My goal was to look at micronutrients in my pasture soils in order to increase both forage production and animal performance through rock dust applications.
I started this project with two fenced pastures totaling 45 acres. One pasture of 25 acres was used for the project and the other 20 acres for the check pasture. The only crop on this farm is pasture being sheep grazed and marketed
Since the inception of this project I have installed three natural water troughs and divided the 45 acres into twelve rotational grazed paddocks.
My cooperators, Suzette Brought, Project Grass Coordinator NRCS, role provided technical advice on pasture layout, water troughs and analysis of soil tests and manure samples.
I took soil samples at inception and conclusion of project. A sample of rock dust was taken at the quarry and delivered to the laboratory. During grazing period manure samples were collected and mailed to Texas A & M (cost covered by NRCS). I had rock dust applied to control pasture. All the results were delivered, telephoned, or mailed to coordinator.
Ph 6.2 6.9
Sulfur 3.6 ppm 13.6 ppm
Mangesium 43 lbs. 593 lbs.
Iron 4.03 ppm 121.4 ppm
The rock dust was from a stone quarry, Valley Quarry in Chambersburg PA.A copy of the analysis done by Express Analytical Services, Inc.,
Chambersburg PA is available in hard copy.
Rock Dust Application
Dates Per Acre
7/29 & 7/30/01 2,440 lbs.
7/12 & 7/13/02 2,601 lbs.
8/21 & 8/22/03 2,706 lbs.
No other amendments were applied to either pasture. As a result of this method, our visual observation and assessment of pasture growth could only come from rock dust.
I have specific results of the weekly manure samples taken on both pastures from July through November 2001. They are being mailed. Not much
change in the results over that extended test period due to the dry weather.
I believe that using rock dust we have reduced the amount of micronutrients that I must provide in feed or minerals. I have applied three application of rock dust since 2001. Due to the dry weather in 2001and 2002 results were
hard to measure. We also feel our results may not be as accurate as we would like due to the change in labs for soil results. However, during the three year period we have noticed that quantity and quality of the forage on the
check side has tripled that of the control pasture. This has been seen with the vast flush of clover, to the point that the brome and rye grass will have to be no-tilled instead of frost seeded this spring.
The soil test taken at the beginning of this project show, a deficiency in micronutrients, such as sulfur, magnesium and iron. Three years later the soil test, show an increase in magnesium and iron and has optimized sulfur.
Even though magnesium is in excess the calcium / magnesium ratio has stayed balanced, close monitoring will be required to keep this ratio in check to prevent any abnormalities in the forages as well the animal. If the calcium /
magnesium ratio becomes unbalanced with an excess of magnesium, this can be taken care of through calcium carbonate application. I am closely monitoring my increase in iron, which can decrease the intake and gain of my animals. At this time I have not seen any problems.
Using the Texas A&M manure sampling, no significant change was seen between the
control and the check pastures. This program analyzed the manure for nitrogen and phosphorus of the forage that is digested by the animal.
I have also come to the conclusion that having soil test and applying rock dust is cheaper than applying lime. In my area rock dust cost $16 ton versus $ 25 ton for lime. Using the rock dust will also benefit my profit since I will not
have to add micronutrient to my feed.
Two successive prior years of dry weather with last year (2002) a severe drought have prevented forage tests.
Economically each additional day the improved pasture extends the grazing season saves one round bale of purchased hay. The 2003 grazing season ended on November 30. Similarly lambs were on feed about one month less time saving
four tons of feed as a result of being on pasture longer. Low input production (primarily rock dust applications) will improve pasture quality, extend the grazing season and eventually reduce the need for supplemental minerals and
feed mill rations. Hence, net farm income will rise.
From this project I realized it should be possible to market lambs directly off
pasture. This would eliminate the expenses of manure handling, also purchasing hay and feed. To accomplish this goal, I’ll continue rock dust usage, no-till grass (without herbicide) and use organic fertilizer.