Chinese Journal of Agrometeorology ›› 2015, Vol. 36 ›› Issue (05): 536-543.doi: 10.3969/j.issn.1000-6362.2015. 05.002

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Soil Water Threshold and its Dynamics of Winter Wheat Aiming Water-saving and High Yield

ZHAO Ye-meng, LI Yu-zhong, LIU Xiao-ying, ZHONG Xiu-li, CAO Jin-feng   

  1. Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences/Key Laboratory of Dry Land Agriculture, MOA, Beijing 100081, China
  • Received:2015-01-05 Online:2015-10-20 Published:2015-10-19

Abstract: It is important to determine soil water threshold affecting crop yield for diagnosis of crop water stress and practice of deficit irrigation. To achieve this, field experiment of winter wheat with seven treatments, irrigated at different growth stages and supplied with varying irrigation amount to maintain their variation in soil water, was conducted in 2011/2012 at a site in Hengshui, Hebei Province. Relations between yield and soil water of different depth at seven growth stages were examined. Soil water threshold based on yield was explored and its dynamics was revealed. Results showed that the largest difference in soil water between the six deficient treatments and the well watered control occurred at shallow soil depth, and it decreased with deepening of soil layer. The difference was respectively 19.7%-36.5%, 9.3%-21.7% and 2.9%-9.7% at the soil layer of 0.4, 0.8 and 1.2m. In addition, variability of soil water decreased as soil depth increases. Relationship between grain yield of winter wheat and soil water of different depth at varying growth stages was parabolic functions of downward opening, but correlation significance changed with both growth stage and soil depth, being most significant for soil layer of 0. 4m. Soil water threshold based on yield diminished with progression of growth stages, from 83.1%-95% to 72.3%-90.0% of the field water capacity from jointing-booting to milk maturing at soil depth of 0.4, 0.6, 1.0, 1.2 and 1.6m. We recommended 0.4m being the most appropriate soil depth for detecting water deficit based on analysis in four aspects: difference in soil water dynamic and its average over the whole growing season between treatments, soil water variability at different soil depth, significance of the relations between soil water and yield at different growth stage. The corresponding water threshold at jointing-booting, heading, flowering, beginning-, middle -, later of grain filling and milk maturing was respectively 95.0%, 98.4%, 79.9%, 73.7%, 88.6%, 79.6% and 75.7%.

Key words: Winter wheat, Soil water threshold, Threshold dynamic, Detection of soil water deficit, Water and yield relation