控释氮肥对苦瓜幼苗生长及养分吸收的影响

摘要

Different application rates of control ed release nitrogen fertilizer (CRFN) were designed to evaluate their effects on the growth and root morphology of bitter gourd (Momordica charantia L.) seedlings, and thus determine the optimal nitrogen amount and suitable nitrogen content in substrate at seedling transplanting, in com-parison with conventional fertilizer application. CRFN was applied at five levels, 0, 0.6, 1.2, 2.4 and 4.8 kg N/m3, and conventional fertilizer was applied at 0.6 kg N/m3 as control. Four replicates were included in each treatment. The results showed that 0.6-2.4 kg N/m3 CRFN provided sufficient N nutrient for bitter gourd, with higher shoot and root dry weights, root length and root surface area than control treat-ments. Correspondingly, the total inorganic nitrogen in substrate ranged from 99.3 to 162.5 mg/pot at seedling transplanting in these treatments. 1.2 kg N/m3 was proven to be the optimal CRFN rate. Compared with conventional nitrogen fertilizer applica-tion, 1.2 kg N/m3 CRFN in substrate increased the dry weight, nitrogen uptake and improved root morphology indices of seedlings, and more than 83.3 mg/pot inorgan-ic nitrogen could be carried with substrate at transplanting, revealing a potential to reduce N-deficient risk after rain and basal N input by continuous release of CRFN.%为探讨包膜控释氮肥对苦瓜幼苗生长及养分吸收的影响,确定育苗阶段合理的控释氮肥用量及移栽时适宜的氮素携带量，该试验共设置5个控释肥料用量处理和1个传统育苗施肥处理，控释氮用量分别为0、0.6、1.2、2.4、4.8 kg N/m3，传统育苗氮处理为0.6 kg N/m3，4次重复，随机排列。结果表明，控释氮肥用量在0.6-2.4 kg N/m3范围内时，苦瓜幼苗都可以正常生长，植株地上部和根系干物质的累积量、根长及根系表面积参数都优于对照处理，与此对应的移栽期基质适宜无机氮含量为每穴盘99.3-162.5 mg。控释氮素用量为1.2 kg N/m3时，育苗效果最优。相比于传统的施氮处理，基质中添加1.2 kg N/m3控释氮素促进苦瓜幼苗累积干物质，增加吸氮量改善了根系生长状况，移栽时单株幼苗可实现139.8 mg的带肥移栽，比传统方法培育的幼苗多携带了83.3 mg氮素，可持续为定植后的苦瓜幼苗及时提供养分，降低前期遇雨脱肥风险并减少基肥投入和损失。