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No-tillage was compared to conventional tillage from 1983 to 1986 in a barley-fallow-cotton-cropping sequence. There was an 11 month fallow period between barley harvest and planting of dryland cotton. Immediately after cotton harvest, the area for barley was disked and rebedded prior to planting and then irrigated to assure emergence. Barley was irrigated three times in the spring and yielded from 60 to 80 bu/A. Conventional tillage during the fallow period was a combination of disking, sweeping, bedding, rolling cultivation, 2.0 lb/A prometryn preemergence, along with cultivation and hoeing the crop. With no-tillage, atrazine, and fluometuron at 1.5 and 2.0 lb/A mixed with dicamba at 0.5 lb/A were sprayed on barley stubble immediately after harvest for residual control of volunteer and weeds during the fallow period. Glyphosate was sprayed on weeds that escaped. Volunteer barley that escaped was difficult to control, usually requiring two sprays of glyphosate at 0.25 lb/A. In early April, 2,4-D and prometryn at 0.5 and 2.0 lb/A were sprayed to control weeds prior to and after planting in May. The cotton was cultivated and hoed once. Primary weeds were flixweed, kochia, and Russian thistle in barley and in the spring prior to planting; and pigweed, puncturevine, witchgrass, and stinkgrass in the cotton. About 12 operations were required with conventional tillage, and 7 with no-tillage from barley harvest to cotton harvest. In 3 of the 4 years a 10 percent granular formulation of aldicarb was banded over the seed row at 1.0 lb/A at planting for control of thrips Gravimetric soil water samples were taken to 6 feet at 1 foot increments just prior to planting cotton. Aldicarb gave excellent control of thrips and increased yield an average of 10 lb/A lint with conventional tillage and 18 lb/ with no-tillage. However these increases were not significant a the 5 percent level. Lack of significance was due to low thrip infestations 2 of the 3 years and an early frost causing lo yields the year with severe thrips infestation. Over the 4 years average yield from no-and conventional tillage was 331 and 23 lb/A lint, respectively, or an increase of 97 lb/A for no-tillage. Increased yield with no-tillage was the result of 1.8 inches o additional stored soil water at planting. Although production costs were higher, increased yield and reduced machinery depreciation made no-tillage over $40.00 per acre more profitable than conventional tillage. |
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©National Cotton Council, Memphis TN |
Document last modified Sunday, Dec 6 1998
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