Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/15/2000
Publication Date: 6/1/2000
Citation: Raper, R.L., Reeves, D.W., Schwab, E.B., Burmester, C.H. 2000. Reducing soil compaction of tennessee valley soils in conservation tillage systems. Journal of Cotton Science. 4 pp. Interpretive Summary: Reduced cotton yields have been found by many farmers in the Tennessee Valley Region of North Alabama when they attempted to adopt no-till farming. Soil compaction limited their yields and prevented proper root elongation. Measurements of soil strength were obtained after a four- year period in a systems experiment that included different depths of tillage, different times of tillage, and the use of cover crops. Results showed that reduced soil compaction and crop yields similar to conventional tillage systems could be achieved simply by adding cover crops. A trend also existed that indicated that fall in-row tillage in conjunction with a cover crop produced the greatest yields. Farmers wishing to adopt conservation tillage systems can use a cover crop and shallow in-row tillage to maintain surface residue without sacrificing crop yield.
Technical Abstract: Inadequate rooting systems from excessive soil compaction have prevented farmers in the Tennessee Valley Region of North Alabama from adopting conservation tillage systems. Cotton (Gossypium hirsutum L.) yields declined on many farms when conventional tillage systems were not used and strict no-till systems were adopted. Experiments were initiated in 1994 to develop conservation tillage systems that incorporated in-row tillage and rye (Secale cereale L.) cover crops as methods of maintaining surface cover and alleviating extreme soil compaction conditions. Depth of in-row tillage [18 cm (7 in) or 33 cm 13(in)] and timing of tillage (fall or spring) were factors also investigated for this experiment. Cone index measurements taken in the spring and fall of 1997 prior to tillage and bulk density measurements taken in fall of 1998 immediately after harvest were used to examine changes in soil condition resulting from several years of experimentation. The results showed reduced cone index and bulk density from either shallow or deep in-row tillage performed in the spring or fall of the year. Although fall measurements in no-till plots showed no effect of cover crops, spring measurements of cone index were found to be reduced substantially by the use of cover crops, most likely due to increased soil moisture. Therefore, reduced soil compaction beneath the row to depths adequate to sustain proper root growth was achieved by either shallow in-row tillage and/or cover crops.