| Preliminary research in the laboratory has shown that continuous cropping of Lilium brownii var.viridulum Baker can lead to soil acidification,decline of soil fertility,imbalance of soil microbial community structure,aggravation of soil-borne diseases,accumulation of autotoxic substances,and decline of seed bulbs yield and quality.Based on the previous research results,this study plans to conduct a two-factor(improvement application and planting years)triple-replicate plot experiment in the on-campus practice base of Hunan Agricultural University,and plans to use the single application of alkaline fertilizer(T1,application rate of 0.1kg/m~2),the single application of biochar(T2,application rate of 0.05 kg/m~2)and the combined application of alkaline fertilizers and biochar(T3,application rate of 0.15 kg/m~2,alkaline fertilizer:biochar=2:1),they were randomly applied to the soil of Lilium brownii var.viridulum Baker of 1 year of planting(1a),2 years of continuous cropping(2a)and 3 years of continuous cropping(3a).The effects on plant growth,soil environment,yield and quality of seed bulbs were determined respectively,laying the foundation for the subsequent multi-factor orthogonal block experiments in the field,in order to explore the method of alleviating the continuous cropping obstacles of Lilium brownii var.viridulum Baker.The research results are as follows:(1)Effects on growth index of Lilium brownii var.viridulum Baker160 days after treatments,the relative chlorophyll content(SPAD value)of leaves,plant height and stem diameter were determined.The results showed that after treatments,the relative chlorophyll content(SPAD value)of leaves and the plant height of Lilium brownii var.viridulum Baker of 1 year of planting,2 years of continuous cropping and 3 years of continuous cropping were not significantly increased compared with the control(CK);after the single application of alkaline fertilizer(T1)and the combined application of alkaline fertilizers and biochar(T3),the stem diameter of 1-year Lilium brownii var.viridulum Baker was significantly increased by 0.24 and 0.29units respectively.(2)Effects on soil enzyme activity index of Lilium brownii var.viridulum Baker126 days(growth period),192 days(blooming period),272 days(bulb expansion period),and 300 days(harvest period)after treatments,the soil urease(S-UE)activities of Lilium brownii var.viridulum Baker in the four periods,soil sucrase(S-SC)and soil acid phosphatase(S-ACP)activities of Lilium brownii var.viridulum Baker in the harvest period were measured respectively.The results showed that after the combined application of alkaline fertilizer and biochar(T3),the soil urease activity of Lilium brownii var.viridulum Baker of 1 year of planting and 2 years of continuous cropping was significantly increased by 6.20%and 18.52%compared with the control(CK)respectively;after three treatments,there was no significant difference in soil sucrase activity compared with the control(CK);after the single application of alkaline fertilizer(T1)and the single application of biochar(T2),the soil acid phosphatase activity of Lilium brownii var.viridulum Baker of 1 year of planting was significantly decreased by 23.15%and 24.67%compared with the control(CK).(3)Effects on microorganisms in the rhizosphere soil of Lilium brownii var.viridulum Baker300 days after treatments,the number of fungi,bacteria,and bacteria/fungi in the rhizosphere soil of Lilium brownii var.viridulum Baker were determined.The results showed that after three treatments,the number of soil fungi in the rhizosphere of Lilium brownii var.viridulum Baker of 1 year of planting was significantly reduced compared with the control(CK),among which the single application of biochar(T2)significantly reduced the most,which was 96.95%,and the single application of alkaline fertilizer(T1)reduced the least,which was 90.27%;after the single application of alkaline fertilizer(T1),the number of soil bacteria in the rhizosphere soil of Lilium brownii var.viridulum Baker of 1 year of planting was significantly increased by 1291.67%.(4)Effects on soil p H of Lilium brownii var.viridulum Baker126 days(growth period),192 days(blooming period),272 days(bulb expansion period),and 300 days(harvest period)after treatments,The results showed that the single application of alkaline fertilizer(T1)and the combined application of alkaline fertilizer and biochar(T3)could significantly improve the soil p H of Lilium brownii var.viridulum Baker of 2 years and 3 years of continuous cropping compared with the control(CK).The single application of alkaline fertilizer(T1)significantly increased soil p H by 0.11～0.76 units during the whole growth period of Lilium brownii var.viridulum Baker of three planting years.(5)Effects on the content of autotoxic substances in the rhizosphere soil of Lilium brownii var.viridulum Baker300 days after treatments,the content of 2,4-di-tert-butylphenol in the rhizosphere soil of Lilium brownii var.viridulum Baker was determined.The results showed that three treatments could significantly reduce the content of 2,4-di-tert-butylphenol in the rhizosphere soil of Lilium brownii var.viridulum Baker of 1 year of planting and 3 years of continuous cropping compared with the control(CK).The single application of biochar(T2)significantly reduced the content of 2,4-di-tert-butylphenol by 27.01%,19.78%and 34.82%respectively in the rhizosphere soil of Lilium brownii var.viridulum Baker of 1 year of planting,2 years of continuous cropping and 3 years of continuous cropping,and the content of 2,4-di-tert-butylphenol in the rhizosphere soil of Lilium brownii var.viridulum Baker of 3 years of continuous cropping was the lowest which was 0.410μg/g.(6)Effects on yield and quality of Lilium brownii var.viridulum Baker300 days after treatments,the bulbs were harvested and the yield and quality(the soluble sugar content)index of Lilium brownii var.viridulum Baker bulbs were determined.The results showed that compared with the control(CK),the single application of alkaline fertilizer(T1)and the single application of biochar(T2)significantly increased the bulbs yield of 1-year planting and 2-year continuous cropping by 123.17%and 23.78%and 55.56%and 28.36%respectively;the single application of alkaline fertilizer(T1)and the combined application of alkaline fertilizer and biochar(T3)significantly increased the soluble sugar content of Lilium brownii var.viridulum Baker bulbs of 1 year of planting by 45.49%and 87.45%.In conclusion,adding alkaline fertilizers and biochar to the soil can promote the growth of Lilium brownii var.viridulum Baker to a certain extent,change the soil environment for continuous cropping,and improve the yield and quality of Lilium brownii var.viridulum Baker bulbs.Among them,alkaline fertilizer has a significant effect on soil microorganisms and p H,and biochar can significantly reduce the content of autotoxic substances in soil.The synergistic effect of three treatments on Lilium brownii var.viridulum Baker of 3-year continuous cropping and the combined application of alkaline fertilizer and biochar is not obvious,and it needs to be further optimized by multi-factor orthogonal experiments on its concentration and ratio. |
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