Combined Application Of Biochar And Piriformospora Indica On Soil Properties Of Coastal Saline Soils And The Growth Of Sorghum Hybrid Sudangrass

In this study,the combined application of biochar and Piriformospora indica was used to improve saline soils with high salt content and low land productivity in the coastal saline soils of Dongying,Shandong Province.Biochar and Piriformospora indica(P.indica)have been shown to promote plant growth,improve stress resistance,and enhance soil fertility,respectively,but the synergistic effects of combined application of P.indica and biochar on plant growth and soil improvement are unclear.Based on this,this experiment was conducted to investigate the growth,photosynthetic characteristics,soil physicochemical properties and nutrient contents of Sorghum bicolor × sudanense treated with different combinations of corn straw biochar(CP)and bamboo charcoal biochar(BP)and P.indica solution(0,40,80 and120 m L)in a pot experiment using Dongying coastal saline soil as substrate.The main findings are as follows.The main findings of the study are as follows:(1)The combined action of biochar and P.indica was effective in promoting the growth of Sorghum hybrid sudangras under salt stress.The addition of biochar significantly increased the rate of mycorrhizal infestation in the roots of Sorghum hybrid sudangras Inoculation of biochar with P.indica significantly increased the number of leaves and biomass of Sorghum hybrid sudangras under biochar treatment compared to P0(P < 0.05),while the effect on plant height was not significant(P > 0.05).The growth-promoting effect of the combined application of biochar and P.indica was higher than that of the single treatment and increased with increasing bacterial dose,with an overall expression of BP > CP > P.(2)The combined effect of biochar and P.indica could increase the chlorophyll content and gas exchange capacity of Sorghum hybrid sudangras under salinity stress.The combined effect of biochar and P.indica on chlorophyll content and gas exchange parameters of Sorghum hybrid sudangras leaves was significant(P < 0.05),and the combination of the two had a significant synergistic effect on gas exchange parameters of Sorghum hybrid sudangras,but did not show a synergistic effect on chlorophyll content.The net photosynthetic rate of Sorghum hybrid sudangras leaves increased with increasing bacterial dose,with the highest in the P group at 120 m L and the highest in the BP and CP groups at 80 m L.The transpiration(3)The combined application of biochar and P.indica had significant effects on soil physicochemical properties,but the combined application of the two did not show significant synergistic effects.Biochar effectively reduced soil p H,electrical conductivity,water-soluble sodium and chloride ions,increased water content,and effectively improved the physical structure of saline soils.Soil water content increased significantly(P < 0.05)with increasing inoculum of P.indica,and soil p H,conductivity,and water-soluble sodium and chloride ions decreased significantly(P < 0.05)with the addition of P.indica.(4)The combined action of biochar and P.indica enhanced the nutrient content of the soil.Biochar had a significant effect(P < 0.05)on organic matter content,which was more than twice as high in CP0 and BP0 treatments compared to P0,but had no significant effect(P > 0.05)on fast-acting phosphorus and alkaline digested nitrogen content.Indian pearshaped spores had significant effects(P < 0.05)on organic matter,fast-acting phosphorus and alkaline digested nitrogen contents.Soil nutrient contents under different treatments tended to increase with increasing inoculum of P.indica,but the combined effect of the two did not have a synergistic effect in improving the nutrient contents of coastal saline soils.(5)By conducting principal component analysis on 16 indicators of four different bacterial solutions under three types of biochar,the combined values of each principal component analysis under different treatments were ranked as follows: BP120 > CP120 >BP80 > CP80 > P120 > BP40 > P80 > CP40 > BP0 > P40 > CP0 > P0.It was found that the combination of biochar and P.indica had better improvement effect than single treatment,and the higher the dose of bacteria,the better the improvement effect.In addition,the combined effect of bamboo charcoal and P.indica was better than that of corn stover biochar.