Abstract
Despite the obvious importance of roots to agro‐ecosystem functioning, few studies have attempted to examine the effects of warming on root biomass and distribution, especially under different tillage systems. In this study, we performed a field warming experiment using infrared heaters on winter wheat, in long‐term conventional tillage and no‐tillage plots, to determine the responses of root biomass and distribution to warming. Soil monoliths were collected from three soil depths (0–10, 10–20, and 20–30 cm). Results showed that root biomass was noticeably increased under both till and no‐till tillage systems (12.1% and 12.9% in 2011, and 9.9% and 14.5% in 2013, in the two tillage systems, respectively) in the 0–30 cm depth, associated with a similar increase in shoot biomass. However, warming‐induced root biomass increases occurred in the deeper soil layers (i.e., 10–20 and 20–30 cm) in till, while the increase in no‐till was focused in the surface layer (0–10 cm). Differences in the warming‐induced increases in root biomass between till and no‐till were positively correlated with the differences in soil total nitrogen (R 2 = .863, p < .001) and soil bulk density (R 2 = .853, p < .001). Knowledge of the distribution of wheat root in response to warming should help manage nutrient application and cycling of soil C‐N pools under anticipated climate change conditions.
Highlights
We hypothesized that: (1) warming increases winter wheat root biomass, (2) the increase is greater under no-till than under till, and (3) in the shallow layer the redistribution of roots within the soil profile depends upon the tillage system
We suggest that the positive responses of root biomass under the two tillage systems resulted from the very limited warming-induced negative effect on root biomass production in our study
We conclude that warming can significantly increase root biomass under both till and no-till in irrigated wheat croplands
Summary
The growth and distribution of roots have a critical impact on the nutrient and water uptake by crops, and on crop growth and yield (Kuchenbuch, Gerke, & Buczko, 2009; Kuzyakov & Blagodatskaya, 2015; Wuertz et al, 2006). Higher temperature has been reported to strongly affect soil properties, such as soil moisture or N cycling (Hou, Ouyang, Wilson, Li, & Li, 2014; Rustad et al, 2001). The greater soil bulk density (BD) in the surface soil layer under no-till, acting as a barrier, is expected to decrease the distribution of the warming-induced changes in the root biomass to the deeper soil layers. Such knowledge is needed to better manage the availability of nutrients to crops and water use under changing climates. We hypothesized that: (1) warming increases winter wheat root biomass, (2) the increase is greater under no-till than under till, and (3) in the shallow layer the redistribution of roots within the soil profile depends upon the tillage system
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