Introduction:
There are two common ways to test for soil nutrients, the SLAN Method (Sufficiency Level of Available Nutrients) and the BCSR method (Basic Cation Saturation Ratio).
The SLAN method measures the amount of nutrients in the soil and makes recommendations based on studies done for that particular soil type and crop. Therefore, using the SLAN method for determining the fertilizer requirements for turfgrasses can be problematic, since soil testing facilities usually make recommendations based upon agricultural row crops.
The BCSR method consists of measuring the relative quantities of cations on the cation exchange sites and comparing their ratios. It is believed that optimal plant growth can be achieved by having Calcium on 60-65% of the cation exchange sites with ratios for the other cations being; Mg+2 10-20%, K+ 5-10%, NH4+ 5% and H+ 5-20%. When test results for a soil are outside the ranges for a cation, fertilizer treatments are recommended to correct any deficiencies and to bring the ratios back in line.
The majority of sand used in construction of greens and athletic fields is termed calcareous, because of the high quantity of calcium carbonate contained in the sand. Moreover, this sand usually, has a high pH around 8.2-8.3 and a low cation exchange capacity around 1.2 meq/100g. It is not unusual for calcium content to be low on cation exchange sites, resulting in recommendations for adding calcium. Calcium is recommended to be added even though the soil media is calcareous and contains a large amount of calcium in the soil.
Objectives:
To discover if adding calcium to calcareous soils that have a low calcium ratio will increase the amount of calcium taken up by the turfgrass plant, and more importantly if this increased calcium is beneficial to the grass plant.
Materials and Methods:
During the fall of 1998, a preliminary greenhouse study was conducted looking at five different calcium treatments (no calcium added, gypsum, lime, calcium nitrate, and calcium chelate) applied to Kentucky bluegrass and creeping bentgrass grown on calcareous sand and silica sand.
Results:
During the 12-week test period some visual response trends among the different treatments were noticed, but the data is still being analyzed to determine if the treatments were significant or not. Preliminary data are listed in Tables 1 and 2.
Table 1. Calcium concentration in dry tissue (ppm) for the two different grasses.
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No Calcium |
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Gypsum |
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Lime |
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Calcium Nitrate |
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Calcium Chelate |
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Table 2. Calcium concentration in dry tissue (ppm) for the two different soil types.
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Sand |
Sand |
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No Calcium |
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Gypsum |
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Lime |
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Calcium Nitrate |
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Calcium Chelate |
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ISU Horticulture:Publications:1999 Turfgrass Report | College of Agriculture |