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Soil moisture is a fundamental determinant of plant growth, but soil moisture measurements are rarely assimilated into grassland productivity models, in part because methods of incorporating such data into statistical and mechanistic yield models have not been adequately investigated. Therefore, our objectives were to (a) quantify statistical relationships between in situ soil moisture measurements and biomass yield on grasslands in Oklahoma and (b) develop a simple, mechanistic biomass-yield model for grasslands capable of assimilating in situ soil moisture data. Soil moisture measurements (as fraction of available water capacity, FAW) explained 60% of the variability in county-level wild hay yield reported by...
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Soil moisture depletion during the growing season can induce plant water stress, thereby driving declines in grassland fuel moisture and accelerating curing. These drying and curing dynamics and their dependencies on soil moisture are inadequately represented in fire danger models. To elucidate these relationships, grassland fuelbed characteristics and soil moisture were monitored in nine patches of tallgrass prairie under patch-burn management in Oklahoma, USA, during two growing seasons. This study period included a severe drought (in 2012), which resulted in a large wildfire outbreak near the study site. Fuel moisture of the mixed live and dead herbaceous fuels (MFM) clearly tracked soil moisture, expressed as...
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Abstract (from Science Direct): Agricultural drought is characterized by low soil moisture levels that negatively affect agricultural production, but in situ soil moisture measurements are largely absent from indices commonly used to describe agricultural drought. Instead, many indices incorporate weather-derived soil moisture estimates, which is necessary, in part, because the relationships between in situ soil moisture and agricultural-drought impacts are not well quantified. Our objective was to use in situ soil moisture data from monitoring networks in Oklahoma and West Texas to identify a soil moisture-based agricultural drought index that is (i) strongly related to crop-yield anomaly across networks, (ii)...
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Abstract (from CSIRO Publishing): Soil moisture conditions are represented in fire danger rating systems mainly through simple drought indices based on meteorological variables, even though better sources of soil moisture information are increasingly available. This review summarises a growing body of evidence indicating that greater use of in situ, remotely sensed, and modelled soil moisture information in fire danger rating systems could lead to better estimates of dynamic live and dead herbaceous fuel loads, more accurate live and dead fuel moisture predictions, earlier warning of wildfire danger, and better forecasts of wildfire occurrence and size. Potential uses of soil moisture information in existing wildfire...
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