A Survey Of Distribution And The Effect Of Additives On The Quality Of Silage Of Cynanchum Komarovii And Astragalus Variabilis In Alxa Left Banner

Cynanchum komarovii and Astragalus variabilis are two main poisonous weeds in western China, distributed in Inner Mongolia, Ningxia, and Gansu Provinces. The toxic principle in A. variabilis is swainsonine, whereas in C. komarovii the main toxic substance is still unknown. Animals which have consumed these two weeds will be poisoned or even dies, which poses a great damage to the grassland and animal husbandry. Although poisonous weeds have been a particularly important part of the ecological communities of the grassland, most research on these two of poisonous weeds are focused on their toxic ingredients and controlling methods, rather than paying attention towards their development and utilization. Since 2008, there has been no update on the status of poisonous weeds in the Left Banner of Alxa, and therefore this study investigated the distribution of the two poisonous weeds from quadrat sampling. The results provided useful information for grassland management for the local authority.In this thesis, I studied the effect of different additives on the quality of silage of the two plants, by evaluating fermentation quality, nutritional value and toxic substance degradation. The results would facilitate the exploitation of these two poisonous weeds in silage.The main findings include:1. In a two-year survey, I observed that the distribution areas of C. komarovii and A. variabilis are 3.95-4.63 and 0.13-1.02105 ha, which showed a marked difference with previous results. This might occur because different sampling strategies were employed. Through a further analysis, I showed that the relative abundance of both poisonous plants not significantly influence species diversity within the ecological community.2. In order to examine the effect of additives on the silage on C. komarovii, I tested lactic acid bacteria (at levels of 1 mg/kg,23mg/kg and 45 mg/kg) and cellulose (at levels of 25 mg/kg,50 mg/kg and 100 mg/kg) respectively. After 60 days of silage, I determined the fermentation quality indexes (sensory evaluation, pH, ammonia nitrogen content, soluble carbohydrates, lactic acid, acetic acid, propionic acid and butyric acid content) and nutritional indexes (dry matter, ash, crude protein, crude fat, neutral detergent fiber, acid detergent fiber, calcium and phosphorus). Results showed that that both additives improved silaging quality, especially at their intermediate and high concentrations. High concentration of the two additives yielded the best result.3. In an aim to test the effect of different treatments on the silage on A. variabilis, I used lactic acid bacteria (at levels of 1 mg/kg,23mg/kg and 45 mg/kg), cellulose (at levels of 25 mg/kg,50 mg/kg and 100 mg/kg), myclobutanil (at levels of 4μl/ml,8μl/ml and 10μl/ml) and azoxystrobin (at levels of 1μg/ml,2.5μg/ml and 5μg/ml) respectively. After 60 days of silage, I determined the fermentation quality indexes (sensory evaluation, pH, ammonia nitrogen content, soluble carbohydrates, lactic acid, acetic acid, propionic acid and butyric acid content), nutritional indexes (dry matter, ash, crude protein, crude fat, neutral detergent fiber, acid detergent fiber, calcium and phosphorus) and in addition, the content of swainsonine. Results showed that additives such as lactic acid bacteria and cellulose have a positive effect on the silage of A. variabilis. At intermediate and high concentrations, these two additives significantly improved silaging quality, and the high concentration group worked best. However, none of the groups of different concentrations of myclobutanil and azoxystrobin had any positive effect. Furthermore, the levels of swainsonine after silaging remained the same.