Abstract
Achieving optimal balance between maize yield and water use efficiency is an important challenge for irrigation maize production in arid areas. In this study, we conducted an experiment in Xinjiang China in 2016 and 2017 to quantify the response of maize yield and water use to plant density and irrigation schedules. The treatments included four irrigation levels: 360 (W1), 480 (W2), 600 (W3), and 720 mm (W4), and five plant densities: 7.5 (D1), 9.0 (D2), 10.5 (D3), 12.0 (D4), and 13.5 plants m−2 (D5). The results showed that increasing the plant density and the irrigation level could both significantly increase the leaf area index (LAI). However, LAI expansion significantly increased evapotranspiration (ETa) under irrigation. The combination of irrigation level 600 mm (W3) and plant density 12.0 plants m−2 (D4) produced the highest maize yield (21.0–21.2 t ha−1), ETa (784.1–797.8 mm), and water use efficiency (WUE) (2.64–2.70 kg m−3), with an LAI of 8.5–8.7 at the silking stage. The relationship between LAI and grain yield and evapotranspiration were quantified, and, based on this, the relationship between water use and maize productivity was analyzed. Moreover, the optimal LAI was established to determine the reasonable irrigation level and coordinate the relationship between the increase in grain yield and the decrease in water use efficiency.
Highlights
The results revealed that grain yield decreased when leaf area index (LAI) exceeded the optimal value and the corresponding ETa was invalid
The current study shows that LAI increased with increasing plant density and irrigation level (Figure 3) and that grain yield and LAI displayed a quadratic relationship (Figure 4)
Through the analysis of the relationship between planting density and LAI, grain yield, and evapotranspiration under different irrigation levels, it was found that increasing the planting density and the irrigation level could both significantly increase the LAI and that both had a linear relationship with the LAI
Summary
Maize (Zea mays L.) is the most widely cultivated crop in the global and plays an important role in ensuring food security [1]. Increasing maize production has become more urgent, driven by increased food production, livestock raising, and biofuel production. Many studies have shown that increasing plant densities to optimal levels can and effectively increase maize yields [2,3,4]. The highest maize yields are obtained under optimal plant density or optimal leaf area index (LAI) [5,6,7]. The sensitivity of maize grain yield to changes in plant density is greatly depends on water availability during the growth season [8], especially in arid areas, where water scarcity is a major factor limiting crop growth and yield. High water use efficiency is the key to the sustainable and stable development of agriculture in arid areas [9]
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