Root length density distribution and associated soil water dynamics for tomato plants under furrow irrigation in a solar greenhouse
QIU Rangjian1,2, DU Taisheng2*, KANG Shaozhong2
1 Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Jiangsu Key Laboratory of Agricultural Meteorology, Nanjing University of Information Science and Technology, Nanjing 210044, China;
2 Center for Agricultural Water Research in China, China Agricultural University, Beijing 100083, China
Abstract urrow irrigation is a traditional widely-used irrigation method in the world. Understanding the dynamics of soil water distribution is essential to developing effective furrow irrigation strategies, especially in water-limited regions. The objectives of this study are to analyze root length density distribution and to explore soil water dynamics by simulating soil water content using a HYDRUS-2D model with consideration of root water uptake for furrow irrigated tomato plants in a solar greenhouse in Northwest China. Soil water contents were also in-situ observed by the ECH2O sensors from 4 June to 19 June and from 21 June to 4 July, 2012. Results showed that the root length density of tomato plants was concentrated in the 0–50 cm soil layers, and radiated 0–18 cm toward the furrow and 0–30 cm along the bed axis. Soil water content values simulated by the HYDRUS-2D model agreed well with those observed by the ECH2O sensors, with regression coefficient of 0.988, coefficient of determination of 0.89, and index of agreement of 0.97. The HYDRUS-2D model with the calibrated parameters was then applied to explore the optimal irrigation scheduling. Infrequent irrigation with a large amount of water for each irrigation event could result in 10%–18% of the irrigation water losses. Thus we recommend high irrigation frequency with a low amount of water for each irrigation event in greenhouses for arid region. The maximum high irrigation amount and the suitable irrigation interval required to avoid plant water stress and drainage water were 34 mm and 6 days, respectively, for given daily average transpiration rate of 4.0 mm/d. To sum up, the HYDRUS-2D model with consideration of root water uptake can be used to improve irrigation scheduling for furrow irrigated tomato plants in greenhouses in arid regions
Fund: This study was supported by the National Key Research and Development Program of China (2016YFC0400207), the National Natural Science Foundation of China (51222905, 51621061, 51509130), the Natural Science Foundation of Jiangsu Province, China (BK20150908), the Discipline Innovative Engineering Plan (111 Program, B14002) and the Jiangsu Key Laboratory of Agricultural Meteorology Foundation (JKLAM1601).
Corresponding Authors: DU Taisheng
E-mail: dutaisheng@cau.edu.cn
Cite this article:
. Root length density distribution and associated soil water dynamics for tomato plants under furrow irrigation in a solar greenhouse[J]. Journal of Arid Land, 2017, 9(5): 637-650.
2017, Vol. 9 
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