METHOD FOR PRODUCING A SOIL CONDITIONING AGENT

Abstract

A method of producing a soil conditioning agent, the method comprising (i) admixing (a) ash from an organic source with (b) an anaerobic digestate.

Claims

1. A method of producing a soil conditioning agent, the method comprising (i) admixing (a) ash from an organic source with (b) an anaerobic digestate.

2. A method according to claim 1 which further includes the addition of (c) a source of nitrate ion and/or a source of sulfate ion.

3. A method according to claim 1 wherein component (a) comprises wood ash.

4. A method according to claim 2 wherein component (c) comprises gypsum.

5. A method according to claim 1 wherein the composition obtained in step (i) comprises less than 20 wt% water.

6. A method according to claim 2 wherein step (i) involves admixing by weight 1 part of component (a) with 1.5 to 2.5 parts component (b) and 0.01 to 0.05 parts component (c).

7. A method according to claim 1 which further involves a step (ii) of contacting the composition provided in step (i) with a composition comprising carbon dioxide.

8. A method according to claim 7 which further involves a step (iii) of pelletising the material obtained after steps (i) and optional step (ii).

9. A method of improving the bioavailability of minerals, especially nitrogen, at the surface of the soil comprising administering to the soil the soil conditioning agent obtained by the method of claim 1.

10. A method of increasing the porosity of the surface of the soil comprising administering to the soil the soil conditioning agent obtained by the method of claim 1.

11. A method of reducing loss of nitrogen at the soil surface due to evaporation comprising administering to the soil the soil conditioning agent obtained by the method of claim 1.

12. A method of reducing loss of nitrogen at the soil surface due to leaching comprising administering to the soil the soil conditioning agent obtained by the method of claim 1.

13. A method of reducing emissions of nitrous oxide comprising administering to the soil the soil conditioning agent obtained by the method of claim 1.

Description

EXAMPLE 1

[0109] A soil conditioning agent was prepared as follows:

[0110] Ash material was collected from the gasification of spruce wood and added to an anaerobic digestate in an atmosphere of carbon dioxide. When the temperature stopped increasing, gypsum was added.

[0111] The weight ratio of digestate to ash to gypsum was approximately 64:34:2.

[0112] The material was formed into pellets having a diameter of 3 mm and pellets having a diameter of 6 mm.

[0113] The 6 mm pellets are shown in FIG. 1.

EXAMPLE 2

[0114] A leaching study was carried out in which pellets of the material obtained in Example 1 were compared with an ammonium nitrate fertiliser.

[0115] Three glass columns were filled with sand. Pellets of each of the test materials were added to two columns. To the other column an equivalent amount (by nitrogen content) of ammonium nitrate fertiliser was added.

[0116] Each day an amount of water equivalent to the UK average rainfall was added dropwise to each column.

[0117] The nitrogen content of soil 20 cm below the surface was measured each day.

[0118] The results in FIG. 2 show the nitrogen content recorded over 14 days. For the 6 mm pellets the content was recorded for a further 28 days.