Agricultural methods with superheated steam

Abstract

Methods for treating plants and fields in agricultural applications are provided by selective delivery of superheated steam. Particularly preferred applications include delivery adjacent to grape vine leaves in order to defoliate basal leaves and to kill localized insect pests, and by injecting superheated steam in strawberry beds prior to planting to kill nematodes. The superheated steam is delivered at temperatures in excess of about 250° F.

1. An agricultural method for in the field use, comprising:
 generating steam in a first steam generator, the steam having water droplets therein;  
 removing substantially all the water droplets from the steam so as to form saturated steam substantially free of water droplets;  
 heating the supersaturated saturated steam to at least about 300° F. in a second steam generator to form superheated steam; and,  
 selectively delivering sufficient of the superheated steam to soil in a field to kill undesired organisms.  
 
     
     
       2. The method as in  claim 1  wherein the superheated steam is delivered at a temperature above about 250° F. 
     
     
       3. The method as in  claim 1  wherein the selective delivery includes penetrating the soil to a depth in a range of about two inches to about twenty inches to deliver the superheated steam therein. 
     
     
       4. The method as in  claim 2  wherein the undesired organisms are weeds. 
     
     
       5. The method as in  claim 2  wherein the undesired organisms are insects or worms. 
     
     
       6. The method as in  claim 2  further comprising turning over an upper soil layer while selectively delivering the superheated steam thereto. 
     
     
       7. The method as in  claim 1  wherein the undesired organisms are nematodes. 
     
     
       8. The method as in  claim 3  wherein the selective delivery is prior to planting a crop. 
     
     
       9. A preplant treatment method for fields, comprising:
 generating steam in a first steam generator, the steam having water droplets therein;  
 removing substantially all the water droplets from the steam so as to form saturated steam substantially free of water droplets;  
 heating the supersaturated saturated steam to at least about 300° F. in a second steam generator to form superheated steam; and,  
 selectively delivering sufficient of the superheated steam to soil in the field prior to planting to kill nematodes therein, the superheated steam being delivered at a temperature above 250° F.  
 
     
     
       10. The preplant treatment method as in  claim 9  wherein the field is for planting strawberries. 
     
     
       11. A method for defoliating grape vines comprising:
 generating a flow of superheated steam; and,  
 delivering the flow of superheated steam to basal leaves adjacent to developing grape berries.  
 
     
     
       12. The method as in  claim 11  wherein the superheated steam delivered contacts the basal leaves and is in a temperature range of about 250° F. to about 500° F. 
     
     
       13. The method as in  claim 11  wherein the flow of superheated steam is generated to be from about 300° F. to about 800° F. and is at a pressure of from about 5 psi to about 60 psi. 
     
     
       14. The method as in  claim 11  wherein the superheated steam is substantially free of water droplets. 
     
     
       15. The method as in  claim 11  wherein the generation of flow of superheated steam includes initially forming steam in a first steam generator followed by generating superheated steam in a second steam generator, wherein water droplets in the steam from the first steam generator are substantially removed before treatment in the second steam generator. 
     
     
       16. A method for treating raisin grapes or prune plums in the field, comprising:
 generating a flow of superheated steam, the superheated steam having a drying adjuvant entrained therein; and,  
 delivering the flow of superheated steam to the raisin grapes or prune plums.  
 
     
     
       17. The method as in  claim 16  wherein the adjuvant is methyl oleate or ethyl oleate. 
     
     
       18. The method as in  claim 16  wherein the flow of superheated steam delivered is effective to increase moisture evaporation from the raisin grapes or prune plums. 
     
     
       19. An agricultural method comprising:
   generating a flow of superheated steam in which substantially all of the water droplets are removed from the steam prior to generating said superheated steam; and        delivering the flow of superheated steam to a plant having a graft, where said delivering is sufficient to inhibit a growth of suckers or canes on said plant.     
     
     
       20. The method of  claim 19 , wherein said plant is a fruit plant.  
     
     
       21. The method of  claim 19 , wherein said plant is a cotton plant. 
     
     
       22. The method of  claim 19 , wherein said plant is a vine, a tree, or a shrub.  
     
     
       23. The method of  claim 22 , wherein said vine is a grape vine. 
     
     
       24. The method of  claim 22 , wherein said tree is a nut tree. 
     
     
       25. The method of  claim 19 , wherein said delivering delivers said flow adjacent to said graft.  
     
     
       26. The method of  claim 19 , wherein said delivering delivers said flow to the root stock of said graft. 
     
     
       27. The agricultural method of  claim 19 , wherein said generating said flow of superheated steam includes:
   generating steam in a first steam generator, the steam having water droplets therein;        removing substantially all the water droplets from the steam so as to form a steam substantially free of water droplets; and        heating the steam substantially free of water droplets to at least about  300 ° F. in a second steam generator to form said superheated steam.     
     
     
       28. An agricultural method comprising:
   generating a flow of superheated steam in which substantially all of the water droplets are removed from the steam prior to generating said superheated steam; and        delivering the flow of superheated steam adjacent to a graft sufficient to inhibit a growth adjacent to said graft.     
     
     
       29. The method of  claim 28 , wherein said graft is the graft of a fruit plant.  
     
     
       30. The method of  claim 28 , wherein said graft is the graft of a cotton plant.  
     
     
       31. The method of  claim 28 , wherein said graft is the graft of a vine, a tree, or a shrub.  
     
     
       32. The method of  claim 31 , wherein said vine is a grape vine. 
     
     
       33. The method of  claim 31 , wherein said tree is a nut tree. 
     
     
       34. The method of  claim 28 , wherein said growth is a leaf, a sucker or a cane.  
     
     
       35. The agricultural method of  claim 28 , wherein said generating said flow of superheated steam includes:
   generating steam in a first steam generator, the steam having water droplets therein;        removing substantially all the water droplets from the steam so as to form a steam substantially free of water droplets; and        heating the steam substantially free of water droplets to at least about  300 ° F. in a second steam generator to form said superheated steam.     
     
     
       36. An agricultural method comprising;
   generating a flow of superheated steam in which substantially all of the water droplets are removed from the steam prior to generating said superheated steam; and        delivering the flow of superheated steam to a plant sufficient to fumigate said plant.     
     
     
       37. The method of  claim 36 , wherein said plant is a fruit plant. 
     
     
       38. The method of  claim 36 , wherein said plant is a cotton plant. 
     
     
       39. The method of  claim 36 , wherein said plant is a vine, a tree, or a shrub. 
     
     
       40. The method of  claim 39 , wherein, said vine is a grape vine. 
     
     
       41. The method of  claim 39 , wherein said tree is a nut tree. 
     
     
       42. The agricultural method of  claim 36 , wherein said generating said flow of superheated steam includes:
   generating steam in a first steam generator, the steam having water droplets therein;        removing substantially all the water droplets from the steam so as to form saturated steam substantially free of water droplets; and        heating the steam to at least about  300 ° F. in a second steam generator to form said superheated steam.