Skip to main content
ARS Home » Pacific West Area » Kimberly, Idaho » Northwest Irrigation and Soils Research » Research » Publications at this Location » Publication #63119
Title: SUBSOILING AND SURFACE TILLAGE EFFECTS ON SOIL PHYSICAL PROPERTIES AND FORAGE OAT STAND AND YIELD

Author
item Sojka, Robert
item HORNE, D - MASSEY UNIVERSITY, NZ
item ROSS, C - LANDCARE RESEARCH, NZ
item BAKER, C - MASSEY UNIVERSITY, NZ

Submitted to: Soil & Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/1/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Soils found in wet environments are prone to compaction from intensive cropping. Subsoiling and/or conservation tillage are often initiated to combat compaction once the problem has been recognized. This study compared forage oat response to conventional and no-tillage surface management in systems without subsoiling or with subsoiling from one of three commercial subsoilers, deep (36cm) and shallow (30cm) standard subsoilers, and the paraplow (40cm). Results showed that stand establishment was best with no-till, and that yield was better for any of the subsoiled treatments than without subsoiling. Decreased soil strength, greater soil aeration, and increased saturated and slightly unsaturated hydraulic conductivity were associated with the three deep tillage operations, especially paraplowing. The combination of surface no-tillage with subsoiling gave the best overall performance, with the Paraplow giving the highest yield of the three subsoiling implements. The worst treatment was the surface tilled, non-subsoiled treatment, which corresponded to the prevailing practice throughout most of New Zealand. This study demonstrates that adoption of new no-till and deep tillage technologies can be of great benefit for cropping systems in wet climates like those of New Zealand.

Technical Abstract: Much of New Zealand's agriculture integrates animal and crop production on poorly drained, easily compacted soils. We hypothesized that soil properties affecting forage oat establishment on land compacted by 15 yrs of conventional cropping was influenced by subsoiling/surface- tillage combinations. Plots on a Moutoa silty clay (Typic Haplaquoll) were Paraplowed (P), deep subsoiled (V), shallow subsoiled (S), or were non-subsoiled controls (C). Subsequently, the surface 15 cm was surface-tilled (T) by a power rotary-tiller and firmed with a Cambridge roller or were not tilled (N). Oats were then sown with a cross-slot drill. Subsoiling greatly reduced soil strength. Cone indices (CI) showed disruption to 40 cm with P, 36 cm for V, and 30 cm for S. About 60% of CI's from subsoiled treatments were <1.5 MPa, compared to 30% for non-subsoiled plots. Surface tillage (T) slightly improved CI distribution in non-subsoiled controls but had little effect in subsoiled treatments. Subsoiling without surface tillage continued to reduce profile CI 233 days after subsoiling. Surface tillage reduced emergence for 142 to 113 plants m-2 and reduced yield from 5318 to 3679 kg/ha. Forage yield increased from 3974 to 4674 kg/ha with subsoiling. Soil porosity, saturated and slightly unsaturated hydraulic conductivities and air permeability were highly variable but generally increased with subsoiling. ODR was also variable, but non-tilled non- subsoiled treatments had lower ODRs than surface tilled or subsoiled treatments. Generally, subsoiling without surface tillage produced better soil conditions and oat crop performance than the prevailing New Zealand practice of surface tillage without subsoiling.