Evaluation of subsurface, mulched and non-mulched surface drip irrigation for maize production and economic benefits in northeast China

Drip irrigation is now commonly used for maize cultivation in China and other regions of the globe. The goal of this study was to compare water and fertilizer use as well as economic benefits for surface and subsurface drip irrigation and for mulched and non-mulched maize production in northeast China. An experiment was conducted during 2015 and 2016 in Chifeng in Inner Mongolia, China that included the following treatments mulched surface drip irrigation (M-DI), non-mulched surface drip irrigation (NM-DI); non-mulched subsurface drip irrigation (NM-SDI), and mulched furrow irrigation (M-FI). The results indicated that film mulching obviously improved the soil temperature and water content during the early growth period, which hastened maize emergence and growth. Compared with the M-FI treatment, the DI techniques significantly decreased the cost of field management and improved water and nitrogen use. The water use efficiency (WUE) and nitrogen partial factor productivity for DI treatments increased by 13.9–39.2% and 16.3–28.1%, respectively, on average for two years, compared to those for the M-FI treatment. The advantages of M-DI were film mulching and in-season fertigation, which improved maize development and achieved the highest yield and net output values, which were 9.2–10.1% and 4.7–19.1% higher than other techniques. The NM-SDI technique is a competitive viable alternative for maize cultivation given the lack of film residue, the ease of field management, which made the annual allocated cost of system decrease by 13.2–24.1% compared with others, and the highest WUE among the treatments. Therefore, the DI techniques showed potential to enhance maize production, but decisions regarding the use of DI should take both economic benefits and environmental impact into consideration.