Soil Warming Changed Growth, Yield and Water Consumption of Winter Wheat

Abstract

【Objective】 Global warming would lead to soil temperature rising and alter the physical and biogeochemical properties of the soil. How these affect the growth and yield of crops remains largely absurd, and the purpose of this paper is to present an experimental study on the effect of soil warming on growth and yield of winter wheat in central China. 【Method】 The experiment was conducted in 2012—2103 at a field in the Comprehensive Experimental Station of Chinese Academy of Agricultural Sciences at Shangqiu. A heating pipeline buried 1.2 m deep warmed the whole soil profile, and the control was a site far away from the pipe (CK). Based on the horizontal distance from the pipe, we divided the topsoil into four warming zones: right above the pipe with the soil temperature increased by 8 ℃ (T8, compared to CK, same hereafter), 0.5 m away from the pipe with the soil temperature increased by 6 ℃ (T6), 1.0m from the pipe with the soil temperature increased by 4 ℃ (T4), 1.5 m from the pipe with the soil temperature increased by 2 ℃ (T2). In each treatment, we measured root growth and its traits, yield traits, water consumption and water use efficiency (WUE). 【Result】 The soil temperature peaked at 14:00 every day. Increasing soil temperature by 2.0 ℃ was beneficial to root growth, while over 4.0 ℃ would impede root growth. Most roots were found in the 0~40 cm of soil, with the root-length density in which accounting for more than 75% of the total root lengths from the tillering stage to the green stage over the soil profile. Soil warming boosted crop height and its leaf area index (LAI) after the greening stage, but slowed down crop growth at the late stages, especially in the high-temperature zones. Increasing soil temperature by less than 4.0 ℃ significantly increased grain and biological yields, the number of spikes, the number of spikes per spike, and the 1 000-grain weight. In contrast, increasing soil warming by more than 4.0 ℃ significantly reduced the yield traits. We found that soil warming also impacted water consumption (ET) and WUE, with the impact ranked in the order T2>CK>T4> T6> T8 for ET, and T2> T4>CK> T6> T8 for WUE, despite the insignificant difference between CK and T4. 【Conclusion】 Increasing soil temperature by 2.0 ℃ over the ambient temperature is beneficial to the yield and WUE of the winter wheat.

Keywords

• soil warming
• root distribution
• yield traits
• grain-filling rate
• water use efficiency