Soil water status shapes nutrient cycling in agroecosystems from micrometer to landscape scales

Abstract

Soil water status, which refers to the wetness or dryness of soils, is crucial for the productivity of agroecosystems, as it determines nutrient cycling and uptake physically via transport, biologically via the moisture‐dependent activity of soil flora, fauna, and plants, and chemically via specific hydrolyses and redox reactions. Here, we focus on the dynamics of nitrogen (N), phosphorus (P), and sulfur (S) and review how soil water is coupled to the cycling of these elements and related stoichiometric controls across different scales within agroecosystems. These scales span processes at the molecular level, where nutrients and water are consumed, to processes in the soil pore system, within a soil profile and across the landscape. We highlight that with increasing mobility of the nutrients in water, water‐based nutrient flux may alleviate or even exacerbate imbalances in nutrient supply within soils, for example, by transport of mobile nutrients towards previously depleted microsites (alleviating imbalances), or by selective loss of mobile nutrients from microsites (increasing imbalances). These imbalances can be modulated by biological activity, especially by fungal hyphae and roots, which contribute to nutrient redistribution within soils, and which are themselves dependent on specific, optimal water availability. At larger scales, such small‐scale effects converge with nutrient inputs from atmospheric (wet deposition) or nonlocal sources and with nutrient losses from the soil system towards aquifers. Hence, water acts as a major control in nutrient cycling across scales in agroecosystems and may either exacerbate or remove spatial disparities in the availability of the individual nutrients (N, P, S) required for biological activity.

Soil science challenges—An interdisciplinary overview of current and future topics

“…The cycling of nutrients such as N and phosphorus is closely linked to the SOC cycle (Kopittke et al, 2022) In the course of climate change, the occurrence of weather extremes, such as droughts and heavy rain events, is increasing with concomitant extremes in contrasting soil moisture states. The impact of contrasting soil water contents on nutrient cycling is reviewed in this issue by Bauke et al (2022) who conclude that it needs to be studied from the molecular to the landscape scale. As a future perspective for soil system modeling, Gerke et al (2022) present within this issue a holistic approach to predict spatially distributed soil functions and their changes in response to external forcing.…”

“…The impact of contrasting soil water contents on nutrient cycling is reviewed in this issue by Bauke et al. (2022) who conclude that it needs to be studied from the molecular to the landscape scale. As a future perspective for soil system modeling, Gerke et al.…”

Effect of the 2022 summer drought across forest types in Europe

“…Elevated temperatures can also increase rates of respiration from the soil and from the trees which leads to reduced net capacity of forests for carbon uptake and reducing anthropogenic CO2 emissions (van der Molen et al 2011;Anjileli et al 2021). Drought also limits movement of nutrients in the soil water and decreases nutrient availability to trees which would affect growth and productivity (Bauke et al 2022). Changes in plant water-use and nutrient cycling can trigger feedback loops that magnify the effects of drought and heat stress.…”

Synergistic relationships between the age of soil organic matter, Fe speciation, and aggregate stability in an arable Luvisol

“…The ecosystem services of soil include nutrient cycling, water storage, carbon (C) storage, and microbial habitats, which are intimately linked to the basic heterogeneous arrangement of soil aggregates and internal pores (Bauke et al., 2022; Totsche et al., 2018). The development of a soil aggregate structure by pedogenesis is a desirable soil characteristic for sustaining agricultural production and maintaining environmental quality (Amézketa, 1999).…”