| In order to investigate the effect of azotobacter fertilizer on the growth of Eucalyptus grandis×Eucalyptus urophylla and its effect on soil nutrition.Based on the Eucalyptus Special Fertilizer(N16% P6% K9%)in Gaofeng forest farm,Treatment 1(N16%+ P6% + K9% +1% azotobacter liquid),CK1(N16%+ P6% +K9%),Treatment 2(N8%+ P6%+ K9% +1% azotobacter liquid),CK2(N8%+P6%+ K9%)and the four fertilizer ratios as Eucalyptus grandis×Eucalyptus urophylla fertilizer,which the stochastic group design was used for afforestation,and the growth measurement,soil microorganism,soil enzyme activity and soil fertility related indexes were analyzed for 1.5 years.The main results are as follows:(1)After 6 months first fertilization,the growth of Eucalyptus grandis×Eucalyptus urophylla the treatment 2 average tree height compared with CK2 growth of 6.2%,treatment 1 average tree height compared with CK1 growth 5.1%,treatment 1 average diameter compared to CK1 growth13.3%,treatment 2 average diameter compared to CK2 growth 8.2%;10 months after first fertilization,The treatment 1 average tree height was 9.2% higher thanCK1,the treatment 2 average tree height was 7.9% higher than that CK2,the treatment 1 average chest diameter increased 14.3% compared with CK1,and the treatment 2 average chest diameter increased by 6% compared with CK2.14 months after first fertilization,the treatment 1 average tree height was 10%higher than CK1,the treatment 2 average tree height was 2.9% higher than CK2,18 months after first fertilization,the treatment 1 average tree height was 8.5%higher than CK1,the treatment 2 average tree height was 1.2% higher than CK2,and the treatment 1 average diameter was 4.8% than CK1,The treatment 2average chest diameter was 5.8% higher than CK2,in general,the effect of the treatment 1 on the growth of Eucalyptus grandis×Eucalyptus urophylla was significant after first fertilization,and the fertilization control of azotobacter liquid was better than that of the fertilization control group which was not added to the azotobacter liquid.(2)Addition of azotobacter liquid in the early stage of fertilization(6months after first fertilization)did not significantly increase the number of soil azotobacter,but the increase in the number of bacteria was very significant.14 months later,after first fertilization by the second fertilizer effect,treatment 1increased the number of azotobacter in the soil,treatment 1 compared to CK1 azotobacter the growth rate was 92.1%,treatment 1 compared to the gap control azotobacter the growth rate was 30.9%.18 months after first fertilization,treatment 2 had a significant effect on the increase of soil azotobacter,treatment 2 compared with CK2 azotobacter growth the rate was133.8%,treatment 2 compared with the gap control azotobacter growth the rate was 29.5%.Compared with CK1 and CK2 pure inorganic fertilizer did not significantly enhance the role of soil azotobacter quantity,and azotobacter fertilizer belongs to organic fertilizer,fertilizer efficiency was relatively slow,it needed for lasting fertilization to play the effect of fattening.(3)According to the correlation analysis of soil microbial quantity and soil enzyme activity and other soil factors,the number of azotobacter was positively correlated with catalase,the number of azotobacter and soil moisture content reached a significant positive correlation,according to the results of correlation analysis Pearson coefficient,the number of azotobacter in fertilization 6months,10 months and 14 months were positively correlated with protease activity,and the effect of fertilization with azotobacter liquid was significantly improved.Therefore,the artificial cultivation of Eucalyptus grandis×Eucalyptus urophylla plantation is suitable for the use of azotobacter fertilizer,which is beneficial to increase the growth of Eucalyptus grandis×Eucalyptus urophylla and the number of azotobacter in soil microorganisms,and enhance the nitrogen fixation effect of the eucalyptus root system.(4)The addition of azotobacter treatment 2 on the soil total nitrogen,total phosphorus,available phosphorus,available potassium content of the lifting effect is better than other treatment.In summary,treatment 1 has significant efficiency in the growth of eucalyptus trees,because of the long-term nitrogen-administered fertilizer hasSoil compaction and other problems,more should consider the ecological effect of fertilization;The effect is reflected in the increase of the number of microorganisms,especially the increase in the number of nitrogen-fixing bacteria,the increase of protease activity,the increase of potassium nitrogen and phosphorus content in soil,etc. |
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