长脐红豆幼苗生长对不同土壤氮磷添加的响应及其对土壤养分的反馈 / Growth performance of Ormosia balansae seedlings and their feedbacks on the soil nutrient under varied soil nitrogen and phosphorus addition conditions
以热带豆科树种长脐红豆（Ormosia balansae Drake）幼苗为研究对象,开展苗期控制试验,共设置了5个添加氮（N, N1—N5）和2个添加磷（P, LP—HP）梯度,观察长脐红豆在不同土壤N、P添加条件下的生长表现及对土壤养分的反馈。测定的植物和土壤响应指标包括:植株地上和地下生长量、叶面积、叶和根的N、P含量、根际和非根际土壤N、P含量等。结果表明:（1）从苗高、总叶面积、地上生物量、地下生物量、总根长和根表面积这6个指标总体来看,在低磷（LP）条件下,中、高浓度的N添加（N4、N5）对长脐红豆生长有抑制作用;高磷（HP）条件下,高浓度的N添加（仅有N5）对长脐红豆生长有抑制作用;表明长脐红豆的最适生长N浓度会随P添加浓度增加而升高;（2）随着N添加浓度的增加,根和叶的全N含量呈先增加后减小的趋势,N4处理条件下达到最大;根和叶的全P含量却呈现相反趋势,符合元素稀释效应。叶的N:P>16,且P浓度<1.0 mg·g-1,表明长脐红豆生长受P限制;（3）基于氨态氮、硝态氮和有效P这3个肥力指标,长脐红豆苗期非根际土壤肥力>根际土壤肥力,表明豆科树种长脐红豆在其幼苗期共生根瘤尚未明显形成时期,需补充适量N、P养分供给。
The seedling control experiment was carried out on the seedlings of Ormosia balansae Drake, a tropical leguminous tree species. Five nitrogen (N, N1 - N5) and two phosphorus (P, LP - HP) gradients were set up. Observe the growth performance of long umbilical red beans under different N and P addition conditions and feedback on soil nutrients. The measured plant and soil response indicators include: aboveground and underground growth, leaf area, N and P content of leaves and roots, and N and P contents in rhizosphere and non-rhizosphere soil. The results showed that: (1) from the six indicators of seedling height, total leaf area, aboveground biomass, underground biomass, total root length and root surface area, under the condition of low phosphorus (LP), medium and high concentration N addition (N4, N5) inhibited the growth of long umbilical red beans; high phosphorus (HP) conditions, high concentration of N addition (only N5) inhibited the growth of long umbilical red beans; indicating the optimum of long umbilical red beans The concentration of growth N increased with the increase of P concentration; (2) With the increase of N concentration, the total N content of roots and leaves increased first and then decreased, and reached the maximum under N4 treatment conditions; roots and leaves The overall P content showed an opposite trend, consistent with the elemental dilution effect. The leaf N:P>16, and the P concentration <1.0 mg·g -1 , indicating that the growth of long umbilical red bean is restricted by P; (3) based on the three fertility indexes of ammonia nitrogen, nitrate nitrogen and effective P, long umbilical The non-rhizosphere soil fertility of red bean seedlings> rhizosphere soil fertility indicates that the leguminous tree umbilical red bean has not formed a significant period in the seedling stage, and it needs to supplement the N and P nutrient supply.
Abstract in Chinese and English; article in Chinese only.