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Broccoli, potatoes, cucumbers and green peas were fertilized respectively with 241, 168, 168 and 28 kg N ha-1. The N accumulation was equivalent to the fertilizer application rates for the broccoli, potatoes and cucumbers while the peas accumulated 321 kg N ha-1. Vegetable yields were not affected by previous cereal rye cover crops when compared to the fallow control. Cover crops following broccoli accumulated the least and peas the most N. Inorganic N in the top 30 cm at harvest were significantly different between vegetables, but not in the 30-60 cm depth.
Chicken manure and ammonium nitrate as N sources were compared. Broccoli was the test crop and was fertilized with both sources at 241 kg N ha-1. Broccoli yields and N accumulation were different between sources of N and between N and no-N treatments. Inorganic N leaching was greatest with ammonium nitrate fertilization and chicken manure was similar to the no-N fertilizer treatment.
A fish waste/hemlock-fi r sawdust compost (FWC) was evaluated as a container growth medium and N source for the greenhouse production of marigold (Tagetes patula `Queen Sophia') and geranium (Pelargonium xhortorum `Sprinter Scarlet') in 10-cm containers. Treatments were a factorial set of three Douglasfir bark (B)/three FWC mixtures (100% FWC; 50% FWC/50% B; 100% B) and three rates of N fertilizer (0, 300 and 600 ppm N) applied every 2 weeks. After the initial irrigation, plants were drip-irrigated to negate leaching from the containers.
Weekly measurements of leachate conductivity, pH, and inorganic N were made on additional replications of the 0-ppm N plants in all growing media. Plant height and width were measured at 2-week intervals and, at the end of the production cycle, flower number, shoot fresh and dry weight, visual quality, and root dry weight were measured. The growing medium by N interaction was significant for all variables. Results indicated that plants receiving 0 ppm N in 100% FWC were larger and of higher quality than plants in 100% B receiving 600 ppm N. In 100% FWC, marigold shoot growth, dry weight, and quality were not influenced by N rate. The observed geranium and marigold growth response indicated that FWC was an effective N source and growing medium when leaching was minimized with drip irrigation.