Study On Modification Of Pinus Sylvestris Bark And Its Water-holding Seedling Substrate

In this study,the bark of Pinus sylvestris var.Mongolica bark was mainly subjected to alkaline pretreatment and rot modification,and then mixed with a synergistic substrate and a water-absorbing resin to prepare a seedling substrate with water absorption and water retention properties.Finally,the water-absorbing and water-retaining properties of the seedling substrate and the germination rate experiment of Chinese cabbage seeds were tested.The main content and results of the study are as follows:1.The two kinds of bark of Pinus sylvestris var.Mongolica bark were pretreated with different concentrations of NaOH.By testing their physical and chemical properties,it was concluded that the best NaOH treatment concentration for large-size pine bark was 1.0wt%,and the best for small-size pine bark The treatment concentration is 0.6wt%,The dry density of the pine bark of the two groups was 0.234g/cm 3 and 0.214g/cm3,which was slightly lower than that of the untreated group.The bark increased by 63.6%and 71.7%;the non-capillary porosity reached 20.4%and 33.8%,respectively.The above data shows that NaOH treatment of pine bark can improve its comprehensive physical and chemical properties as a matrix.2.Adding EM bacteria agent and alkali pretreatment to the bark of Pinus sylvestris var.Mongolica bark can significantly shorten the maturation modification time.The effect is best when the moisture content in the maturation modification process is 60%.The dry density,wet density and non-capillary of the camphor pine bark of group Z2 The porosity is 29.5%,0.217g/cm3,0.603g/cm3,and 29.5%respectively;the dry density,wet density,and non-capillary porosity of Pinus sylvestris var.Mongolica bark in group Z5 are 0.208g/cm3,0.693g/cm3,and 43.7%,respectively..After elemental analysis and testing,the C/N of the two groups were 57.81 and 45.62 respectively,which was a significant decrease compared to the untreated group C/N ratio of 222.62.The bark of Pinus sylvestris var.Mongolica after decomposed treatment showed excellent water absorption and aeration.3.Adding vermiculite and micro-nanocellulose water-absorbent resin to the modified Pinus sylvestris bark to mix into a seedling-growing substrate with water retention function;by examining the water absorption and water loss rate of the substrate,the best addition of vermiculite and water-absorbent resin to the Pinus sylvestris bark The optimal ratio is:the ratio of large-size pine bark to vermiculite is 3:1,the ratio of small-size pine bark to vermiculite is 4:1,and the addition of 0.3%water-absorbent resin to the small-size pine bark can significantly improve its Water absorption and water retention;the germination rate test of this substrate showed that the germination rate was 84.6%,and the germination index GI was 34.52,which was greatly improved compared with fresh bark of Pinus sylvestris var.mongolica.