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  • NutraDrip Irrigation

What Your Water Is, Your Soil Becomes

Greg Creson, Superior Soil Supplements

Our Journey

              We at NutraDrip came to meet Greg Creson over 5 years ago. When we started installing drip irrigation 11 years ago, we knew water quality was a big deal; if it isn’t addressed properly a drip system can plug up. This led to us getting water samples before installing each drip irrigation system so we are aware of potential minerals that can plug up a drip irrigation system. Through that process, we became aware that there are things in the water that impact nutrient availability in the soil. Irrigation water, and the quality of it is directly tied to how efficient that plant will be at extracting nutrients from the soil. One example of this: in 2020, one of our farms had been irrigated for close to 20 years via a center pivot. The corner outyielded the irrigated portion by 29 bushels. We started looking at the yield map and realized something was going on underneath the center pivot. We started to dig into the “why” and through that journey learned about bicarbonates, and the impact that has on soil and nutrient availability. Around that time, we also started getting into some salty water with different customers, and trying to learn how to deal with that, we found out about Diamond K Gypsum in Utah; they supply a soluble gypsum that can be run through drip irrigation. They introduced us to Greg Creson and told us he is the expert we need to talk to. He hails from California and deals with a lot of salty irrigation water and has a good handle on how to address bicarbonates, sodium, when to treat water and the impact that has on nutrient availability in the soil. We haven’t known Greg for a long time, but we immediately knew he has a special talent and passion for water and water use efficiency, as well as ensuring that the water applied is doing the most it can in the soil.

Introduction

Greg Creson with Superior Soil Supplements was selling gypsum and found that many farmers had to increase their application of it year after year. He started digging into the “why”, and because intensely interested in soil and water quality. He found Dr. Albrecht (has quite a few books out – here is a link https://bookstore.acresusa.com/collections/william-a-albrecht) and Brookside labs, and started learning and following Dr. Albrecht’s theory. He quickly became passionate about helping growers correct imbalances and problems in their soil and water to help them become more profitable and productive.

What is the biggest component you apply to your fields right now?  Many will answer nitrogen, but consider this: does water have an impact on your fertility program? It's the heaviest application of anything most of us do, and whatever is in that water, your soil becomes. The components of your irrigation water matter more to the health of your soil, plants, and profit than almost any other component in your agricultural practices.

Soil Quality Basics

Without even considering water quality, important components of soil quality are often overlooked. Your CEC (cation exchange capacity) which includes calcium, magnesium, sodium and potassium have to be in line before you start worrying about zinc. 80% of your soil structure is just calcium and magnesium. We often worry about nitrogen which is 2% of the picture. Does it make sense to worry about 2% and ignore the 80%?

Even if you do have all your soil quality elements perfectly aligned, and your irrigation water is poor quality, you will have poor yields. Nutrients are available to your crops only when they are dissolved in the soil solution, with ideal irrigation and a pH of less than 7 which allows those nutrients to remain in the soil solution and available to your crops. A pH of 6.5 is the perfect zone, because all 17 nutrients that are available can be absorbed by the plant at that pH. What many don’t realize is that at a pH of 7.2, a chemical reaction starts to happen. Calcium starts to change from a sulfate form to a carbonate form. Every step between 7.2-7.8 is 12% of free nutrition that is being lost. After a pH of 7.8 is hit, no matter how much money and nutrients you throw at the soil, you will not get it into the plant. Sounds pretty simple to just keep the pH lower, right? However, the pH is only a symptom of a bigger problem.

Do You Know Your Water?

Water has two essential tasks: distribution and survival. The first 6-8 inches of the soil is the distribution zone for fertilizer, herbicides and pesticides. It’s also the aerobic zone where the biological activity by microorganisms takes place. The survival zone is the area below the distribution zone and is essential for the survival of the plant.



Water will take the path of least resistance. A study done at the University of Georgia showed that 30 percent of applied irrigation water reaches a distribution root zone.  What do you think happens to the other 70? Evaporation and nutrient makeup will affect this number. For example, in northeast Kansas, we have high magnesium water. That can lead to water running sideways instead of down. The top picture is poor quality irrigation water. The second picture shows acidified water applied with a wetting agent. You can see how the layers go down into the distribution zone.

Your water will be the biggest thief of nutrients if you aren’t paying attention to it. Water can only hold so much before it will “let stuff fall out of it”. If you do the math, every 100 ppm (parts per million) of something in your water will equal 2.72 pounds per acre foot in your field. Consider this: if the water you are applying contains bicarbonates, each pound of bicarbonate will tie up one pound of calcium. Starting at a pH of 7.8 one pound of carbonates will tie up two pounds of calcium.

Water that is too pure, such as snow melt or rain water is almost always taking something with it. If the water EC is too low, the first thing it's grabbing is calcium and magnesium, and it's pulling that out of the soil. Typically in California, growers are trying to get the salt and calcium balanced. This year, the EC got so low from all the snowmelt water we had that it is acting like a solvent on grease, and stripping out the salts with magnesium and calcium.

Poor quality water that contains high levels of bicarbonates, magnesium, sodium, chlorides, or boron and low levels of calcium, is almost always leaving something behind. One common problem is high bicarbonates. Bicarbonates are common in natural water and are a leading cause of crusting and sealing of soils. A water pH above 7.2 is usually associated with high bicarbonates and calcium that has been converted from calcium sulfate to calcium carbonate or lime that is unavailable for plant uptake. The same happens in the soil at levels above 180 ppm or 1.5 mEq/l. Signs of this are:

·       Plugged emitters and sprinkler heads.

·       Blossom end rot of tomatoes.

·       Tip burn of lettuce and cabbage.

·       Brown/bitter pit of apples.

·       Hollow heart/brown spot of potatoes.

·       Yellowing of leaves due to iron chlorosis.

·       Overall reduction of both quality and yields



This is an almond tree with a nozzle spraying high bicarbonate water onto it. It works better than roundup; you can see there is no grass underneath the tree because the bicarbonate is blocking anything from happening.

Solutions to the Problems

Now the best part to this: solutions! How do we troubleshoot our irrigation water quality? The basics:

1.      Determine the cause if you have a high pH

2.      Treat high bicarbonates with acid. A water titration test will determine the amount of acid needed.

3.      Treat high Sodium, Magnesium, Chloride and Boron by adding gypsum to irrigation water. This will help leach these out of the root zone.

4.      Water is seldom perfect.

5.      Know the impact that your water is having on your soils.

6.      Understand the damage bicarbonates and carbonates can have on your nutrition program.

Treating Bicarbonates with Acid

As stated earlier, bicarbonate and carbonate react with calcium and magnesium to precipitate insoluble lime. Applied amendments become less effective as they are changed into insoluble forms. Acidification of irrigation water is a preferred method of treatment as it allows calcium and magnesium to remain available and displace sodium from the CE sites. Soil amendments remain effective instead of being precipitated into insoluble.

The simplest way to understand this bicarbonate and acid reaction is to conduct an experiment. Anybody have an idea what baking soda is? Calcium carbonate. It's that stuff that we're talking about the bicarbonate. It's exactly what we don't want. If you have a emitter and you start seeing white stuff showing up on there, it starts blocking stuff and you could chip it off, that's calcium bicarbonate. Vinegar is 2.3 pH; sulfuric acid is -2. Imagine one of the first experiments you did growing up: baking soda+vinegar = reaction; it gases off. This is essentially what we do with acidization of an irrigation system that has high bicarbonates.  What was bad in the bicarbonate gets burned off. You'll see that disappear from your pivots, you'll see it disappear from your emitters, and the good calcium will be left behind.

Options for acidifying water:

-sulfuric acid

- n-pHfuric acid (sulfuric acid and urea mixed together)

- phosphoric acid

Your soil and water samples will determine which acid is best. If you need sulfur, sulfuric acid will leave sulfur behind. N-pHfuric acid will leave sulfur and urea behind. Phosphoric acid will leave phosphorus behind.

Treating with Gypsum applied through irrigation water

Gypsum injection is a practical way of preventing problems that are created by pure irrigation water and also by sodium and high chloride water. Pure water has an EC of 0.50dS/m (deci-Siemens) or less and usually originates from snowmelt sources. Prolonged use can strip cations and salts from the soil resulting in low nutrient levels while also causing crusting and reduced water infiltration because the clay particles will become dispersed after drying. It is necessary to increase dissolved calcium in pure water by 1.0 to 4.0 mEq/l. Gypsum injection is a practical way of preventing problems that are created by irrigating with pure water. Soil applied gypsum works for about three irrigation cycles and then begins to leach out of the first inch of soil. Once the gypsum is leached out of that first inch the magnesium and sodium again become dominant, and the soil structure is destroyed. Applying soluble gypsum through the irrigation system effectively keeps the soil open for water infiltration.

Ideal Levels for Water Samples

Irrigation water is the medium that must deliver nutrients to the plant roots. The following are idea ranges for levels in water.

·       pH 6.2 – 7.2

·       EC .5 – 1.5 dS/m

·       HCO3 120 ppm or less

·       Ca < 100 ppm

·       Mg < 40 ppm or less

·       Na < 70 ppm or less

·       Cl < 70 ppm or less

·       B < 0.5 ppm or less

Some reports say that bicarbonates at 300 ppm is acceptable. By the time you hit that, you are already upside down and it is hard to correct. By the time you hit 120 ppm, it is recommended that you be acidifying water. If you wait until bicarbonates hit 300 ppm, everything will be locked up and it will be hard to fix and break it up.

Look Beyond the Surface

"I (Greg) had a gentleman that called me up and said, Hey, I got a bad problem with boron in the water. What can you do to fix it?  I don't know, he said, but I also have high bicarbonate water, and I have high sodium water. It was in a vineyard, I went up there, and I was pretty impressed. When I drove up on the vineyard and I see this guy's got a cover crop,  I'm like, in between the vines, that's awesome.  And in between the vines, he's got sheep out there. And the sheep are going to town on the cover crop.  And in the cover crop, the guy's got a whole bunch of mustard planted in the cover crop. And the sheep are going to town on the mustard.  And I said, that's awesome.  We just have one problem.  He looks at me, he said, what's that, Greg?  I said, if the sheep are eating it,  and they're excreting it.  And we still have the same problem.  He said, man, don't tell me that.  So we literally picked up some sheep stuff and we sent it to the lab. And when it came back, guess what?  Smoking high. And he's thinking it's fertilizer. It's putting right back on what he just took off. He said that's crazy, man. Because the sheep love it. And I said, you got an open field over there.  Harvest it. Take it off the vineyard. Because it did. That mustard worked just like a sponge on boron."

 

Conclusion

If you are feeling overwhelmed by all this, the best thing you can do is educate yourself. Get regular soil and water tests. Watch for trends. Work with a knowledgeable soil and water professional and a reputable lab. Don’t settle for poor quality irrigation water and the loss of production and crop quality. Water can be the silent thief of your nutrients, and the only way to know what it is doing is to test it and learn.

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