2012 Annual Report
1a.Objectives (from AD-416):
1) Improve current decision making capabilities by building robust data on current practices existing agricultural systems where biomass production could be incorporated (Temple, Parlier, Mandan, Riverside);.
2)Create management plans to optimize yield and stability of feedstock production (Temple, Palier, Mandan;.
3)Optimize biomass stability and yield while minimizing environmental impacts at greater than field scales (Temple, Parlier, Mandan); and.
4)Improve water and air resource management and optimize biomass production for other production areas in the Hawaiian Islands, Pacific Basin, and western United States (Temple, Parlier, Mandan, Hilo).
1b.Approach (from AD-416):
Objective 1: Develop spatial and temporal data sets from historic data for baseline analyses. Objective 2: Simulate current management impacts on feedstock yields and resource inputs. Objective 3: Demonstrate applicability of simulation approaches with validated present practices and explore watershed scale impacts of changes. Objective 4: Improve decision support for assessment of resource conditions, and utilize parallel computing and deep hydrology water balance as needed.
This project supports objective 1 of the parent project. There has been a recent, renewed interest in Hawaiian sugarcane as a biofuel feedstock. This research will contribute to the development of a decision support system to determine the feasibility of biofuel feedstock production and environmental sustainability on the HC&S sugar cane lands in Maui, Hawaii, and assessments of other potential biofuel feedstock sources across the Hawaiian Islands and other areas of the Pacific Basin. During this reporting period, we have operated and maintained two Eddy Covariance towers in contrasting climatic and soil conditions at the HC&S plantation, which directly measure net carbon balance, evapotranspiration (ET), and meteorological conditions through non-invasive atmospheric and soil observations. The towers have confirmed the extremely high productivity and radiation use efficiency of Hawaiian sugarcane. One surprising finding has been the lower than expected measured ET compared to predicted-ET from standard methods (FAO-56/ASCE). Research into this discrepancy is ongoing, and has important implications for scaling up biofuel production elsewhere in the Pacific Basin. Ground-based remotely-sensed data, spectral reflectance and crop cover, has also been measured. A series of Landsat-7 NDVI maps has been developed to depict sugarcane canopy development over time. Crop cover was highly correlated with NDVI values calculated from image and ground data. The NDVI based canopy cover has been used to estimate crop coefficient (Kc) curves for sugarcane plants. A series of satellite-based evapotranspiration (ETc) maps have been developed to indicate crop water use information for sugarcane lands in Maui, Hawaii. There is also little information on how much soil carbon (C) and nitrogen (N) is stored in Hawaiian sugarcane fields under normal, monoculture operations. Soil and plant C and N data are needed to assess the life cycle impacts of this biofuel system. Because of lack of quantitative and qualitative information on soil C and N with respect of Hawaiian sugarcane varieties, we collected soil samples from fields with different soil texture, management practices (i.e. burning before harvest vs. green harvest), four sugarcane varieties and sugarcane growing stages. Collected soil and plant samples were dried, ground and analyzed for total carbon (TC) and total nitrogen (TN). First year data for the tower fields showed that heavier textured soils had higher TC than relatively lighter soils. There was no consistent response for TN and dissolved organic carbon. Also, there was no consistent sugarcane variety response with respect to soil type and growing stages. The research is ongoing and additional results will help further elucidate the soil C and N status for this growth environment. An additional component of the project is to utilize poor quality soils and waters in the Westside of the San Joaquin Valley on Brassica crops for the eventual production of biofuel. The approach is to grow mustard and salt and boron tolerant varieties of canola on drainage impacted soil and utilize saline water as source of irrigation water. Seed yields will be estimated and seed will be processed for biofuel and other byproducts on site. Progress made so far showed that mustard was more tolerant of adverse growing conditions. Seed yields ranged from 1 to 2 tons/acre for canola and mustard, respectively. Seed will be processed for biofuel and other seed meal by products.