Micronized earth alkali carbonate-containing material, for regulating the pH of a soil

Abstract

The present invention relates to a method for regulating the pH of a soil as well as the use of at least one earth alkali carbonate-containing material having a weight median particle size d.sub.50 value of ≤50.0 μm for optimizing or improving the pH of a soil as well as the use of an irrigation or spraying system for the application of an aqueous suspension comprising at least one earth alkali carbonate-containing material in order to optimize or improve the pH of a soil.

Claims

1. A method for regulating the pH of a soil, the method comprising: applying an aqueous suspension comprising 0.001 to 30 wt.-% at least one earth alkali carbonate-containing material that is limestone, based on the weight of the aqueous suspension and comprising 0.1 to 30 wt.-% of a water softener based on the weight of the aqueous suspension, on and/or into soil through an irrigation or spraying system, in an amount from 1.0 to 100.0 kg/ha, based on the at least one earth alkali carbonate-containing material, per pH increase of 0.1 of the soil, to regulate the pH of the soil, wherein the at least one earth alkali carbonate-containing material comprises natural ground calcium carbonate, wherein a ratio of the pH of the soil at 2, 4, 6, 8, 24 and/or 52 weeks after applying the at least one earth alkali carbonate-containing material to the pH of the soil before applying the at least one earth alkali carbonate-containing material is 1.05 to 1.4, and the at least one earth alkali carbonate-containing material comprises: a) a weight median particle size diameter d.sub.50 in the range from 0.3 μm to 20.0 μm, b) a specific surface area (BET) in the range from 1.0 m.sup.2/g to 10.0 m.sup.2/g as measured by a BET nitrogen method, and c) a density in the range from 2.5 to 3.5 g/cm.sup.3.

2. The method of claim 1, wherein the at least one earth alkali carbonate-containing material comprises: a) a weight median particle size diameter d.sub.50 in the range from 0.5 μm to 15.0 μm, b) a specific surface area (BET) in the range from 3.0 m.sup.2/g to 8.0 m.sup.2/g as measured by the BET nitrogen method, and c) a density in the range from 2.6 to 3.0 g/cm.sup.3.

3. The method of claim 1, wherein the aqueous suspension comprises at least one compound selected from the group consisting of fertilizer, soil conditioner, bactericide, fungicide, insecticide, herbicide, anti-evaporation agent, anti-freezing agent, buffering agent, and any mixture thereof.

4. The method of claim 1, wherein the irrigation system is selected from the group consisting of drip irrigation, fertigation, sprinklers, pivots, distribution with booms, and any mixture thereof.

5. The method of claim 1, wherein the soil before applying the at least one earth alkali carbonate-containing material has a pH≤7.2, and after applying the at least one earth alkali carbonate-containing material has a pH≤7.2, wherein the pH is determined after 2, 4, 6, 8, 24 and/or 52 weeks of applying the at least one earth alkali carbonate-containing material on and/or into the soil.

6. The method of claim 1, wherein the soil has pH, before applying the at least one earth alkali carbonate-containing material of 3.5<pH≤7.0, and a pH, after applying the at least one earth alkali carbonate-containing material of 5.1<pH≤7.2, wherein the pH is determined after 2, 4, 6, 8, 24 and/or 52 weeks of applying the at least one earth alkali carbonate-containing material on and/or into the soil.

7. The method of claim 1, wherein the at least one earth alkali carbonate-containing material is applied on and/or into a soil for domesticated plants, top fruits, small-plant fruits, crops, legumes, vegetables either open field or green house, industrial crops, commodities, or ornamental plants.

8. The method of claim 1, wherein a ratio of the pH of the soil at 2, 4, 6, 8, 24 and/or 52 weeks after applying the at least one earth alkali carbonate-containing material to the pH of the soil before applying the at least one earth alkali carbonate-containing material is 1.05 to 1.2.

9. The method of claim 1, wherein the pH of the soil at 8 weeks after applying the at least one earth alkali carbonate-containing material is higher than the pH of the soil before applying the at least one earth alkali carbonate-containing material.

10. The method of claim 1, wherein the pH of the soil at 12 weeks after applying the at least one earth alkali carbonate-containing material is higher than the pH of the soil before applying the at least one earth alkali carbonate-containing material.

11. The method of claim 1, wherein the pH of the soil at 16 weeks after applying the at least one earth alkali carbonate-containing material is higher than the pH of the soil before applying the at least one earth alkali carbonate-containing material.

12. A method for regulating the pH of a soil, the method comprising: applying an aqueous suspension comprising at least one earth alkali carbonate-containing material that is limestone and comprising 0.1 to 30 wt.-% of a water softener based on the weight of the aqueous suspension, on and/or into soil through an irrigation or spraying system, in an amount from 1.0 to 75 kg/ha, based on the at least one earth alkali carbonate-containing material, per pH increase of 0.1 of the soil, to regulate the pH of the soil, wherein the at least one earth alkali carbonate-containing material comprises natural ground calcium carbonate, wherein a ratio of the pH of the soil at 8, 24 and/or 52 weeks after applying the at least one earth alkali carbonate-containing material to the pH of the soil before applying the at least one earth alkali carbonate-containing material is 1.05 to 1.1, and the at least one earth alkali carbonate-containing material has: a) a weight median particle size diameter d.sub.50 in the range from 0.3 μm to 20.0 μm, b) a specific surface area (BET) in the range from 1.0 m.sup.2/g to 10.0 m.sup.2/g as measured by a BET nitrogen method, and c) a density in the range from 2.5 to 3.5 g/cm.sup.3.

13. The method of claim 1, wherein the water softener comprises monosodium citrate, monopotassium citrate and mixtures thereof.

14. The method of claim 12, wherein the water softener comprises monosodium citrate, monopotassium citrate and mixtures thereof.

15. The method of claim 1, wherein the weight median particle size diameter d.sub.98 is less than or equal to 75 μm.

16. The method of claim 15, wherein the weight median particle size diameter d.sub.98 is less than or equal 20 μm.

17. The method of claim 12, wherein the weight median particle size diameter d.sub.98 is less than or equal to 75 μm.

18. The method of claim 17, wherein the weight median particle size diameter d.sub.98 is less than or equal 20 μm.

19. The method of claim 1, wherein the aqueous suspension is 2 to 20 wt.-% of the water softener.

Description

EXAMPLES

Measurement Methods

(1) The following measurement methods are used to evaluate the parameters given in the examples and claims.

(2) Particle Size Distribution (Mass % Particles with a Diameter<X) and Weight Median Diameter (d.sub.50) of a Particulate Material

(3) As used herein and as generally defined in the art, the “d.sub.50” value is determined based on measurements made by using a Sedigraph™ 5100 of Micromeritics Instrument Corporation and is defined as the size at which 50% (the median point) of the particle volume or mass is accounted for by particles having a diameter equal to the specified value.

(4) The method and the instrument are known to the skilled person and are commonly used to determine grain size of fillers and pigments. The measurement is carried out in an aqueous solution of 0.1 wt.-% Na.sub.4P.sub.2O.sub.7. The samples are dispersed using a high speed stirrer and supersonics.

(5) BET Specific Surface Area of a Material

(6) Throughout the present document, the specific surface area (in m.sup.2/g) of the earth alkali carbonate-containing material is determined using the BET method (using nitrogen as adsorbing gas), which is well known to the skilled man (ISO 9277:1995). The total surface area (in m.sup.2) of the earth alkali carbonate-containing material is then obtained by multiplication of the specific surface area and the mass (in g) of the earth alkali carbonate-containing material prior to treatment.

(7) Density

(8) The density is measured according to Norm DIN 66137-2: December 2004 using helium gas pycnometry with an AccuPyc 1330 gas pycnometer from Micromeritics, wherein the helium gas is of 99.995% purity (helium gas 4.5 grade). AccuPyc calibration standard from Micromeritics, serial no. 3059 was used.

(9) pH

(10) The free acidity, relating to the H+ in the soil solution, was determined by the water pH as follows:

(11) For the pH assessment, soil samples were taken from 5 to 10 cm depth. The soil samples were thoroughly mixed before taking 30 ml of volume of soil subsample. The subsample was placed in a plastic container together with 30 ml of distilled water and the soil-water mixture was thoroughly mixed. The resulting soil/water mixture thus equates to a 1:1 soil to water ratio on a volume basis. Subsequently, the container was closed and then shaken for about 25 times. After a settling of the soil particles for about 10 to 15 μminutes, a pH meter (model Mettler Toledo F20—FiveEasy), calibrated with 4.0 and 7.0 standard buffer solutions, AC or battery operated with reproducibility to at least 0.05 pH units, was inserted into the upper most portion of the solution and the pH was digitally recorded.

Example 1

(12) One walnut orchard in Escalon, Calif., was chosen as test site. The site suffered from high acidity and poor water penetration; mean pH was about 4.9-5.1. To balance this acidity the grower used in the past 2 years about 2 tons of dolomite powder per acre, i.e. about 4 tons/ha in total. After these two applications the results showed a slight increase in pH, from 5.0 to 5.2, which dropped again to 5 after 6 months from the time of application.

(13) Furthermore, this standard product is applied on the top soil and reacts slowly with the acidity and moisture of the soil. Due to the uneven particle size and the high presence of dust it could happen that a significant amount of product is lost with the wind and is thus not available for treating the soil.

(14) A plot of about 24 ha (60 acres) was defined as test site containing about 6 000 trees of which about 5% were suffering poor plant health. Water source was supplied by snow melt from the South San Joaquin Irrigation District Canal with pH 7 and EC, (electrical conductivity) of 2.7 S/m, very low mineral content.

(15) It was decided to apply 280.2 kg/ha of a calcium carbonate-containing material (available as Agrocarb® 100 from Omya Inc., USA) in form of an aqueous suspension on the test site. For distributing the aqueous suspension, an available irrigation system for applying powder solution grade of Gypsum or any liquid fertilizer/amendment was used. In particular, the water is introduced into the bottom of a 180 US gal lqd (about 680 liters) capacity container mounted on a trailer. Subsequently, the calcium carbonate containing material is added in situ to the water, no mixing was involved and then the obtained slurry was discharged through gravity into a basin where canal water enters. Subsequently, the aqueous suspension was pumped onto the soil of the test site. In order to ensure the suspension properties, the water was taken from sprinklers at farthest distance from the pump. The irrigation system consumed about 340 kg (750 lb) per hour of the aqueous suspension comprising the calcium carbonate containing material. Twenty four hours were required to irrigate and apply about 280.2 kg/ha (250 lb/a) on 24 ha (60 acres) on the soil. The soil samples from the test site were tested at 2, 4, 6 and 8 week intervals.

(16) From the results given in FIG. 1, it can be gathered that the pH of the soil sharply increases within 2 weeks after applying of the aqueous suspension comprising the calcium carbonate-containing material. The pH stayed stable for the remaining 6 weeks of the test period.

Example 2

Test 1

(17) The aqueous suspension comprising the calcium carbonate-containing material was also tested on test sites cultivating corn.

(18) The experimental design was a randomized complete Block with 8 replications. For distributing the aqueous suspension, an available arrangement of bar for applying herbicide solutions on the soil was used on every singly block for applying the aqueous suspension comprising the calcium carbonate-containing material.

(19) The treatments were:

(20) 1=Untreated,

(21) 2=about 2 240 kg/ha (2 000 lbs/a) of regularly used ground dolomitic limestone (reference “dolomitic aglime”, available from a local producer), and

(22) 3=about 1 537 liters/ha (166 gal/a) of the aqueous suspension comprising a calcium carbonate-containing material (available as Top Flow 130 from Omya Inc., USA).

(23) The pH was determined in water at Waters lab in Camilla, Ga., before applying the aqueous suspension comprising a calcium carbonate-containing material or the standard reference on soil (point 1) as well as every 2 (point 2), 4 (point 3), 8 (point 4), 12 (point 5) and 16 weeks (point 6) after applying the aqueous suspension comprising a calcium carbonate-containing material and the standard reference on the soil.

(24) From FIG. 2, the trend of the soil pH after the application of the aqueous suspension comprising a calcium carbonate-containing material (continuous line) and the standard reference (dotted line) on soil pH can be gathered.

(25) Two weeks (point 2) after the application of the different products, the pH of the soil increased for both treatments, showing a clear effect of pH spike.

(26) After four weeks (point 3) the untreated test sites showed a sharp pH decrease, same did the treatment 2 (i.e. reference), where the pH level was lower than the starting pH, i.e. the pH before applying the soil conditioner.

(27) Treatment number 3 (i.e. the aqueous suspension comprising a calcium carbonate-containing material) also showed a pH decrease after four weeks (point 3) of treatment, in comparison to the pH measured after 2 weeks (point 2), but the determined pH was higher than the starting pH, i.e. the pH before applying the pH soil conditioner (point 1).

(28) After 16 weeks (point 6) the pH of plots treated with the inventive aqueous suspension comprising a calcium carbonate-containing material showed a difference vs. either the dolomitic aglime (i.e. +0.55 pH) or the untreated check (i.e. +1.050 pH).

Test 2

(29) The aqueous suspension comprising the calcium carbonate-containing material was also tested on test sites cultivating cotton.

(30) The experiments were conducted as described for Test 1 above, with the exception that the treatments 1, 2 and 3 were performed on cotton.

(31) From FIG. 3, the trend of the soil pH after 2 (point 2), 4 (point 3), 8 (point 4) and 12 (point 5) weeks of the application of the aqueous suspension comprising a calcium carbonate-containing material (continuous line) and the standard reference (dotted line) on soil pH can be gathered.

(32) Two weeks (point 2) after the application of the different products, the treatment number 3 (i.e. the aqueous suspension comprising a calcium carbonate-containing material) reacted faster with the soil water when compared to the reference treatment (i.e. treatment number 2) and the untreated sample. Even 12 weeks (point 5) after the application of the aqueous suspension comprising a calcium carbonate-containing material (treatment number 3), the pH of this sample was above the pH of the reference treatment (i.e. +0.525 pH) and the untreated sample (i.e. +1.2 pH).

Test 3

(33) The aqueous suspension comprising the calcium carbonate-containing material was also tested on test sites cultivating peanuts.

(34) The experiments were conducted as described for Test 1 above with the exception that the treatments 1, 2 and 3 were performed on peanuts.

(35) From FIG. 4, the trend of the soil pH after 2 (point 2), 4 (point 3) and 8 (point 4) weeks of the application of the aqueous suspension comprising a calcium carbonate-containing material (continuous line) and the standard reference (dotted line) on soil pH can be gathered.

(36) Even starting from a lower pH, (i.e. pH 6.225 for treatment number 3 vs. 6.375 for treatment number 2, point 1) the aqueous suspension comprising a calcium carbonate-containing material showed a faster reaction and conditioned the soil from the earliest stage of its application. All the pH measurements carried out after 2 (point 2), 4 (point 3), and 8 (point 4) weeks showed that the test sites treated with the aqueous suspension comprising a calcium carbonate-containing material staid above pH 7, whilst the reference treatment was slower in the reaction and never reached that pH level.

(37) As a result, it can be concluded from Tests 1 to 3 that the treatment of a soil by using an aqueous suspension comprising a calcium carbonate-containing material and which has been applied on the soil by using a spraying or irrigation system showed in every trial a better performance when compared to the reference samples. Indeed its unique formulation and the better distribution of the soil obtained by the liquid application allowed the soil plots to reach pH levels that were not reached by the common practice.

(38) TABLE-US-00001 TABLE A Field trial on acid soil (Vietnam) Average Average pH pH Weeks Field trials before Rate after after plots Treatments treatment (kg/ha) treatment treatment Ploughed GCC slurry 5.4 88 6.6 4 plots Hydrated 5.4 2500 5.6 4 lime Unloughed GCC slurry 5.2 88 6.6 4 plots Hydrated 5.2 2500 5.4 4 lime

(39) GCC slurry refers to a calcium carbonate slurry with 76 wt % of solid content, d50 of 0.5 μm and a top cut of 4 μm, which was applied by a fertilizer slurry application tanker. Hydrated lime was a commercially available hydrated lime with 200 μmesh (75 μm) of 94%, and the powder was distributed manually on the field. Measurement of pH was done directly in the field with a soil tester from Takemura Electric Works LTD. model DM/15.