不同氮素用量对黄瓜幼苗生长及养分吸收的影响

为确定黄瓜幼苗对氮素用量及氮素形态的响应特性以指导育苗期间合理施肥,以硝酸铵磷(NO_3~--N:NH_4~+-N为0.9:1.0)为供试肥料,研究同时提供NO_3~--N和NH_4~+-N的情况下,不同氮素用量对黄瓜幼苗生长及养分吸收的影响。结果表明:与不施氮对照相比,氮素施用可显著增加植株叶面积和株高,但各施氮处理之间差异不明显(50~200 mg N/株);植株幼苗茎粗和地上部干物质累积量不同处理间差异不显著;施用氮素黄瓜幼苗根系的根长、根表面积和干物质累积量降低(尤其氮用量100 mg/株),根系直径在0.5~1.3 mm和1.8~2.6 mm范围内的根长下降明显。氮素用量显著影响了地上部氮、磷、钾的浓度及吸收量,对根系的磷、钾浓度和氮、磷、钾的吸收量影响较小;综合地上部和根系的生长状况,氮素用量在50 mg/株及150 mg/株时,黄瓜幼苗的生长健壮。

Seedling Growth and Nutrients Uptake Response to Nitrogen Application Rates During Cucumis sativus Nursery Period

Response characteristics of cucumber seedlings to nitrogen (N) application rates and forms were determined for optimizing fertilization during seedling nursery period, ammonium nitrate phosphorus fertilizer as tested material (NO_3--N:NH₄ -N 0.9:1.0), the influence of different application rates of N on growth and nutrients uptake of cucumber seedlings were studied under providing NO_3--N and NH₄ -N simultaneously condition in this experiment. The results indicated that nitrogen application could significantly increase leaf area, plant height of seedlings but no statistical differences were found within the four N applied treatments (50~200 mg N/plant), compare with no N applied treatment (control). There were no significant difference between all N treatments in shoot dry matter accumulation and stem diameter of cucumber seedlings. N utilization inhibited root growth, with the decrease of root length, root surface area and root dry matter accumulation (especially at the rate of 100 mg N/plant), and root length decreased markedly with 0.5~1.3 mm and 1.8~2.6 mm root diameters. Significant effects were found in concentrations and contents of N, phosphorus (P) and potassium (K) of shoot, but no significant effects in P, K concentrations and N, P, K contents of root with different N application rate. Shoot and root growth status were taken into consideration, N application rates at 50 mg and 150 mg per plant could produce stronger seedlings.