Abstract
Irrigation practice for rice culture can be especially challenging in areas with limited water supply and soil salinization. In this study, we carried out a field experiment to assess the effects of different water discharge frequencies on soil salt content, rice yield and water use efficiency on a saline-sodic soil in a semi-arid region of Northeast China. The experiment comprised of three frequency levels of discharge [9-time (I-9-30), 6-time (I-6-30) and 3-time (I-3-30) discharge, all followed with a 30-mm irrigation] in comparison with the traditional irrigation practice of 2-time discharge followed with an 80-mm irrigation (I-2-80). Our initial hypothesis was that increasing discharge frequency would increase both salt reduction and rice yield. Daily precipitation was recorded by a nearby weather station, and evapotranspiration and soil water percolation rates were measured at experimental sites using soil pits. The measurements were used to establish a water balance for each treatment. Our results showed that soil salt reduction increased with the increasing discharge frequency at a 30-mm irrigation water depth. The 9-time discharge reduced a large amount of soil salt (995.0 kg ha−1) after five months of the study. Rice yield also increased with the increasing discharge frequency with a 30-mm irrigation water depth; however, when compared to the traditional 2-time discharge followed with an 80-mm irrigation, rice yield at the sites with more frequent discharge (i.e., I-9-30, I-6-30 and I-3-30) was 11%–18% lower. Because of this, rice yield and irrigation water use efficiency were significantly higher under the traditional practice of high-irrigation with low-frequency discharge (I-2-80) than under I-9-30, I-6-30 and I-3-30. These results indicate a need for a trade-off amongst salt reduction, rice yield and water use when considering selection of irrigation and discharge schedules.
Highlights
Covering approximately 187,000 km2, the Songnen Plain in northeast China is among the country’s most important commodity grain production bases, where much of the rice crop is cultivated [1,2]
In the saline-sodic soil plots, different reduction in root zone salt content was found before rice transplanting and after rice harvesting: 995.0 kg ha−1 under treatment I-9-30 (30-mm irrigation water depth with 9-time discharge), 275.1 kg ha−1 under treatment I-6-30
The reduction was remarkably lower under I-3-30 than under I-2-80, the discharge frequency was slightly higher under I-3-30 than under I-2-80
Summary
Covering approximately 187,000 km, the Songnen Plain in northeast China is among the country’s most important commodity grain production bases, where much of the rice crop is cultivated [1,2]. Many different ways have been used to ameliorate salt-affected soils over the last 100 years including crop-assisted interventions, tillage operations, chemical amendments, water-related treatments, and electrical currents [9,10,11,12,13]. These methods often bring prohibitively high costs for local farmers or are ineffective. Ameliorating salt-affected soils by irrigated rice culture can be accomplished through one or more of the following:
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
