Modeling tillage and manure application on soil phosphorous loss under climate change

Nutr Cycl Agroecosyst https://doi.org/10.1007/s10705-022-10192-7 (0123456789().,-volV) ( 01234567 89().,-volV) ORIGINAL ARTICLE Modeling tillage and manure application on soil phosphorous loss under climate change Zhaozhi Wang . Tiequan Zhang . Chin Sheng Tan . Lulin Xue . Melissa Bukovsky . Zhiming Qi Received: 22 June 2021 / Accepted: 6 January 2022 Ó Crown 2022 Abstract Phosphorus (P) losses from non-point sources into receiving water bodies play a significant role in eutrophication. Given their failure to adequately control eutrophication in the Lake Erie, conservation recommendations for agricultural watersheds should be reconsidered, particularly under climate change. Using the Environmental Policy Integrated Climate model, the potential impacts on crop yield, surface runoff, tile drainage, and relevant dissolved reactive phosphorus (DRP) losses from manure-amended corn-soybean rotation plots in the Lake Erie basin were estimated for six tillage methods with different mixing efficiencies and manure broadcast application. These were investigated under twelve different regional and global future climate simulations. Tillage alone proved to have only a minor impact on mean corn yield (± 2%). Climate change led to large uncertainties under the single tillage treatment. As a result of the combined effects of Z. Wang
T. Q. Zhang (&)
C. S. Tan Harrow Research and Development Centre, Agriculture and Agri-Food Canada, Harrow, ON N0R 1G0, Canada e-mail: L. Xue
M. Bukovsky National Center for Atmospheric Research, Boulder, CO 80307-3000, USA Z. M. Qi Department of Bioresource Engineering, McGill University, Sainte-Anne-de-Bellevue, QC, Canada biogeochemical processes (e.g., supply) and hydrological (e.g., transport), strong negative relationships (R2 = 0.98) were found between tillage mixing efficiency and DRP loss in surface runoff, tile drainage, and total DRP loss. The impacts of combined manure application (broadcast) and tillage on crop yield and flow volume were similar as those of tillage alone. With respect to total DRP losses, the effects of labile P content change outweighed those of surface runoff or tile drainage change (hydrologic). This resulted in a change in total DRP losses ranging from - 60% to ? 151%, with being closely correlated with decreasing tillage mixing efficiency (R2 = 0.94) from moldboard to no-till. Therefore, rotational tillage should be considered for DRP loss reduction and energy saving. Keywords Tillage mixing efficiency
Manure broadcast
Dissolved reactive P (DRP) loss
Climate change
EPIC model Introduction Given its critical role in the prolonged eutrophication of aquatic ecosystems, phosphorus (P) loss from agricultural lands via surface runoff and tile drainage to receiving water bodies has become a serious water quality issue, especially in view of the added issues under climate change. Non-point source P pollution 123 Nutr Cycl Agroecosyst leading to eutrophication has left the public sceptical regarding improvements in water quality and recent conservation efforts to reduce sediment-bound P loadings (Smith et al. 2018). For example, lake Erie’s cyanobacterial bloom of 2011 was the worst on record (Daloglu et al. 2012; Michalak et al. 2013), and that of 2014 left 400,000 people without potable water (Smith et al. 2015b). Soil P enrichment brought on by conservation practices, compounded with climate change, has led many to doubt whether the 40% reduction of P loading targets announced by the Canada-US Great Lakes Water Quality Agreement (GLWQA) and the Canada-Ontario Agreement on Great Lakes Water Quality and Ecosystem Health (COA) are feasible (Jarvie et al. 2017). Accordingly, we should reconsider the unintended consequences of conservation recommendations (e.g., the adoption of no-till) (Smith et al. 2018). The mobilization of P from agricultural lands is tied to both supply (biogeochemical, i.e., fertilizer type, and application timing, amount and method) and transport (hydrologic, i.e., surface runoff and tile drainage) factors (Plach et al. 2018). Motew et al. (2018) indicated that given the increase in precipitation events expected under climate change scenarios, a heightened supply of manure P in the soil would likely exacerbate water quality impairment. Similarly, Michalak et al. (2013) noted the concurrence of intense rainfall events and the dissolved reactive phosphorus (DRP) loss from agricultural lands led to Lake Erie’s harmful algal bloom of 2011. Ockenden et al. (2017) also showed that, averaged across three representative catchments in the UK, increased rainfall volume would be the most important contributing factor to projected (2050s) increases in winter P losses. Besides the impacts of climate change on regional hydrology, the supply factor is also of serious concern. Broadcasting fertilizer or manure without incorporation can result in P stratification, and a subsequent rise in DRP loss in runoff (Motew et al. 2018). Stratification often comes hand-in-hand with the reduced- or no-till field management protocols widely implemented throughout the Lake Erie basin to reduce particulate P and soil erosion losses, but ends up increasing DRP in runoff (Baker et al. 2017). With a growing implementation of conservation tillage, the perception exists that manure or fertilizer P must be applied by broadcast to adhere to the conditions of notill (Smith et al. 2018). Jarvie et al. (2017) indicated 123 that although these conservation practices reduced particulate P transport and soil erosion, they may unintentionally increase DRP loads. Rather than merely accelerating soil P stratification (Bullerjahn et al. 2016), reduced- or no-till crop field management can accelerate the development and/or retain soil macropores. This increases the connectivity between the surface and subsurface via preferential flow (Jarvis 2007), thereby increasing soil surface P transport to tile drainage by bypassing sorption/desorption processes within the soil matrix (Smith et al. 2015a). Conventional tillage, such as moldboard plow, can reduce buildup of P in the top soil layer, and therefore has potential to reduce risk of DRP loss to Lake Erie (Baker et al. 2017). It can also change water flow pathways, altering the balance of surface runoff and tile flow, thereby influencing P transport dynamics (King et al. 2015). The Environmental Policy Integrated Climate (EPIC) model is a process-based model capable of predicting a crop’s physiological growth process arising under a particular crop management strategy and its response to (sub-)daily time scale weather variables, such as atmospheric carbon dioxide concentration (CO2), precipitation and temperature (Schauberger et al. 2017). The EPIC model, calibrated to local conditions, has been widely used to investigate future climate change scenarios (Ahmed et al. 2017; Folberth et al. 2016; Lychuk et al. 2017a; Rosenzweig et al. 2014; Schauberger et al. 2017; Srivastava et al. (...truncated)