2018 | USA | Visala Tallavarjula

Irrigation Efficiency Improvement by Percolation Water Loss Reduction Using Carbon Sequestration

Water issue adressed: Too much
Conventional Irrigation Method suffers from significant loss of water due to evaporation

A significant amount of food production is from arid regions around the world. Climate change and the resulting global warming are leading to increasing aridity. Irrigation consumes more than 80% of the world’s fresh water. The exploding global population and increasing food demands lead to higher withdrawal of water, while the available water is decreasing causing water stress. Irrigation efficiency improvement will help to mitigate water stress. Perlite and peat-moss top soil bed reduces evaporation loss, while a low cost infiltration insert innovation enables sub-surface-like irrigation without requiring expensive equipment. Hypothesis: In addition water percolation loss can be reduced using a percolation control layer (PCL) by amending the root zone soil with charcoal. Charcoal amendment is expected to improve water retention, root health, and microbial activity. Buried charcoal achieves carbon sequestration by reducing greenhouse gas emission and slows down climate change. The design of experiments’ study was conducted by varying PCL thickness, charcoal amendment percentage and charcoal grain size. Water retention is found to be directly proportional to charcoal amendment percentage and PCL thickness, while it is inversely proportional to charcoal grain size. With 33% charcoal amendment, 4 cm PCL thickness, and two different charcoal grain sizes, field tests were conducted with radish and pea plants. The PCL with coarse grain charcoal amendment showed 49% lower water consumption while also producing 50% higher yield. Scanning Electron Microscope images show that coarse grain charcoal has higher micro roughness that enhances nutrient adsorption and microbial growth and could explain higher plant yield.

This is how I came up with the idea for this project:

When I saw water evaporating from sprinkler irrigation systems in central valley during midday while big electronic signs were screaming “Save water Drought Alert” – I could not believe how much water was being wasted. Upon further research I found that 80% of global fresh water is used in irrigation. And increasing global population (expected to reach 9 billion) will increase food demand by 70%. This increases fresh water usage demand while the fresh water sources are reducing in arid regions of the world due to climate change. Most of the world’s food production is in arid regions. This combination of factors will increase our water withdrawal leading to water stress. I worked on reducing water losses in irrigation to help make efficient use of fresh water that is available.