"Application of 10 to 20 pounds of chloride per acre resulted in a 23 bushel per acre yield increase by Cimarron' winter wheat!" That's what KSU agronomists say.
Update: more information on "Chloride for Wheat". This note is a combined effort of Jim Bauder, Rick Engel, Don Mathre, and Bill Grey, MSU faculty from the College of Agriculture, and Dr. Ray E. Lamond and colleagues of Kansas State University Department of Agronomy.
You may remember that a while ago I reported on some work by Dr. Rick Engel from here at MSU. Since then I've found some additional research, have made some additional contacts here at MSU, and Rick has organized a very nice, visually based WEB site that has a lot of pictures of chloride (wheat interactions and leaf spot suppression). That site is: http://agadsrv.msu.montana.edu/chloride.
A few weeks ago I contacted Dr. Ray E. Lamond, Soil Fertility and Management Specialist at Kansas State (address email to: rlamond@bear.agron.ksu.edu; phone 785 532 5776). His home page address is: http://www.ksu.edu/agronomy/FACULTY/LAMOND/. Ray and his colleagues have done a lot of research on chloride and winter wheat. Here's what I learned from two studies they completed last year:
§ Several researchers (SD, CO, MT, KS) have found that wheat responses to chloride (Cl) are variety specific', i.e., not all varieties respond the same
§ Some do and some don't respond to Cl additions. Check out the variety first. Some varieties seem to consistently respond to Cl and others do not.
§ Yield increases seem to be most consistent when soil Cl levels are less than 20 lb/acre in the 0 to 24" soil depth and when plant Cl concentrations are less than 0.1% (1/10 of 1 percent or less than 1,000 ppm)
(NOTE: Here's a piece of information to put in your memory bank or your file (which you are going to make) on critical and threshold levels for plant nutrients and soil tests. For winter wheat: Cl soil test level of 20 lb/acre in the 0 to 24" depth or approximately 2 to 3 ppm in soil test; tissue test of Cl at boot stage of 0.1% or 1000 ppm Cl).
Ray Lamond, D.D. Roberson and colleagues looked at 16 winter wheat cultivars and how they responded to Cl, rates, sources, top dressed in early spring. Their results . . . in a nutshell:
§ Cl fertilization significantly increased plant Cl concentrations for all cultivars (at each of two sites)
§ Different cultivars take up Cl differently
§ Cl fertilization significantly increased yields of 12 of the cultivars at one site but had no effect at the second site (which had higher soil test Cl levels)
Some interesting statistics:
|
Marion site: Soil test level in 0 to 24" was 7 lb/Cl/acre. |
|
|
Average yield without Cl |
79.5 bu/acre |
|
Average yield with Cl |
84.9 bu/acre |
|
Average tissue Cl without Cl |
0.06% (<1/10%) |
|
Average tissue Cl with Cl |
0.43% (almost = %) |
|
Saline site: Soil test level in 0 to 24" was 22 lb Cl/acre |
|
|
Average yield without Cl |
89.3 bu/acre |
|
Average yield with Cl |
88.3 bu/acre |
|
Average tissue Cl without Cl |
0.35% (1/3 of 1%) |
|
Average tissue Cl with Cl |
0.53% (about = %) |
Bottom Line: Keep in mind that this kind of work has not been reported (or completed), in Montana, so don't rush into it! But, maybe it's worth looking into on a small piece of land . . more on that at a later date.
*In this Kansas study: "Both soil and plant analysis appear to be good predictors of POTENTIAL Cl responses, however, the possibility of a Cl nutrition/plant disease interaction can also be a factor."
Question: Does either the RATE or SOURCE of chloride made a difference? Ray's second study compared yield and plant tissue chloride for four sources and two rates of Cl at 10 and 20 pounds of Cl per acre. The sources were: KCl (potassium chloride, 47% Cl), MgCl2 (magnesium chloride, 74% Cl), NaCl (sodium chloride, 60% Cl), SR (slow release) NaCl (sodium chloride).
Results: Chloride significantly increased grain yield at both sites, although not all treatments increased yield.
|
|
Site A |
Site B |
|
Check yield |
66 bu/acre |
81 bu/acre |
|
10 lb Cl/acre |
72 bu/acre |
90 bu/acre |
|
20 lb Cl/acre |
74 bu/acre |
87 bu/acre |
|
Source KCl |
72 bu/acre |
88 bu/acre |
|
MgCl2 |
72 bu/acre |
93 bu/acre |
|
NaCl |
75 bu/acre |
88 bu/acre |
|
SR-NaCl |
75 bu/acre |
87 bu/acre |
Keep this in mind that Cl is an ‘anion’, a negatively charged molecule like nitrate. That means it generally will readily leach out of the soil. Adding more than what the plant can use in a single season is not economical, because it probably won't be there for the next crop. Small amounts appear to be better than large amounts at about 10 pounds per acre. And, do not expect more than a 4 to 6 bu/acre response (if at all).
So.... you decide. Our best guess:
§ 10 to 20 pounds of Cl per acre on low testing soils (<20 lb Cl/acre in the 0 to 24" depth or less than 3 ppm soil test) might result in a 4 to 6 bushel per acre yield increase, depending on variety of winter wheat. Not all varieties respond the same. Key issue is variety and soil test. Likely soils to find a response: well drained, sandy, irrigated, frequently fallowed.
§ Apply as a top dress operation early in the spring when you top dress nitrogen.
§ If you leaf tissue sample for indicators of future management decisions tissue, then sample at boot stage and test for chloride. Critical tissue level is 0.1% (1/10%) or 1000 ppm. If the levels are less than these, consider a 10 pound per acre application of any form of chloride.
Before closing this story, however ..... Not being an expert at this topic and knowing that plant diseases can play a significant role in the response to chloride additions, I decided that I would better get some information from some plant pathologists. I sought out the advice and recommendation of Bill Grey and Don Mathre of the Department of Plant Pathology here at MSU. Bill had this advice: "Physiologic leaf spot is very similar to leaf spots caused by plant pathogenic fungi, in particular, Tan spot = Pyrenophora triticei repentis and the Septoria 'complex', including Septoria nodorum and S. triticei. Accurate diagnosis will be necessary but growers in high residue management may have a higher incidence of tan spot disease. Chloride will not control the disease but there may be an indirect effect on yield from the improved plant nutrition. On the other hand, expensive fungicide applications will not 'cure' the physiologic leaf spot, so once again an accurate diagnosis will pay big dividends."
Bill's comments and cautions were seconded by Don Mathre, who offered the following: "....tan spot of wheat symptoms look very much like chloride deficiency symptoms. This disease is caused by a fungus, so growers should make sure that tan spot is not one of their problems. This can be done by applying a fungicide such as Tilt (to a limited area as a small plot trial) to see whether they get a response. Chloride deficiency will not respond to Tilt or similar fungicides."
Categories: Chloride, Wheat Fertility
Date: 1998