Effect Of Arecanut And Pandan Intercropping On Soil Physicochemical Properties And Volatile Aroma Compounds Of Pandan

With the increase of pandan plants under arecanut,it’s very important to explore the effects of intercropping on soil physicochemical properties and volatile aroma compounds of pandan plants,so as to provide a theoretical basis for irrigation and fertilizer management in field,thus improving crop quality.In this study,the effects of intercropping on soil enzyme activity and crop growing were analyzed through the combination of pot experiment and field experiment.In addition,the correlation between environmental factors and aromatic composition of pandan plants was explored.The main research results are as follows:1.As for the volatile aroma composition of pandan with different shade degrees,the Bray-Curtis index is 62.44%.The shading between 30% and 60% could increase the content of main volatile aroma compounds of 2-acetyl-1-pyrrolidine,3-methyl-2-(5H)-furanone,squalene,phytol,coumaran,and so on,and improve the flavor quality.At the same time,the shading between 30% and 60% can also promote the photosynthesis of pandan plants,increase the number of leaves and reduce tillers,so it is a suitable shade for the growth of pandan plants.2.The intercropping of arecanut and pandan has certain regulating effects on p H,and has significant effects on the soil structure in Wanning and Lingshui areas.The intercropping of arecanut and pandan changes soil porosity,reduces soil bulk density and increases soil moisture content.Intercropping of arecanut and pandan could promote the absorption of nitrogen,phosphorus and potassium and increase soil enzyme activity.On the other hand,the improvement of absorption efficiency of soil phosphorus and potassium nutrient is positively correlated with root morphology.3.GC-MS detection technology was applied to identify the volatile aroma compounds of pandan leaves in three regions under different planting patterns.It was obvious that the richness of volatile aroma compounds was(26.33±3.61)species(n=6,the value range was20-29).After intercropping,the contents of the main volatile aroma compounds significantly increased,including 2-acetyl-1-pyrrolidine,3-methyl-2-(5H)-furanone,neophytadiene,ethyl palmitate,acetoin and so on,which improved the flavor quality of pandan to a certain extent.4.With the main volatile aroma compounds of pandan plants,there exists a close correlation between the photosynthesis of leaves and the soil physicochemical properties.The net photosynthetic rate of leaves is positively correlated with the content of3-methyl-2-(5H)-furanone(r=0.8164,P<0.05)and squalene(r=0.8243,P<0.05),and the correlation between leaf temperature and the main volatile aroma compounds of pandan plants is negative.The RDA analysis on the volatile aroma compounds of pandan plants in three regions under different planting patterns revealed that the ranking characteristic values of the first two restrictive axes of RDA1 and RDA2 accounted for 97.99% of the total variation.2-acetyl-1-pyrrolidine,acetol,neophytadiene and3-methyl-2-(5H)-furanone are positively related to p H and bulk density,and negatively related to soil physicochemical properties,including soil porosity,available phosphorus,total nitrogen,soil moisture content and organic matter.In summary,it proved that the intercropping of arecanut and pandan is a reasonable intercropping system.The research on the physical and chemical properties of soil physicochemical properties and the volatile aroma compounds of the arecanut intercropping pandan can provide a theoretical basis for the cultivation mode of the arecanut intercropping pandan,which plays an important role in the sustainable development of the arecanut and pandan industries.