Document Type

Thesis - Open Access

Award Date

1982

Degree Name

Master of Science (MS)

Department

Plant Science

First Advisor

Paul E. Fixen

Abstract

Sunflower (Helianthus annuus L.) has recently become a major crop in the north-central United States. This is the result of the development of high yielding oilseed hybrids, a steadily expanding export market and the plant's inherent adaptability to severe weather conditions. During the early part of this century research was conducted throughout the nation investigating sunflower's potential for silage. As farmer interest declined, the crop was almost forgotten until the introduction of high oil cultivars from the Soviet Union where sunflower had been grown for oil since the mid-1700's. The discovery of cytoplasmic male sterility and fertility restoration then made possible the production of large quantities of pure hybrid seed. Production in North America originally centered around the Red River Valley of North Dakota, Minnesota and Manitoba, but has steadily expanded to the south and west. Presently, it is grown on 200,000 hectares in South Dakota and ranks sixth in area planted to crops in this state. As the importance of sunflower in South Dakota has grown, the need for research under local growing conditions has also grown. This study began as a field calibration of the nitrate soil test and has grown into a more general study of the fertility needs of the sunflower plant. This thesis will concern itself with two aspects of the subject: 1) Seed yield, seed oil percentage and plant nitrogen content response to nitrogen fertilization, and 2) Description of the dry matter production and nutrient uptake patterns and partitioning of the sunflower plant.

Library of Congress Subject Headings

Sunflowers
Nitrogen fertilizers
Plants, Effect of nitrogen on
Sunflowers -- Fertilizers and manures

Format

application/pdf

Number of Pages

88

Publisher

South Dakota State University

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