Drought conditions alter litter decomposition and nutrient release of litter types in an agroforestry system of China

Abstract

Evaluating how decomposition rates and litter nutrient release of different litter types respond to changes in water conditions is crucial for understanding global carbon and nutrient cycling. However, it is unclear how decreasing water affects litter mixture interactions for the maize–poplar system in arid regions. Here, the responses of the litter decomposition process and litter mixture interactions in the agroforestry system to changes in water conditions (control, light drought, and moderate drought) were tested. Moderate drought significantly decreased the decomposition rate for poplar leaf and mixed litters, and decomposition rate was significantly reduced for maize straw litter in light and moderate drought stress. The mass loss rates of maize straw and mixed litters were significantly higher than that of the poplar leaf litter under drought conditions, but there was no significant difference among the three litter types in the control. There was no interaction between mass loss of the mixed litter in the control and light drought conditions, and the litter mixture interaction showed nonadditive synergistic interactions under moderate drought. In terms of nutrient release, there was also no interaction between litter mixture with nitrogen and carbon, but there was antagonistic interaction with potassium release under the light drought condition. Our results demonstrate that drought conditions can lead to decreasing decomposition rate and strong changes in the litter mixture interactions from additive effects to nonadditive synergistic effects in moderate drought. Moreover, light drought changed the mixture interaction from an additive effect to an antagonistic interaction for potassium release.

Species Richness Interacts with Drought to Affect Litter Decomposition via its Effect on Litter Nitrogen Concentration

“…Drought can affect litter decomposition in multiple ways (Allison et al 2013;Santonja et al 2015). For instance, drought can decrease litter decomposition via decreasing litter quality (Sanaullah et al 2012;Xie et al 2020), reducing quantity, diversity and activities of decomposers (Kheir et al 2019;da Silva et al 2020) and altering soil physio-chemical properties (Duarte et al 2017). We found that drought directly decreased litter decomposition (Fig.…”

“…Climate change is projected to result in more intensive drought in some regions in the world (Peltier and Ogle 2019;da Silva et al 2020). Drought can not only affect litter traits such as litter N concentration (Sanaullah et al 2012;Xie et al 2020), but also influence soil physio-chemical properties (e.g. soil moisture, temperature and pH) and diversity, quantity and activities of decomposers (e.g.…”

Nitrogen dynamics in agroforestry systems. A review

“…With increasing effects of climate change (e.g., warming, drought, extreme heat, heavy rainfall) on ecosystem processes (Runting et al 2017;Pires et al 2018), patterns of N dynamics described here will be destabilized (Nielsen and Ball 2015;Homyak et al 2017). For instance, changes in the quality of litter inputs caused by droughts will arguably affect N inputs via decomposition processes (Prieto et al 2019;Xie et al 2020). The effects of soil moisture limitations caused by droughts will constrain N mineralization processes (Homyak et al 2017;Schimel 2018) and affect N 2 O emissions (Li et al 2020;Barrat et al 2020).…”