings in Salt Lake City, Utah (Nov. 4th, 1999) and Javier Marcos completed his Ph.D. dissertation entitled ASimulation-based asessment of alternative croips in the dryland Pacific Northwest@. Derek Appel (M.S. graduate student) presented results at the American Society of Agronomy meetings in Minneapolis, MN (Nov. 8th, 2000) entitled A Establishment of alternative crops no-till seeded into wheat stubble@.

Table 2. Alternative crop establishment, development, growth, and grain yield under no-till (NT) or conventional tillage (CT) treatments following winter wheat (1999-2000).

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