芹菜老苗的原因1底施化学肥料太多造成烧根烧苗:化学肥料施用过量会出现烧根烧苗现象,主要原因是复合肥在生产过程中如有处理不当或高温时间持续过长,会产生缩二脲,而缩二脲含量过高就会导致烧苗、烧根,造成肥害。另外就是复合肥过量施用后却耕层较浅,芹菜定植后的根系与肥料直接接触较多,就会直造成烧根、烂根。2过量施用未熟粪类:过量施用未熟粪类也会同过量施用化肥一样产生危害,其表现为作物根部吸水困难,易发生烧根、黄叶、僵苗不长、叶片畸形等病状,严重时作物逐渐萎缩而枯死。其主要原因是,未熟粪类肥 Celery seedlings reason 1 at the end of the chemical fertilizer too much cause Burned root Burning seedlings: excessive use of chemical fertilizers burning burned phenomenon occurs, the main reason is that if the improper handling of fertilizer in the production process or high temperatures continued to be too long, Will produce biuret, biuret content will lead to burning seedlings, burning roots, resulting in fertilizer damage. The other is over-fertilization of fertilizer is tillering, celery colonization of the roots and fertilizer direct contact with more, it will directly into the burning roots, rotten roots. Excessive application of uncommon excrement: Excessive application of unripe excrement also results in the same hazard as the excessive application of fertilizers, which is manifested as water absorption difficulties in the root of the crop, burns prone to occur, yellow leaves, stiff seedling, leaf malformations and other serious diseases Gradually shrink and die. The main reason is that it is not cooked manure