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在盆栽试验中,用~(15)N_2还原法测定稻株总氮,其中1.09%来自接种的固氮蓝藻。蓝藻当季固定的氮素只有11.93%被利用。接种蓝藻增加稻田的氮量为16.3kg·hm~(-2)。实验室条件下按固氮量推算,自然水稻田土壤生物固氮量为14.2kg·hm~(-2),植株总氮的16.8%来自生物固氮;接种蓝藻的稻田土生物固氮量为31.2kg·hm~(-2),比自然稻田多固氮17kg·hm~(-2),植株总氮的25.8%来自生物固氮。测定北京稻田土固氮酶还原 C_2H_2与 N_2的转换比在2.71～3.71:1之间。
In the pot experiment, total nitrogen was determined by ~ (15) N_2 reduction method, of which 1.09% was from inoculated nitrogen - fixing cyanobacteria. Cyanobacteria fixed nitrogen only 11.93% of the time being used. Inoculation of cyanobacteria increased the nitrogen content of paddy field to 16.3kg · hm -2. According to the nitrogen fixation amount under laboratory conditions, the amount of nitrogen fixation in soil was 14.2kg · hm -2, and 16.8% of the total nitrogen was from biological nitrogen fixation. The amount of nitrogen fixation in the paddy soil inoculated with cyanobacteria was 31.2kg · hm ~ (-2), which is 17 kg · hm -2 more nitrogen fixation than natural paddy field, and 25.8% of the total nitrogen comes from biological nitrogen fixation. The conversion ratio of C_2H_2 to N_2 in soil nitrogenase was determined to be between 2.71 ~ 3.71: 1 in Beijing.