| Flue-cured tobacco is an important commercial crop in China, and Sichuan Province is a main province that planting flue-cured tobacco. And Liangpan ecological zone are the main production areas of flue-cured tobacco. A good soil ecological environment is the basis of obtaining high-quality flue-cured tobacco, and content of phenolic acids in the planting tobacco soil affect the growing of tobacco plants and the quality of flue-cured tobacco directly. Therefore, with the Liangpan ecological zone plant tobacco soil in sichuan province as the research object, considering the altitude, soil type, fixed number of year of the previous, crop planting and other influencing factors, a total of 335 soil samples collected, the determination of soil pH, organic matter, soil nutrients, total phenol, phenol, water-soluble phenolic compound state and phenolic acids, monomer phenolic acids, explore the planting tobacco soil allelochemicals accumulation characteristics and its influencing factors. The main results were as follows:(1) Overall characteristics of phenolic acids accumulation and change of soil phenolic acids in the tobacco planting soils in Liangpan area? Liangpan climbing flue-cured tobacco soil phenolic acids of allelochemicals accumulation characteristics obviously. Compare the plant tobacco and no-planting tobacco soil, total phenol, phenol, water-soluble phenolic increased by 4.2 times,5.1 times and 3.4 times, reached significant level. In terms of the monomer phenolic acid, planting tobacco soil in p-hydroxy benzoic acid, ferulic acid, benzoic acid, cinnamic acid, vanillic acid content than no-planting tobacco soil were increased by 3.8 times,3.9 times,3.8 times,3.6 times,7.4 times.? Liangpan climbing flue-cured tobacco soil accumulation of phenolic acids allelochemicals change significantly between different ecological area. YanYuan biome, low temperature, strong light, promoted the formation of phenolic acids in soil, its planting tobacco soil total phenolic acids, phenolic composite state, water-soluble phenolic content reached 2843.1 ug/g,1304.82 ug/g and 142.07 ug/g, significantly higher than Renhe and Huidong area. The phenolic acids in the plant tobacco soil of Renhe biome has the characteristics of formed quicly and decomposited quicly. water-soluble phenolic compound state in the cumulative effect is weak, inferior YanYuan biome. Is located in the valley area of the Huidong zone, air temperature, rainfall is relatively stable, phenolic acids matter accumulation is not obvious, and the coefficient of variation is small.(2) Effects of altitude and soil type on the phenolic acids in tobacco growing soils.? During 1200-2000m altitude, YanYuan and Huidong zones rooted in the soil content of total pHenol, phenol, water-soluble phenolic compound state increases with altitude increases; When the altitude is greater than 2000 m, YanYuan biome plant smoke total pHenol, compound state of pHenol content in the soil have dropped significantly.? Soil phenolic acids between different soil types have significant accumulation of allelochemicals. Smoke planting paddy soil total phenolic acids, phenolic composite state, benzoic acid, p-hydroxy benzoic acid content is higher, respectively was 2885.39 ug/g, 1632.47 ug/g and 12.91 ug/g,68.74 ug/g, significantly higher than that of red soil and purple soil. Plant smoke the lowest total phenolic acid, benzoic acid content in red soil, only 2140.37 ug/g.9.47 ug/g, significantly lower than in paddy soil and purple soil.(3) The elevation of soil phenolic acids accumulation had different effects.? Soil pH, organic matter on the accumulation of phenolic acids allelochemicals influence is bigger. When soil pH between 5.5 to 6.0, the soil total phenol, phenol, water-soluble phenolic compound state, vanillic acid, benzoic acid, ferulic acid, p-hydroxy benzoic acid content were presented significant accumulation. Directly affect the formation of phenolic acid conversion of soil organic matter, the influence of all kinds of phenolic acids were extremely significant level. When the organic content of 20-30 g/kg, the highest soil total phenol, compound state of phenol content, then decreased with increasing organic matter content of continue.? Soil nutrient change and the accumulation of the phenolic acids allelochemicals in the soil there is a close relationship between. Soil AN content< 60 mg/kg, planting tobacco soil total phenolic acids cumulant lowest, AN> 90 mg/kg, total phenolic acid content increases with soil AN content and accumulation; The content of soil AP> 5 mg/kg, total phenolic acid content decreased with increasing the effective phosphorus content; Soil AK content in 100-150 mg/kg, total phenolic acid content of the highest. AK content is less than 100 mg/kg or greater than 150 mg/kg. total phenolic acid content is on the decline.(4) Effect of crop rotation and duration on tobacco soil phenolic allelochemicals? Previous to crop soil accumulation of phenolic acids allelochemicals features has significant influence. The overall trend is:leisure (3116.24 ug/g)> perennial ryegrass (2407.85 ug/g)> barley assists (2379.86 ug/g)> light flower shao (2087.35 ug/g) (and)> light assists flower shao (1974.15 ug/g) (YanYuan). Had significantly lower crop planted before the leisure soil the effect of phenolic acids matter accumulation, crop for light assists before flower shao is the most effective, the total phenol, water-soluble phenolic, p-hydroxy benzoic acid and ferulic acid were more leisure soil is lower by 36.7%,24.0%,20.2%,14.1%.? Plant fixed number of year of the smoke on the soil phenol acids allelochemicals accumulation effect is remarkable. With the increase of fixed number of year, planting tobacco soil in all kinds of phenolic acids content of allelochemicals are showing up before falling or stable characteristics. Water-soluble phenolic acids in plantation age in 1-3 years, its content reached a maximum 142.34 ug/g, and this is obviously the flue-cured tobacco production began to appear in the disease symptom time points, showed that water-soluble phenolic is the main factor of the toxic effect.(5) Analysis on main controlling factors of phenolic acids in soil of Liangpan areaPhenolic acids soil allelochemicals and the regression analysis, the factors which influence the results showed that the soil pH. organic matter, soil types on soil total phenol, phenol compound state, the influence of water-soluble phenolic reached extremely significant level (P<0.01), the organic matter of compound phenol, total phenol content explain independently reached 29.6% and 25.0% respectively; The most significant the influence of altitude on hydroxyl benzoic acid, cinnamic acid in the next; Previous, crop organic matter is the main influence factors of ferulic acid explain independently are 13.2% and 13.2% respectively; Cinnamic acid, vanillic acid affected by preceding crop and soil pH is the largest. In agricultural production, may choose the effect better crop before, through the improvement of the soil pH, organic matter to control the accumulation of phenolic acids in soil material, improve the soil quality, to ensure sustainable agricultural production. |
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