Full Text
(55 K)

The Effect of Cover Crop and Crop Rotation on Cotton: Soil-Plant Relationship

D.M. Azevedo, J.A. Landivar, R.M. Vieira, D.W. Moseley


In the lower Coastal Bend Region of Texas, rainfall during the critical fruiting and boll filling periods is often deficient in terms of cotton (Gossypium hirsutum L.) needs. Crop yield is closely related to stored soil moisture in dryland areas. Cropping strategies to improve infiltration and/or storage of rainfall in the soil would benefit the crop by providing more moisture at critical periods of growth. A field trial was conducted in 1995 (as part of a long-term cropping experiment) on a predominant Victoria Clay soil to investigate the effect of cover crop and crop rotation on soil water storage and cotton growth. The experimental design was a randomized complete block in a split plot arrangement, with four replicates. Cotton rotations comprised of continuous cotton, cotton/sorghum [Sorghum bicolor (L.) Moench], and cotton/soybean [Glycine max (L.) Merr] were the main plots and oat (Avena sativa L.) cover crop (cover and no-cover), the subplots. Cover crop was seeded on September 1994 at the rate of 170 kg/ha and terminated with herbicide on January 1995. Plots were 13.7m wide and 61m long. Soil moisture measurements were taken only on cotton/sorghum rotation every 15 days period during the growing season. Cotton cultivated under cover crop had its growth reduced when compared to cotton under no-cover. This effect was correlated to reduced amount of available soil N and less soil water storage at the cover system in the beginning of the growing season. The oat residue in the soil acted as a N sink through competition and/or immobilization instead of an N source to cotton. The time of cover termination was certainly responsible for more soil water use by the oat plants and a consequent less soil water storage in the beginning of the cotton growing season. Consequently, this effect was aggravated by the lack of adequate rainfall during the first period of cotton plant growth, i.e., from planting to blooming stage. Crop rotation had no significant effect on cotton growth, but plant height and DM yield were consistently higher under continuous cotton than under rotation.

Reprinted from Proceedings of the 1996 Beltwide Cotton Conferences pp. 1405 - 1410
©National Cotton Council, Memphis TN

[Main TOC] | [TOC] | [TOC by Section] | [Search] | [Help]
Previous Page [Previous] [Next] Next Page
Document last modified Sunday, Dec 6 1998