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Is UK biofuel supply from Miscanthus water‐limited?
Author(s) -
Richter G. M.,
Riche A. B.,
Dailey A. G.,
Gezan S. A.,
Powlson D. S.
Publication year - 2008
Publication title -
soil use and management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.709
H-Index - 81
eISSN - 1475-2743
pISSN - 0266-0032
DOI - 10.1111/j.1475-2743.2008.00156.x
Subject(s) - environmental science , evapotranspiration , arable land , miscanthus , growing season , agronomy , yield (engineering) , precipitation , dry matter , water content , sowing , hydrology (agriculture) , biofuel , bioenergy , agriculture , geography , ecology , meteorology , biology , materials science , geotechnical engineering , engineering , metallurgy
Sustainable Miscanthus plantings encouraged under publicly funded schemes should be based on sound economic and environmental assessments. We developed an empirical yield model for Miscanthus from harvestable dry matter yields at 14 field trials in the UK to estimate site‐specific and regional yields derived from meteorological variables and soil available water. Harvestable yields of crops established for at least 3 years at 14 arable sites across the UK ranged from 5 to 18 t/ha, averaging at 12.8 (±2.9) t/ha. Variables considered to affect yield were number of years after planting, length of season ( T air > 9 °C), temperature, global solar radiation, precipitation and potential evapotranspiration during the season, and soil available water capacity ( AWC ). At a single site (Rothamsted), AWC and the relative average potential soil moisture deficit during the main growing season explained 70% of annual yield variation (RMSE = 1.38 t/ha, P < 0.001). For the complete UK data set ( n = 67), yield variation was related to AWC , air temperature and precipitation (RMSE = 2.1 t/ha, P < 0.01). Linking soil survey and spatially interpolated weather data we calculated an overall national average dry matter yield of 9.6 t/ha. As shown for two counties (Oxfordshire and North Yorkshire), estimated yield may decrease by 1 t/ha, and its uncertainty may rise from 15 to >20%, when soil survey instead of local soil data are used. Using data from a single weather station can introduce a bias (<1 t/ha) because of differences in elevation and local temperature and precipitation. Overall, it seems most important for bioenergy plantings to assure sufficient water supply from the soil ( AWC > 150 mm) during the main growing season.