水稻根际固氮量及根系不同部位的固氮活性

• 作 者: 莫文英 贾小明 钱泽澍
• 机 构: 浙江农业大学,浙江农业大学,浙江农业大学
• 出 处: 土壤学报
• 发表日期: 1985年01期
• 关键词: 固氮量 固氮活性 早稻品种 根段 供试水稻品种 乙炔还原法 固氮细菌 腐生性 细菌数 微生物群落

采用乙炔还原法测定水稻根际原状土粒的固氮活性,以3∶1的换算比例推算为田间固氮量。每季水稻根际固氮量早稻为0.4一0.45斤氮/亩/66天;晚稻为0.6—0.79斤氮/亩/72天。其中早稻80—90%的氮素在抽穗至成熟期固定,而晚稻在这段期间固定的氮素占总数的40—52%。经多次测定表明:水稻根系不同部位固氮活性的趋势是,埋入土中带根基茎段2.5厘米活性最高,根基以下3厘米根段次之,3厘米以下根段活性很低,水稻根系结合的腐生性细菌以固氮菌占优势,同时也含有少量的丁酸固氮梭菌。

The acetylene reduction method was used to determine the nitrogen fixation activity in rhizosphere of rice rhizosphere. The 3: 1 conversion ratio was used to calculate the amount of nitrogen fixation in the field. The nitrogen fixation rate of rice in rhizosphere every season was 0.4-0.45 kg nitrogen / mu / 66 days and that of late rice was 0.6-0.79 kg nitrogen / mu / 72 days. Among them, 80-90% of the nitrogen in early rice was fixed from heading to maturity, while that of late rice was 40-52% of the total during this period. The results showed that: the trend of nitrogen fixation activity in different parts of rice roots was that 2.5 cm was the highest activity in roots with roots embedded in the soil, followed by 3 cm roots below roots and very low in roots below 3 cm. The saprophytic bacteria are predominantly Azotobacter, and also contain a small amount of Clostridium butyricum.