We are two students at Roskilde University who have made a bachelor thesis on Rock Dusts.

You will find a reference list of 17 pages attached to this mail, with
literature that is relevant to rock dust questions. I hope you will find it
useful. Our report gave the highest grade to our exam, which is very
rarely given. We made growth experiments which turned out to show a statistically significant higher plant growth as the effect of granite dust fertilizing, against the unfertilized control.

This reference list was used, making the bachelor thesis at Roskilde University, Denmark, discussing rock dusts as an organic fertilizer, in 2004. It is an assessment of the possibility for implemention of rock dusts as an organic fertilizer in Denmark. The thesis concludes that rock dusts are indeed useful as fertilizer and that it has potential in Danish agriculture.

Authors: Stine Margit Lindegård and Irene Durinck Nicolajsen

Abstract:

http://diggy.ruc.dk/handle/1800/506

Full text in Danish:

http://www.remineralize.org/ThesisPDF.pdf

Rock Dust References:

http://www.remineralize.org/RockDustReferences.doc

Ms. Stine Lindegard:
Congratulations for joining the Forum and conveying your valuable results to the members. May I request you to analyse the soil for physical, chemical and microbiological properties of both control plot and treated plot. You might have mineral nutrient analysis of granite rock dust. If you have all these data readily available, it will be great to share to others and will highly useful for popularising the application of rock dusts. Can you kindly enumerate your visual observations on the growth pattern of the applied plots, i.e., how many days from the date of granite dust application the plants start showing changes in color, height and additional growth in terms of side shoots, emergence of new leaves, etc. And also stability of the growth in terms of duration.
In deed it is a valuable information for popularisation of granite rock dust.
I wish you many more success in your pursuit.
N. S. Rao







» We are two students at Roskilde University who have made a bachelor thesis
» on Rock Dusts.
»
» You will find a reference list of 17 pages attached to this mail, with
» literature that is relevant to rock dust questions. I hope you will find
» it
» useful. Our report gave the highest grade to our exam, which is very
» rarely given. We made growth experiments which turned out to show a
» statistically significant higher plant growth as the effect of granite dust
» fertilizing, against the unfertilized control.
»
» This reference list was used, making the bachelor thesis at Roskilde
» University, Denmark, discussing rock dusts as an organic fertilizer, in
» 2004. It is an assessment of the possibility for implemention of rock dusts
» as an organic fertilizer in Denmark. The thesis concludes that rock dusts
» are indeed useful as fertilizer and that it has potential in Danish
» agriculture.
»
» Authors: Stine Margit Lindegård and Irene Durinck Nicolajsen
»
» Abstract:
»
» http://diggy.ruc.dk/handle/1800/506
»
» Full text in Danish:
»
» http://www.remineralize.org/ThesisPDF.pdf
»
» Rock Dust References:
»
» http://www.remineralize.org/RockDustReferences.doc

Dear N. S. Rao and others who are interested.

I'm sorry that we haven't had the time yet to make a more detailed english summary. In this reply, I have translated our main results and most important details.

We made studies on both a rich clay-soil and a poorer sandy soil. The clay soil contains on average 22 % clay, 50 % fine sand, 25 % coarse sand and 3 % humus. The poor sandy soil is from the depth of 30-60 cm, taken near a sand gravel. To make a full analysis of the soil for physical, chemical and microbiological properties might have been useful, but was not within our possibilities.

Furthermore, we tested three different kinds of rock dusts, all from local gravels. Two of them consisted of iceage-remains, one with a high content of granite (From Bregninge-area, 65,5% granite) and another with 30,5% granite (From the Svogerslev-area). The third was freshly crushed pure granite (From Svebølle gravel in Jyderup).

16 % of the rock dust from Bregninge was less then 0,075 mm in diameter, and 92,6 % was less than 2 mm in diameter. 21,3 % of the content was in the ideal grain sizes.

13,1 % of the rock dust from Svogerslev was less than 0,075 mm and 98,3 % was less than 4 mm in diameter, and only 74,3 % was less than 2 mm in diameter. 17,5 % of the content was in the ideal grain sizes.

13,6 % of the rock dust from Jyderup was less then 0,075 mm in diameter, and 93,2 % was less than 2 mm in diameter. 18,1 % of the content was in the ideal grain sizes.

The three rock dust fertilizers were compared with artificial fertilizer ("kunstgødning" in Danish) and unfertilized control. The amount of rock dust used is comparable to 50 tons per acre (which corresponds to 10 tons per acre of the correct sized, fine rock dust), and the artificial fertilizer given was an NPK (21-3-10) from Kemira Growhow.

1400 seeds were planted, 700 in each soil type, with 140 seeds for each fertilizer type (three rock dusts, one artificial fertilizer and unfertilized control). There were 100 pots in total, with 14 seeds in each pot. They were watered every second day for a week, and after the first seven days the hights of the plants were measured (only the six highest plants in each pot were measured).

We had help from a supervisor, Per Homan Jespersen, to make three statistical analysis of the data, in the program SPSS. The results of the third analysis could explain the highest amount of the plant growth variations, 47%. The result of this analysis show that the rock dust from Bregninge (65,5% granite) increased plant growth in both soil types, compared to control, and this effect is significant at 6,7% (the probability that the found correlation is correct is therefore at 93,3%. Normally, you would like to have at least 95% probability of a correlation.). Compared with artificial fertilizer, it seems that it worked just as good as this.

The 30,5% granite rock dust (from Svogerslev) gave a significant increase of plant growth in the rich clay soil, but a decrease in the sandy soil, compared to control. The pure granite from Jyderup gave a significant increase of plant growth in the poor, sandy soil, but a decrease of plant growth in the richer soil.

On page 57 in our report, you will find the graph showing our results.

To get an overview of our literature analysis, I suggest that you take a look at page 60-65 in our report. Here you can see the percentages of growth increases and decreases from numerous other sources. The results are shown against control (“mod kontrol” in Danish), against artificial fertlilzers (“mod kunstgødning” in Danish) and against organic fertilizers (“mod husdyrgødning eller anden org. gødning” in Danish). One Danish ha is approximately two acres. Forsøg = trial. Merudbytte = increase of yield. Ved = by. Stenmelsanvendelse = use of rock dust. Stenmelstype = type of rock dust. Afgrøde = the plant sort. Forfatter = Author. Ukendt = unknown. Gødning = fertilizer. Havre = oats. Hvede = wheat. Kartoffel = potato. Rug = rye. Byg = barley. Jord = soil. Græs = grass. Mark = field. Drivhus = greenhouse. Lerjord = clay soil. Næringsfattig = poor. Skov = forest.

I hope this can take you the necessary step further, making it easier to mak use of our results.

Best wishes,
Stine Lindegaard.

The Danish letters turned out to look quite funny, so I will try again to translate the words, this time with modifications of the letters.

"To get an overview of our literature analysis, I suggest that you take a look at page 60-65 in our report. Here you can see the percentages of growth increases and decreases from numerous other sources. The results are shown against control (“mod kontrol” in Danish), against artificial fertlilzers (“mod kunstgodning” in Danish) and against organic fertilizers (“mod husdyrgodning eller anden org. godning” in Danish). One Danish ha is approximately two acres. Forsog = trial. Merudbytte = increase of yield. Ved = by. Stenmelsanvendelse = use of rock dust. Stenmelstype = type of rock dust. Afgrode = the plant sort. Forfatter = Author. Ukendt = unknown. Godning = fertilizer. Havre = oats. Hvede = wheat. Kartoffel = potato. Rug = rye. Byg = barley. Jord = soil. Gras = grass. Mark = field. Drivhus = greenhouse. Lerjord = clay soil. Naringsfattig = poor. Skov = forest."

Best wishes,
Stine Lindegaard.

Any idea what this means?

"Du fatter ikke en meter hr Sam"

thanks