Effects Of Oil Shale Compound Substrate On Photosynthetic Physiology,Yield And Nutritional Quality Of Strawberry

Oil shale is a natural resource containing a large amount of organic matter and mineral nutrients.In the agricultural field,oil shale is mostly used as organic fertilizer and soil conditioner,but there are few studies and reports on its application in substrate cultivation.So this experiment takes’Yanli’strawberry as test material,oil shale as the main material,peat and perlite as auxiliary materials;solid column pot experiment of strawberry with different volume ratio of composite substrate.Treatment I（peat:oil shale:perlite=5:4:1）,treatment II（peat:oil shale:perlite=4:5:2）,treatment III（peat:oil shale:perlite=3:6:3）and treatment IV（peat:oil shale:perlite=0:1:1）.The effects of compound substrate on plant growth,photosynthetic physiology,yield and nutritional quality of strawberry were studied to provide theoretical basis for evaluating the feasibility of oil shale application in cultivation substrate and suitable substrate formula for cultivating strawberry.The main results of this experiment are as follows:（1）The physical and chemical properties of the five treatments met the requirements of ideal strawberry cultivation substrate.Among them,the bulk density and Ec value decreased first and then increased;total porosity and p H showed a downward trend;the water-gas ratio showed an upward trend;during the whole growth cycle of strawberry,the variation of physicochemical properties of treatment II was the smallest,and the physicochemical properties were the most stable.（2）There were significant differences in morphological indexes among the five treatments.Treatment II had the best growth vigor,and the plant height,rhizome diameter,petiole length,leaf number,leaf area and crown width were the largest,which were 24.2cm,18mm,16.68cm,9 pieces,31.63cm² and 215.62cm²,respectively.（3）Chlorophyll content of treatment II;the net photosynthetic rate（Pn）,stomatal conductance（Gs）,intercellular CO₂ concentration（Ci）,primary photochemical efficiency of PS II（Fv/Fm）,potential activity of PS II（φPS II）and photosynthetic electron transfer rate（ETR）in the photosynthetic fluorescence indexes were significantly higher than those in the control CK（p<0.05）,and each value was the largest.The results showed that the leaf senescence of treatment II was slow and the physiological activity was strong,which could significantly improve the photosynthetic fluorescence performance of strawberry leaves and promote the material accumulation of strawberry.（4）The total N,P and K contents of strawberry leaves in the five treatments all showed a trend of first increasing and then decreasing,and the nutrient contents of each treatment reached the peak at the early fruit stage.Total N and total K in leaves of treatment II were significantly higher than those of CK（p<0.05）,which were 35.89 g/kg and 46.86 g/kg,respectively,which were 11.65%and 16.74%higher than those of CK.（5）Treatment I and treatment II could improve the nutritional quality and yield of strawberry,and their indexes were significantly higher than CK（p<0.05）.The soluble sugar and titratable acid content of treatment I were the highest,9.5%and 0.89%,respectively,which were higher than CK 24.92%and 37.63%.The contents of ascorbic acid and soluble protein in treatment II were the highest,which were 73.19 mg/100g and 0.65 mg/g,respectively,which were 3.34%and 3.98%higher than those in CK.Treatment II had the highest average single fruit weight and average yield per plant,which were 24.43 g and256.23 g,respectively,which were 15.27%and 17.66%higher than those of CK.（6）The principal component analysis showed that treatment II was the best and treatment I was good,which was suitable for wide application.