Grower Experiences With Direct Seeding
Higher Rainfall Annual Cropping Regions
Nathan and Steve Riggers
Riggers Brothers Farm
Riggers Brothers is a 2300 acre grain, legume, and grass seed farm located in north central Idaho 40 miles east of Lewiston on the Camas Prairie. Our annual precipitation averages about 25 inches and elevation varies between 3200 and 3800 ft. We typically have snow cover through most of the winter followed by cold wet springs and mild summers.
The ground on the Camas Prairie is commonly described as gently rolling hills with about 50% of our farm classified as highly erodible due to slope; though very few hills exceed 30% slope and 10% slope is probably the average.
Our soils are black heavy silt loams that average 2 to 3 feet in depth. Organic matter averages between 4% and 6%.
Crops and Rotation
Our farm is typically seeded to 40% Soft White Winter Wheat, 20% Spring Wheat and Spring Barley, 20% Legumes and Canola, and 20% Kentucky Bluegrass. Winter wheat fields are generally alternated between 2 and 3 year rotations.
Mature bluegrass fields are rotated back into annual crop production via continuous direct seeding. Since beginning this practice in 1991, these fields have become our most productive. Trying to achieve this level of productivity on the rest of the land we farm is one of our primary motivations in pursuing a direct seeding system on the entire farm.
The most significant change in rotations on our farm with direct seeding has been the elimination of summer fallow for winter wheat. 50% of our wheat is direct drilled on legume or canola ground while another 50% is direct drilled on spring grain stubble either left standing or burned. For the past five years, yields of winter wheat direct seeded into spring grain stubble have yielded with - and in some cases have exceeded - yields of winter wheat on legume, canola, and fallow ground.
Tillage and Seeding Equipment
Beginning in 1987, we started direct seeding winter wheat with a leased 24 ft Palouse Zero Till drill. In 1991 we purchased a 15 ft Ag Pro Conservation drill. Both of these drills were set up with hoe openers, dry starter fertilizer, and deep band anhydrous or aqua ammonia placed 1 to 2 inches below the seed row. Due to the 15 ft width of the Ag Pro drill some winter wheat was seeded after legumes with a conventional system consisting of a cultivation, shanked anhydrous ammonia, and seeded with IH 510 end wheel grain drills equipped for dry starter fertilizer. Conventional spring crops were seeded with the same end wheel drills into ground that had been fall plowed and then spring cultivated, fertilized with anhydrous (spring grain), and cultivated again.
In 1991 we started direct seeding spring crops on a trial basis with the Ag Pro drill. Our present system for direct spring seeding includes drilling into standing stubble, drilling into residue remaining after spring burning, and knocking down stubble residue in the fall with a disc or disc/harrow operation. Our plans are to continue using a mixture of all three techniques as we try to fine tune the system and find what works the best for each situation.
With seven years of successful direct spring seeding on a limited amount of acres, we wanted the capacity to begin phasing in direct seeding on 100% of our farm and purchased in May 1997, a 33 ft Flexi-Coil 5000 air-hoe drill with the same deep band fertilizer placement 1 to 2 inches below the seed row as our previous drills. We used this drill last spring to seed both conventional and direct seed spring wheat, conventional and direct seed green peas, and some conventional barley. We then direct seeded all of our winter wheat last fall. About 20% of our spring crop will still be conventionally seeded with the Flexi-Coil drill this spring but it is our intention to eliminate moldboard plowing next fall and be in a 100% direct seeding system. Ultimately, we envision using a 24 ft disc, heavy harrow, 80 ft sprayer, and air drill to crop 3000 to 3500 acres.
Direct Seeding Benefits
Our farm began direct seeding spring crops to try and replicate the efficiency, soil health improvements, erosion reductions, and yield increases due to fertilizer placement we were witnessing with direct seeded winter wheat.
A direct seed spring cropping system using shallow fall tillage, harrow, and 1-2 roundup applications is more than twice as efficient in terms of hp-hours as the typical system in our area using fall plowing/conventional seeding. A true no-till system without any tillage would be even more efficient. Assuming that current economic trends in production agriculture continue, a direct seed system is one of the few ways we see our farm being able to grow and remain profitable without significant increases in equipment and labor.
Soil Health and Erosion
Organic matter, humus, and earthworm populations have increased dramatically in our fields with seven years of continuous direct seeding. In the absence of tillage, these soils become much more "forgiving" and crops are better able to withstand extreme weather such as frost heaving and summer drought. In addition, water infiltration improves which allows for earlier seeding in the spring and makes the winter wheat crop much less prone to saturation during heavy winters like those of 1996 and 97.
Historically, some of our worst erosion has occurred in May and early June during heavy thunderstorms on conventional seedbeds of peas and lentils. Direct seeded spring crops are much less prone to runoff due to increased surface residue, less soil disturbance, and higher water infiltration rate.
The most notable benefit of direct seeding on our farm has been apparrent yield increases in both fall and spring crops. During the ten years that we have been raising winter wheat with both direct seed and conventional systems, direct seeded winter wheat has consistently out performed our conventional wheat with yield differences of 5 to 10 bushels/acre being noted between the two systems where similar rotation history and variety selection allow valid comparisons.
Yield improvements with direct seeded spring crops have also been significant. Direct seeded green peas in 1993, 95, and 97 (years with both conventional and direct seeded peas) yielded an average of 570 lbs more per acre than conventional seeded green peas the same year. For the past six years, our highest spring wheat and green pea yields have been achieved with direct seeding. Because none of these comparisons have come from replicated plots, caution is warranted in making outright productivity claims. However, the consistent differences over a 7 year time frame lead me to believe that the yield increases with direct seeding are not a fluke.
Keys to Success
1. Residue Management
- Chaff spreaders, harrowing, flailing, etc....
2. Crop Rotation
- Any crop that you now conventionally seed can be successfully direct seeded. Continuous no-till does not mean continuous winter wheat.
3. Patience in the spring
- Improved moisture, soil health, and fertilizer placement will compensate for a slightly delayed seeding date.
4. Use the right equipment
- Don't use conventional drills in no-till situations.
5. Round-up, Round-up, Round-up
- As tillage is reduced, weeds need to be controlled prior to spring seeding with Round-up.
-There is no substitute for experience. While it may be less embarrassing to wait for the neighbors to make the rookie mistakes, there isn't a textbook guide to direct seeding for each farm. As your experience with this new system increases, so will your rate of success.
Future of Direct Seeding
As mentioned above, one of our farm's long term goals is to evolve to a true direct seeding system that eliminates tillage without burning. Given the biomass material produced in a 25 inch rainfall region, this may require flailing or bailing of some residue to improve seedling growth. A viable local market for large tonnages of grain straw would greatly facilitate our conversion to true no-till eliminating the need to burn excess residue. In the near term, we are working on replacing fall plowing with the more efficient operation of fall disking to manage residue prior to spring cropping.
Other developments that would facilitate direct seeding on our farm and in our area would be more pre-plant herbicides that are effective in residue.
Finally, Round-up Ready wheat, barley, peas and lentils or other herbicide resistance genetics would accelerate the conversion to direct seeding in the Northwest.