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Calcium (In Turfgrass Management) |
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Calcium is one of the six macronutrients required by turfgrass. The others are: nitrogen, phosphorus, potassium, magnesium, and sulfur.
The highest distribution of calcium within the plant is in the cell walls. Building strong cell walls can help in resistance to many plan pathogens. Plants with high levels of calcium also have an increased tolerance to many other stress conditions such as drought and close mowing.
The new growth are of the root absorbs the majority of the calcium from the rhizosphere. Therefore it can be cyclic with higher rates absorbed during times of new root growth and little being absorbed under conditions of little root growth.
Most experts agree tissue content of the turfgrass leaves should contain from a minimum of 0.50% to 1.50% Ca in the dried tissue for optimum health of the plants. 1% would be a good level to maintain on fine golf course greens.
Calcium is abundant in many soils and normally dominates the cation exchange sites in those soils. A base saturation of 70% Ca on the soil colloids would be an ideal level for soil health.
Just because the Ca levels look good on a soil test report does not mean the calcium can be actively taken up by the roots for several reasons. Poor new root growth, the passive way roots absorb Ca, and tight absorption of Ca by anion exchange sites in the soils, being the more important ones. Uptake of Ca by plant roots is a complicated process. The only true way to be sure of uptake in the plant is with regular tissue testing. To make matters worse artificial rootzone mixes high in sand such as USGA and California type greens are often low in exchangeable Ca due to the low CEC of sands.
Besides being very important for plant health and growth as a nutrient, calcium is also important in the correction of soils high in sodium. Many types and formulations of calcium are available to turfgrass managers. Most of these calcium sources are highly insoluble in water making it difficult to get the Ca cation into the soil profile. For this reason complexed Ca such as 'Grigg Brothers Calcium Complex 12%' may be more effective than non-complexed calcium in treating your soil rhizosphere for both flushing of Na and uptake of Ca into the plant.
Why would our Calcium be better than regular Calcium in treating sodic or saline soils?
Treatment of sodic soils depends on many factors such as the amount of sodium present, type of salt, pH, CEC, water quality etc. The standard treatment has been to use fertilizers containing calcium, gypsum or calcium chloride in soils of low Ca levels, or sulfuric acid/elemental sulfur in soils with high Ca as in calcitic soils.
The main thing is you need calcium for sodium replacement. Sodium in general is detrimental to soils because it destroys soil structure and in the plants affects osmotic potential and it disturbs cell membrane integrity and eventually toxicity.
Calcium does the opposite of sodium in that it stabalizes both the soil and plant's cell membrane in addition of being an essential nutrient.
When you add calcium, it has to be available for replacing the sodium. In some cases, if you add gypsum, for example, and your soil and/or water is high in carbonates and bicarbonates, the calcium will precipitate into insoluble calcium carbonate and you will will not get the benefit of the added calcium.
When you use complexed Ca, the calcium is protected, to a certain degree, from precipitating with the carbonates or sulfates in the water and soil solution. To make a fair statement this calcium is slow to react with soil particles; however the calcium will not be in soil solution indefinitely. It will react with soil and will replace sodium but this also depends on the type of soil and the presence of organic matter.
Calcium can be absorbed by the tissue and can be effective as a plant nutrient when applied as a chelated true foliar such as 'Grigg Brothers Sili-Kal B.'
Grigg Brothers produces both soil applied and foliar absorbed high quality calcium products!
Since most golf greens, especially those grown on a sand base rootzones, are usually maintained under some degree of stress it is safe to assume that adequate levels of Ca in the plants will be beneficial in your program. At times of limited root growth the best way to keep adequate levels of Ca in the plant is with either regular foliar applications of good quality chelated calcium foliar products such as 'Grigg Brothers Sili-Kal B' or the application to the rootzone of quality complexed calcium such as 'Grigg Brothers Calcium Complex 12%.'
Keep in mind that turfgrass varieties and cultivars may vary widely in their utilization of calcium.
We hope this information is a valuable aid to your selection of quality products that will help in your program.
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release 1/19/2011 |
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