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Spring Crop Choice (Canola, Lentil, Cereal, Bluegrass) and Tillage Influence
on Yields, Erosion and Weed Control

Ray Olson
with Paul Peterson and Lawrence Brown, Spokane Co. Extension;
Baird Miller and Ron McClellan, WSU

Objective

Evaluate the effects of tillage and spring only rotation crops on weed control, erosion, and residue and humus.

• Location: Mt. Hope (Rockford), WA
• Annual precipitation: 17 inches
• Soil series: Larkin silt loam
• Rotation:
  • 95 - spring rotation crops
  • 94 - winter wheat
  • 93 - spring rotation crops (lentil and canola plots)
  • 92 - winter wheat
  • 91 - lentil

Treatments

Spring rotation crops: lentil, wheat, canola, Kentucky bluegrass.
Tillage: Deep Tillall, light Tillall, standing stubble, deep chisel, uphill plow, light disk.

Comments

These plots were established following winter wheat severely infested with grassy weeds including jointed goatgrass, wild oats and cheatgrass. Plots are small, ranging from .075 to .137 ac., and were harvested in their entirety. Bluegrass was in the establishment year and not harvested for seed.

Two applications of Roundup, 10-14 days apart were made, followed by spring tillage operations and late spring seeding. Recommended rates of herbicide were applied to all crops: lentil - Sencor and Post; canola - Tri-4 and Post; wheat - buctril and Hoelon. Spring wheat had 175#/ac 25-10-0-7 banded with the seed; lentil and canola received no fertilizer. Crop yield by tillage is reported below (Tables 1-3) as well as a comparison of canola and lentil yields for all tillage treatments (Table 4).

Crop residue measurements were taken at harvest from all spring wheat plots and samples for canola and lentil were taken at a later date from between the light Tillall and standing stubble treatments only. These results are compared below by using the averaged spring wheat measurements for light Tillall and standing stubble treatments (Table 5). This may be misleading as spring wheat overall appeared to produce more residue than canola. Spring wheat residue by tillage treatment is also compared below (Table 6).

Data

Yield of canola x tillage, lb/ac

Treatment	Rep 1	Rep 2	Rep 3	Average
Deep Tillall	992	263	552	602
Light Tillall	803	213	672	563
St. stubble	934	541	590	688
Deep chisel	869	426	410	568
Uphill plow	705	721	639	688
Light Disk	587	853	880	773
CV			33%

Not significant at 20%

Yield of lentil x tillage, lb/ac

Treatment	Rep 1	Rep 2	Rep 3	Average
Deep Tillall	929	540	373	614
Light Tillall	1180	656	459	765
St. stubble	951	623	754	776
Deep chisel	721	754	607	694
Uphill plow	525	607	689	607
Light Disk	400	533	613	515
CV			30%

Not significant at 20%

Yield of spring wheat x tillage, bu/ac

Treatment	Rep 1	Rep 2	Rep 3	Average
Deep Tillall	33.3	39.4	33.8	35.5
Light Tillall	38.8	43.5	32.8	38.3
St. stubble	36.6	35.5	37.7	36.6
Deep chisel	32.5	30.9	35.8	33.1
Uphill plow	30.3	35.8	49.5	38.5
Light Disk	29.3	37.3	31.6	32.7
CV			15%

Not significant at 20%

Yield of canola vs lentil for all tillages, lb/ac

Treatment	DT	LT	Stub	DC	Plow	Disk	Average
Canola	602	562	688	568	688	773	647
Lentil	614	765	776	694	607	515	662
CV							18%

Not significant at 20%

Spring crops residue from between light Tillall and standing stubble treatments, lb/ac

Treatment	Rep 1	Rep 2	Rep 3	Average
Sjpring wheat	2661	3176	3204	3013a
Canola	2522	2988	3660	3057a
Lentil	1929	1345	1069	1448b
CV				21.1%
LSD (5)				1197 lb

Not significant at 20%

Spring wheat residue x tillage, lb/ac

Treatment	Rep 1	Rep 2	Rep 3	Average
Deep Tillall	2661	3170	3320	3050a
Light Tillall	2787	3264	2489	2847a
St. stubble	2534	3088	3678	3100a
Deep chisel	3275	2315	2796	2795a
Uphill plow	2382	3142	5442	3655a
Light Disk	2092	2927	3689	2902a
Deep Tillall (no fert.)	3872	2266	3071	3070a
Uphill plow (no fert.)	3697	3638	4235	3857
CV				22.8%

Conclusions

First year yield data showed no differences for any crop by tillage. Also, no significant yield differences when comparing canola to lentil. Residue for the treatment measured (light Tillall/standing stubble, Table 5) showed a significant disadvantage to lentil but not canola.

In the tillage treatments, deep chisel was observed to be the worst choice for erosion control followed by shallow Tillall, then deep Tillall. Uphill plowing appeared to be effective but some soil was probably lost. Standing stubble was observed to be the most effective treatment against erosion in a very bad erosion year.

Germination of weed seed was greatest with light disking, followed by deep chisel. Uphill plowing was the worst. However, crop competition with weeds was the best in the uphill plow, followed by deep Tillall and light disking. Standing stubble was the worst for weed competition.

Spring seedbed preparation was poorest with light disk followed by standing stubble and deep chisel.

Future results may shed light on the other questions being asked.

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