When I finished my B.Sc. I wanted to study sanitary engineering but after sometime working on an irrigation technology transfer project, I decided to go back to agronomy and actually learn more about such a fascinating topic. I took some courses on water quality and sanitary engineering but later I moved completely to irrigation and biofuels. For 18 months I collaborated in a project for bioethanol production from sweet sorghum, with my project we particularly looked at:

1. We evaluated different irrigation levels for sweet sorghum production and its effect on bioethanol production. We tested sweet sorghum at the 80% of depletion of the available water capacity. Our results showed that there is no significant effect of the water stress on sweet sorghum juice not bioethanol production, i.e. we do not produce more ethanol by stressing the plants; however, we save water. We have a conference paper on this part of the research and we hope to publish the findings by the end of this year.
2. Crop modeling using the Growing Degrees Days  (GDD) concept vs photosensitivity. In a simple way, some plants flower when day gets “certain amount of light”, which means flowering is limited to the geographic location and season. However, using the concept of GDD we can think of heat “as the food for plants”, plants require some units of heat to reach flag leaf, flowering, maturity, etc. Thus, in Arizona we tested some “day neutral varieties” of sweet sorghum to estimate if they could actually grow based on the GDD given that in Arizona is warm most of the time, we chose two planting seasons to probe our hypothesis. This becomes important because Arizona for its climatic conditions could allow more than one cropping season if we had a “good day neutral variety” allowing to have multiple planting and harvest dates through the year and a constant feed-stock for ethanol production, being the storage one of biomass/feed-stock one of the main limitations for bioethanol production. We found a good day neutral variety called SM. However, because even when the SM was a day neutral variety, comparing its bioethanol yields vs yields from photo-sensitivity varieties, the bio-ethanol yields were statistically significant. Yet more research was recommended to find the best combination of planting seasons and varieties to make the systems economically efficiently.
3. Why sweet sorghum? Because it is a drought tolerant plant and know for perform well in poor soils reducing the competence for arable land, water resources and food security. Additionally, the process to turn the juice into bio-ethanol is simpler than other alternatives.

More information about this research:

https://onlinelibrary.wiley.com/doi/abs/10.1002/ird.1882