Dryland No-Tillage Winter Wheat Response to Planter Type

Crop planting becomes increasingly difficult as surface residue amounts increase, as with conservation tillage. Planters for such conditions are available, but costly. With relatively low residue amounts, as for winter wheat (Triticum aestivum L.) and grain sorghum [Sorghum bicolor (L.) Moench.) grown in rotation on dryland, it was hypothesized that drills used under conventional tillage conditions could satisfactorily plant wheat into no-tillage sorghum residues. Objectives of this study were to test this hypothesis. The information would show whether different planting equipment is needed when switching to a conservation tillage system. Drills were John Deere 8200 (Deere and Co., Moline, IL) with single-disk, Graham-Hoeme PD-160 (United Farm Tools, Oelwein, IA) and Fabco M-10 (Fabco Ltd., Swift Current, SK, Canada) with doubledisk, and International 7100 (J. I. Case, Racine, WI) with hoe openers. No drill provided 1.5 in. (target depth) of seed coverage; it was least (0.75 in.) with the John Deere, which moved more soil from the seed row than other drills. The number of seedlings emerged was not affected by drill types. Mean yields with the John Deere (2000 lb/acre grain; 4200 lb/acre residue) were lower than with other drills (2410 to 2670 lb/acre grain; 4900 lb/acre for residue). Differences in seed coverage depth and soil removal from the drill row possibly caused the yield differences. A suitable drill should be used for planting wheat under conservation tillage, but using a heavy-weight drill, as the Fabco, is not warranted when grain sorghum residues on dryland are similar to the amounts present under the conditions of this study (4900 lb/acre). Research QuestionCrop planting becomes increasingly difficult as surface residue amounts increase, as with conservation tillage. Equipment for planting under high-residue conditions is available, but costly. Some farmers, therefore, are reluctant to switch to conservation tillage. Where residue production is relatively low, however, as for dryland grain sorghum and winter wheat, special planting equipment may not be needed. This study evaluated the effect of three conventional and one heavy-weight drill on establishment and yield of dryland no-tillage winter wheat planted into dryland grain sorghum residues. Study DescriptionThis 3-yr study involved no-tillage planting of winter wheat in residues of the previous grain sorghum crop on Pullman clay loam at Bushland, Texas. The crops were in a dryland rotation that resulted in one wheat and one sorghum crop in a 3-yr cycle with a 10- to 11-mo fallow period after each crop. Chlorsulfuron was applied for weed control during fallow after sorghum. Glyphosate was used for additional weed control during fallow, if needed. Broadleaf weeds in wheat were controlled with 2,4-D. Planters (drills) evaluated were one single-disk opener, two double-disk opener (one light-weight and one heavy-weight), and one hoe opener. Determinations included opener penetration depth, seed coverage depth, emerged seedlings, tillers at harvest, and wheat grain and residue yields. Applied QuestionsIs wheat establishment affected by drill type? Opener penetration depth was greatest for the drill with hoe openers and least for the light-weight drill with double-disk openers. Seed coverage depth was least for the single-disk-opener drill and identical for the other drills, and the number of seedlings emerged within years was similar for all drills. What was the effect of drill type on wheat grain yield? Average grain yield was less (410 to 670 lb/acre) with the single-disk-opener drill than with other drills for which the differences in yield were not significant. Should farmers invest in a heavy-weight drill when adopting a conservation tillage system for dryland winter wheat? Results of this study suggest that farmers having conventional drills with double-disk or hoe openers need not invest in a heavy-weight drill. Farmers having a single-disk-opener drill should evaluate the economics of switching to a different drill. Factors to consider in all cases include grain yield increase expected, grain price, acres to be planted, and drill cost.