黄腐酸和聚天冬氨酸对蕹菜氮素吸收及氮肥去向的影响

为了解黄腐酸(FA)和聚天冬氨酸(PASP)对蕹菜氮素吸收及氮肥去向的影响,采用15N尿素示踪技术,设置不施氮肥(CK),单施尿素(N),尿素配施低、中、高用量的FA和PASP(NF1、NF2、NF3、NP1、NP2、NP3)8个处理,在温室条件下进行盆栽试验。结果表明,与N处理相比,配施FA和PASP后蕹菜地上部鲜重增加了7.46%~17.55%;NP2、NP3和各NF处理显著提高了蕹菜的吸氮量,提高幅度为10.84%~18.25%,其中,蕹菜对非标记氮的吸收量显著增加,且随FA和PASP用量的增大而增加;NF3处理的15N利用率显著低于N处理,其余处理无显著变化;NF2、NF3、NP2和NP3处理的15N损失率比N处理减少了5.41~14.58个百分点;NF2、NF3和NP2处理的15N土壤残留率增加了5.08~20.02个百分点。研究表明,中、高用量的FA和PASP与尿素配施促进了蕹菜对氮素(尤其是非标记氮素)的吸收,同时减少了氮肥的损失,增加了氮肥在土壤中的残留,对土壤氮库的贡献作用显著。

Effects of fulvic acid and polyaspartic acid on nitrogen uptake and fate of nitrogen fertilizer in water spinach

In order to study effects of fulvic acid(FA)and polyaspartic acid(PASP)on nitrogen uptake of plant and fate of nitrogen fertilizer,a pot experiment was conducted in greenhouse by the tracer technique of 15N urea.The designed experiment included eight treatments and four replications:no N application(CK),labeled urea(N),combined application of urea and low,medium and high amount of FA and PASP(NF1,NF2,NF3,NP1,NP2 and NP3).The results indicated that the shoot fresh weight of water spinach of combined application treatments was increased by 7.46%~17.55% than pure N treatment.All NF treatments,NP2 and NP3 treatments significantly increased the uptake rate of total nitrogen of plant with in the range of 10.84%~18.25%,and non labeled nitrogen uptake rate of water spinach was higher than that of N treatment,which increased significantly with the increase of FA and PASP applied.Compared with N treatment,only NF3 treatment significantly decreased the 15N use efficiency.The 15N loss ratio under FA and PASP treatments of medium and high amount was decreased by 5.41~14.58 percentage points.The residual 15N ratio of NF2,NF3 and NP2 treatments was increased by 5.08~20.02 percentage points compared to that of N treatment.In conclusion,combined application of urea and medium and high amount of FA and PASP improved total nitrogen(especially non labeled nitrogen)uptake rate of water spinach,reduced 15N loss rate and increased residual 15N rate which showed significant contribution function for the nitrogen pool of soil.