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Chinese Agricultural Science Bulletin ›› 2023, Vol. 39 ›› Issue (14): 74-79.doi: 10.11924/j.issn.1000-6850.casb2022-0325

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The Impact of Soil Moisture Control on Crop Coefficient and Water Use Efficiency of Drip-irrigated Alfalfa

TONG Changfu1,2(), LI Heping1,2, NIU Hai3, LIU Jianfeng4, LUO Penghuai5   

  1. 1 Yinshanbeilu Grassland Eco-hydrology National Observation and Research Station, China Institute of Water Resources and Hydropower Research, Beijing 100038
    2 The Institute of Water Resources for Pastoral Area, Huhhot 010020
    3 Water Conservancy Bureau of Erdos, Erdos, Inner Mongolia 017010
    4 Inner Mongolia Water Conservancy Research Institute, Huhhot 010019
    5 Water Conservancy Bureau of Wushen Banner, Erdos, Inner Mongolia 017300
  • Received:2022-04-19 Revised:2022-07-06 Online:2023-05-09 Published:2023-05-09

Abstract:

In this paper, field irrigation experiments were carried out for two consecutive years, and the effects of four soil water treatments under drip irrigation of alfalfa (70%θfc, 60%θfc, 50%θfc and 40%θfc) on crop coefficient (Kc) were studied, to explore a path to improve alfalfa water use efficiency (WUE). The results showed that branching to budding stage were the critical period of water demand for alfalfa; the relationship between ETa of alfalfa and yield was a quadratic parabola (R2=0.9433). The Kc of alfalfa was 0.61-0.88 in greening-jointing stage, 0.68-0.79 in jointing-branching stage, 1.07-1.16 in branching-budding stage and 0.57-0.96 in budding-flowering stage, and the crop coefficient of the whole growth period was a quadratic parabola. Under the conditions of different soil water contents and precipitation, the irrigation volume had a significant effect on the WUE of alfalfa in the years with less precipitation; while on the contrary, the irrigation volume had no significant effect on the WUE of alfalfa.

Key words: drip irrigated, crop coefficient, soil water, water use efficiency, alfalfa