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Accueil du site → Projets de développement → Projets de recherche pour le Développement → 2014 → STABILITY IN RANGELAND PRODUCTION WITH INCREASED PRECIPITATION VARIABILITY : LINKING FUNCTIONAL DIVERSITY AND NUTRIENT RETENTION

United States Department of Agriculture (USDA) 2014

STABILITY IN RANGELAND PRODUCTION WITH INCREASED PRECIPITATION VARIABILITY : LINKING FUNCTIONAL DIVERSITY AND NUTRIENT RETENTION

Rangeland Precipitation Variability

United States Department of Agriculture (USDA) Research, Education & Economics Information System (REEIS)

Titre : STABILITY IN RANGELAND PRODUCTION WITH INCREASED PRECIPITATION VARIABILITY : LINKING FUNCTIONAL DIVERSITY AND NUTRIENT RETENTION

Identification : CA-B-ECO-0101-CG

Pays : Etats Unis

Durée : Apr 1, 2014 à Mar 31, 2018

Domaine : rangelands ; drought ; functional diversity ; nitrogen and carbon cycling ; soils

Partenaire : UNIVERSITY OF CALIFORNIA, BERKELEY BERKELEY,CA 94720

Objectifs
Global circulation models consistently forecast increases in the frequency of extreme events such as severe storms and droughts. As precipitation more frequently departs from the historical range of variability, maintaining stability in forage production to increased climatic variability will be a critical management priority in range agroecosystems. A key mechanism that can lead to stability in forage production is compensatory dynamics, where plant functional groups respond differently to climate fluctuations (e.g., one group tolerates drought, another group is highly productive in non-drought conditions). We hypothesize that trade-off among functional groups should buffer the response of overall forage production to climate variability and better retain soil nutrients in dry-wet up cycles. Our specific objectives are to : 1) quantify relationships among the fate and retention of nitrogen, soil moisture dynamics, and species compensatory dynamics in drought and non-drought conditions ; and 2) incorporate these relationships into process-based models of nitrogen retention and forage production in rangelands.

Descriptif
We will use an field experimental approach that manipulates precipitation quantity (drought, non-drought) and variability (drought with wet pluses or uniform rainfall distribution) over time, and the presence of functional groups available to "match" climate variability (grass, forbs, mixed functional diversity). We will use rainout shelters to vary the annual distribution precipitation, standardized water pulses to evaluate soil response to wet-up events, and a combination of species removals and seed additions to manipulate functional group composition. We will measure a full suite of biogeochemical processes affecting C, N, and water dynamics, including leaching, plant uptake, and cycling rates. Based on these measurements, we will use variations on the DAYCENT model to quantify water, C and N states and fluxes at annual, monthly and daily time steps, and the interactive influence of functional group compensation and drought.

Présentation : USDA

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