The use of lupine seeds as nitrogen fertilizer

Abstract

We studied the use of lupine seeds as fertilizer to provide a slow release N source. The main objective was to compare different strategies to apply lupine seeds (Lupinus angustifolius L. cv. Azuro and cv. Boruta) as N-fertilizers for a white cabbage crop (Brassica oleracea capitata L. cv. Impuls). Since during the germination process the seedlings use storage carbohydrates as an energy source by respiration, the amount of carbon in the plant and hence the C:N ratio decreases with time. With leaf expansion and the onset of photosynthesis the flow of carbon will invert. Thus the main hypothesis of this research was that incorporating germinated lupine seeds after a certain time of growth (when the C:N ratio reached its minimum value) could increase the N release of this plant-derived fertilizer.

The incorporation of lupine seeds with a short germination period of 12 days increased the N released from this plant-derived fertilizer. However, N release and cabbage yield were similar in this treatment and when shredded lupine seeds were used, which represent a more practical fertilizing method. The use of shredded does not imply soil tillage needed to prepare the seed bed, sowing, and incorporating of seedlings.