Effects Of Biogas Slurry,biogas Residue And Sodium Selenite Treatment On Growth Characteristics And Nutritional Quality Of Brassica Napus Sprouts

Biogas slurry and biogas residue are the main byproducts of biogas production that are commonly used for agricultural production because of its abundant nutrients and microelements.Selenium is an essential trace element in human body.Appropriate intake of selenium plays an important role in maintaining life activities and ensuring health.Brassica napus l.,a brassica herb crop in brassica of brassicaceae,is rich in vitamins,ascorbic acid,and polyphenols,which are beneficial to human body.in addition,the content of bioactive substances in brassica sprouts is significantly higher than that of their mature nutrients.In order to solve the problem of treatment of biogas slurry and biogas residue and study the growth characteristics and selenium enrichment effect of Brassica napus sprouts under the biogas slurry and biogas residue culture.In this study,the effects of different treatments on sprouts growth characteristics and nutritional quality of Brassica napus were discussed by setting different biogas slurry concentrations（5%,10%,15%,20%）,biogas residue mixed substrate volume ratio（1:10,1:5,3:10,2:5）and sodium selenite concentration(50μmol·L^-1,100μmol·L^-1,150μmol·L^-1).Based on the growth characteristics（Sprout length,Fresh weight,Dry weight Moisture content,）,antioxidant enzyme activity（Superoxide dismutase activity,Peroxidase activity,Catalase activity）and nutritional quality（Soluble sugar,Soluble protein,Vitamin C）of Brassica napus sprouts,the most suitable biogas slurry concentration and biogas residue mixed substrate volume ratio were sought,and then selenium-enriched Brassica napus sprouts were cultured.According to the related indicators and selenium-enriched effects,the best combination of biogas slurry and biogas residue with sodium selenite was determined,and the economic benefits of biogas slurry biogas residue and sodium selenite were calculated,which provided theoretical basis and support for the cultivation of biogas slurry biogas residue and the industrial production of selenium-enriched Brassica napus sprouts.The main conclusions include:（1）The biogas slurry concentration of 5%-20%can obviously promote the growth of Brassica napus sprouts,significantly improve the sprout length,fresh weight and dry weight of sprouts,but has no significant effect on the nutritional quality of sprouts.Among them,BS2 significantly increased the sprout length on the fourth and eighth days,increasing by 80.47%and 116.38%respectively.On the fourth day,the fresh weight and dry weight of BS3 increased significantly by 24.33%and51.20%respectively,and on the eighth day,the fresh weight and dry weight of BS4increased significantly by 106.29%and 77.24%respectively.According to the results of enzyme activity index determination,the stability of antioxidant enzyme activity of the sprouts was improved to some extent by different concentrations of biogas slurry.（2）The ratio of biogas residue mixed substrates（vermiculite:perlite is 2:1）of1:10,1:5,3:10 and 2:5 can obviously promote the growth of Brassica napus sprouts,and the content of vitamin C is significantly increased,except BR4,which significantly improves the sprout length,fresh weight and dry weight of Brassica napus sprouts,indicating that the ratio of biogas residue mixed substrate is too high,which will inhibit the growth of Brassica napus sprouts,and should not exceed 2:5.Among them,on the fourth day,the sprout length of the Brassica napus sprouts was significantly increased by BR1,and on the eighth day,the sprout length of the Brassica napus sprouts was significantly increased by BR2,which increased by36.83%and 39.61%respectively.On the fourth day,the fresh weight and dry weight of BR1 and BR2 increased significantly by 34.47%and 13.50%respectively,and on the eighth day,the fresh weight and dry weight of BR1 increased significantly by69.05%and 57.06%respectively.According to the results of enzyme activity index determination,the stability of antioxidant enzyme activity of sprouts with different proportions of biogas residue mixed substrate was improved to some extent.（3）Four kinds of biogas residue mixed substrates（vermiculite:perlite is 2:1）with four kinds of biogas slurry concentrations can promote or inhibit the growth of Brassica napus sprouts.Any biogas residue mixed substrate with 20%biogas slurry concentration can not promote or inhibit the growth of Brassica napus sprouts.When the biogas residue mixed substrate volume ratio is 2:5,it can also promote the growth of Brassica napus sprouts with low concentration biogas slurry,and the vitamin C content increases significantly in the presence of biogas residue mixed substrate.Among them,RS13 significantly increased the sprout length on the fourth day,and RS6 significantly increased the sprout length on the eighth day,increasing by160.62%and 56.10%respectively.On the fourth day,the fresh weight and dry weight increased significantly by 103.50%and 45.09%respectively in RS13 and RS10,and on the eighth day,the fresh weight and dry weight increased significantly by 75.33%and 44.09%respectively in RS13 and RS9.The stability of antioxidant enzyme activity of sprouts can be improved by proper biogas residue mixed substrate volume ratio and biogas slurry concentration.（4）Single addition of sodium selenite had no significant effect on the sprout length,fresh weight and dry weight of Brassica napus sprouts.In the case of biogas slurry,biogas residue and biogas slurry and biogas residue culture,the sprout length,fresh weight and dry weight of Brassica napus sprouts are significantly increased after adding sodium selenite,and the vitamin C content is significantly increased in the case of biogas slurry culture,but not in the case of biogas residue and biogas slurry and biogas residue mixed culture.Among them,the most significant increase in sprout length on the fourth day was S5,which was increased by 81.48%.On the eighth day,the most significant increase in sprout length was noticed in S4,which was increased by 96.53%.The most significant increase in fresh weight on the fourth day and eighth day was noticed in S4,which was increased by 45.91%and 85.69%,respectively.The most significant increase in dry weight on the fourth day was S9,increased by 55.33%.The most significant increase in dry weight on the eighth day was S8,increased by62.41%.The selenium enrichment effect of Brassica napus sprouts cultured with biogas slurry was greater than that of biogas residue,and the biogas residue culture was greater than the mixed culture of biogas slurry and biogas residue.The selenium content of Brassica napus sprouts cultured in biogas slurry and biogas residue was significantly higher than that of the control,but the selenium content of Brassica napus sprouts cultured in biogas slurry and biogas residue did not change significantly compared with the control as a whole.According to the results of enzyme activity index determination,the antioxidant capacity of Brassica napus sprouts was improved by adding sodium selenite.According to the results of index correlation,the selenium content is positively correlated with vitamin C,indicating that the accumulation of selenium content may be related to vitamin C.（5）Biogas slurry and biogas residue as well as mixed culture can improve the economic benefits of Brassica napus sprouts.Therefore,according to the research results,in actual production,the biogas slurry concentration of 10%was recommended to cultivate the Brassica napus sprouts,the biogas residue mixed substrate（vermiculite:perlite=2:1）was recommended to cultivate the Brassica napus sprouts with the matrix ratio of 1:5,and the biogas slurry and biogas residue mixed culture using the biogas slurry concentration of 10%and the biogas residue mixed substrate volume ratio of 1:5 was the best,with the highest profit,and the net profits were 21.81 yuan/kg,84.51 yuan/kg and 115.94 yuan/kg,respectively.In selenium-enriched culture,the addition of 100μmol·L^-1sodium selenite was the best for Brassica napus sprouts under the treatment of 10%biogas slurry,the treatment of1:5 biogas residue mixed substrate volume ratio and the mix treatment of 10%biogas slurry and 1:5 biogas residue mixed substrate volume ratio,with the net profit of144.44 yuan/kg,71.92 yuan/kg and 71.66 yuan/kg,respectively.