Simulating soil-carbon-water interactions in two profiles to select precision cover for soil-health and drought-resilience

Abstract

BackgroundThe disseminated information to the stakeholders is mostly regional as the urge to meet global production goals and adoption of intensive agricultural practice have been amplified. Regional management strategies (MS) are mainly based on a broad-spectrum of ecoregions and climate scenarios and thus, are not always successful to prescribe a cover without failure. This produces a dilemma which restrains the farmers from adapting soil-covers as a climate-smart conservation practice. Simulating agroecosystems for better-understanding of soil-plant-water relationships within a soil profile would improve the societal acceptance of using cover crops. We intended to bring light into the uncertain conditions of production during drought and inconsistencies in soil organic carbon (SOC) sequestration through analyzing the impacts of soil cover, residue decomposition and inherent soil characteristics on soil moisture variability. MethodIn-situ effects of cover, residues and manure application on specific soil-layers were considered to simulate above and belowground biomass contents and impacts of applied residues, C, nitrogen and moisture content of soils at different crop-growth phases. Soil-environmental factors of seven MS were modeled to reveal the subtle conditions within the profiles of two similar soils of closely-located sites. Decision support systems with Strategic Analysis along with the simulated-results were used for long-term impact-analysis and select a precision cover based on soil and site. Moisture movement through whole soil profiles during drought was analyzed to understand the scope of improving the resiliency of the forage systems. We also compared the impacts of fallow, manure application along with the residue incorporation from rye, clover and winter wheat on two loamy fine-sand soils with similar reaction but contrasting permeability and clay +silt contents. ResultsIrrespective of soil types, impacts of management strategies on SOC were found statistically significant for both 0–20 cm and 20–40 cm soil layers. Slight differences in clay+silt fractionation resulted in different SOC in soil layers and ultimately the moisture availability status. Due to complex interaction effects of management-strategies and soil properties, N leaching was different within two soil profiles. N-uptake was found definable by SOC up to 96% in residue-only treatments and 83% in manure-based MS. ConclusionsA cover of winter-wheat with 50–50 manure +fertilizer and residue application could prove as the best management strategy to improve soil-health and long-term productivity. A precision-cover of clover which results in maximum residue, surface residual-C and SOC addition, and minimum N-leaching could be recommended for resource-use efficiency on low-fertile acid loamy sand soils during drought.