Bhardwaj, A.K., P. Jasrotia, K. Kahmark, S. Bohm, D. Weed, S.K. Hamilton and G.P. Robertson
Presented at the All Scientist and GLBRC Sustainability Meeting (2009-05-05 to 2009-05-07 )
Water use may prove to be a central issue in the global and local development of the biofuel industry. While most studies on biofuel water use only take into account the processing phase, feedstock cultivation may account for more than 90% of the life-cycle embedded water for fuels. We are studying water use and production efficiency of biofuel crops at different stages and over a prolonged period of cultivation, revealing patterns of water replenishment and use, and potential water limitations to biomass accumulation. In this direction, intensive experiments were started at Kellogg Biological Station on potential biofuel crop production systems, through the Great Lakes Bioenergy Research Center (GLBRC). The studies are being conducted on a 22 ha site that has been subdivided into ten treatments representing eight different production systems and three common agricultural practices, each replicated in five blocks. These production systems are being monitored using automated Time Domain Reflectometry (TDR) to reveal the amount and movement of water in the soil profiles under biofuel crops. Seven TDR probes are installed in one soil horizon at different depths to 1.25 m. The continuous scans will provide us the real time changes in water movement, replenishment and depletion, providing indications of water uptake by plant roots and potential seasonal water limitation of biomass accumulation. The overall goal of the study is to quantify the components of water balance in these cropping systems. Automated weather stations on the site provide precipitation events and automated gas flux chambers will also be used for computing the evaporative losses. Studies are being coordinated to monitor the agrochemical movement in soil profile using lysimeter samplers, nitrogen availability in root zone, and foliage nitrogen status, root growth and distribution to identify the effects of water on the soil and plant functions. The goal of our study is to analyze the production of different biofuel crops in light of potential limitations and strengths with regard to water use and efficiency. Until unless biofuel feed stocks are grown in a manner that enhances soil and water resources, water consumption for feedstock growth may be the limiting factor for bioenergy production in many regions of the United States and the world.
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