Effect Of Modified Biochar And Its Extract On Flue-cured Tobacco

Biochar has shown unique advantages and potential in repairing and improving soil pollution and has become one of the research hotspots in the field of agriculture and the environment.However,how to fully understand the impact of biochar agricultural use and promote biochar value-added utilization technology to make biochar production and application economically feasible is also a major problem.If biochar can be modified to achieve effective utilization of solid-liquid products,multiple benefits can be obtained,which not only increases the value of agricultural products but also reduces the cost of biochar for soil improvement.In this experiment,rice husk biochar was selected and modified by deionized water,phosphoric acid,and potassium hydroxide,respectively,to prepare modified biochar and leaching solution.Three different dilutions of leaching solution were used for the seed germination test,acid-modified biochar was used to replace peat for the tobacco seedling floating seedling test,and three modified biochars and different multiples of leaching solutions were used for the pot experiment.The effects of leaching solution on tobacco seed germination,acid-modified biochar as a substitute for peat on tobacco seedling and seedling growth,and the effects of adding different modified biochars and spraying leaching solution on tobacco soil and plant growth were analyzed.The main results are as follows :1.The dilution of 0 times modified biochar extract has an inhibitory effect on tobacco seeds,especially the dilution of 0 times acid-modified biochar extract,the indicators decrease significantly,but with the increase of the dilution factor of modified biochar extract,it can significantly promote the germination of tobacco seeds.The seed germination rate of 50 and 100 times diluted acid-modified biochar extract was 81.65% and 83.69% higher than that of diluted 0 acid-modified biochar extract.The seed viability index of acid-modified biochar extract diluted 100 times was optimal.The seed germination potential and germination index were diluted 100 times by alkali-modified biochar extract,which was 4.77% and 3.21% higher than those treated with CK.2.When the replacement ratio ≤ was 60%,the total root length,and total surface area increased by 93.92% and 59.66% respectively compared with CK,and the total root length and total root length of L≤0.5 mm and the medium root system of 1.0 mm <≤ 2.0 mm increased by 110.52% and 85.33%,respectively.When the replacement ratio was 50%,root viability was the highest,which was 65.86% higher than that treated with CK,and leaf SOD and NR activities increased by 49.94% and394.22%,respectively,compared with the control.3.On the whole,the application of modified biochar and different multiples of the extract could promote the improvement of agricultural traits,dry matter accumulation,nitrogen,phosphorus,and potassium accumulation of tobacco plants,etc.,and the plant height and maximum leaf length of water-modified biochar treatment increased by 75.85% and 20.58% respectively compared with CK treatment,and the root and leaf dry quality increased by 89.09% and 61.27% respectively compared with CK treatment.In the flue-cured tobacco boom period,the stem and leaf dry masses of acid-modified biochar diluted 100 times increased by 110.73% and96.94%,respectively,compared with CK-treated flue-cured tobacco.Compared with CK and new biochar treatment,the root activity of acid-modified biochar extract diluted 0 times increased by 62.99% and 65.9%,respectively.Compared with the new biochar treatment,the nitrogen accumulation of water-modified biochar extract was increased by 26.72% and the phosphorus accumulation was increased by 118.18%compared with the CK treatment.The potassium accumulation of acid-modified biochar extract extracted by 50 times increased by 7.84% compared with the new biochar treatment,and the potassium content of alkali-modified biochar leaves increased by 81.82% compared with the CK treatment.4.The soil available nitrogen content of 50 times diluted water-modified biochar extract was increased by 30.91%and 2.34% compared with CK and new biochar treatment,respectively.The soil-available potassium content of alkali-modified biochar extracts diluted 100 times decreased by 30.16% compared with CK treatment.Among the top 10 phyla of the relative abundance of soil bacteria,the three dominant phyla of modified biochar and different multiples of extract were Proteobacteria,Actinomycetes,and Acidobacteria.In terms of the relative abundance of the Proteobacteria phylum,Compared with CK and new biochar treatment,the relative abundance of water modified biochar extract with 0 times diluted increased by 4.94 and 6.43 percentage points,respectively,and the relative abundance of acid-modified biochar extract diluted 0 times increased by3.17 percentage points compared with CK treatment,the relative abundance of acido-modified biochar was the highest with acid modified biochar treatment,which increased by 3.49 percentage points compared with CK,while the relative abundance of acid anhydride phylum decreased with the increase of dilution factor,but the relative abundance of alkali modified biochar extract phylum diluted 100 times increased by 2.06 percentage points compared with CK;Water-modified biochar was the highest on the Shannon index,with an increase of 1.28% compared to the new biochar treatment,while the water-modified biochar extract diluted 100 times was 2.76% higher than the new biochar treatment on the Chao1 index.In summary,diluting 50 and 100 times modified biochar extract can stimulate the germination of tobacco seeds and improve the germination rate,germination potential,germination index,and vitality index of seeds.When the substitution ratio≤ 70%,acid-modified biochar can replace the grass charcoal matrix to cultivate high-quality tobacco seedlings.The addition of modified biochar and spray extract in the soil can improve soil physical and chemical properties,promote the diversity of rhizosphere soil bacterial communities,promote soil physical and chemical properties,increase soil available nutrients and organic matter content,and have a positive effect on the growth and development of flue-cured tobacco.