| The study is to explore the effects of vapor-permeable reflective film mulch on canopy microenvironment,shoot growth and fruit quality of Satsuma Mandarin(Citrus unshiu Marc),and provide a new reference model for the Chongming citrus industrial transformation.The experimental material was 32-year-old Satsuma Mandarin,the consistent vigor plants both in the open field and the facility were selected while laying the white vapor-permeable reflective film on the ground in July 15 th,2015.Light intensity and spectrum of the reflected light,soil indicators such as temperature,nutrients and microbes,as well as a variety of internal and external changes in fruit quality were measured.The results showed: vapor-permeable reflective film inhibited the shoots growth,filming in the open field showed a lower growth rate compared with CK.Vaporpermeable reflective film can significantly improve the reflected light intensity of facilities and open field by 2-7 times.The absolute radiation of visible light significantly improved as well.Meanwhile,vapor-permeable reflective film reduced the soil temperature at different depths,the largest decline happened in 20 cm,the open field reduced by 1.89 ?,the facility reduced by 1.84 ?.Filming obviously reduced the soil moisture content at depths of 100 mm,300 mm and 400 mm depth in open field,which declined by 7.55%,2% and 6% respectively;filming showed little decrease in the facility.Filming in facility can reduce the quantity of bacteria,actinomycetes of the root rhizosphere soil in fruit ripening stage,while increasing the quantity of fungi;filming in the open field saw a growing number of three microorganisms.Filming had the biggest influence on the number of fungi.Filming to day 75,reflective film reduced soil total N,available P and K contents at different depths in open field.In the facility,total N content decreased while available P,K contents increased.Filming had the biggest influence on total N and available K.Leaves,one-year-old shoots and biennial shoots have the highest element contents of Ca and N,and the contents of 10 kinds of mineral elements are highest in leaves.Filming to day 60,the contents of N,P,Ca,Mg and B in leaves,shoots and biennial branches had increased while K and Cu decreased.Vapor-permeable reflective film significantly improved the fruit edible rate in open field.Peel chlorophyll a content decreased obviously by nearly 17%,total carotenoids in open field enhanced apparently by 36%,filiming in the facility had no significant difference.Filming significantly improved fruit total soluble solids(TSS)content,while reducing the titratable acidity in the open field,TSS increased by nearly 3%.No obvious difference happened in the facility.In the open field,the glucose and fructose content of citrus fruit were improved by about 30%,sucrose increased by 20% and the total sugar improved by 26%,filming in the facility grew to a less extent,glucose and fructose had no significant increase.Vitamin C content in fruit ripening stage was significantly higher than the control in the open field,which improved by 22%,while no obvious difference happened in the facility.Vapor-permeable reflective film significantly improved the luminance value(L)and the red-green value(a*)of citrus fruits in the open field by 10% and 18% respectively compared with the control,blueyellow value(b*)had a smaller improvement,Filming had little effect on the fruit color in the facility.Mulch of Vapor-permeable reflective film can significantly improve internal and external fruit quality in the open field.Filming in the facility had a less improvement. |
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