Dry matter and water-soluble carbohydrate contents of Italian ryegrass at cutting as affected by environmental factors [Lolium multiflorum Lam.; Piedmont]
2004
Tabacco, E. (Turin Univ. (Italy). Dipartimento di Agronomia, Selvicoltura e Gestione del Territorio) | Borreani, G. (Turin Univ. (Italy). Dipartimento di Agronomia, Selvicoltura e Gestione del Territorio) | Valente, M.E. (Consiglio Nazionale delle Ricerche, Grugliasco, Turin (Italy). Istituto di Scienze delle Produzioni Alimentari) | Peiretti, P.G. (Consiglio Nazionale delle Ricerche, Grugliasco, Turin (Italy). Istituto di Scienze delle Produzioni Alimentari)
Italian ryegrass (Lolium multiflorum Lam.) is a high yielding crop widely grown in Italy as a Winter crop preceding maize for silage in the same year. This research studied the effect of weather conditions, plant maturity, ploidy and rate of application of N fertilizer on dry-matter (DM) content, water-soluble carbohydrates (WSC), buffering capacity (BC), total plant nitrogen (TN) and nitrate content of Italian ryegrass grown in Winter and Spring as a double crop with maize. The research was carried out from 1991 to 1996 in Po Valley, Italy. A data set of 168 observations was available for regression analyses. A multiple regression analysis was used to correlate DM content, WSC, BC and nitrate content to weather and crop variables. DM content at cutting was inversely related to nitrogen application. DM content at cutting was high in the very early stages of crop maturity, decreased quickly to reach a minimum around the middle period of stem elongation and then increased with maturity, varying from 101 to 326 g kgE-1 fresh matter (FM). The diploid cultivars, on average, had a DM content of 20 g kgE-1 FM higher than the tetraploid ones. The WSC content showed a great variability, ranging from 94 to 474 g kgE-1 DM. Night temperatures in the three days before harvesting, rate of application of N fertilizer applied in Spring and advanced stage of development negatively affected WSC content. BC was observed to have a high variability with no significant relationship to the measured climatic and plant variables. For ensiling, it is necessary to selected diploid cultivars and to limit N fertilizer top dressing especially when a large amount of organic N was applied to the preceding maize crop, in order to avoid herbage with low DM and WSC contents at cutting
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