jefflab

Yes, we measure ET through an energy balance approach. It is called surface renewal.

Thanks for the link. I'll add it to my queue to read.

For those interested in this topic, you also might be interested in sensors that can measure evapotranspiration (ET). ET is directly related to photosynthesis and crop yield.

Here is a quick refresher from the textbook on plant water relations:

> Stomata are microscopic valves present in all leaves, formed by the pairing of specialized cells called guard cells on the leaf surface. Stomata are the main ports through which water vapor is lost. Of equal importance is the fact that stomata also are the main ports through which carbon dioxide gas moves from the air into the leaf and is photosynthesized into plant material and accounts for most of the plant dry matter produced. - Hsiao

Our company, Tule Technologies (YC S14) is the commercial vendor of sensors that can measure evapotranspiration. We solve many of the problems mentioned in this article.

Tule | Full-Stack Developer | Oakland | Full-Time | ONSITE

Tule helps farmers grow more food with less water through precision irrigation. Our service is backed by the only sensor technology that works on large farm fields and can detect water stress problems before damage is irrevocable.

We are looking for someone who can help us build our core infrastructure as well as customer features. This includes sensor data processing pipeline, remote sensing image processing, billing integrations, mobile UI, and web UI. We are only considering senior engineers who have built impressive things in the past.

Founders are a rare combination of expertise in agriculture and venture backed software entrepreneurs.

Investors include YCombinator, Khosla Ventures, and Bloomberg Beta Ventures.

Stack includes: Ruby on Rails, R, Swift

You can apply through AngelList here:

https://angel.co/tule/jobs/45271-senior-full-stack-developer

Tule - tuletechnologies.com | Full-stack Engineer | Oakland | ONSITE

Product: Help farmers improve production through optimal irrigation. Powered by novel sensor technology.

Software Stack: We use Rails for our web server, swift for our iOS app, R for our atmospheric and remote sensing data pipeline, python for working with Google Earth Engine, and we are starting to use machine learning for some unreleased prediction algorithms. As a full stack engineer, you could work across all these projects.

Mission: Increase the carrying capacity of the planet by increasing food production and reducing environmental impact.

https://angel.co/tule/jobs/45271-senior-full-stack-developer

I like your title. Appreciate the explanation for future HN posting.

sorry! This was a tricky title because I know the HN moderators like it to match the title in the link. However, the Forum title only makes sense in the context of the forum (where Particle is implied).

Tule (YC S14) - SF - Fulltime iOS and Full Stack developers

What makes Tule unique

- We work on a very important problem (feeding the world)

- We make the world a better place (environmental impact of ag)

- We have a core technology advantage (breakthrough sensor out of UC Davis that can measure evaporation over 10 acres)

- Enjoyable field testing (in vineyards and farm fields)

Technologies are:

- iOS for UI

- Rails for web server

- R for data manipulation (micro meteorology, radiation modeling, heat flux calculations, etc)

We are looking for experienced candidates who can be the owner/lead of the app or server respectively.

https://angel.co/tule/jobs

The technology definitely applies to the big dollar crops (corn, soybean, etc), and we plan to serve those markets someday. We are starting in specialty crops (almonds, grapes, tomatoes, etc) because these customers have a "hair on fire" problem with intensive irrigation management and the California draught.

Thanks for the kind words! Links posted above.

I'm a cofounder of Tule and happy to answer any questions.

A few corrections for the technical crowd:

This technology hasn't existed since the 1800's. It is derived from a technology called Surface Renewal that measures the turbulent transport of mass and energy from the planetary surface to the atmosphere. The concepts behind Surface Renewal were first developed in the 1930s by chemical engineers. These chemical engineers developed a model to describe the movement of gases into liquid media by fluid volumes interacting with the air-liquid interface. In the 1990s, UC Davis researchers adapted the Surface Renewal concept to the planetary surface-to-atmosphere interface. Recent improvements in the technology enable Tule to measure the amount of water vapor carried away from crop field by wind eddies.

Our technology was validated for accuracy against the gold standard research tools used in academia, lysimetry and eddy covariance.

What truly makes our technology exciting is that we can tell farmers the optimal amount of water to apply to maximize plant growth (yield) and plant stress (quality). Studies have shown that getting irrigation right can radically change yield and quality. Before our technology, farmers have never had the feedback to optimize irrigation. This is analogous to NewRelic locating the bottlenecks in your server performance. You can't optimize until you can measure.

edit:

As requested, here are links to the technology:

An easy to read summary is here:

http://edu-tuletechnologies-com.s3.amazonaws.com/Tule_Surfac...

The original academic paper is here:

http://myweb.ecu.edu/suh/PawU1995.pdf

Clearly people who work in nurseries do more than move plants back and forth 5 feet away, but this is an interesting step in the right direction. When I worked in a nursery in high school I had 2 primary tasks a) keep the plants watered b) help customers load their cars with big items. I've read about projects that use water sensors to enable plants to request water individually as they get dry. Adding a water tank and a sprayer to these little robots might be an interesting addition if it isn't cost prohibitive. I look forward to seeing more applications of technology in agriculture.