Water use efficiency and yield responses of cotton to field capacity-based deficit irrigation in an extremely arid area of China

Haifeng Li,Zhiming Qi,Dongwei Gui,Fang Zeng

doi:10.25165/j.ijabe.20191206.4571

Abstract

The objectives of present investigation were to test the effects on water use efficiency (WUE) and cotton yield of implementing a range of deficit irrigation regimes triggered at specific fractions of root zone soil moisture, field capacity (θfc) and different crop phenological stages. The study was conducted on southern oasis of the Taklamakan desert, China. The cotton crop’s WUE was quantified, as were leaf photosynthesis and yield. From a photosynthetic perspective, deficit irrigation resulted in 16.8%, 10.3% and 2.2% increases in leaf WUE under θfc-based regulated deficit irrigation (T1, T2, and T3), compared to the control, respectively. Cotton yield and its components were significantly affected by irrigation depths (p≤0.05). A relatively high seed yield (0.65 kg/m3) and the highest WUE were achieved, under T3 (70% θfc at seedling stage, 60% θfc at squaring, 50% θfc at full-bloom, 70% θfc at boll, 70% θfc at boll cracking stage), showing it to be the most effective and productive irrigation schedule tested. As the application of θfc-based deficit irrigation in surface-irrigated cotton fields showed great potential in saving water, maintaining a high WUE, and improving cotton seed yield, a management strategy consisting or irrigation thresholds of 70% θfc in the root zone at the seedling, boll and boll cracking stages, and of 60% θfc at the squaring stage, and 50% θfc at the full-bloom stage, would be recommended for this extremely arid region. Keywords: regulated deficit irrigation, evapotranspiration, seed cotton yield, water use efficiency, Qira Oasis DOI: 10.25165/j.ijabe.20191206.4571 Citation: Li H F, Qi Z M, Gui D W, Zeng F J. Water use efficiency and yield responses of cotton to field capacity-based deficit irrigation in an extremely arid area of China. Int J Agric & Biol Eng, 2019; 12(6): 91–101.

Highlights

Given that water scarcity is the major bottleneck limiting sustainable agricultural development in northwest China[1,2], especially in the region’s extremely arid areas where precipitation is insufficient to meet crop water requirements[3], irrigation is critical for agricultural production[4,5]
Compared with the fixed amount irrigation treatment, deficit irrigation resulted in 16.8%, 10.3% and 2.2% increase of leaf water utilization efficiency (WUE) under T1, T3 and T4, respectively
The lowest value of soil water depletion was found in T3, demonstrated that a suitable water supply can sustain a dynamic soil water balance of the root zone

Summary

Introduction

Given that water scarcity is the major bottleneck limiting sustainable agricultural development in northwest China[1,2], especially in the region’s extremely arid areas where precipitation is insufficient to meet crop water requirements[3], irrigation is critical for agricultural production[4,5]. Given rising yields and net profits per unit area over the last two decades, the area of irrigated cotton production has expanded rapidly[23,24,25,26] This has exacerbated the negative consequences of over-abstraction of water resources in this region that already water-scarced[4,27]. Given farmer’s confidence and reliance on traditional irrigation methods and their experience-based management of its quantity and timing, approximately 40% of fields in Xinjiang province receive flood irrigation[28]. This potentially results in substantial deep seepage losses and inefficient use of water resources. It is critical to optimize the region’s water resource use efficiency by improving the cotton production process in terms of WUE[29]

Methods

Results

Conclusion