1998 Table of Contents

1998 STEEP III Progress Report

INVESTIGATORS: David Bezdicek¹, John Hammel², Mary Fauci¹, Dennis Roe³, and Jon Mathison^{2 1}WSU, ²UI, and ³NRCS

OBJECTIVES:

1. Identify additional grower cooperators who have practiced NT for 10 years or more in the 3 agroclimate zones, but particularly in the intermediate and low rainfall zones.
2. Document changes in soil quality through soil physical, chemical, and biological measurements on grower fields and in research plots.
3. Develop educational tools which demonstrate the benefits of NT agriculture and conservation tillage.

KEY WORDS: no-till, tillage, soil quality, crop productivity

STATEMENT OF PROBLEM:

No till (NT) agriculture presents some unique opportunities for reducing wind and water erosion and for improving crop productivity and economic returns. Higher surface residue in NT hinders planting, yet is essential for control of wind and water erosion. Heavy NT drills may compact the soil. Crop yield potential can increase through more efficient use of soil moisture, and thus can expand cropping options to the high and intermediate rainfall areas by allowing for more spring-grown crops. Reduction in tillage can increase soil organic matter and thereby increase soil quality. Many producers and researchers believe that soil quality improves under NT, but long-term documentation is needed. Our goal is to document changes in soil quality attributed to NT agriculture. We have evaluated soil physical, chemical, and biological properties in cooperating grower fields in NT operation for 10 to 25 years in comparison to adjacent conventional practices.

ZONE OF INTEREST: This study is conducted in the, high, intermediate, and low rainfall zones.

ABSTRACT OF RESEARCH FINDINGS:

Soil physical, chemical, and biological properties for five cooperating grower fields and one research plot in direct seed for 10 to 25 years were compared to adjacent conventional tillage practices in 1997. Soil organic matter, microbial activity, soil N release, and soil test P and K tended to be higher at all sites under direct seeding compared to conventional tillage. The greatest increase in soil organic matter of 50% was noted at Palouse, WA under 25 years of direct seeding. Fewer significant differences were noted at the drier sites due to the accumulation of less soil organic matter. Soil under direct seed was more compact, with higher bulk densities and greater penetration resistance. However they tended to have greater water infiltration. We propose that there is a change in soil pore size distribution after years of direct seeding, resulting in larger soil pores from undisturbed old root channels and earthworm channels. Winter soil water storage and water consumption by crops grown under direct seed and conventional tillage tended to be the same in 1998. However water use efficiency was greater for direct seeded winter wheat in the annual rainfall area. Greater water use efficiency was also noted for spring barley grown under direct seed compared to spring wheat in the wheat-fallow rainfall zone. Maintaining surface cover in annual cropping and eliminating fallow are key reasons for the improved water use efficiency.

RESULTS AND INTERPRETATION:

We continued to follow soil quality changes attributed to no-till (NT) agriculture in three agroclimatic zones in eastern Washington and northern Idaho was evaluated by assessing soil physical, chemical, and biological properties of long-term NT fields (Table 1) Most of the field results were reported in the 1997 STEEP III report. A summary of these results show that soil organic matter, microbial activity, soil N release, and soil test P and K were higher at all sites under DS compared to conventional tillage. The greatest increase in soil organic matter of 50% was noted at Palouse, with a slight increase noted at the wheat-fallow site at Touchet. Many of the above measurements were highest for direct seed compared to conventional at the soil surface 0-5 cm (0-2 inches), but were lower at the 5-20 cm depth due to the lack of surface soil inversion.

Water infiltration into soil is often increased under direct seed because surface residues facilitate infiltration into the soil, although the soil may be more compact due to heavy equipment traffic. Bulk density at the annual cropping site in Palouse and the wheat-fallow site in Touchet were generally higher under direct seed than conventional (Table 2). Ponded infiltration of water shows that water entry is generally higher under DS than under conventional tillage (Table 3).

Surface impedance was generally higher under DS at the Palouse and Colfax that likely reflects the heavy no till drills used (1997 STEEP Report). We propose that direct seed systems may be more compact just below the soil surface, but that water infiltration may actually be enhanced due to the different soil pore size distribution. Under direct seed conditions, we propose that old root channels and earthworm channels are being maintained from the lack of disturbance that facilitate infiltration of water through more macro pores. How this affects water and nutrient movement should be studied as water movement and leaching of nutrients may be facilitated through macro pores.

In late 1997, weather stations were set up as part of Juan Pablo Fuentes’s M.S work at the Palouse and Touchet sites (Table 1) to study winter soil water storage, seasonal changes in soil profile temperature and moisture, crop water use efficiency. Both locations were in winter wheat in 1998. We monitored continuously for soil moisture at 30-cm (1 ft) intervals to 150 cm (5ft) using time domain refractrometry (TDR). The weather stations monitored total radiation, wind speed, air temperature, and soil temperature (seed zone at 5-cm depth). Data were stored in storage modules, down loaded into a lap top computer, and assembled into one of several models to estimate crop water use efficiency. Soil nitrogen (ammonium and nitrate) was measured at monthly intervals to determine crop N use efficiency. Our results show that surface residues increased the water infiltration rate and suggest that there is greater potential for more storage of water under DS. Data in Fig. 1 show that seasonal soil temperature was consistently lower for no-till than conventional at Palouse in 1998. Surface resides under direct seed maintained lower soil temperature as would be expected.

Total precipitation, total water consumed, crop yield, and crop water use efficiency for winter wheat at Palouse is shown in Table 4. Excellent yields were noted for both the direct seed and conventional fields. However, water use efficiency was higher under direct seed due to the higher yield obtained. Total water consumed was similar. Total precipitation, total water consumed, crop yield, and water use efficiency for direct seed spring barley and spring wheat under wheat-fallow is shown in Table 4. Water use efficiency was higher under direct seed compared to wheat-fallow. Spring wheat was grown continuously for 14 years at the direct seed site, but replaced with spring barley in 1998. Winter wheat is normally rotated with fallow, but was replaced with spring wheat in 1998.

Table 1. Agroclimate zones, locations, and production systems in 1997

COOPERATORS:

Jim Cook, USDA-ARS Plant Pathology: Provide access to USDA long-term plots and collaborate in interpretation of data

Tim Fiez, WSU Cooperative Extension: Collaborate on direct seeding research

Roger Veseth, WSU and UI Cooperative Extension: Assist in site selection and collaborate in research

David Huggins, USDA-ARS: Collaborate on interpretation of data and statistical analysis

Steve Albrecht USDA-ARS: Collaborate on research

PULICATIONS AND PRESENTATIONS:

Presentations:

Bezdicek, D. F., Mary Fauci, John Hammel, and D. Roe. Soil quality changes under direct seed systems. NRCS Regional Agronomists meeting, Portland OR, Nov. 17, 1997- attendance 50.

Hammel, J., D. Bezdicek, M. Fauci, J. Matheson, and D. Roe. 1998. Physical, chemical, and biological properties of long-term cereal-based no-till systems. P. 285. American Society of Agronomy Abstracts. ASA meeting,s Baltimore, MD, Novenber 2, 1998. Attendance-250.

Bezdicek, David, John Hammel, Mary Fauci, Dennis Roe, and Jon Matheson. 1998. Effects of long-term direct seeding on soil properties on northwest farms. In Northwest Direct Seed Intensive Cropping Conference. STEEP III, WSU, Pullman, WA – Attendance-250

Publications:

Huggins, D. R., D. L. Allan, J. C. Gardner, D. L. Karlen, D. F. Bezdicek, M. J. Rosek, M. J. Alms, M. Flock, B. S. Miller, and M. L. Staben. 1997. Enhancing carbon sequestration in CRP-managed land. P. 323-334. In R. Lal, J. M. Kimble, R. F. Follett, and B.A. Stewart (ed.) Management of carbon sequestration in soil. CRC Press, Boca Raton.

Staben, M. L., D. F. Bezdicek, J. L. Smith, and M. F. Fauci. 1997. Assessment of soil quality in Conservation Reserve Program and wheat-fallow soil. SSSAJ 61: 124-130.

Bezdicek, D. F., Robert Papendick, and Rattan Lai. 1997. Introduction: Importance of soil quality to health and sustainable land management. p 1-8 in John Doran and Alice J. Jones (ed) Methods for Assessing Soil Quality. SSSA Special Publication No. 9, Soil Science Society of America, Madison, WI.

ACKNOWLEDGEMENTS:

We appreciate the cooperation of the following growers: Mike Cronk, Duane Kjack, Frank Lange, Dick Lloyd, Roger Pennell, Bob Rea, John Rea, Rick Repp, and Garry Schwank in providing plot land.

Contact us: Hans Kok, (208)885-5971 | Accessibility | Copyright | Policies | WebStats | STEEP Acknowledgement
Hans Kok, WSU/UI Extension Conservation Tillage Specialist, UI Ag Science 231, PO Box 442339, Moscow, ID 83844 USA Redesigned by Leila Styer, CAHE Computer Resource Unit; Maintained by Debbie Marsh, Dept. of Crop & Soil Sciences, WSU