氮磷钾配施对甘草育苗质量的影响

摘要

The nutrient N,P,K combinations liquid was designed using a '3414' experimental design.Seeds from Glycyrrhiza uralensis were sown and cultivated under the different nutrient irrigations to explore rational fertilizer combinations,and to provide some evidence for its effects in seedling culture in soil or under soilless conditions.The N,P,K treatments had significant effects on the emergence quality and seedling growth of plants under Hoagland irrigation in a pure sand medium.Under the N2K2 fertilizer,the emergence quality was higher than that in the CK,but it deteriorated with increased levels of P fertilizer,resulting in an emergence quality ranking of: N2P0K2>N2P1K2>N2P2K2>N2P3K2.However,the emergence vigor rank was N2P1K2> N2P0K2>N2P2K2>N2P3K2,Both the N2P2K2 and N2P1K2 treatments improved the seedling root TTC (2,3,5-triphenyltetrazolium chloride) vigor,establishing a good basis for healthy seedlings.Treatments lacking N or K but rich in N,P or K were all detrimental to seedling emergence and growth.These results suggest that the plants need a little P in the emergence stage,but the main P nutrient effect will appear after seedling emergence.Considering seedling culture efficiency and environmental protection,the optimum nutrient combination of N2P1K2 is 80 mg/L NH4NO3,89 mg/L KH2PO4 and 298 mg/L KNO3 as N,P and K source respectively,applied once every 20 days during seedling culture.Some water should be applied immediately to take ammonia-cal N to the bottom of the medium after fertilizing to,protecting the seedlings from NH3 toxicity.%利用“3414”方案进行N、P、K营养液配方设计,在配方营养液浇灌条件下进行甘草育苗质量比较,旨在探寻适宜甘草育苗的施肥配方,为其测土配方施肥和无土栽培育苗提供依据.结果表明,以纯沙石作为育苗基质,在添加Hoagland营养液条件下,不同N、P、K配比营养液对经98％硫酸处理的甘草种子的出苗质量和幼苗生长发育均具有极显著影响.N2 K2配比下出苗质量均优于空白对照,且随着施磷水平的提高出苗质量呈下降趋势,出苗质量依次为N2PoK2＞N2P1K2＞N2P2K2＞N2P3K2.而出苗活力依次为N2P1K2＞N2P0K2＞N2P2K2＞N2P3K2.N2P2K2和N2P1K2处理均可极显著提高甘草根系活力,为培育壮苗奠定良好基础.单纯缺N、缺K和过量N、P和K肥均不利于甘草出苗和幼苗的生长发育.以上说明在甘草出苗阶段需P量小,但出苗后开始显示其营养效应.从育苗效益和环境保护双重考虑,配方施肥宜采用N2P1K2,即添加80 mg/L NH4NO3、89 mg/L KH2PO4和298 mg/L KNO3作为N、P和K营养源,每隔20 d浇1次.需要注意的是浇灌后应及时喷灌适量水,使氨态氮下渗到底部基质,以避免氨的挥发而灼伤幼苗.