Application Of Poly-γ-Glutamic Acid In Tobacco Planting

Poly-γ-glutamic acid(γ-PGA) is a kind of polymer formed by the glutamic acid units which are connected by amide linkages betweenα-amino andγ-carboxyl groups. Owning the property of water solubility,biodegradability and amity to environment,it is a new efficient and environmental friendly fertilizer synergist.In this subject,the application method and effect ofγ-PGA to tobacco planting were systematically studied,as well as its demonstration and extension.The effects of application concentration,period and molecular ofγ-PGA on yield, value and quality of burley tobacco were studied.The effects ofγ-PGA on yield,value and quality of burley tobacco in the condition of different fertilization level was also studied.By comprehensive comparison of yield,value and quality,the conclusion was that:1) the proper concentration was 100 mg/L;2) the proper application period was spherical plant stage;3) the effects of two kinds ofγ-PGA(molecular ranges＞1200 kD or molecular ranges＜100 kD) were equivalent;4) the yield and value of burley tobacco could be increased by 4.4～11.1%and 8.6～10.9%respectively by root-irrigation with 100 mg/Lγ-PGA;5) 10～20%of fertilizer amount could be saved by application ofγ-PGA when planting tobacco,while the yield,value and quality of tobacco would not decline;6) the chemical qualities of burley tobacco was more harmonious and the smoking quality was better.In the condition of two different fertilization levels,the effects of three kinds ofγ-PGA synergic fertilizer(the contents ofγ-PGA were 0.025%,0.5%and 0.01% respectively) on yield,value and quality of burley tobacco was studied.The conclusion was that:1) when the contents of theγ-PGA were 0.025%,0.5%and 0.01%,the increase amplitude thatγ-PGA synergic fertilizer brought to burley tobacco yield were 12.2%, 13.8%and 17.8%respectively,and that to burley tobacco value were 23.4%,18.5%and 16.5%respectively.When cutting the fertilizer amount down by 20%,the yield and value were still remarkably increased;2) when the contents of theγ-PGA were 0.025～0.01%, the increase amplitude thatγ-PGA synergic fertilizer brought to burley tobacco yield and value were increased as the contents of theγ-PGA;3) in the condition of lower fertilization levels,γ-PGA content has better effect on increasing burley tobacco yield;4) there was no adverse effects on smoking quality of tobacco by application ofγ-PGA synergic fertilizer;5) when usingγ-PGA synergic fertilizer,the fertilizer utilization efficiency of burley tobacco was increasing significantly,so the the fertilizer amount should be cut down to guarantee the harmony between quantity and quality.The conclusion of the experiment that the effects of poly-γ-glutamic acid on yield, value and quality of flue-cured tobacco in the condition of different fertilization level was that:1) the yield,value and the percentage of high and middle class leaf of flue-cured tobacco could be increased by 11.3%,18.4%and 9.3 percents respectively by root-irrigation with 100 mg/Lγ-PGA;2) 10～20%of fertilizer amount could be saved by application ofγ-PGA when planting flue-cured tobacco,while the yield,value and quality of tobacco were still improved.The application ofγ-PGA andγ-PGA synergic fertilizer in tobacco planting have been demonstrated and popularized.They have remarkable effects on burley tobacco and flue-cured tobacco in increasing yield and value.The yield and value of burley tobacco could be increased by 9.5～10.7%and 8.7～12.9%respectively,while those of flue-cured tobacco could be increased by 6.5～14.2%and 8.7～16.6%respectively.The average weight per flue-cured tobacco leaf was significantly increased.The result of the demonstration and popularized further verifies the concolusion derived from field experiments ofγ-PGA andγ-PGA synergic fertilizer in tobacco planting.The result of these studies suggests thatγ-PGA andγ-PGA synergic fertilizer,which are able to improve the yield,value,quality and the fertilizer utilization efficiency significantly,have great application value in tobacco planting and are worthy to be popularized.