WO2015066576A2 - Polymeric crop protection system - Google Patents

Abstract

A polymer based system for protection of agricultural plants by using high water content and the ability to include additional beneficial elements and characteristics. This invention provides options for application and use as well as the ability to tailor the application for specific needs.

Description

Polymeric Crop Protection System

[001] This application claims the benefit of U.S. Provisional Application No.

61/899,265, entitled "Polymeric Crop Protection System," filed November 3, 2013, the contents of which are hereby incorporated by reference.

Background of Invention

[002] Each year, a portion of the world's fruit and vegetable crop is lost to environmental damage. Such environmental damage may result from too little or too much water, heat, sun exposure, pollution, low temperature or myriad other issues. The cost of such loses total of millions of dollars and, in some cases, can wreak havoc on community economies. While protection methods exist, they are not without drawbacks, including initial or ongoing costs and other limitations.

[003] There has been a great deal of attention paid to reducing occurrence of damage to growing crops in agriculture. The use of temporary covering structures, covering the vegetation with hay, straw or other light insulating materials and techniques and incorporation of additional systems like sprinklers are well known. However, few breakthroughs have been developed to help minimize the impact of several types of damage with a common base that is economical and readily deployed.

[004] That is the subject of this invention - a means to affect a more efficient covering on the vegetation with a greater capability to protect the vegetation from damage based on the use of a high water content polymeric material that improves upon the utilization of characteristics of water and additives to maximum advantage.

Summary Of The Invention

[005] The invention described herein provides a novel system for using a high water content polymer and its various implementations to provide a means of protecting plant life, especially edible food crops from damage from various conditions, including draught, sunburn and cold weather. This invention will provide benefits not previously available and at much lower initial and ongoing costs than alternative solutions. [006] In the preferred embodiment, a polymer is used to retain water on fruits or vegetables to enable simple protection of the fruits or vegetables from extreme temperatures. In alternative embodiments, a polymer incorporates specific enhancements to protect against other environmental factors, including but not limited to, sun exposure, insects, bacteria, fungus and others. Moreover, the invention allows for the use of multiple, possibly different polymer to further enhance protection.

[007] Several application implementations are described. These various application implementations include the use of existing or ad hoc irrigation systems and the advantageous use of other systems and mechnisms that may be available.

Detailed Description Of The Invention

[008] With the potential of substantial economic loss at stake, protecting crops and vegetation from damage is very important. Damages range from losing a harvest due to drought or hot temperatures, reduced yield due to sun exposure, to overall crop setback in the spring to loss of fruit in the fall due to cold weather. Prevention or substantial reduction of the damage is possible and existing techniques are used. However, a novel solution that can provide myriad benefits without common drawbacks is of great interest. For the purposes of this description, vegetation can be taken to mean and is used interchangeably with plant, vegetable, grain, cereal,and fruit.

[009] Most damage mitigation techniques are either active, including adding heat or cooling or covering vegetation, or passive, including site selection and proper planting and harvesting scheduling to avoid problems. The impact of potentially damaging conditions are based on many variables, including plant species, variety, growth or development stage, plant vigor, soil conditions, surface cover, heat or freeze intensity and duration, thawing conditions, cloud and wind conditions, and others.

[0010] Further, duration is a key factor when considering the damage that may occur at the critical temperatures. In heat conditions, fruit trees may survive, but may have diminished or damaged yield at temperatures over 38°C and damaged fruit with increased sun exposure. During freezing conditions, fruit tree buds may be damaged if exposed for an extended time to temperatures below 0°C but may avoid damage if exposed to an even lower temperature for a short period. Also, thawing conditions often affect the extent of damage after a frost.

Freeze damage conditions are well documented. As an example, Table 1 from North Carolina State University indicates approximate freeze-related critical temperatures for some crop types.

Table 1. Critical temperatures that result in freeze damage to crops

[0012] According to North Carolina State University research, the proper choice of protection equipment for preventing or replacing radiant heat loss for a particular site depends on many factors. Many of these same methods can help mitigate other potential damage conditions.

[0013] The advantages, relative costs, and operating principles of the predominant methods are summarized in Table 2 below. Advantages Disadvantages Comments

Site Selection Preventive measure— Best method of protection;

choose location with visualize airflow and/or good air drainage. monitor temperatures.

Heaters Radiant heat helpful in Fuel oil expensive. Freestanding or pipeline;

freeze; installation costs freestanding heaters need lower than irrigation; no power source.

allows delay; no risk if

rate not adequate.

Irrigation Operational cost lower Installation costs relatively Plant part protected from than heaters in freezing high; risk damage to crop if feezing by heat of fusion; conditions; can be used rate inadequate; ice buildup from heat by evaporation; for other cultural may cause limbs to break; irrigation must continue purposes such as over- watering can waterlog until conditions change; drought prevention. soils; does not provide backup power source freezing protection in wind essential.

above 5 mph.

Wind machines Can cover 10-acre area Not effective in wind above 5 Mixes warm air near top of if flat and round; mph or advective freeze. inversion down to crop installation cost similar height; may be used with to heaters. heaters; may use

helicopters.

Fog Blocks outgoing radiant Has potential but is not Uses greenhouse effect to heat and slows cooling. currently practical. trap heat in crop canopy and limit radiation cooling; difficult to erect in other than cold conditions.

Table 2. Characteristics of frost/freeze protection methods.

(Source: http://www.ces.ncsu.edu/hil/hil-705.html)

The protection most relevant for consideration of this invention is irrigation. Irrigation makes use of the change of state of water to vapor or water to ice. In warm conditions, the phase change to vapor removes 600 calories per gram of water and provides 80 calories of heat for each gram of water as it freezes. This heat removal or contribution provides some level of protection for the vegetation.

[0015] The water for this means of protection is delivered typically by a sprinkler system that is either in-place (above or below the vegetation) or can be installed as necessary. A key advantage of an irrigation system is that costs are relatively low and the systems are well understood and easily operated and maintained. These same systems can also be used for normal, i.e., non-extreme, operations like normal watering, fertilizer application and the like.

[0016] However, there are also some disadvantages if used incorrectly. Additional water may magnify certain conditions like sun exposure or increase certain bacterial or mold growth. In cold conditions the potential for more severe damage if the flow rate is insufficient. This latter case can happen if the water rate is not enough to freeze, but rather is allowed to evaporate. In this case, heat will actually be taken away from the vegetation at a rate of 600 calories per gram of water - over 7.5 times that of the heat of fusion resulting from freezing. This same phenomenon becomes advantageous during heat conditions.

[0017] The freeze-related issue can be further exacerbated in wind conditions that are above 5 miles per hour. Other disadvantages related to freezing conditions include the potential for ice build up causing breakage. Irrigation use for freezing and other conditions may also result in over-watering of the soil, which can also lead to nutrient depletion, plant and soil fungal growth, wet rot and system design related issues like flow rates.

[0018] An ideal solution would capitalize on the advantages of a low-cost irrigation based system while reducing or eliminating the disadvantages of such a system. This invention is just such a system.

[0019] Of particular interest for this invention is the ability to provide a protection barrier utilizing less water than current means aided by the high water content polymer that holds water on the vegetation surfaces rather than the majority of it falling onto the ground. This polymer may be used in a standard configuration or variants of the standard may be used to enable specific characteristics. This can be important because the ability to use a basic polymer system, even with variants, can mean fewer independent alternatives are required, handling and application can be similar and the ability to maintain a single or reduced set of stock of materials will reduce costs.

[0020] Because of the heat of evaporation during warm periods and the heat of fusion during cold conditions, effective surface water retention can have direct and immediate effects in the preservation of vegetation. Widespread applications of the invention disclosed herein can additionally help reduce or eliminate vegetation damage during such conditions.

[0021] For the purposes of this description, a high water content polymer is considered.

Such a polymer may be found in US Patent 6,201,089, but myriad other polymers, including non-synthetic polymers, may be suitable. This patent describes hydrophilic polymers with 95-99.9% water content that also allow for relatively high gas permeability. While developed for other applications, the characteristics of the polymers described are very suitable to the application of this invention. Additionally, as will be described later, the formulation of the polymer provides features that enhance the benefits beyond simple protection.

[0022] A key element of novelty of this invention is that by virtue of using a high water content polymer, a number of potential damage conditions can be addressed with a single solution core. Simple variations to the polymer or the additives do not change the baseline solution, but provide for a multi-season capability of a largely consistent baseline polymer system.

[0023] The preferred embodiment of this invention is best considered in terms of a layer of polymer on the surface of the vegetation as shown in Figure la and Figure lb (edge perspective). This layer 102, which can be varied in thickness, will conform to the plant surface 101 in order to maximize the protection of the plant. As shown in Figure la, the layer 102 is shown covering only part of the surface, but may cover any portion or all of the surface(s).

[0024] Properly hydrated, the polymer of this invention will be predominately water that, as the temperature changes, will begin to evaporate during warm conditions taking heat energy away from the vegetation or, in cold conditions, freeze thereby releasing its heat of fusion. Moreover, as the temperature changes, additional high rates of water application will not be necessary because of the retention of the water on the plant by the polymer layer. That is, the water retained on the plant by the polymer will not need to be replaced because it has dripped/run off of the plant onto the ground.

[0025] An important enhancement to these inherent capabilities of the invention is the incorporation of various means to change the characteristics for either the heat of fusion or the heat of evaporation or both by incorporating elements or monomers into the polymer compositions. These characteristic changes may include specific temperatures at which fusion or evaporation occurs or the rate at which such occurs.

[0026] The polymer of this invention can also incorporate various additives, whether in the aqueous state or as a monomer in the polymer to provide additional capabilities. Such additives may include ultra-violet (UV) blockers to provide sun protection, specific conditioners applicable to specific vegetation or other protection means.

[0027] It will be obvious that, while water is suitable for this invention and used throughout this document, other fluids or fluid mixes may be used as well. Additionally, many variables can be manipulated to gain maximum advantage for the location or specific use. Some of these variables may include thickness of the layer, format of the layer, and other enhancements. It is the inherent adhesive properties of the polymer to the vegetation and its capability to contain a high percentage of water that make the invention particularly advantageous.

[0028] In the preferred embodiment, the polymer is applied to the vegetation. Sprayed on to the vegetation, as one would consider a standard irrigation system or handheld sprayer, the polymer can be applied either dry or pre-hydrated. Alternatively, as in the case of application during immediate need like a local or approaching weather front or event, the hydrated application may be seen as a replacement for simple dousing water or other plant covering means that are applied with traditional equipment.

In the preferred embodiment, in a spray-on application, the hydrated polymer will be part of a liquid mix that may include an adhesive component. The adhesive component provides for a means to keep the polymer layer attached to the plant surface in addition to any natural adhesion found in the polymer itself. The correct mixture of polymer to adhesive can be varied depending on the target surface type, expected thickness of the polymer layer, environment and other variables. Alternatively, a layer of adhesive may be applied prior to the spray-on of the polymer as shown in Figure 2a and Figure 2b (edge perspective). In this case, polymer layer 102 is affixed to plant surface 101 with adhesive layer 203.

[0030] A variation of this embodiment is the inclusion of one or more food-safe adhesive components to eliminate the issue of digestion by humans or animals. This may not only provide useful adhesive properties, but may also enable the polymer to remain on the fruit until received by the consumer or other end user.

[0031] This can be taken even further with the inclusion of various bactericides, fungicides or other augmentations to reduce issues during harvest, transport, storage or sales. It is often during the post-harvest period that problems may arise for crops. Moreover, because of the high water content and gas transport mechanism inherent in the polymer, oxygen access to the surface and removal of outgasses from the crops are far greater than other possible solutions.

[0032] The advantage of the spray-on application is that specific vegetation surface structure does not matter. For example, the polymer will conform to any roughness of fruit, leaves, thin stems or the trunk of a larger citrus tree. Additionally, because the polymer will flow into small plant crevices, blossoms and blooms will be better protected by the insulating value and heat of fusion given off during freezing. Further, because of the inherent gas permeable nature of the polymer, natural gas intake and outtake will not be substantially degraded.

[0033] The insulating value of this invention can be enhanced by the ability for multilayer application of the polymer. This may enable for additional insulation abilities by further removing the cold surface from the fruit and allowing for a tiered, i.e., layer by layer, freezing to occur from the outside towards the inside.

[0034] The ability of multi-layer applications is further enhanced with the use of different compositions at different times in the process. For example, an initial layer may provide basic protection of the fruit simply by means of heat of fusion, but subsequent layers may provide additional protection by incorporating novel features to enhance protection performance. Such additional novel features may or may not present new considerations in the removal and handling of fruit.

[0035] Alternative means of application of the polymer are also considered in this invention. In one alternative, the polymer may be sprayed over a protective covering, e.g. a tunnel row covering, over a layer of straw or hay covering the plants, such that the beneficial water layer is present but not touching the plant surface directly. Such may be more suitable in cases that require more precise polymer thickness or other special considerations, especially for delicate vegetation that does not tolerate extreme conditions well. In the case of such a coating arrangement, adhesive may be applied prior to application or may already be integrated into one or more surfaces of the polymer holding covering. Here again, the specific implementation may guide the choice.

[0036] Yet another alternative is to integrate the polymer into existing structural elements. For example, the polymer may be applied to the surface of or integrated into the composition of various covering treatments like mesh used otherwise to dissuade birds or insects. A further advantage of such an implementation is that it allows for the use of a pre -manufactured polymer containing covering to be used as the cover to protect the plants. This cover with the polymer integrated into the structure as described herein can be wetted by standard irrigation equipment to replenish water content and/or to build a further thicker layer of ice to add heat of fusion to the protecting structure and plants.

[0037] Still another implementation of the invention is the formation of the polymer into a rollable form that is similar to other covering materials. As such, the polymer may be fully or partially hydrated or unhydrated at any time prior to installation and rolled onto the surface. As with other implementations, an adhesive may be integrated or may be added at the time of installation.

[0038] It is important to consider that a hydrated polymer may be quite fragile. Polymer fragility may be mitigated somewhat with increased thickness but may also incorporate additional means to provide structural stability. A simple example to be considered, as shown in Figure 3, is a mesh 301 around which the polymer 102 is cast. Such casting may an active part of the polymerization process or it may be post-polymerization stages and include adhesive to provide connection to the mesh. The mesh may be flexible or rigid.

[0039] Whether formed directly around a mesh or applied on a mesh, the structure provides additional benefit during periods of dehydration. One would reasonable expect a drying polymer to separate during shrinkage. With a properly designed and sized mesh, the shrinkage will take place in the mesh gaps while allowing the polymer to remain attached to the mesh. An example of this is shown in Figure 4, in which polymer 102 is affixed to mesh 401 such that any shrinkage occurs in the gaps of the mesh 401, thereby maintaining the integrity of the polymer layer upon rehydration.

[0040] Additionally, the polymer may be encapsulated in some porous layer as shown in

Figure 5. The porous layer 501 will allow for water to enter and escape the polymer 102 but will also provide for some protection of the polymer itself. The porous layer 501 may be that of a fabric material or rigid and may be on a single side or both top and bottom. It may also provide additional fire retardation capability. An advantage of this implementation is the ability for the polymer layer to be installed temporarily or moved and adjusted to fit the specific and/or changing needs. Another advantage of the polymer being encapsulated in a porous layer 501 is that it can help contain the polymer if it becomes completely dehydrated. In a case of complete dehydration, a nominally 95% water content polymer can shrink, become brittle and fracture into small pieces.

[0041] It is with possible shrinkage in mind that the selection of a flexible adhesive may be beneficial. With sufficient elasticity in the adhesive component, during dehydration the polymer remains in place and will upon rehydration return to its desired form. This capability can be enhanced by applying in a very specific manner such that the polymer is applied in the dry state and in a pattern that allows for rapid expansion upon rehydration.

[0042] In the preferred embodiment, the polymer used will have sufficient hydrophilicity that rehydration will be easily accomplished. In some high humidity areas, such rehydration may occur naturally during low-heat periods like at night. An alternative that is particularly useful during a freeze threat like a swift moving cold front or valley winds off of a mountain is to provide water to rehydrate the polymer. As shown in Figure 6, providing water 601 may be accomplished in a manner similar to that provided to agricultural plants with sprinklers, misters or trickle water systems 602. Fortunately, such a system can be tied directly into a irrigation system. The use of non-potable water, used in many locations specifically for irrigation, is readily compatible with this embodiment of this invention.

[0043] An advantage of using this invention is that any excess from application or as it is washed off or dries and falls off of the vegetation onto the ground, it will act as a super-absorbent water-retaining agent in the soil. The polymer can be incorporated into the soil either by natural means or through various ground treatment means like plowing and cultivating. As such, future irrigation of the crops will require less water as that water is being retained in the soil by action of the polymer. This is beneficial in that it further helps reduce the use of water in agriculture.

[0044] To capitalize on this additional soil enhancement feature, the polymer may incorporate one or more soil augmentations, like fertilizers, minerals, biological elements or others, such that when excess polymer is applied and goes to the ground or the polymer is washed off or dehydrates and separates from the plant, it adds missing or necessary nutrients to the soil.

[0045] The aspect of soil enhancements highlights another benefit of this invention. The polymers used herein, whether synthetic or non-synthetic, do not require the use of dangerous monomers. An example of a polymer that may be otherwise suitable for crop protection are various forms of polyacrylamides, the monomers for which are known to be toxic.

Example 1

[0046] High water content polymers are well known in patent literature and prior art.

Examples like those disclosed in US Patent 6,201,089 or variants thereof provide a baseline for this example. [0047] The selected polymer, combined with a suitable adhesive component if necessary, is hydrated as necessary for the application and application means. The level of hydration has a direct impact on the viscosity of the hydrated polymer, the specification of which may be based on several factors, but at a minimum will have to allow compatibility with application means. In this example, the application means is a spray system commonly used in the agricultural irrigation trade for applying water and other water based agricultural materials (fertilizers, pesticides, etc.) to plants.

[0048] For the sake of this example, one may consider a location that is subject to regular periods of freezing. As such, a grower may apply a layer of the polymer in anticipation of a freeze event. Using the in-place irrigation system with a suitable reservoir of polymer attached, the grower sprays the plants with the water containing the polymer.

[0049] Based on local temperature and humidity, the polymer will hold water for some period. In advance of a freezing event, the grower may spray additional water onto the previously covered plants such that rehydration of the polymer occurs. This hydrated layer will provide sufficient protection during the freeze event while eliminating the grower's need for continuous spraying during the freeze event.

Example 2

[0050] Another example use of this invention is the ability to provide sun protection for valuable fruit. Sun damage to crops can range from superficial that affects only appearance to deeper damage that can damage the actual flesh of the fruit itself. In either case, the negative economic impact is felt by the grower.

[0051] In this example, one may consider an extended period of clear skies. Not only does this usually mean little or no rain or cloud cover, but it can also mean particularly harsh sunshine on plants. Of particular interest are fruits and vegetables that are exposed directly to the sunshine and not otherwise covered by a protective husk or shell. [0052] For such an example, the polymer of this invention will incorporate ultra-violet protective measures. After being hydrated, the polymer is sprayed on the plants via the in-place irrigation system. This is particularly useful in that the irrigation spray carrying the polymer will certainly land on any exposed parts of the plants, fruits and vegetables, but will also allow the polymer to spread to other areas that may be exposed later.

[0053] While specific polymer types and embodiments are cited in this description, it will be well understood by those schooled in the art that variations are possible. Nothing in this description is to be read as limiting with respect to such potential variations. Moreover, while synthetic polymers are used for example purposes, the invention disclosed herein may be applicable to the use of naturally derived or hybrid natural/synthetic formulations.

Claims

claimed is:

A system consisting of at least one high- water content polymer applied to agricultural plants to provide protection from weather conditions.

The polymer of claim 1 in which the hydrated polymer contains at least 90% water by weight.

The polymer of claim 1 that provides for high throughput of gasses necessary for plant life.

The polymer of claim 1 in which a ultra-violet inhibitor is incorporated to provide protection from sunshine.

The polymer of claim 1 in which at least one anti-biological element is incorporated.

The anti-biological element of claim 5 that is comprised of at least one of anti- bactericide, anti-fungal, or mildewcide.

The polymer of claim 1 in which one or more additives are incorporated to modify at least one phase change points.

The polymer of claim 1 in which soil enhancing substances are incorporated into the polymer.

The soil enhancements of claim 8 that includes at least one of fertilizer, oxygenator, insecticide, anti-microbial, or similar substance.

The system of claim 1 in which the application is by a spray-on means.

The spray-on means of claim 10 that relies on an irrigation system for application.

The system of claim 1 that incorporates an adhesive element with the polymer.

The adhesive element of claim 12 that is considered food-safe.

The polymer of claim 12 in which the adhesive element is integrated into the polymer. The system of claim 1 in which multiple polymers may be applied to the agricultural plants.

The system of claim 15 in which the multiple polymers applied have at least one different characteristic.

The system of claim 15 in which the multiple polymers are applied separately.

A system consisting of a high- water content polymer applied to coverings used to protect plants from weather conditions.

The polymer of claim 18 in which the hydrated polymer contains at least 90% water by weight.

The polymer of claim 18 in which a ultra-violet inhibitor is incorporated to provide protection from sunshine.

The polymer of claim 18 in which at least one anti-biological element is incorporated.

The anti-biological element of claim 21 that is comprised of at least one of anti-bactericide, anti-fungal, or mildewcide.

The polymer of claim 18 in which one or more additives are incorporated to modify at least one phase change point.

The system of claim 18 in which the application to the covering is by a spray- on means.

The spray-on means of claim 24 that relies on an irrigation system for application.

The system of claim 18 that incorporates an adhesive element with the polymer.

The adhesive element of claim 26 that is considered food-safe.

The polymer of claim 26 in which the adhesive element is integrated into the polymer.

29. A system consisting of a high- water content polymer is integrated into a covering used to protect plants from weather conditions.

30. The polymer of claim 29 in which the hydrated polymer contains at least 90% water by weight.

31. The polymer of claim 29 in which a ultra-violet inhibitor is incorporated to provide protection from sunshine.

32. The polymer of claim 29 in which at least one anti-biological element is incorporated.

33. The anti-biological element of claim 32 that is comprised of at least one of anti-bactericide, anti-fungal, or mildewcide.

34. The system of claim 32 in which the polymer is attached to the covering.

35. The system of claim 32 in which the polymer is cast around the covering material in order to form an inherent bond.

36. The system of claim 32 in which additional polymers may be applied to the covering.

37. A system consisting of a high- water content polymer is encapsulated by a porous covering used to protect plants from weather conditions.

38. The polymer of claim 29 in which the hydrated polymer contains at least 85% water by weight.

39. The polymer of claim 29 in which at least one anti-biological element is incorporated.

40. The anti-biological element of claim 39 that is comprised of at least one of anti-bactericide, anti-fungal, or mildewcide.