The effect of calcium silicate in barley pot experiments

Authors

• Gotfred Uhlen Agricultural University of Norway, 1432 Ås-NLH

DOI: https://doi.org/10.23986/afsci.71887

Abstract

In a greenhouse pot experiment lasting five years, 14 tons per hectare of calcium silicate (12 % Ca) were compared with an equivalent calcium hydroxide application, 3.2 t/ha, on a loam soil (»A»). Also, the experiment included excess liming with 16 t Ca(OH)2/ha, with and without the addition of the 14 tons of the calcium silicate material. A two year experiment with silicate and lime was conducted on another loam soil (»B»), The silicate application produced higher yields of barley grain and straw; the effect being proportionately higher than that of an equivalent Ca(OH)2 application. Neither a yield depression caused by an excess lime excess potassium treatment nor a yield reduction due to boron application in the low lime series could be counteracted by silicate application (soil »A»), Significant yield increases for silicate and for lime were found in the 4th and 5th years after application, although the effects were reduced compared to the responses during the first 3 years. The silica content of barley grain and straw increased considerably after silicate application. In the first year, for example, the percent of SiO2 on straw dry matter rose from less than 1 percent to 7 percent. The silica treatments and the large SiO2 uptake, apparently had no direct effects upon the phosphorus, calcium, potassium or the magnesium content of the barley crops, although the silicate seemed to improve the soil phosphorus availability. In the high-lime series, potassium applications in the first two years of the experimental period roughly doubled the silica content of barley straw and grain, whereas such an effect by the potassium fertilizers was absent in the low-lime series for both soil (»A») and (»B»). After the five year cropping period, lime and silicate were found to have influenced the soil aggregate size distribution percentages, and had markedly improved the water stability of the soil aggregates.