Preparation And Application Of Rare Earth Amino Acids Complexes

In order to overcome the shortcomings of solid compound fertilizers that tend to block fertilizing and slow absorption by crops,liquid compound fertilizers?foliar fertilizers?have developed rapidly in recent years.With the increase in the demand for vegetables,fruits,flowers,medicinal herbs and specialty crops,and the development of greenhouse cultivation and soilless cultivation techniques,higher requirements have been put forward for the quality and demand of foliar fertilizers.In addition to the extensive use of various organic complexes to improve the solubility of various metal ions,the addition of rare earth elements to liquid compound fertilizers has become a new measure to improve the quality of foliar fertilizers.Many years of research and practice have proved that light rare earths such as strontium and barium can be used as plant growth regulators to promote the absorption and utilization of nutrients such as nitrogen,phosphorus and potassium in crops,promote seed rooting and germination,increase chlorophyll in crop leaves,and enhance photosynthesis.It is conducive to the accumulation of dry matter.At the same time,it can enhance the crop resistance,drought,waterlogging and anti-pollution ability,and ultimately achieve the effect of increasing yield,improving quality,early maturation and reducing disease.The main results are as follows:?1?The two solid ternary complexes of rare earths chloride with L-Methionine and Glycine have been synthesized in Ethanol solution.The resultant complexes were characterized by elemental analyses,thermal analysis,FT-IR,XRD,¹HNMR spectrum and.The compositions of complexes have been confirmed to be RE?Met??Gly?₃Cl₃·3H₂O.The fluorescence properties of the ligand complexes were investigated by fluorescence spectrum,the result showed that the fluorescence intensities of the complex of La³⁺increased by 3.5time and Ce³⁺increased by 5time as compared with those of rare earth chloride.?2?Nitrogen,phosphorus,potassium,magnesium,calcium,sulfur,zinc and other elements and rare earth amino acid complexes are used as raw materials,and EDTA and citric acid are used as chelating agents,and Tween-80 is used as a surfactant at a temperature of 40°C.0.5 h,and the pH value can be controlled around 5.5.The final prepared foliar fertilizer not only meets the national standard of amino acid foliar fertilizer in terms of amino acid content,trace element content,pH value,etc.but also contains a large amount of elements such as nitrogen,phosphorus and potassium,and medium amount of elements such as calcium,magnesium,sulfur and rare earth element.The weight percentage of each nutrient composition is:a large amount of elements?nitrogen,phosphorus,potassium?of 7.0%,a medium trace element of 11.0%,a rare earth element of0.6%,and an amino acid of 12.4%.?3?The effect of rare earth composite fertilizer on vegetative growth and photosynthesis of leaves were studied.In order to provide reference for the promotion of apple leaf and the improvement of fruit quality by rare earth fertilizer The result shows that when rare-earth composite fertilizer with concentration of 0.01,0.1 and 1 mg/L were spraying during growth season,the leaf chlorophyll contents,the net photosynthetic rate?P_n?,the instantaneous carboxylation efficiency?P_n/C_i?,the fast induction curves of chlorophyll a fluorescence?OJIP Curve?and the photosynthetic performance index(PI_ABS)were significantly improved.Meanwhile,it can alleviate the effect of photosynthetic midday-depress.Additionally,rare-earth composite fertilizer treatment also increased the fruit hardness,soluble solid,vitamin C,total sugar and titratable acid.The above results show that the application of rare earth composite foliar fertilizer can obviously improve the chlorophyll content of leaves and the photosynthetic energy conversion efficiency of leaves,and finally improve the quality of fruit.