| A series of problems such as the decline of agricultural production efficiency and the quality of agricultural products because of the neglect of organic fertilizer application and the destruction of agricultural ecological environment in peanut production.Bacillus subtilis,Paenibacillus polymyxa and Trichoderma harzianum,which can promote the growth of peanut were selected from the strains preserved in the laboratory and made into a compound microbial agent.Effects of the application amount of the compound microbial agent on the growth of peanut and the changes of bacterial flora in the rhizosphere soil of peanut were studied by pot experiment.The main results are as follows:1?Effects of Bacillus subtilis,Paenibacillus polymyxa,Trichoderma harzianum and their compound microbial agent on peanut growth were studied by sand culture with chlorophyll content,main agronomic characters,protective enzyme activity and MDA content as index.The results showed that the chlorophyll content,plant height and the first branch length of peanut were 47.03 SPAD,26.50 cm and 8.97 cm,respectively,which were7.06%,25.71%and 52.55%higher than those of the control,and the protective enzyme activity in roots,stems and leaves of peanut were significantly increased and MDA content was reduced when the compound microbial agent 2 kg/666.7m~2 was applied.The aboveground fresh mas,the aboveground dry mass,the fresh weight of shoot and the dry weight of shoot weight of peanut seedlings increased by 23.60%,137.50%,29.76%and77.78%compared with the control.2?Effects of different application rates of compound microbial agents on the SPAD value of chlorophyll,main agronomic characters,protective enzyme activity,MDA content and yield components of peanut were studied by pot experiment.The results showed that the application of compound microbial agents could increase the value of chlorophyll SPAD in peanut leaves,enhance the main agronomic characters of peanut,significantly improve the activities of protective enzymes in peanut roots,stems and leaves,and reduce the content of MDA.When the dosage was 1.5 kg/666.7m~2,the number of pods per plant,weight of pods,weight of seeds,weight of 100 fruits,weight of 100 kernels and yield per plant of peanut increased by 24.63%,20.22%,14.10%,4.86%,7.63%and 12.85%respectively compared with the control.3?Effects of compound microbial agents on soil nutrients changes.The results showed that the content of total nitrogen,alkali hydrolyzed nitrogen,available potassium and water soluble calcium in the soil increased by 26.60%,14.15%,18.41%and 99.88%compared with the control when the application amount of compound microbial agent was 1.5kg/666.7m~2.pH value,organic matter,total potassium and available phosphorus in the soil increased by 1.31%,16.17%,8.47%and 45.45%compared with the control when the application amount was 2.0 kg/666.7m~2.4?The high-throughput 16S r DNA sequencing of rhizosphere soil bacteria was carried out by using the method of paired-End on the I11umina HISeq sequencing platform,combined with alpha diversity analysis,beta diversity analysis and apparent species diversity analysis.The results showed that the composition of rhizosphere soil bacterial community including Sphingomonas,Gemmatimonas,Bryobacter,Nitrospira,RB41 and some groups to be divided,which had been changed at genus level by using compound microbial agents.Sphingomonas and RB41 were dominant in the rhizosphere soil at four growth stages.The diversity index analysis and PCA analysis of rhizosphere soil samples based on the software of mothur(version v.1.30)showed that the bacterial communities of rhizosphere soil samples with different treatments were quite different at different growth stages,which improved the bacterial abundance and dominant species of the community at the genus level. |
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