| To solve the issues about reduced biological activity of potato soil and decreased potato tuber yield and quality in the soil by long-term application of large amounts of fertilizer,this experiment will screen the five plant growth promoting rhizobacteria(PGPR)(QHZ-1,QHZ-2,QHZ-3,QHZ-4,QHZ-5)Through using secondary biofermentation process to prepare a small test product of bio-organic fertilizer.Pot experiment was conducted to study the application of no fertilizer(control,CK)and chemical fertilizer(CF),general organic fertilizer(OF),amino acid hydrolyzate(AA)and five bio-organic fertilizers(BOF1,BOF2,BOF3,BOF4 and BOF5)on soil biological activity(number of culturable microorganisms,microbial biomass carbon/nitrogen,enzyme activity,etc.)and the effect of potato root growth,morphology,vigor,and tuber yield.The main results are as follows:(1)The application of bio-organic fertilizers can significantly increase the amount of culturable bacteria and actinomycetes in the soil and reduce the number of culturable fungi.Compared with other treatments,the amount of soil culturable bacteria treated with the five bio-organic fertilizers was higher since the tuber formation stage of the potato,and the difference between the treatments reached the maximum at the ripening stage,the amount of culturable bacteria in the soil treated with five bio-organic fertilizers averaged 52% higher than CF,37% higher than OF,and 54% higher than AA.Among the five bio-organic fertilizers,BOF2 and BOF3 being the most significant that increased 52 %?37 %?54 % and 53 %?38 %?55 % than CF,OF and AA.,the increase of OF is small.It means application of common organic fertilizer can increase the amount of culturable bacteria in the soil.All bio-organic fertilizers from the tuber can suppress the increase of the number of fungi in the soil,to a starch accumulation period,the difference between the five kinds of bio-organic fertilizers and other treatments reaches the maximum,compared with CF,the decline of OF and AA from 55 % to 58 %,there was no significant difference among the five organic bio-fertilizers.The amount of culturable actinomycetes in all bio-organic fertilizer-treated were significantly higher than that of other treatments since the tuber formation stage of the potato,and the difference between the treatments reached the maximum when the tuber enlargement period was reached.The increase of the number of five bio-organic fertilizer treatments soil-cultured actinomycetes was 45% to 55%,35% to 45%,and 46% to 56%,respectively,compared with CF,OF and AA,BOF2 and BOF3 were the most significant results,which were 52%,41%,54% and 55%,43%,56% higher than those of CF,OF and AA.The increase in OF was smaller.Indicating that the application of common organic fertilizer can increase the number of culturable actinomycetes in the soil.(2)Application of bio-organic fertilizers can significantly increase soil microbial biomass carbons and nitrogenThe microbial biomass carbons of part of five bio-organic fertilizers significantly higher than that of other treatments from the potato seedling stage,and the difference between treatments reached the maximum at the maturity stage.The average of the five bio-organic fertilizer treatments was 31% higher than that of CF,27% higher than OF,32% higher than AA,with BOF2 and BOF3 being the most significant,higher 33%,29%,34% and 38%,34%,39% than CF,OF,and AA.The soil microbial biomass nitrogen of all bio-organic fertilizer treatments was significantly higher than that of other treatments from the potato seedling stage,and reached the maximum in the starch accumulation period.The average of the five bio-organic fertilizer treatments was 24% higher than CF and 16% higher than OF,26% higher than AA,and BOF3 had the most significant effects,36%,27% and 38% higher than CF,OF and AA.(3)Bio-organic fertilizers application can significantly increase soil enzyme activitiesThe urease activities of all bio-organic fertilizer treatments and OF was significantly higher than that of other treatments from the beginning of potato seedling stage,and reached the maximum during the tuber formation period.five kinds of bio-organic fertilizer on average were higher than CF,OF and AA 37%,36% and 39%,Among them,the effects of BOF2 and BOF3 were the most significant,which were increased by 50%,49%,53% and 62%,61% and 64% respectively compared with CF,OF and AA.The small increase of OF can indicate that the application of common organic fertilizer can also increase soil urease activity;The invertase activities of all bio-organic fertilizer treatments was significantly higher than that of other treatments since the seedling stage of the potato,and the difference between the treatments at the ripening stage reached the maximum,Compared with CF,OF and AA,the average increase rate of sucrase activities in soils treated with five kinds of bio-organic fertilizers was 11% to 128%,BOF3 had the most significant effects.Among them,the effect of BOF3 was the most significant,which was increased by 130 %,20 % and 145% respectively compared with CF,OF and AA.The increase of OF was relatively small,indicating that application of common organic fertilizer can also increase soil invertase activity;The phosphatase activities of all bio-organic fertilizers was significantly higher than that of other treatments since the seedling stage of the potato,and the difference between the treatments of tuber enlargement reached the maximum.The increase of soil phosphatase activities by 5 bio-organic fertilizers was 25% to 74% higher than that of CF,OF and AA.Among them,the effects of BOF2 and BOF3 were the most significant,which were 78%,28%,63% and 81%,30% and 65% higher than those of CF,OF and AA.The increase of OF was smaller,indicating that organic fertilizers were also used.Increase soil phosphatase activity;The activities of catalase in all bio-organic fertilizer treatments was significantly higher than that of other treatments since the potato seedling stage,and the difference between tuber enlargement treatments reached maximum,The activities of catalase in the soil treated with five bio-organic fertilizers were increased by 9% to 16% compared with CF,OF and AA.The effect of BOF3 was most significant,which was 13% and 12% higher than CF,OF and AA,respectively;the increase of OF is smaller,it can be shown that the application of common organic fertilizer can also increase soil catalase activity.(4)The application of bio-organic fertilizers can significantly improve the morphology of potato roots and increase root biomass and root activities.The total root lengths of BOF3 and CF were significantly higher than those of other treatments since the seedling stage of the potato,and BOF3 was significantly higher than other treatments,and the difference between tuber expansion treatment reached the maximum,which was 0.69,0.83 and 1.14 times higher than those of CF,OF and AA respectively;The root surface areas of BOF2,BOF3 and CF were significantly higher than those of other treatments since the seedling stage of the potato,even higher than that of other bio-organic fertilizers,and the difference between treatments reached the maximum at the ripening stage.The root surface area of five kinds of bio-organic fertilizers was significantly higher than other treatments,compared with CF,OF and AA,the root surface area of five kinds of bio-organic fertilizer treatment increased by an average of 0.69,0.37 and 0.87 times,with the BOF3 effect being the most significant.0.98,0.61,and 0.82 times higher than CF,OF and AA;The root volume of BOF3 in bioorganic fertilizer treatment was significantly higher than that of other treatments from the tuber formation stage of potato,and reached the maximum at the tuber formation stage,which was 1.49,3.14,and 3.7 times higher than CF,OF and AA respectively.The number of root tip of BOF3 in bio-organic fertilizer treatment was significantly higher than that of other treatments from the beginning of potato tuber formation,and the difference between the treatments at maturity was the largest,the root tip number of BOF3 increased by 1.04,0.75 and 2.31 times compared with CF,OF and AA respectively.The biomass of all bio-organic fertilizers was significantly higher than that of other treatments from the beginning of potato seedling stage,and reached the maximum difference between the treatments at maturity stage.The biomass of roots treated with five bio-organic fertilizers increased by 0.73,0.51 and 1.17 times on average compared with CF,OF and AA.Among them,the effect of BOF3 was the most significant,which was 1.27,0.97 and 1.81 times higher than CF,OF and AA respectively;The root vigor of all bio-organic fertilizer treatments was significantly higher than that of other treatments from the beginning of potato tuber formation,and the difference between treatments at the starch accumulation stage was the largest,and the root activity of five bio-organic fertilizer treatments was higher than that of CF,OF,and AA.It was increased by 1.93,1.48 and 2.08 times,among which the effect of BOF3 was the most significant,which increased by 3.25,2.61 and 3.41 times compared with CF,OF and AA respectively.(5)The application of bio-organic fertilizers can significantly increase potato tuber yieldCompared with CF,OF and AA,all bio-organic fertilizer treatments increased average tuber yield by 16%,21% and 30%.Among the five bio-organic fertilizer treatments,the effect of BOF3 was the most significant,which was 22%,28% and 38% higher than those of CF,OF and AA respectively.(6)Correlation analysis showed that there was a significant positive correlation among the amount of soil culturable bacteria,actinomycetes and microbial biomass and enzyme activity(P<0.01);there was a significant positive correlation between potato root growth,morphology and vigor,and soil bioactivity indicators.(P<0.01).In summary,the bio-organic fertilizer supplemented with PGPR increases the amount of soil culturable microorganisms,microbial biomass carbon,microbial biomass nitrogen,and enzyme activity,improves the biological activity of the soil,the rhizosphere environment of the potato,thereby increasing the The root absorption ability of potato promotes potato root growth and increases potato tuber yield. |
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