Key Laboratory of Animal Embryo Engineering and Molecular Breeding of Hubei Province, Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Science, Yaoyuan 1, Hongshan, Wuhan, 430064, China.
State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, 768 Jiayuguanxi Road, Lanzhou, 730020, China.
Sci Rep. 2021 Jul 22;11(1):15049. doi: 10.1038/s41598-021-94472-2.
Plants and soil interactions greatly affect ecosystems processes and properties. Ecological stoichiometry is an effective means to explore the C, N, P correlation between plants and soil and the relationship between plant growth and nutrient supply. Serious soil erosion on China's Loess Plateau has further barrenness the soil. Fertilization solves the problem of ecosystem degradation by improving soil fertility and regulating the ecological stoichiometric between soil and plants. No fertilization (CK), nitrogen fertilization (N), phosphorus fertilization (P) and N and P combined fertilization (NP) treatments were set in an alfalfa grassland. Organic carbon (C), nitrogen (N) and phosphorus (P) nutrients and their stoichiometry were measured in shoot and soil. P and NP fertilization increased shoot C concentration (3.12%, 0.91%), and all fertilization decreased shoot N concentration (6.96%). The variation of shoot C and N concentrations resulted in a greater increase in shoot C:N under the fertilization treatment than that under CK (8.24%). Most fertilization treatments increased shoot P concentration (4.63%) at each cut, which induced a decrease of shoot C:P. Shoot N:P of most treatments were greater than 23, but it was lower under N and NP fertilization than that under CK. Fertilization only increased soil C in 2014, but had no effect on soil N. Soil P content was significantly higher under P fertilization in 2014 (34.53%), and all fertilization in the second cut of 2015 (124.32%). Shoot and soil C:P and N:P having the opposite changes to shoot and soil P, respectively. Our results suggest that the change of P after fertilization largely drove the changes of stoichiometric. The growth of alfalfa in the Loess Plateau was severely restricted by P. It is an effective method to increase the biomass of alfalfa by increasing the addition of N or NP fertilizer to alleviate P limitation.
植物与土壤的相互作用极大地影响着生态系统的过程和性质。生态化学计量学是一种有效的方法，可以用来探索植物与土壤之间的 C、N、P 相关性，以及植物生长与养分供应之间的关系。中国黄土高原严重的土壤侵蚀使土壤更加贫瘠。施肥通过提高土壤肥力和调节土壤与植物之间的生态化学计量来解决生态系统退化的问题。在苜蓿草地中设置了不施肥（CK）、氮施肥（N）、磷施肥（P）和氮磷联合施肥（NP）处理。测量了地上部和土壤中的有机碳（C）、氮（N）和磷（P）养分及其化学计量。P 和 NP 施肥增加了地上部 C 浓度（3.12%，0.91%），所有施肥都降低了地上部 N 浓度（6.96%）。施肥处理下地上部 C 和 N 浓度的变化导致 C:N 比大于 CK（8.24%）。大多数施肥处理在每次刈割时都增加了地上部 P 浓度（4.63%），这导致地上部 C:P 降低。大多数处理的地上部 N:P 大于 23，但在 N 和 NP 施肥下低于 CK。施肥仅在 2014 年增加了土壤 C，但对土壤 N 没有影响。2014 年 P 施肥显著增加了土壤 P 含量（34.53%），2015 年第二次刈割时所有施肥处理（124.32%）都显著增加了土壤 P 含量。地上部和土壤 C:P 和 N:P 的变化与地上部和土壤 P 的变化相反。我们的结果表明，施肥后 P 的变化在很大程度上驱动了化学计量的变化。苜蓿在黄土高原的生长受到 P 的严重限制。通过增加 N 或 NP 肥料的添加来缓解 P 限制，增加苜蓿生物量是一种有效的方法。
