Theses and Dissertations

Issuing Body

Mississippi State University


Irby, Jon Trenton

Committee Member

Dodds, Darrin M.

Committee Member

Sarver, Jason M.

Committee Member

Catchot, Angus L. Jr.

Committee Member

Maples, William E.

Other Advisors or Committee Members

Golden, Bobby R.

Date of Degree


Original embargo terms

Visible to MSU only for 1 Year

Document Type

Dissertation - Open Access



Degree Name

Doctor of Philosophy


College of Agriculture and Life Sciences


Department of Plant and Soil Sciences


Experiments were conducted to evaluate the most profitable and effective management practices for non-irrigated soybean production. Common production practices were compared side by side to evaluate yield response and economic returns. Combinations of row spacings and planting dates were evaluated to determine interactions between the two factors and also the effects on yield. Lastly, the effectiveness of various iron sources was examined in iron deficiency chlorosis (IDC) susceptible soybeans when applied foliar, inurrow at planting, and a split application. These data suggest that in non-irrigated soybeans, “low input management” practices do not maximize yields, but can be more profitable, depending on soybean market price and input costs, when compared to “full management”. Results also reveal that no interaction between row spacing and planting date occurred with respect to soybean yield. However, planting date did influence soybean yield with the earlier planting dates, mid-April, and mid-May providing the greatest yield. When examining row spacing, soybean grown on rows spaced 38.10 cm apart resulted in greater yield when compared to those grown on 96.52 cm rows. The iron product that consistently provided the greatest visual reduction of IDC symptoms was Sequestar 6% EDDHA chelate applied at 0.20 and 0.27 kg ai ha-1. This treatment was only effective when applied inurrow at planting. However, it was found that soybean yield was not influenced by any iron product or application timing, indicating that visual symptoms of IDC may be managed, but that the visual reduction in symptoms does not translate into yield.