Soil, Water, and Climate Change Integrated Impact Assessment on Yields

This article describes the potential yields of maize, wheat and barley which were modeled with climate change, soil degradation and water balance scenarios in central Mexico. Two adaptation measures were also evaluated. To estimate yields the AquaCrop-FAO model was applied. Three study cases were chosen and their climate, soil, phenological and management information was compiled. Once calibrated, the authors tested the response in yields for 28 climate change scenarios: five General Circulation Models, two RCP and three-time horizons. Two adaptation actions were evaluated: changing planting date and increase of organic mulches. Results show that yield of maize in the near future (2015-2039) would fall 50% average, barley and wheat yields would decrease in 40% and 25% respectively. If soil degradation and loss is considered, the yield will reduce considerably. Adaptation measure based on changing planting date was as effective as increasing mulches. It is necessary to consider soil together with climate change scenarios in yield modeling. It is possible to suggest wrong adaptation measures if only the climate is considered and not all the variables involved.

A Critical Review on Lignocellulosic Biomass Yield Modeling and the Bioenergy Potential from Marginal Land

Lignocellulosic biomass from marginal land is needed for a social–ecologically sustainable bioeconomy transition. However, how much biomass can be expected? This study addresses this question by reviewing the limitations of current biomass yield modeling for lignocellulosic crops on marginal land and deriving recommendations to overcome these limitations. It was found that on the input side of biomass yield models, geographically limited research and the lack of universally understood definitions impose challenges on data collection. The unrecognized complexity of marginal land, the use of generic crop growth models together with data from small-scale field trials and limited resolution further reduce the comparability of modeling results. On the output side of yield models, the resistance of modeled yields to future variations is highly limited by the missing incorporation of the risk of land use changes and climatic change. Moreover, several limitations come with the translation of modeled yields into bioenergy yields: the non-specification of conversion factors, a lack of conversion capacities, feedstock yield–quality tradeoffs, as well as slow progress in breeding and the difficulty of sustainability criteria integration into models. Intensified political support and enhancement of research on a broad range of issues might increase the consistency of future yield modeling.

Debris Yield Modeling Application under Post-Wildfire Conditions with the Hydrologic Modeling System (HEC-HMS)

<p>Predicting debris yield under post-wildfire conditions is important for hazard mitigation and flood risk planning. Current prediction efforts aim to reduce the amount and impacts of debris flows that minimizes environmental and economic impacts for communities. However, recovery efforts are difficult and costly. Debris flows and excess runoff block access roads and bridges, inhibiting emergency responses. It also effects the surrounding community's water supply and property. Therefore, having a debris flow sediment management plan is crucial. Predicting debris yield volume, estimating debris basin capabilities, and developing yield mitigation alternatives will mitigate future debris yield disasters. In previous versions of the Hydrologic Engineering Center, Hydrologic Modeling System (HEC-HMS) contains no capacity to simulate debris yield. However, the need for debris yield modeling exists throughout the Corps of Engineers, especially mountainous in arid and semi-arid regions. The HEC has added empirical models for prediction debris yield volumes under post-wildfire conditions. The goal is to develop tools within HEC-HMS that provide outputs necessary for developing debris yield mitigation strategies for managing debris yields within the burned watershed. This research discusses the addition of debris yield methods under post-wildfire situations within the watershed available in HEC-HMS 4.5. The new debris yield modeling capabilities will increase the application of HEC-HMS for debris yield modeling studies by directly computing yields from burn watersheds. Additionally, the model was coupled with the Hydrologic Engineering Center, River Analysis System (HEC-RAS) to ensure that debris yield output from HEC-HMS could be easily used as boundary conditions for predicting the hydraulic non-Newtonian debris flow runout and inundation.  The new debris yield methods use precipitation, topography, and soil burn severity information within the watershed to model debris yield. Reach and reservoir debris routing methods are being further developed, meanwhile existing sediment flow routing methods in reach and reservoir elements can be used with certain limitations.</p><p> </p><p>Keywords: Debris Yield Prediction; Post-Wildfire; Hazard Mitigation; Hydrology Modeling System</p>