硅酸盐水泥含量对种基盘特性的影响

Effects of portland cement concentration on the characteristics of seed base

摘要:

种基盘是一种四周有一定硬度的圆柱状空心植物育苗装置。以普通硅酸盐水泥作为基质粘结材料,设置7个浓度(0%,2%、4%、6%、8%、10%、12%,W/W),研究种基盘的抗压强度、保水特性及根系扩展特性。结果表明:低含水率时,水泥含量越高,基盘抗压强度越高,10%和12%水泥含量显著高于对照。随着水泥含量的增加,水泥基质配方的饱和含水量呈降低的趋势,蒸发失水比呈升高的趋势。水泥含量在10%、12%时,种基盘外壁强度大,中心孔内的根系长度比例高于孔外根系的长度比例,其他处理下,孔外的根系长度比例均高于孔内;随着水泥含量的增加,种基盘中心孔内及孔外根系总长度逐渐降低,总根中不同径级的根系长占总根长的比例为细根远大于中根及粗根。综合硅酸盐水泥处理下种基盘的抗压强度、保水特性及根系扩展特性,水泥含量为2%时效果最好。

Abstract:

The seed base is a cylindrical hollow seedling structure with a certain hardness around it.Ordinary Portland cement was used as the matrix bonding material at six different concentrations (2%,4%,6%,8%,10%,12%,w/w) to study the compressive strength,water retention and root expansion characteristics,with no addition of cement as the control.The results showed that under low water content,the strength of the seed base increased with the increased level of cement,with the strength at 10% and 12% cement content being significantly higher than the control.Along with the increased level of cement,the water content of the seed base decreased while its strength and stability increased.As the level of cement increased,the saturated water content of the cement matrix formula reduced,while the evaporation loss ratio increased.When the cement content was 10% and 12%,the strength of the outer wall of the seed substrate was strong,and the length of the root system in the central hole was higher than outside the hole.Under the other cement treatments,the proportion of the root length outside the hole was higher than that in the hole.With the increased cement content,the total root length of the inner roots and the outer roots of the seed center disc gradually decreased.The proportion of the root length in smaller root diameter to the total root length was much higher than those with medium and thick roots.At low cement dosages (2%,4%,6%),the total length of the root system was longer than the control,which was conducive to the expansion of the root system.Too high cement concentration was not beneficial for root growth.The purpose of adding Portland cement to the seed-base was to benefit the seedling establishment,transportation and transplanting.Therefore,the seedling growth after the addition of Portland cement was the most direct parameter.When the moisture content was about 15%,the strength of the cement matrix was high and therefore suitable for the transportation and transplanting of the substrate.Combing the effects on the compressive strength,water retention characteristics and root expansion characteristics in seed base,the optimum cement dosage was about 2%.