A novel, ridged enlarging lateral space drip irrigation pattern (ReDiP) for high- yield and WUE spring wheat in Xinjiang, China

Abstract

Context

Drip-irrigated wheat systems typically require more drip tubes, leading to higher costs. We previously developed the enlarging lateral space (ELS) wheat drip irrigation patterns, which reduced drip tube input but resulted in fluctuating yields. Balancing economic benefits with stable yields and water use efficiency (WUE) remains a significant challenge.

Objective

To develop a ridged ELS drip irrigation pattern (ReDip) facilitating water transportation for better grain yield and WUE in wheat, and to decipher the underlying mechanisms in terms of soil water status and plant growth.

Methods

A three-year field experiment was conducted with seven drip irrigation patterns, the conventional pattern (TR4, one drip Tube serves four wheat Rows with row-space of 15 cm and Lateral Spacing of 60 cm), ELS patterns (TR6S (LS = 80 cm) and TR8S (LS = 100 cm), with narrowed row-space of 10 cm and inter-block space of 25 cm), and the ridged ELS patterns (TR6S-R₁₀ and TR8S-R₁₀, with hill angle of 10⁰; TR6S-R₁₅ and TR8S-R₁₅, with hill angle of 15⁰).

Results

In comparison to TR4, TR6S and TR8S separately caused a yield loss of ca. 1.30 % – 10.5 % and 6.82 % – 17.69 %, whilst the corresponding ridged pattern showed much less yield reduction (2.75 % – 7.40 % and −3.32 % – 3.13 % for TR6S-R₁₀ and TR6S-R₁₅, and 8.34 % – 16.09 % and 1.50 % – 14.52 % for TR8S-R₁₀ and TR8S-R₁₅, respectively). Ridging significantly improved horizontal water movement, reducing the coefficient of variation of soil water content and ensuring uniform moisture distribution across the root zone. This was closely related to the better maintained soil water status, which facilitated both root and shoot growth in terms of higher root dry weight and modified canopy structure than the non-ridged patterns. Additionally, ridged patterns mainly improved dry matter accumulation after anthesis and its contribution to grain to increase biomass and harvest index. The optimal pattern, TR6S-R₁₅, achieved 18.91 % – 24.12 % higher in WUE and 0.56 % – 9.11 % higher in profit while maintaining yields comparable to or exceeding TR4 (e.g., 3.32 % higher in 2023).

Conclusions

Ridging facilitates horizontal water movement to maintain better soil moisture status and promotes wheat growth and yield formation. The TR6S-R₁₅ pattern was recommended considering performances of grain yield, WUE and profit.

Implications

The ReDiP system will potentially improve wheat production and WUE in arid regions and be adapted for other crops, offering a sustainable solution for water-saving agriculture.