Effects Of Different Fertilizers On The Growth And Soil Properties Of Pennisetum Under Salt Stress

Based on the proposed methods for biological improvement of saline-alkali soils,this paper uses salt-tolerant plant Pennisetum to apply different fertilizers under salt stress to explore the effects of fertilizers on plant growth and soil under different salt stresses.Under the four salt levels of 0%,0.2%,0.4%,and 0.6%,four types are designed: no fertilization(F0),single application of microbial fertilizer(F1),single application of chemical fertilizer(F2),and mixed application of microbial fertilizer and chemical fertilizer(F3)Fertilization treatments,compare the effects of fertilizers on Pennisetum growth,soil and physiological responses under different salt stresses,and analyze the main components and correlations among different indicators to explore the mechanism of different fertilizers in order to find the most suitable fertilizers under different salt stresses.Treatment provides a theoretical basis for the improvement of saline-alkali land and the increase of salt-tolerant crops.The main results are as follows:(1)Salt stress inhibits the growth of the upper and underground parts of Pennisetum grassland.Adding fertilizers can alleviate the inhibition of salt stress.The overall expression is mixed application(F3)> single application of microbial fertilizer(F1)> single application of chemical fertilizer(F2),the mitigation effect is best at 0.4% salt concentration.F3,F2,and F1 are 107.89%,56.17%,40.32% higher than F0;At 0.6% salt concentration,F3 significantly increases plant height,leaf area,root length and above-ground biomass under this salt concentration,and its above-ground biomass increases by 48.88%,But the effect on tiller number is not significant;Pennisetum is salt-tolerant and can grow normally under 0.2% salt concentration.Single application of microbial fertilizer,single application of chemical fertilizer and mixed application can alleviate the growth inhibition caused by salt threat at 0.4%salt concentration,while at 0.6% salt concentration the effect of mixed application is better than other treatments.(2)Salt stress affects the membrane permeability and root vitality of Pennisetum,photosynthesis and photosynthetic pigment synthesis are weakened,its osmotic regulation is activated,and the antioxidant enzyme system is stimulated to cope with adversity.In this experiment,it was reduced by adding fertilizers.The degree of membrane peroxidation of Pennisetum,F3 is the best at all salt levels,and it is significantly lower than other treatments under 0.6% saline.Its MDA content is reduced by 20.26% and REC is reduced by30.07%.The content of osmotic adjustment substances in the fertilization treatment was lower than that of no fertilization,and the free proline(Pr)content of the three fertilizer treatments was significantly lower than F0 under different salt.Among them,the effects of F1 and F2 were significantly reduced by 37.96%,27.95%,under 0.2% salt.while the F3 treatment reduces 45.93% under 0.4% salt concentration,and the effect is better than other salt concentrations.The addition of fertilizer can adjust the opening and closing of stomata to promote plant photosynthesis,and alleviate the decrease in net photosynthetic rate(Pn)caused by salt stress.F2 is increased by 69.52% at 0.2% salt concentration,and F3 is at 0.4%.The concentration increased by 84.79%.(3)Fertilizer application can improve the soil to a certain extent.F1 treatment can reduce the electrical conductivity.The soil nutrients under different salt stresses are reflected as F3>F2>F1.Mixed application under salt stress has a certain effect on the N and P in its components.Synergistic effect,especially on the impact of available phosphorus(AP),where0.4% F3 treatment AP increased by 15.31%.Fertilizer application can also increase soil enzyme activity,and mixed application has the best effect,and its urease activity increased by51.87% and 59.71% under S1 and S2,respectively.Fertilizer treatment can provide soil nutrients,improve soil enzyme activity.The mixed application method has the best effect on soil improvement.(4)Comprehensive analysis found that fertilizer addition under salt stress mainly affects plant height,biomass,photosynthetic index,free proline,relative conductivity,soil available phosphorus content and alkaline phosphatase activity,by changing soil available nutrients And enzyme activity,alleviate the damage of salt stress to plants,affect the physiological response of plants to salt stress,and then cause changes in plant growth and propagation.In summary,0.2% salt stress has little effect on the growth of Pennisetum,and Pennisetum can be used for planting in mild saline-alkali land to obtain larger biomass;Pennisetum has obvious physiological response and growth under 0.4% salt stress Inhibited,the application of microbial fertilizer can alleviate the stress of the environment on plants,and the application of chemical fertilizer can provide sufficient nutrients for plant metabolism.The effect of mixed application of microbial fertilizer and chemical fertilizer is better than that of single application;Pennisetum growth is severely inhibited under 0.6% salt stress.The mixed application of fertilizers has a certain improvement effect on the soil environment,but the effect on plants is not obvious.