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| Rodrigues, M.A.; Coutinho, João; Martins, F.. |
| During 3 consecutive years (1996/97–1998/99) the efficacy was studied of Triticale as a nitrogen (N) catch crop sown after the harvest of the potato crop cultivated in the preceding summer season under several N fertilizer treatments. In October, shortly after the harvest of the potatoes, there were registered significative differences in the soil N–NO3− levels among N fertilizer treatments of the potato crop. The higher values were recorded on the plots corresponding to higher N doses. At the end of winter, the N status of plants and at the end of experiments (late in April), the N–NO3− in soil, the biomass yield and the N uptake by the catch crop did not reflect the differences registered before in the soil inorganic N. This comparison may suggest that... |
| Tipo: Article |
Palavras-chave: Soil residual N; Soil N reserves; N- and biomass yield; Rainfall. |
| Ano: 2002 |
URL: http://hdl.handle.net/10198/2204 |
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| Rodrigues, M.A.; Coutinho, João; Martins, F.. |
| The study was conducted over a 4 year period with the purpose of measuring N mineralization using an in situ incubation technique, following the application of farmyard manure, poultry manure or municipal solid waste. The results varied from –10 % (net immobilization) to +28 % (net mineralization) in relation to the total organic N applied. N fluxes were assessed through plant N analysis during the growing season and through determination of potato tuber dry weight (TDW), N uptake by tubers and the apparent N recovery (ANR) of added N at harvest. Organic material applications slightly increased TDW above the control treatment (9 to 25%), although the results indicate a shortage of N, where no N was added to the crop. The effect of organic fertilization on... |
| Tipo: Article |
Palavras-chave: Farmyard manure; Municipal solid waste; Poultry manure; Nitrogen mineralization; Nitrogen uptake; Solanum tuberosum L.. |
| Ano: 2001 |
URL: http://hdl.handle.net/10198/2205 |
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| Rodrigues, M.A.; Coutinho, João; Martins, F.; Arrobas, Margarida. |
| The quantification of sidedress N rate from in-season information on crop N nutritional status is extremely important in order to use only the necessary amount of nutrient to achieve maximum yields without significant N losses from soil. During three consecutive years (1996, 1997 and 1998) field N fertilizer experiments with irrigated potato (Solanum tuberosum L., cv. Désirée) were conducted in Bragança (NE Portugal). Eight preplant treatments (0, 50, 100, 200 and 300 kg urea-N/ha and poultry manure, farmyard manure and municipal solid waste in rates equivalent to 100 kg organic-N/ha) were arranged as main plots and five sidedress N rates (0, 25, 50, 100 and 200 kg urea-N/ha) included as subplots. Petiole nitrate concentration, determined by a laboratory... |
| Tipo: Article |
Palavras-chave: Solanum tuberosum; Crop N management; Decision support system; Plant analysis; Tissue testing. |
| Ano: 2005 |
URL: http://hdl.handle.net/10198/2201 |
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