Effects of Irrigation Amount and Irrigation Frequency on Flue-Cured Tobacco Evapotranspiration and Water Use Efficiency Based on Three-Year Field Drip-Irrigated Experiments

Jianfang Guang,Fuzhang Ding,Qisong Miao,Youbo Yuan,Chao Gao,Xu Yang,Xiaohou Shao

doi:10.3390/agronomy9100624

Abstract

This study aimed to determine the effect of irrigation amount and irrigation frequency on drip-irrigated flue-cured tobacco evapotranspiration (ETa), yield, and water use efficiency. Four irrigation treatment levels were imposed: 100% IRT (fully irrigated treatment, no stress), 85% IRT, 70% IRT, RFT (rainfed treatment), and high, medium, and low irrigation frequencies were set. The relationship between irrigation volume and yield is a quadratic curve. The evapotranspiration had a positive relationship with the irrigation amount. The yield of flue-cured tobacco was the highest in 2016 (wet year), and the corresponding ETa was the smallest. The irrigation water use efficiency (IWUE) in the driest year, 2017, was lower than IWUE in the wet years 2015 and 2016, and the crop water use efficiency (CWUE) had similar results for the three years. IWUE increased with irrigation amount. The effect of irrigation frequency on CWUE was not significant. The CWUE had a positive relationship with yield. No significant differences due to irrigation frequency were found for yield.

Highlights

In some areas of China, flue-cured tobacco is an important cash crop
Different from corn and wheat, our results showed that increased with higher than a dry year
Different from corn and wheat, our results showed that irrigation water use efficiency (IWUE) increased with irrigation amount, the wet year was higher than the dry irrigation amount,but butthe thesimilar similarresults resultsshow showthat thatIWUE

Summary

Introduction

In some areas of China, flue-cured tobacco is an important cash crop. China’s flue-cured tobacco planting area is about 1,010,937 hectares and accounts for about 50% of worldwide total tobacco production [1]. Well-managed irrigation can improve water production efficiency. In terms of enhancing water use efficiency and reducing soil evaporation, drip irrigation (subsurface and on surface) has been shown to be more effective than other forms of irrigation [4], because it is easy to control the irrigation flow rate, which leads to a smaller wetting root zone, smaller runoff, and less deep percolation. Studies on more than 30 crops have shown that yield under drip irrigation is higher than that under other irrigation methods, and less water is required in most instances [5]. The drip irrigation amount and frequency are critical for plant growth, yield, and water use efficiency (WUE) [6,7].

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