Abstract: This experiment was conducted to investigate the effects of adding lactic acid bacteria （LAB） on nutrient composition， fermentation quality and microbial populations of stylo （Stylosanthes guianensis） silage treated with potassium carbonate solutions. Stylo treated with potassium carbonate at different concentrations （0%， 1.5%， 2.0%， and 2.5%） were used as raw materials. Two groups were set up： one with adding lactic acid bacteria （LAB group） and the other with adding an equal volume of sterile water as the control group （CK group）. After 60 days of ensiling， samples were taken， and the nutritional components， fermentation quality， and microbial counts of the stylo silage were measured. The results indicated that spraying potassium carbonate significantly increased the counts of LAB and aerobic bacteria in the silage （P<0.05）， but significantly decreased their water-soluble carbohydrates content （P<0.05）. The addition of LAB significantly increased the lactic acid content in silage and reduced the pH value of the system （P<0.05）. However， the ammonia nitrogen content decreased significantly only in the group treated with 2.5% potassium carbonate solutions （P<0.05）， and there was an increasing trend in butyric acid content across different potassium carbonate levels. Furthermore， the addition of LAB significantly increased the count of LAB in silage （P<0.05） and significantly decreased the water-soluble carbohydrate content （P<0.05）. In summary， spraying potassium carbonate of different concentrations and adding LAB could improve the nutritional value of silage to a certain extent. Therefore， it is recommended to consider adding LAB when preparing semi-dry stylo silage.

Key words: Stylosanthes guianensis, Semi-dry silage, Potassium carbonate, Lactic acid bacteria, Silage quality

摘要： 本试验旨在研究添加乳酸菌对不同浓度碳酸钾溶液处理的柱花草（Stylosanthes guianensis）半干青贮营养成分、发酵品质和微生物数量的影响。以不同浓度碳酸钾（0%，1.5%，2.0%和2.5%）溶液处理的半干柱花草为原材料，设置添加乳酸菌组（LAB组）和添加等体积无菌水为对照组（CK组），青贮60 d后开袋取样，测定柱花草青贮饲料的营养成分、发酵品质和微生物数量。结果表明：喷洒碳酸钾溶液显著地增加了青贮饲料的乳酸菌和好氧细菌数量（P<0.05），但显著地降低了柱花草青贮饲料中的可溶性糖含量（P<0.05）。添加乳酸菌显著增加了半干青贮饲料的乳酸含量，降低体系pH值（P<0.05），但其氨态氮含量仅在2.5%碳酸钾处理组中显著下降（P<0.05），甚至不同浓度碳酸钾处理间均有丁酸含量增加趋势。此外，添加乳酸菌显著增加了半干青贮饲料中乳酸菌数量（P<0.05），显著降低了可溶性糖含量（P<0.05）。综上所述，喷洒不同浓度碳酸钾溶液和添加乳酸菌一定程度上可改善半干青贮饲料营养价值。因此，建议在调制柱花草半干青贮饲料时，可考虑同时添加乳酸菌。

关键词: 柱花草, 半干青贮, 碳酸钾, 乳酸菌, 青贮品质