Differences in the nutritive value of two rice straw varieties as influenced by season and location

Two varieties of rice straw, MR 84 and MR 77, harvested from three locations and over two consecutive cultivation seasons, were compared for their botanical composition, chemical composition and in vitro dry matter digestibility (IVD). For both varieties, botanical composition was not significantly different between seasons (P > 0.05) but the IVD of whole straw was significantly higher in the main season (P < 0.01). The proportion of stem and blade and the contents of ash and silica were significantly different between locations (P < 0.01). Canonical correlations between seasons and between locations were significant (P < 0.01) and positive for chemical composition and IVD suggesting that varietal differences were consistent across these environmental influences.