Alkynylpyrazoles as nitrification inhibitors

Abstract

The invention concerns novel nitrification inhibitors.

Claims

1. A method for reducing nitrification, comprising treating a plant growing on soil or soil substituents and/or the locus or soil or soil substituents where the plant is growing or is intended to grow with a composition comprising a pyrazole compound of formula I ##STR00025## or a stereoisomer, salt, tautomer or N-oxide thereof, wherein R.sup.1 is C.sub.1-C.sub.4-alkyl; R.sup.2, R.sup.3 and R.sup.4 are independently of each other selected from the group consisting of H, C.sub.1-C.sub.4-alkyl, and C.sub.2-C.sub.4-alynyl; with the proviso that at least one of R.sup.2, R.sup.3 and R.sup.4 is C.sub.2-C.sub.4-alkynyl.

2. The method of claim 1, wherein in said compound of formula I at least two of R.sup.2, R.sup.3 and R.sup.4 are C.sub.2-C.sub.4-alkynyl.

3. The method of claim 2, wherein in said compound of formula I at least two of R.sup.2, R.sup.3 and R.sup.4 are C.sub.2-C.sub.3-alkynyl.

4. The method of claim 1, wherein said reduction of nitrification occurs in or on a plant, in the root zone of a plant, in or on soil or soil substituents and/or at the locus where a plant is growing or is intended to grow.

5. The method of claim 1, wherein the plant and/or the locus or soil or soil substituents where the plant is growing or is intended to grow is additionally provided with a fertilizer.

6. The method of claim 5, wherein the application of said compound of formula I and of said fertilizer is carried out simultaneously or with a time lag.

7. The method of claim 1, wherein said plant is an agricultural plant; a vegetable sorghum; a silvicultural plant; an ornamental plant; or a horticultural plant, each in its natural or in a genetically modified form.

8. The method of claim 7, wherein said plant is an agricultural plant selected from the group consisting of wheat, barley, oat, rye, soybean, corn, potatoes, oilseed rape, canola, sunflower, cotton, sugar cane, sugar beet, and rice.

9. The method of claim 7, wherein said plant is a vegetable selected from the group consisting of spinach, lettuce, asparagus, and cabbages.

10. The method of claim 1, wherein the composition further comprises a fertilizer.

11. The method of claim 10, wherein the composition further comprises at least one carrier.

12. The method of claim 11, wherein said fertilizer is a solid or liquid ammonium-containing inorganic fertilizer; a solid or liquid organic fertilizer selected from the group consisting of liquid manure, semi-liquid manure, biogas manure, stable manure and straw manure, worm castings, compost, seaweed and guano; or a urea-containing fertilizer.

13. The method of claim 12, wherein said fertilizer is a solid or liquid ammonium-containing inorganic fertilizer selected from the group consisting of an NPK fertilizer, ammonium nitrate, calcium ammonium nitrate, ammonium sulfate nitrate, ammonium sulfate and ammonium phosphate.

14. The method of claim 12, wherein said fertilizer is a urea-containing fertilizer selected from the group consisting of urea, formaldehyde urea, anhydrous ammonium, urea ammonium nitrate (UAN) solution, urea sulphur, urea based NPK-fertilizers, and urea ammonium sulfate.

15. The method of claim 1, wherein in said compound of formula I R.sup.1 is C.sub.1-C.sub.2-alkyl.

16. The method claim 1, wherein in said compound of formula I, R.sup.2, R.sup.3 and R.sup.4 are independently of each other selected from the group consisting of H, C.sub.1-C.sub.2-alkyl, and C.sub.2-C.sub.4-alkynyl.

17. An agricultural composition comprising a compound of formula (I) ##STR00026## or a stereoisomer, salt, tautomer or N-oxide thereof, wherein R.sup.1 is C.sub.1-C.sub.4-alkyl; R.sup.2, R.sup.3 and R.sup.4 are independently of each other selected from the group consisting of H, C.sub.1-C.sub.4-alkyl, and C.sub.2-C.sub.4-alynyl; with the proviso that at least one of R.sup.2, R.sup.3 and R.sup.4 is C.sub.2-C.sub.4-alkynyl; and a fertilizer.

18. The composition of claim 17, wherein the composition further comprises at least one carrier.

19. The agrochemical composition of claim 18, wherein said fertilizer is a solid or liquid ammonium-containing inorganic fertilizer; a solid or liquid organic fertilizer selected from the group consisting of liquid manure, semi-liquid manure, biogas manure, stable manure and straw manure, worm castings, compost, seaweed and guano; or a urea-containing fertilizer.

20. The agrochemical composition of claim 19, wherein said fertilizer is a solid or liquid ammonium-containing inorganic fertilizer selected from the group consisting of an NPK fertilizer, ammonium nitrate, calcium ammonium nitrate, ammonium sulfate nitrate, ammonium sulfate and ammonium phosphate.

21. The agrochemical composition of claim 19, wherein said fertilizer is a urea-containing fertilizer selected from the group consisting of urea, formaldehyde urea, anhydrous ammonium, urea ammonium nitrate (UAN) solution, urea sulphur, urea based NPK-fertilizers, and urea ammonium sulfate.

Description

EXAMPLES

Example 1

(1) The compounds of the invention have been tested as follows in terms of the inhibition of nitrification:

(2) Soil was sampled fresh from a field (e.g. Limburgerhof), dried and sieved through a 500 m sieve. Approximately 200 mg of soil were placed into each well of a 48 well plate. Compounds, or DMSO alone, were added at a concentration of 10 ppm, dissolved in 1% DMSO. 6 mol ammonium sulfate was added per well as well as 4.8 mg NaClO.sub.3.

(3) Subsequently, the samples were incubated at room temperature for up to 72 hrs. After the incubation period 64 mg KCl were added and mixed. 25 l of the supernatant were placed into a fresh plate and 260 l of a color reaction solution (from Merck Nr 1.11799.0100) were added.

(4) Measurements were taken with a Tecan plate Reader at 540 nm wavelength.

(5) The results of the measurements (with a dose of 10 ppm) were that all compounds 1 to 3 as shown in Table I below, supra demonstrated an inhibition of 10% compared to a control (DMSO only).

(6) Inhibition is calculated as x=% activity compared to control, and converted to 100x to give the value of inhibition, rather than activity.

(7) The results for the compounds tested with a dose of 10 ppm are provided in the following Table I. In each case, the best inhibition value (IN) obtained for a compound is provided.

(8) TABLE-US-00002 TABLE I Number 1 2 3 Compound IN 55 24 27