JIA-2019-11

Journal of Integrative Agriculture 2019, 18(11): 2472–2482 RESEARCH ARTICLE Available online at www.sciencedirect.com ScienceDirect The effects of soil moisture and salinity as functions of groundwater depth on wheat growth and yield in coastal saline soils ZHANG He 1 , LI Yan 1 , MENG Ya-li 1 , CAO Nan 1 , LI Duan-sheng 1 , ZHOU Zhi-guo 1 , CHEN Bing-lin 1 , DOU Fu-gen 2 1 College of Agriculture, Nanjing Agricultural University/Key Laboratory of Crop Physiology Ecology and Production Management, Ministry of Agriculture and Rural Affairs/Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing 210095, P.R.China 2 Texas A&M AgriLife Research Center at Beaumont, Beaumont TX 77713, USA Abstract In the coastal saline soils, moisture and salinity are the functions of groundwater depth affecting crop growth and yield. Accordingly, the objectives of this study were to: 1) investigate the combined effects of moisture and salinity stresses on wheat growth as affected by groundwater depth, and 2) find the optimal groundwater depth for wheat growth in coastal saline soils. The groundwater depths (0.7, 1.1, 1.5, 1.9, 2.3, and 2.7 m during 2013–2014 (Y1) and 0.6, 1.0, 1.4, 1.8, 2.2, and 2.6 m during 2014–2015 (Y2)) of the field experiment were maintained by soil columns. There was a positive correlation between soil moisture and salinity. Water logging with high salinity (groundwater depth at 0.7 m in Y1 and 0.6 m in Y2) showed a greater decline towards wheat growth than that of slight drought with medium (2.3 m in Y1) or low salinity (2.7 m in Y1, 2.2 and 2.6 m in Y2). The booting stage was the most sensitive stage of wheat crop under moisture and salinity stresses. Data showed the most optimal rate of photosynthesis, grain yield, and flour quality were obtained under the groundwater depth (ditch depth) of 1.9 m (standard soil moisture with medium salinity) and 2.3 m (slight drought with medium salinity) in Y1 and 1.8 m (standard soil moisture with medium salinity) and 2.2 m (slight drought with low salinity) in Y2. The corresponding optimal soil relative moisture content and conductivity with the 1:5 distilled water/soil dilution, in the depth of 0–20 cm and 20–40 cm in coastal saline soils, were equal to 58.67–63.07% and 65.51–72.66% in Y1, 63.09–66.70% and 69.75–74.72% in Y2; 0.86–1.01 dS m –1 and 0.63–0.77 dS m –1 inY1, 0.57–0.93 dS m –1 and 0.40–0.63 dS m –1 inY2, respectively. Keywords: couple stress, soil relative moisture content, soil conductivity, photosynthesis, growth stage 1. Introduction Due to ever-increasing population, the safety of food supply in the world is facing severe challenges (Xie et al . 2017). There are approximately 1 billion ha soil resources equivalent to the 7% of the mainland’s area affected globally by soil salinization (Metternicht and Zinck 2003). Therefore, the abundant resources of the salt-affected soils should be utilized rationally. Wheat ( Triticum aestivum L.) is the main staple crop in China and is grown in arable soils. The Received 26 December, 2018 Accepted 12 April, 2019 Correspondence CHEN Bing-lin, Tel/Fax: +86-25-84396129, E-mail: blchen@njau.edu.cn © 2019 CAAS. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/) . doi: 10.1016/S2095-3119(19)62713-9