| Selenium(Se)is an essential trace element for the body,and the application amount of Se is limited.The supplied general raw materials for selenium(RMS)are chosen to prepare the fermentation broth,in which the accumulation capacity of organic Se is relatively weak and safety risk.In order to ensure the biological safety of Se,to selected as natural fruit and vegetable waste(leaves,fruits and stems)to prepare Se-enriched Agricultural fermentation broth(SAFB)by means of fermentation broth preparation.This not only solves the problem of Se loss and Se poisoning caused by long-term application of inorganic Se,but also solves the difficult problem of controlling the selenium content of natural Se-enriched raw materials.It is an effective way to realize the efficient recycling of agricultural waste.At the same time,there are many problems in the preparation of SAFB,such as poor fermentation stability,many influencing factors,and less refinement of application standards.Therefore,it is particularly important to solve the problems of safety,scale and application standardization in the actual preparation of SAFB.In order to solve preferably such problems,the influen ce characteristics of different RMS on the accumulation capacity of organic Se,it based on the influence of different RMS on SAFB.Through the control of six single factors,such as temperature,material amount,raw material,raw material ratio,glycogen,analysis of different factors and levels on the stability of products,nutrients and antioxidant quality differences.Through the action of multiple factors,the process parameters of three kinds of SAFB were determined.By constructing these mathematical models,such as entropy weight fuzzy mathematical model,principal component analysis(PCA)and so on,we can use it to analyze and evaluate the measured results,which will provide necessary theoretical and technical support for the development and appli cation of SAFB.The main finding and conclusions are as follows:(1)Under the influence of the different RMS,the total selenium content and organic selenium accumulation capacity in SAFB were different,which leaded to the risk of Se poisoning in SAFB.Compared with Se yeast and common raw materials,the organic Se accumulation ability of SAFB was significantly increased(P<0.05)when natural Se rich raw materials were used as RMS.The organic Se accumulation in SAFB prepared from three natural Se-enriched raw materials(Chinese cabbage,cucumber and pepper)reached:90%,86.67%and79.69%,and they were 36.83%,51.12 and 27.07%higher than which in SAFB prepared from Se yeast+common raw material.Through the evaluation model,it showed that natural Se-riched raw material RMS was more beneficial to improve the Se biosafety of SAFB.(2)In the process of single factor preparation,the influence of each factor and level on the stability,nutrient,antioxidant,organic Se accumulation rate and other indexes of SAFB product was different.The results showed:with the increase of temperature,the quality of SAFB also improved,but the low temperature(9?)inhibited the fermentation rate obviously,and the preparation was not completed at 100d.The quality of SAFB decreased when the additive amount of material was lower or higher,and the SAFB quality was the best when the additive amount was 28%.In the 12 samples treated with brown sugar and white sugar respectively,the quality of SAFB treated with brown sugar was significantly higher than that treated with white sugar(P<0.05).With the increase of natural Se content,the organic Se accumulation ability of SAFB changed obviously.When the natural Se content was 0.100 mg·kg-1-0.150 mg·kg-1,the organic Se accumulation rate of SAFB was significantly higher than that of other treatments(P<0.05).At the same time,it was found that the organic Se accumulation ability of tomato,Chinese cabbage,pepper and cucumber in Hailun was significantly higher than that of other raw materials(P<0.05).When tomato was used as auxiliary material,cabbage,cucumber or pepper as main material,and the ratio of auxiliary material and main material was 5:5,the comprehensive ranking of SAFB was significantly higher than that of other treatments.Through the entropy weight fuzzy mathematics evaluation model,the evaluation system was established with temperature,material addition,glycogen,natural Se content,raw materials and raw material ratio as the influencing factors,and the results were evaluated to determine that the selected index was reasonable.(3)The four kinds of Se-enriched fruit and vegetable wastes(tomato,cucumber,pepper and Chinese cabbage)from Hailun City,Heilongjiang Province(126°97'E,47°46'N)were finally selected as the mixed raw materials in consideration of the significance and consideration of the factors and experimental indicators(the natural Se content was adjusted to 0.100mg·kg-1).The preparation process of SAFB was established:the fermentation temperature was 27?,the amount of material added(the mass ratio of brown sugar to raw material was 1:3)was 28%,and the fermentation time was 100 days.According to the preparation process,the accumulation rate of organic Se in SAFB was significantly improved.SAFB was rich in organic matter,total acid,total amino acid,GABA and other nutrients,and rich in calcium,magnesium,cobalt,manganese and other metal elements.(4)Through indoor cultivation experiments,the remediation effect of SAFB and c ommon agricultural fermentation broth on continuous cropping obstacle soil and the growth and stress resistance of M.micromalus were evaluated.Correlation analysis and PCA were used to analyze soil nutrients(Organic matter,alkali-hydrolyzable nitrogen,readily available phosphorus and readily available potassium),soil enzymes(urease,sucrase,phosphatase and catalase)and soil microorganisms(Bacteria,actinomycetes,and fungi).During the remediation period,SAFB maintained soil nutrient content significantly higher than that of ordinary agricultural fermentation broth,had significantly higher effect on soil urease activity than that of ordinary agricultural fermentation broth,and had obvious inhibitory effect on pathogens and stimulating effect on beneficial bacteria.Through the establishment of an evaluation system,it showed that SAFB was more suitable for the remediation of continuous cropping obstacle soil than the common agricultural fermentation broth.Compared with common agricultural fermen tation broth,SAFB significantly improved the growth and resistance of Malus octularis.It showed that the activities of SOD,POD and CAT in the roots were significantly correlated with plant height,ground diameter,fresh weight and dry weight.(5)The results showed that under the same retreatment time,the decrease of alkalization degree of soil treated by SAFB was significantly higher than that of soil treated by common agricultural fermentation broth.In the remediation of alkalized soil with different dilution ratios of SAFB,it showed that the dilution ratios of 100 and 1000 times were significantly lower than those of other treatments,and the dilution ratio interval of SAFB was determined.(6)Through indoor flower pot cultivation,six gradients of SAFB with dilution multiples of200,350,500,650,800 and 950 are selected to monitor and analyze the alkalization degree and soil nutrients of the soil during the 60-day restoration period.Compared with the control group,all treatments promoted the decrease of soil alkalinity and improved soil fertility.At 5d,10d,15d,25d and 60d,the soil ESP of each treatment was significantly negatively correlated with the increase of CEC and available potassium(P<0.05),and was significantly positively correlated with the increase of p H,exchangeable sodium ions,and EC(P<0.05).Through the establishment of an evaluation system,it showed that SAFB can promote the restoration of alkalinized soil. |
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