Application Of Biochar Mixed Substrates Instead Of Peat On Pepper Seeding

With the rapid development of economy and the better life quality of people in China,more and more industrial and agricultural wastes were produced.It has been a hot topic for seeking some suitable and efficient way to utilize these wastes.Waste biomass carbonization technology which is developed in recent years can be an effective way of utilization of waste resources.Biochar widely used in agriculture,into the soil,not only can improve the structure of soil organic matter,retention of water and fertile,but also can increase crop yield and improve the quality of the fruit.Considering the common vegetable seedling substrate peat is increasingly depleted and short-term non-renewable,we apply biochar which has rich source,light texture and full of porosity on the substrate.It can not only open up a new direction for the application of biochar,also contribute to alleviate the pressure of peat resources.Therefore,we choosed herb residue,straw dust,coffee residue and pig manure as the experimental material,thermal cracking at 350? and 500°C in limited oxygen.The properties of the biochars from different raw material and temperature were determined.Meanwhile,we mixed biochar and vinegar to improve the porosity and pH of biochar to study the possibility of biochar application on substates.Main results are as follows:(1)The influence of raw material and temperature on biochar properties show that biochar production rate decreased with the increase of temperature;conductivity and pH of each biochar increased with the rise of temperature;Among these biochars,in the same carbonization temperature,the pig manure biochar behave highest in yield,pH and conductivity;With the increase of temperature,the nitrogen content of all kinds of biochars is reduced,but the content of phosphorus,potassium increased accordingly;Adsorption of inorganic nitrogen(NO3-,NH4+)is higher than the adsorption of inorganic phosphorrus(PO43-).PO43-in biochar showed a certain amount of release in aqueous solution.(2)Effect of biochar mixed substrate on pepper seeding showed that after biochar with vinegar beingmixed at different mixing ratio(4:2,3:3,2:4),the majority of the pH value of these media were between 6-7.5,porosity from 3.5%to 15%,bulk density between 0.14 to 0.22 g/cm3.During full period of Pepper seeding,the treatments containing 20%biochar in plant height,stem diameter,leaf area and ground biomass were significantly better than that of peat substrate.20%and 40%herb residue biochar composite substrate behave well in root surface area,root volume of pepper seedlings.Furthermore,there was no significant difference compared with peat substrate in the prophase,the late significantly higher than peat substrate.Comparing three kinds of biochars' effect on seedling growth of underground part,we found that root growth of pepper seedling containing pig manure biochar were weaker than other two biochars.Stem diameter,plant height,ground dry weight,dry weight of pepper seedlings are positively relevant to the electrical conductivity,available nitrogen and aeration porosity of substrate significantly.The seedling index of treatments(BlA2(herb residue biochar:vinegar residue:vermiculite:perlite=4:2:3:1),B1A4(herb residue biochar:vinegar residue:vermiculite:perlite=2:4:3:1),B2A4(sawdust biochar:vinegar residue:vermiculite:perlite=2:4:3:1))were higher significantly than other treatments.Considering the multiple growth indicator of pepper seedling,the treatments B1A2 and B1A4 performed best among all treatments.So we concluded that the two substates can replace peat for the pepper seedlings growth.(3)Effect of biochar on enzyme activity of pepper seedlings showed that after adding a certain amount of biochar,SOD,CAT and POD of leaves increased at different levels.With the increasing amount of herb residue biochar,the enzyme activity of leaf improved.However,with the increasing amount of pig manure biochar,the CAT and POD inproved firstly and reduced gradually.The leaf CAT activity among most treatments were significantly higher than control peat substrate.Thus,it was significant in terms of increasing plant seedling physiological activity by biochar.