Effect Silicon Fertilizer On Growth,Forage Production And Quality Of Alfalfa Under Water Stress

The effects of silicon fertilizer on seed germination,growth,physiological characteristics,yield and quality of alfalfa under different water stress were studied.This study from the silicon fertilizer on alfalfa "Sadie 7" seed germination and seedling growth under drought stress and the effect of silicon fertilizer on alfalfa branching stage of growth and physiological characteristics,study two aspects of regulation of yield and quality of forage.The petri dish using polyethylene glycol(PEG)laboratory simulated drought stress method of PEG[0%,5%,10%,15%(0.00MPa,-0.10MPa,-0.20MPa,-0.40MPa)]under water stress of potassium silicate(0,1.0,2.0,2.5 mmol/L)effect on germination and seedling physiology of alfalfa seeds.At the same time the greenhouse pot experiment was conducted to study the maximum field under different water conditions[water holding capacity of 30%,45%,60%,80%(followed by the corresponding severe water stress and moderate water stress,mild water stress and normal water supply)],application of different concentration of sodium silicate(0,0.7,1.4,2.8,3.5mmo/L)on the branching stage of alfalfa growth and physiological characteristics,influence the yield and quality of forage.The main results are as following:(1)Potassium silicate influence on alfalfa seed germination under drought stress.Under the stress of 10%PEG,the application of 1.00mmol/L potassium silicate significantly increased alfalfa seed germination potential and germination rate when potassium silicate concentration of 2.50mmol/L could inhibit the seed germination and growth.(2)Potassium silicate had an impact on physiological characteristics of Alfalfa Seedlings under drought stress.Under 5%and 10%PEG stress,2.00mmol/L potassium silicate treatment significantly increased superoxide dismutase(SOD)activity in Alfalfa Seedlings.Under 15%PEG concentration,2.50mmol/L potassium silicate treatment significantly reduced the content of malondialdehyde(MDA)in seedlings,and increased the activity of peroxidase(POD)and catalase(CAT)activity.(3)The effects of sodium silicate on plant height,branch number,root neck diameter and lateral root number of Alfalfa under drought stress were studied.Under severe water stress,1.4mmo/L sodium silicate could increase the number of lateral roots and root neck rough of alfalfa.Under mild water stress,3.5mmo/L sodium silicate significantly increased the number of branches of Alfalfa.(4)The suitable concentration of sodium silicate on drought stress also plays a positive role in regulating physiological processes of Alfalfa under changes,can effectively improve the leaf relative water content and decrease the evapotranspiration,maintain the osmotic adjustment ability and membrane stability,and improve the photosynthetic enzyme activity.Under severe water stress,0.7mmo/L of sodium silicate increased the glutamine synthetase of Alfalfa(GS)activity;1.4mmo/L of sodium silicate can significantly reduce the alfalfa evapotranspiration,the chlorophyll content,Rubisco enzyme,sucrose synthase(SS)and sucrose phosphate synthase(SPS)activity increased significantly enhance alfalfa photosynthesis;2.8mmo/L and 3.5mmo/L the sodium silicate free proline content of Alfalfa(Pro)increased significantly.(5)Under water stress,spraying the sodium silicate,the alfalfa grass,affect the yield and forage quality of hay.Under severe water stress,1.4mmo/L of sodium silicate can make the alfalfa total potassium,total calcium content increased significantly;under mild water stress treatment,2.8mmo/L and 3.5mmo/L were made of sodium silicate in alfalfa dry matter yield increased significantly;1.4mmo/L sodium silicate increased crude protein(CP)of Alfalfa,crude ash(CA)content significantly,neutral detergent fiber(NDF)content decreased significantly.In summary 1.4mmol/L sodium silicate can improve drought resistance of Alfalfa.