ABSTRACT

Cotton growers in Alabama currently use a variety of chemical inputs in conventional tillage systems. While pesticide, machinery, fuel, and labor costs have increased, prices received for cotton lint and seed have seldom increased accordlingly. Federal regulations will require many farms where land is classified as highly erodible to use some form of conservation tillage as a requirement for participation in government programs starting in 1994. Reducing production costs through reducing tillage and/or reducing chemical inputs offers the possibility of maintaining profitability.

Field trials were conducted at the Alabama Agricultural Experiment Station, Belle Mina,AL in 1991 and 1992 to evaluate the economic feasibility of changing tillage systems and reducing chemical inputs. Cotton was planted April 24 both years. Both conventional and conservation tillage systems were evaluated. Conventional tillage consisted of chiseling followed by heavy disking and light disking prior to planting. Conservation tillage consisted of planting into the previous year's cotton stubble after spraying Roundup at 1 quart/A. An in-furrow insecticide, Temik 15G, was used at either 3 lb./A or 5 lb./A at planting. A hopper-box fungicide treatment of Apron + Terrachlor (2 oz/A) was compared to Terrachlor SuperX in-furrow fungicide (8 lb./A). Finally, Cotoran 4L herbicide was used at either 2 pts or 4 pts/A at planting. Cotaran was applied broadcast in notill plots and applied in a band over the row in conventional plots. Conventional plots were cultivated twice each year and post-directed with Bladex + MSMA in order to maintain acceptable weed control. Notill plots received only Cotoran at planting in 1991. In 1992, notill plots were post-directed with Bladex + MSMA in July to supplement the Cotoran treatments. All combinations of tillage, Temik rate, fungicide, and Cotoran rate were represented in a range of treatments. All plots received foliar insecticide sprays as needed. Data obtained included crop stand counts, thrips counts, visual weed control ratings, boll counts, and seed cotton yields. Alabama Cooperative Extension Service cotton production budgets were used to calculate net returns for each treatment assuming 624/lb. for lint, 34/lb. for seed, and no program participation.

Crop stand counts and total bolls per plant were not affected by either tillage or any chemical input variable. Prickly sida and annual morningglory control was good to excellent (avg 90%) in both tillage systems regardless of Cotoran rate. Thrip counts revealed total thrip numbers (adults and larvae) were significantly higher on no-till plots in both years. Thrip counts were not affected by Temik rate either year. Yields were much higher overall in 1992 (avg 3726 lb./A) than in 1991 (avg 1601 lb./A) due to general growing conditions. However, yields were approximately equal for both tillage systems, Temik rates, fungicides, and Cotoran rates in both years. Although yields were not statistically different, the 5 lb Temik rate produced numerically higher yields than the 3 lb rate in conventional tillage systems.

Net returns above variable costs for treatments which provided the lowest and highest dollar amounts in each tillage system show a grower would have made the lowest yearly average of $276/A using no-till with the lower Temik rate and higher Cotoran, or $297/A using these inputs in conventional tillage. Highest net returns in no-till, averaging $304/A yearly were provided using lower Temik and Cotoran rates, while the highest returns in conventional tillage, averaging $337/A, were provided using the higher Temik rate. Net returns above all specified expenses, both fixed and variable, resulted in all treatments losing money in 1991.

Reducing tillage and most pesticide inputs at planting did not greatly affect yield either year. Numerically lower yields overall with no-till treatments resulted in conventional tillage treatments generally providing higher net returns. The 5 lb./A Temik rate provided higher net returns in conventional tillage. During the two years of this study good weather conditions prevailed at planting. Stand counts and thrips control may change significantly in adverse weather conditions. This study indicates that cotton producers in the Tennessee Valley may be able to reduce tillage and some chemical inputs and still obtain positive net returns. The two best no-till treatments compared favorably with some conventional till treatments.