J Plant Ecol ›› 2022, Vol. 15 ›› Issue (2): 223-236 .DOI: 10.1093/jpe/rtab084

• Research Articles •     Next Articles

Interspecific interactions affect N and P uptake rather than N:P ratios of plant species: evidence from intercropping

Wei-Ping Zhang1, Dario Fornara2, Guang-Cai Liu1,6, Josep Peñuelas3,4, Jordi Sardans3,4, Jian-Hao Sun5, Li-Zhen Zhang1 and Long Li1, *   

  1. 1 Beijing Key Laboratory of Biodiversity and Organic Farming, Key Laboratory of Plant and Soil Interactions, Ministry of Education, Department of Ecology and Ecological Engineering, College of Resource and Environmental Science, China Agricultural University, Beijing 100193, China, 2 Sustainable Agri-Food Science Division, Agri-Food & Biosciences Institute, BT9 5PX Belfast, UK, 3 CSIC, Global Ecology Unit CREAF-CSIC-UAB, 08913 Bellaterra, Catalonia, Spain, 4 CREAF, 08913 Cerdanyola del Vallès, Catalonia, Spain, 5 Institute of Soil, Fertilizer and Water-Saving Agriculture, Gansu Academy of Agricultural Sciences, Lanzhou 730070, China, 6 Present address: Gansu Agro-technology Extension Station, Lanzhou 730020, China

    *Corresponding author. E-mail: lilong@cau.edu.cn
  • Received:2020-12-09 Revised:2021-01-16 Accepted:2021-07-03 Online:2021-08-02 Published:2022-04-01

Abstract:

Quantifying stoichiometry of crop N and P acquisition (i.e. removal from farmland) under different agronomic practices is essential for understanding nutrient budgets and optimizing N and P fertilizer application in agroecosystems. It is not clear how plant N and P uptake and N:P stoichiometry vary between monoculture and intercropping throughout an entire growing season under different N fertilization and mulching practices. Here, we addressed how plant interspecific competition for nutrients have affected the temporal dynamics of crop N and P uptake (and N:P ratios) in five cropping systems (wheat, maize and barley monocultures, and wheat/maize and barley/maize intercropping), under two N levels (0 and 225 kg N ha−1) and two maize mulching treatments (with and without). Wheat and barley had greater N and P competitive ability than maize, leading to an increase in N and P uptake of wheat and barley and a decrease in N and P uptake of maize during co-growth stages in intercropping. N:P ratios of three crop species decreased with plant growth. Crop-level N:P ratios were either not affected by intercropping or did not change consistently with N fertilization while film mulching decreased maize N:P ratios. Community-level N:P ratios of the two intercrops were different from those of the corresponding monoculture at maturity. Because (i) the proportion of N and P removal from intercropping differs from monocultures, and (ii) N and P uptake by crops is decoupled under N fertilization and mulching, these findings may have practical implications for the nutrient budget of intercropping systems.

Key words: ecological stoichiometry, growth-rate hypothesis, intercropping system, interspecific competition, nitrogen addition, nutrient budget, plastic film mulch

摘要:
种间相互作用影响植物氮和磷的吸收量而不是氮磷比

量化不同农艺措施下作物氮和磷吸收量(即从农田中移除的量)的化学计量特征对理解农田生态系统中的养分收支和优化氮、磷肥施用至关重要。目前还不清楚在不同的氮肥和覆膜措施下,单作和间作体系作物氮和磷吸收量以及氮磷化学计量特征随整个生长季的变化。本研究探讨了植物种间养分竞争如何对(1) 5种种植模式(小麦、玉米和大麦单作、小麦/玉米和大麦/玉米间作),(2)两种施氮水平(0和225 kg N ha−1)和(3)两种玉米覆膜处理(覆膜和不覆膜)下的作物氮、磷吸收量(以及氮磷比)时间动态的影响。研究结果表明,小麦和大麦的氮、磷竞争能力强于玉米,导致间作体系共生期的小麦和大麦氮、磷吸收量相比于单作增加,而玉米氮、磷吸收量相比于单作减少。3种作物植株氮磷比随作物生长而降低。作物氮磷比不受间作的影响,也不随施氮呈现一致的变化,覆膜降低了玉米的氮磷比。两种间作体系群落水平的氮磷比在成熟期与相应单作不同。由于(1)间作从土壤移除的氮和磷的比例不同于单作,以及(2)作物对氮和磷的吸收在施氮和覆膜下均是不耦合的,这些发现可能对间作系统的养分收支有启示意义。

关键词: 生态化学计量学, 生长速率假说, 间作系统, 种间竞争, 氮添加, 养分收支, 覆膜