What’s wrong with watering plants? Tom A. Reynolds, Professional Irrigation Advisor

I design large irrigation systems. From 1997 to 2003 I designed precision irrigation systems for the State of Arizona Department of Transportation spanning over 50 urban miles of depressed freeway slopes, 2-sidses, each over 110 M wide. New irrigation system water use efficiency potential exceeded 92%.

From 2003 to present, I have designed systems for desert-lands farmers (6500 hectares; drip and sprinkler) and developed USDA-NRCS Conservation Activity Plan 118 (Irrigation Water Management) for Arizona farmers spanning 2,500 acres (1010 hectares). My last project was a 0,7 hectares urban farm which features cloud-based control and monitoring, anywhere, of the 32-valves system. This system is formed as a Community Supported Agriculture (CSA) site. The production will provide fresh produce 365 days to 400 households, referred to as CSA shares, all within walking, certainly biking, distance of the residences.

This is a Big Deal. Twenty percent of Southern California energy is expended lifting, treating, pressurizing water distribution systems (Pacific Institute, 2006). In irrigated landscapes, farm and urban, usually over 50% of all water used is for irrigation. But consider your own community water management.

There is a massive industry forming mostly with venture capital funds. Big Data in agriculture, think Silicon Valley IT companies, emerges as something new, but that is not at all true. I refer to the promise of cheap HD intel of crops in 11 western states, using communication, data networks, satellites and drones. There is none, in the real and practical sense, any REALLY new knowledge and methods on how to produce crops efficiently in irrigated regions. The challenge is getting farmers to pay for real intel. Boots on the ground must be included in those systems you can find, the Wall Street claims of risk avoidance using technology. People probably do not grasp where their food comes from, let alone that newfangled sensors can collect data from the field, but it requires human and expert interpretation of that data. Wall Street’s, meaning the VC’s and the developers, algorithms are hardly an ideal surrogate. More likely, this is more of the “capitalism run amok” syndrome. It always amazes me how we tolerate blatant partial, oblique truths into our living rooms, eaten by our children, kept living with television, paper, internet, and mail.

Most of the “smart irrigation” technology, available off the shelf, requires that users provide the algorithm’s “set-points.” So given the very unscientific method, users are only given garbage, or GIGO.

For over 60 years, American taxpayers have supported the work by the USDA, which is married to the hip of the Land-grant college system. Every state has their own land-grant college. Let’s see…50 states, 60 years, 80 upper-tier scholars and researchers, an average of 400 critical (WAG) topics addressed = 96 M scholarly and extension papers and boots-on-the-ground progress in high production agriculture in the USA.

Let’s see: Agribusiness has been roundly estimated to employ 25% of the US work force. I mean, all manner of putting food on your plate. Transport, retailing, wholesaling of food: Yes. corporate agricultural R&D: YES. Government attention: Yes. Production, marketing, and distribution of irrigated plant production inputs, including machinery, fertilizer, seed: Yes. Irrigated sports fields: Yes. Any lawyer that has large land owner and/or water rights clients: Yes.

In this time of unholy climate disruption, after all these enormous investments, we get promised something new, with asinine claims like “Saves 60% of your past water use,” the hard, cold reality is that the irrigation system was probably never a) engineered for very high distribution uniformity, b) scientifically managed, or c) pre-designed in a soil, climate, exposure manner.

Take for example, an exception. For the past 25 years, ADOT Standard Specifications require that freeway landscaped areas provide the landscaped areas with topsoil plating. The originator of this standard, E. Leroy Brady, RLA fought with state highway engineers over the need to institute this specification; he won, and it has survived. So when new freeways for the PhoenixMetro were in pre-design, the alignments, meaning the roadway corridor, transversed all manner of soils across Maricopa and Pinal Counties, generally along the Salt River (Phoenix).

Several soil types present. But topsoil is a very valuable resource. Only millions of years have formed them; it is when and where the plants primarily have survived all that time before mankind’s intrusion. Moving soil is an extremely expensive task, so irrigation techniques advanced where field topographies were suitable for surface, or gravity, irrigation of crops and neighborhoods. Since our statehood (1912), the lands where the freeway would course, were about 70% (WAG) very fertile alluvial soils. Many of the disruptions to these fine crop landscape soils were reversible with resting and cultural practices. This is one place man is wholly-unable to trump nature. However, digging 35 feet deep, 500 foot-wide depressions upon these soils for a 218 mile urban system, calamitously moved a S***load of soil. We don’t call it dirt.

Brady insisted that the first step was to evaluate the “undisturbed” quality of the topsoil within the alignment. This way, the general contractor (or their subs-) could know, through analysis and interpretation by the State’s Agronomist, E. Ray Bigler, CPAg, how to chemically amend the soil(s). The contractor awarded the contract would fulfill the full intent of the specification to avoid penalty. Through the process of capturing, amending, stockpiling the upper12–24 inches of parent topsoil within the alignment, when the topsoil was subsequently “laid down uniformly compacted”, used as “plating” over the newly cut slopes, as root zone !, The movements tend to mix all constituents, tending to make them much more uniform as a whole. This makes water management MUCH more plausible !

Few people grok the importance of this to communities in water scare areas. We voted for somewhat demanding, beautiful, heat island and pollution-mitigating, efficient transportation systems. There should also never be any denial that these irrigated landscapes provide huge environmental services that go unaccounted in any financial system. BTW: My designs supplemented historical effective rainfall with 18” — 30” of potable or reclaimed water, net.

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