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.

Description

[0001]This is a continuation-in-part of Ser. No. 08 / 642,534, filed May 3, 1996 pendingnow U.S. Pat. No. 5,867,935.FIELD OF THE INVENTION[0002]The present invention generally relates to superheated steam for agricultural uses, and more particularly relates to delivering superheated steam in the field in fumigating, weeding, defoliating, and drying applications where the superheated steam is selectively delivered above and / or below the soil such as with a portable apparatus.BACKGROUND OF THE INVENTION[0003]Selective defoliation of a field growing crop such as grape vines has long been known as a desirable practice. Thus, for example, U.S. Pat. 2,865,135, issued Dec. 23, 1958, inventors Gamboni et al. discloses a grape leaf stripping mechanism to strip the leaves from grape vines by a mechanical apparatus rather than manual defoliation. The apparatus disclosed by this patent uses a pair of heaters to effect the defoliation.[0004]More recently, the University of California publication o...

AI Technical Summary

Benefits of technology

[0021]In another aspect of the present invention, a method for defoliating plants, preferably grape vines, is provided whereby superheated steam is delivered to basal leaves. When treating grape vines, the superheated steam is preferably delivered adjacent to developing grape berries within a desired volume, or envelope. The desired envelope has a characteristic dimensional size within which the treating steam has a temperature range sufficient for defoliation, but which surprisingly does not damage the grape berries themselves.

[0022]In yet another aspect of the present invention, a method for treating raisin grapes or prune plums is provided to decrease time of drying on the cane or tree prior to harvest.

Problems solved by technology

Manual defoliation is, obviously, labor intensive and thus tends to be costly.

In addition, manual defoliation when performed shortly after fruiting tends to bruise the very small berries in the fruit cluster.

The presently known mechanical means for defoliating are disadvantageous because those that blow air or pull a vacuum tend to damage the berries by bruising or removing the berries themselves.

Another problem area for cultivated fields and crop maintenance such as vineyards particularly in California are that typical soils contain nematodes that feed on roots, which reduce root efficiency.

Nematode infestation of vineyards are manifested by reduced vigor and yield with a light yellowing of leaves because nematode-infected vine roots are unable to meet above-ground demands for nutrients and water.

However, methyl bromide bas been implicated in harming the ozone layer.

As a consequence, considerable environmental pressure has been building against its use.

A reason for delaying the proposed ban was due to lack of effective alternatives for agriculture in soil pest control, particularly for crops such as strawberries.

But such small scale soil treatments are not presently practical or possible for in the field use.

Further the steam used is not a very efficient process, since it involves for example, temperatures close to 212° F.

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