Fresh market broccoli (Brassica oleracea L. var italica) production is increasing in southcentral Virginia because it provides growers with a new economic opportunity while complementing the traditional tobacco-growing in that region. Little research data is available for vegetable fertilization on these southern Piedmont soils. The objectives of this study were to amend the current recommended nitrogen rates for broccoli production, and to measure plant N uptake and soil nitrate status throughout the growing season in order to develop an efficient N fertilization program for this emerging industry. A preliminary study in 1985 indicated no significant yield response to eight treatments varying in amount of total N applied from 56 to 290 kg N/ba. A more detailed study was conducted in 1986 with N treatments expanded as follows: main plot factor of base rate N at 0, 56, 112, and 168 kg N/ha, and 3 subplot factors of 0, 1, or 2 sidedressings at 56 kg N/ha each applied at 3 and 6 weeks after seeding. Yield differences for base rate N were significant at the first harvest only, while sidedressing effects on yield were significantly different for 3 of the 4 harvests and total yield. Nitrogen uptake during the first 32 days after seeding (DAS) was minimal, 0.17 kg N/ha/day, but increased to 8.05 kg N/ha/day during head formation (55 to 77 DAS). Initial soil nitrate status was 52 kg NO₃-N/ha in the top 25 cm and decreased to 10.6 kg NO₃-N/ha in the control plot by the end of the season. Total N uptake of broccoli with no fertilizer applied averaged 200 kg N/ha demonstrating the capability of these soils to supply N. These results suggest the current practice of applying the first sidedressing at 3 weeks after seeding may not be necessary. However, later sidedressings, prior to and during head formation, are recommended to maintain an adequate available nitrogen supply throughout the growing season. / M.S.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/106148 |
| Date | January 1987 |
| Creators | Borowski, Alicia M. |
| Contributors | Horticulture |
| Publisher | Virginia Polytechnic Institute and State University |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis, Text |
| Format | x, 57 leaves, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | OCLC# 17012906 |
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