Effects Of Different Cultivation Measures On Seedling Quality Of Straw Substrate Seedling-raising

In order to explore the standardization,appropriate age,and suitable machine robust seedlings rice seedlings-raising techniques under the condition of straw substrate.This experiment studied the influence of seedling stage water control and plant growth regulator control measures on the comprehensive seedlings quality and seedling vigor by mechanical transplanting.The influence of seedling stage increasing application of Silicon,Zinc,Potash fertilizer and biological fertilizer on the seedlings quality are also studied.The results were as follows:(1)Water deficit at seedling stage would affect the growth of seedlings,which meant the leaf numbers was less,leaf and leaf sheath were shorter,and leaf color became lighter.But moderate water deficit could regulate and control the height of seedling,promote root growth,increase the dry matter weight,weight-height ratio,root-shoot ratio,strong seedlings index,root activity,starch content and C/N.It was also beneficial to form strong seedlings,improve the quality of machine-transplanted,promote seedlings grow new leaves,new roots and turning green after transplanting,and extend the effective tillering stage,increase the stem tiller numbers.(2)Increasing application of Silicon,Zinc,and Potash fertilizer at seedling stage could improve the total nitrogen content and the relative chlorophyll content of leaf.The comprehensive quality of the seedling was better when stiring in 150mg/L Silicon fertilizer in raising seedling substrate.The effect of spraying Zinc fertilizer at the stage of one mature leaf and one new leaf of rice seedlings to improve the comprehensive quality was not obvious,so as to spraying Potash fertilizer at the stage of one mature leaf and one new leaf of rice seedlings,even the height of seedlings was too high to suitable for machine-transplanted.(3)Seed soaking with Brassinolide or spraying at the stage of one mature leaf and one new leaf of rice seedlings or stiring in raising seedling substrate before sowing could enlarge the false stem width of seedlings,increase root numbers,raise root dry weight,root-shoot ratio,relative chlorophyll content of leaf,starch content,C/N,anti-oxygen protective enzyme activity,root activity and so on,all advantageous to form robust seedling.All treatments could promote seedlings grow new leaves,new roots and turning green after transplanting.Seed soaking and spraying also could raise the relative chlorophyll content of leaf,the quality of machine-transplanted,tillering ability and number of stem tillers.Soaking seed with 0.15mg/L,spraying with 0.10 mg/L and mixing the substrate with 0.40mg/L treatments were synthetically best.(4)Seed soaking with Paclobutrazol or spraying at the stage of one mature leaf and one new leaf of rice seedlings or stiring in raising seedling substrate before sowing could enlarge the false stem width of seedlings,raise root dry weight,root-shoot ratio,weight-height ratio,strong seedlings index,the relative chlorophyll content of leaf,total nitrogen content,soluble sugar content,anti-oxygen protective enzyme activity,root activity and so on,all conducive to form strong seedling.All treatments could promote seedlings grow new leaves,new roots and turning green after transplanting,increase tillering ability and stem tiller numbers.But decreased the quality of machine-transplanted.Seed soaking and stiring in raising seedling substrate treatments also could improve seedling of emergence rate and adult seedling rate.Soaking seed with 300~400mg/L,spraying with 400 mg/L and mixing the substrate with 500~700mg/L treatments were synthetically best.(5)The indices for strong rice seedling of straw substrate seedling-raising were as follows: Early rice of 20~25d for seedling age,2.5~3.5 for leaf age,12~16cm for seedling height,2.20~2.40 mm for thickness of fake-stem,6~8 for root number,24~28mg for dry weight per plant,0.35~0.45 for root-shoot ratio,3.00~4.00 for strong seedlings index,35~45mg/g for total nitrogen content,1.00~1.50 for C/N.Late rice of 20~25d for seedling age,3.5~4.5 for leaf age,12~18cm for seedling height,3.10~3.50 mm for thickness of fake-stem,9~12 for root number,great than or equal to 26 mg for dry weight per plant,0.30~0.60 for root-shoot ratio,6.00~8.00 for strong seedlings index,30~40mg/g for total nitrogen content,1.00~2.00 for C/N.