Chin J Plant Ecol ›› 2020, Vol. 44 ›› Issue (7): 752-762.DOI: 10.17521/cjpe.2019.0337

• Research Articles • Previous Articles     Next Articles

Hydraulic lift of Medicago sativa and Astragalus laxmannii and its effect on their neighborhood plants

ZHU Lin1,2,*(), WANG Tian-Tian1,2, ZHAO Xue-Lin1,2, QI Ya-Shu3, XU Xing1,2   

  1. 1State Key Laboratory Breeding Base of Land Degradation and Ecological Restoration of Northwestern China, Ningxia University, Yinchuan 750021, China
    2Key Laboratory for Restoration and Reconstruction of Degraded Ecosystem in North-western China, Ministry of Education, Ningxia University, Yinchuan 750021, China
    3Center for Extension and Training of Agricultural Technique, Zhongwei, Ningxia 755099, China
  • Received:2019-12-03 Accepted:2020-06-17 Online:2020-07-20 Published:2020-07-03
  • Contact: ZHU Lin: ORCID:0000-0002-1234-5837,E-mail:zhulinscience@126.com
  • Supported by:
    National Natural Science Foundation of China(31160478);National Natural Science Foundation of China(31830135);Forage Breeding Program of Ningxia Hui Autonomous Region(2014NYYZ0401);Natural Science Foundation of Ningxia Hui Autonomous Region(NZ17040)

Abstract:

Aims A variety of plant species can release soil water which is absorbed from wet soil layers to the dry soil layers during the period when transpiration rate is low (hydraulic lift). The purpose of this study is to explore the phenomenon of hydraulic lift for the mixed sowing combinations of two leguminous forages with gramineous forage, uncover the inter-specific relationship between forages with deep and shallow roots and provide theoretical basis for the establishment of mixed grassland.
Methods A split-root pot experiment was conducted outdoors. Two leguminous forages Medicago sativa and Astragalus laxmannii were sowed individually or sowed with a gramineous forage (Secale cereal ‘Dongmu 70’) with proportions of 3:7, 5:5 and 7:3. While the soil water content was measured continuously, deuteroxide (D2O, D% > 99.9%) tracing technique was adopted to test the occurrence of hydraulic lift and to calculate the lift water quantity.
Important findings The yield of S. Cereal ‘Dongmu 70’ in mixed sowing with A. laxmannii was higher than that with M. sativa. The yield of AC2 (Medicago sativa:gramineae being 5:5) and BC3 (A. laxmannii : gramineae being 7:3) was higher than other mixed sowing proportions in the same mixed sowing combination. There was a significant difference in the average daily water lift during the whole growth period among different single sowing or mixed sowing combinations. The lift water amount for a given leguminous forage was higher in mixed sowing combinations than in single sowing combinations. A. laxmannii displayed higher daily water lift quantity regardless of single sowing or mixed sowing. The average daily water lift of BC2 (A. laxmannii : gramineae being 5:5) was significantly higher than other combinations. Hydrogen stable isotope ratio (δD) of soil water in upper and bottom pots significantly increased after treated with deuteroxide tracer. The values of soil water δD in the upper pot, xylem water δD, whole plant carbon isotope discrimination (Δ13C) and yield of Secale cereal ‘Dongmu 70’ have provided the evidence that the water status or yielding performance of S. cereal ‘Dongmu 70’ in the combinations of BC1 (A. laxmannii : gramineae being 3:7) and AC2 was better than other mixed combinations. This study validated the hypothesis that the phenomenon of hydraulic lift occurred when the deep-rooting leguminous and gramineous forages with shallow root were sown together. The water lift by the tested leguminous forages has been absorbed by their neighboring gramineous forage.

Key words: mixed sowing between leguminous forage and gramineous forage, hydraulic lift, stable isotopic technique