Silage Quality Of Forages In Hulunbuir Grassland

To learn the silage quality of forages in hulunbuir grassland,163forage materials from27samplingpoints were collected and made into163raw materials and163silages, which were chosen to determinethe contents of nitrate, nitrite, lead, chromium, cadmium, mercury and arsenic. The main conclusionsare as follows:1.All163raw materials and163silages had nitrate and nitrate, and lead and chromium were detected inall silages while cadmium, mercury and arsenic not. Contents of7kinds of poisonous chemicals wereall below the allowable levels of National Hygienical Standard for Feeds.2.Contents of nitrate and nitrite lowered after ensiling. Nitrate contents in84.66%samples lowered20%~50%; nitrite contents in2silages increased respectively23.60%and10.20%while the otherslowered2%~50%. Reduced levels of nitrate content in Iris lactea and Astragalus membranaceus wereall lower than30%while Elytrigria repens and Scutellaria baicalensis lowered52.02%and52.20%respectively; reduced levels of nitrite content in3forage species including Linum stelleroides, Irislactea and Astragalus membranaceus were lower10%while Inula britanica up to40.34%.3.No matter raw materials or silages, contents of nitrate and nitrite in leguminosae were bothhigher;gramineae had higher nitrate content while lower nitrite content; labiatae and rosacea had highernitrite content while lower nitrate content; contents of nitrate and nitrite in compositae were both lower.Contents of lead, chromium, cadmium and arsenic in labiatae silages were higher while mercury contentlower; leguminosae silage had higher contents of mercury and arsenic while lower cadmium content;gramineae silage had higher mercury content while lower chromium content; compositae silage hadhigher lead content while lower contents of chromium, cadmium, mercury and arsenic; rosaceae silagehad higher contents of chromium, cadmium and mercury while lower contents of lead and arsenic.4.163silages were classified into6groups by clustering analysis.87.12%silages belonged to the fristgroup with lower contents of poisonous chemicals;4.30%silages belonged to the second group with thehigher nitrate content and the lower nitrite content;2.45%silages belonged to the third group withhigher nitrite content while lower contents of cadmium, mercury and arsenic;4.30%silages belonged tothe forth group with higher contents of chromium,cadmium and lead while lower contents of nitrite andarsenic;1.23%silages belonged to the fifth group with the lowest nitrate content while higher content ofnitrite, lead, chromium,cadmium,mercury and arsenic; the sixth group included only No.59sample withlower contents of lead and chromium while higher contents nitrate,nitrite,cadmium, mercury and arsenic.Contents of7kinds of poisonous chemicals were lower in18species including Stipa baicalensis,Agropyron cristatum and Leymus chinensis; Agrostis matsumurae and Inula britanica had highercontents of chromium, mercury and arsenic while lower contents of nitrate, nitrite and cadmium;Cleistogenes polyphylla and Astragalus membranaceus had higher contents of nitrate, nitrite, mercuryand arsenic while lower chromium content.