Abstract
A propagation tray for growing a plurality of plug plants in bounded transplantable growing media has two spaced apart aperture plates. The plug plants are held loosely in the apertures in a top plate while retained at the apertures in the bottom plate over air cells associated with and under the apertures in the bottom plate. The air cells provide a volume into which roots from the plug plant may grow, and the air cells have at least one port for drainage and/or ventilation and toward which roots are guided to be air pruned. The propagation tray maximizes air flow around the plug for air pruning of roots, while minimizing contact of the plug with the structures on the tray to reduce the formation of root defects.
Claims
1. A propagation tray for growing a plurality of plug plants in bounded transplantable growing media, the tray comprising: (a) a top plate and a bottom plate spaced apart to provide a gap between the top and bottom plates, the top plate comprising a first array of apertures configured to receive therethrough plants in bounded transplantable growing media and to limit lateral movement of the bounded transplantable growing media in the first array of apertures, the bottom plate comprising a second array of apertures corresponding to the first array of apertures, the second array of apertures configured to retain the bounded transplantable growing media at the bottom plate proximate a bottom of the bounded transplantable growing media; (b) a plurality of air cells associated with and disposed below the second array of apertures, the bounded transplantable growing media retained at the bottom plate substantially above the air cells, each air cell comprising a wall structure defining a volume of the air cell, the wall structure comprising at least one port configured to permit drainage of water from the air cell and/or ventilation of the air cell, the air cell configured to guide root growth toward the at least one port; and, (c) at least one support configured to support the tray on a surface while providing a gap between the surface and bottoms of the wall structures of the air cells.
2. The tray according to claim 1, wherein bottoms of the bounded transplantable growing media are supported on the wall structures of the air cells.
3. The tray according to claim 1, wherein the gap between the top and bottom plates is substantially unbounded.
4. The tray according to claim 1, wherein the gap between the surface and bottoms of the wall structures of the air cells is substantially unbounded.
5. The tray according to claim 1, wherein the apertures of the first array of apertures are the same size as and concentric with the apertures of the second array of apertures.
6. The tray according to claim 1, wherein the apertures of the first array of apertures are larger than and concentric with the apertures of the second array of apertures.
7. The tray according to claim 1, wherein the wall structure comprises a conical frustum having opposed faces, one face having a larger diameter than the other face, the face having the larger diameter located where the air cell is associated with an aperture of the second array of apertures.
8. The tray according to claim 7, wherein the wall structure has an interior angle of decline in a range of about 110 to about 130.
9. The tray according to claim 1, wherein the at least one port comprises an open bottom or an opening in a bottom of the air cell.
10. The tray according to claim 1, wherein the at least one port comprises one or more side ports in the wall structure having a combined total size in a range of about 25% to about 45% of total surface area of sides of the wall structure.
11. The tray according to claim 10, wherein the one or more side ports comprises four side ports spaced equidistantly around the wall structure.
12. The tray according to claim 1, wherein the wall structure has a smooth interior surface.
13. The tray according to claim 1, wherein 82% or more of the bounded transplantable growing media supported in the tray is exposed to air.
14. The tray according to claim 1, wherein 90% or more of the bounded transplantable growing media supported in the tray is exposed to air.
15. The tray according to claim 1, wherein the at least one support comprises four legs.
16. The tray according to claim 1, wherein the at least one support comprises a base connected to the bottom plate in spaced apart relation.
17. The tray according to claim 1, wherein the top plate is separable from the bottom plate.
18. The tray according to claim 1, wherein the top plate is inseparable from the bottom plate.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) For clearer understanding, preferred embodiments will now be described in detail by way of example, with reference to the accompanying drawings, in which:
(2) FIG. 1A is an isometric view of a first embodiment of a propagation tray in accordance with the present invention;
(3) FIG. 1B is a top view of the propagation tray of FIG. 1A;
(4) FIG. 1C is an end view of the propagation tray of FIG. 1A;
(5) FIG. 1D is a side view of the propagation tray of FIG. 1A;
(6) FIG. 1E is a magnified side view of an air cell of the propagation tray of FIG. 1A;
(7) FIG. 1F is a sectional view through A-A in FIG. 1B;
(8) FIG. 1G is a magnified view of detail B in FIG. 1F;
(9) FIG. 2A is a side view of a second embodiment of a propagation tray, which is the same as the propagation tray of FIG. 1A except that each air cell comprises open-edged side ports connected at a port in a bottom of the air cell;
(10) FIG. 2B is a bottom view of an air cell of the propagation tray of FIG. 2A;
(11) FIG. 3A is an isometric view of a third embodiment of a propagation tray in accordance with the present invention;
(12) FIG. 3B is a top view of the propagation tray of FIG. 3A;
(13) FIG. 3C is an end view of the propagation tray of FIG. 3A;
(14) FIG. 3D is a side view of the propagation tray of FIG. 3A;
(15) FIG. 4A is an isometric view of a fourth embodiment of a propagation tray in accordance with the present invention;
(16) FIG. 4B is a top view of the propagation tray of FIG. 4A;
(17) FIG. 4C is a side view of the propagation tray of FIG. 4A;
(18) FIG. 4D is an isometric view of two propagation trays of FIG. 4A stacked together;
(19) FIG. 4E is a side view of FIG. 4D;
(20) FIG. 5A is an isometric view of a fifth embodiment of a propagation tray in accordance with the present invention;
(21) FIG. 5B is a top view of the propagation tray of FIG. 5A;
(22) FIG. 5C is a top isometric view of the propagation tray of FIG. 5A without a top plate;
(23) FIG. 5D is a bottom isometric view of the propagation tray of FIG. 5A without a top plate;
(24) FIG. 5E is a top view of the propagation tray of FIG. 5A without a top plate;
(25) FIG. 6 depicts graphs showing effect of tray type on root deformity dry weight of quaking aspen (FIG. 6A) and red oak (FIG. 6B) grown in a propagation tray of the present invention (RootSmart Tray) and two prior art trays (Solid-walled Tray and Porous-walled Tray), where data means are SD (n=30) and bars bearing different letters are significantly different using Dunn's multiple comparisons test at P<0.05;
(26) FIG. 7 is a graph showing effect of tray type on root dry weight (g) per total root length (cm) for quaking aspen grown in a propagation tray of the present invention (RootSmart Tray) and two prior art trays (Solid-walled Tray and Porous-walled Tray), where data means are SD (n=34) and bars bearing different letters are significantly different using Tukey's multiple comparisons test at P<0.05;
(27) FIG. 8 depicts graphs showing effects of tray type on trunk cross sectional area (TCSA) (FIG. 8A), height (FIG. 8B), leaf dry weight (FIG. 8C) and leaf area per substrate volume (FIG. 8D) for red maple seedlings grown in a propagation tray of the present invention (RootSmart Tray) and a prior art tray (Porous-walled Tray), where data means are SE (n=30), illustrating that the RootSmart Tray produced seedlings with significantly greater TCSA and height at P<0.05;
(28) FIG. 9 depicts graphs showing effects of tray type on trunk cross sectional area (TCSA) (FIG. 9A), height (FIG. 9B), leaf dry weight (FIG. 9C) and leaf area per substrate volume (FIG. 9D) for quaking aspen seedlings grown in a propagation tray of the present invention (RootSmart Tray) and a prior art tray (Porous-walled Tray), where data means are SE (n=30), illustrating that the RootSmart Tray produced seedlings with significantly greater TCSA and height at P<0.01;
(29) FIG. 10 depicts graphs showing effects of tray type on trunk cross sectional area (TCSA) (FIG. 10A), height (FIG. 10B), leaf dry weight (FIG. 10C) and leaf area per substrate volume (FIG. 10D) for red oak seedlings grown in a propagation tray of the present invention (RootSmart Tray) and a prior art tray (Porous-walled Tray), where data means are SE (n=30), illustrating that the RootSmart Tray produced seedlings with significantly greater TCSA, leaf dry weight and leaf area at P<0.0001;
(30) FIG. 11 depicts a graph showing effect of tray type on root deformity dry weight of red maple grown in a propagation tray of the present invention (RootSmart Tray) and two prior art trays (Solid-walled Tray and Porous-walled Tray), where data means are SD (n=28) and bars bearing different letters are significantly different using Dunn's multiple comparisons test at P<0.05;
(31) FIG. 12 depicts graphs showing percentages of red maple, red oak and quaking aspen seedlings with deformed roots present at the end of a growing season in a propagation tray of the present invention (RootSmart tray) and prior art trays (Solid-walled Tray and Porous-walled Tray), where striped areas within each bar indicate the average proportion of deformed root dry weight to total root dry weight among all seedlings that had deformed roots present.
(32) FIG. 13 depicts a graph showing proportion of red oak seedlings with deformed roots present at the end of a growing season in 9 different bottom plate designs of propagation trays of the present invention compared to seedlings grown in a prior art tray (Solid-walled Tray), where each bottom plate design is described by a first number referring to the angle (i.e. 110, 120 and 130) and a second number referring to percent openness of the air cells to the air (i.e. 25%, 35%, 40% and 45%), and striped areas within each bar indicate the average proportion of deformed root dry weight to total root dry weight among all seedlings with deformed roots present;
(33) FIG. 14 depicts a graph showing average proportions of deformed root dry weight to total root dry weight among all trembling aspen seedlings with deformed roots present in 9 different bottom plate designs of propagation trays of the present invention, where each bottom plate design is described by a first number referring to the angle (i.e. 110, 120 and 130) and a second number referring to percent openness of the air cells to the air (i.e. 25%, 35%, 40% and 45%), (p<0.05) using Tukey's multiple comparisons test with error bars representing 95% confidence intervals, where at a 95% confidence interval the results were not significantly different;
(34) FIG. 15 depicts a graph showing average proportions of deformed root dry weight to total root dry weight among all red oak seedlings with deformed roots present in 9 different bottom plate designs of propagation trays of the present invention, where each bottom plate design is described by a first number referring to the angle (i.e. 110, 120 and 130) and a second number referring to percent openness of the air cells to the air (i.e. 25%, 35%, 40% and 45%), (p<0.05) using Tukey's multiple comparisons test with error bars representing 95% confidence intervals; where at a 95% confidence interval the results were not significantly different;
(35) FIG. 16 depicts a graph showing average proportions of deformed root dry weight to total root dry weight among all red oak seedlings with deformed roots present in 3 different bottom plate designs of propagation trays of the present invention, where each bottom plate design is described by a first number referring to the angle (i.e. 110) and a second number referring to percent openness of the air cells to the air (i.e. 25%, 35% and 45%), and lowercase letters indicate significant differences among the designs (p<0.05) using Tukey's multiple comparisons test with error bars representing 95% confidence intervals; and,
(36) FIG. 17 depicts a graph showing average proportions of deformed root dry weight to total root dry weight among all red oak seedlings with deformed roots present in 3 different bottom plate designs of propagation trays of the present invention, where each bottom plate design is described by a first number referring to the angle (i.e. 110, 120 and 130) and a second number referring to percent openness of the air cells to the air (i.e. 40% and 45%), and lowercase letters indicate significant differences among the designs (p<0.05) using Tukey's multiple comparisons test with error bars representing 95% confidence intervals.
DETAILED DESCRIPTION
(37) With reference to FIG. 1A, FIG. 1B, FIG. 1C, FIG. 1D, FIG. 1E, FIG. 1F and FIG. 1G, a first embodiment of a propagation tray 10 comprises a top plate 11 vertically spaced apart from a bottom plate 12, the top plate 11 comprising a first 55 array of 25 apertures 13 (only one labeled) concentrically aligned with a second 55 array of 25 apertures 14 (only one labeled) in the bottom plate 12. The apertures 13 may have larger diameters than the apertures 14, which can be seen in FIG. 1B illustrating the concentric apertures 13, 14 as viewed from the top of the tray 10, although in other embodiments the apertures 13, 14 may have the same diameters. Some of the bottom plate 12 may be seen through the apertures 13 in the top plate when viewed directly from above. The top and bottom plates 11, 12 are spaced apart by a sufficient distance that EllePots (not shown) inserted though the apertures 13 in the top plate 11 are loosely held within the apertures 13 while being retained proximate bottoms of the EllePots in the apertures 14. Small amounts of the EllePots extend through the apertures 14 so that the bottoms of the EllePots are supported on inner surfaces of walls 21 of frustoconical air cells 20 (only one labeled) associated with and disposed below the apertures 14. The air cells 20 may be integrally formed with the bottom plate 12, for example by thermoforming the apertures 14 together with the air cells 20 into a sheet of plastic.
(38) The top and bottom plates 11, 12 are held spaced apart by a pair of leg assembles 30 at opposite sides of the tray 10. Each of the leg assemblies 30 comprise a pair of vertically oriented legs 31 located at corners of the tray 10 and connected together by upper and lower horizontally extending elongated frame elements 32, 33, respectively. Opposed sides of the bottom plate 12 are supported by the leg assemblies 31 in dado joints in the lower frame elements 33, while the top plate 11 resting on the upper frame elements 32 is connected to a top portion of the leg assemblies 31.
(39) As illustrated best in FIG. 1E and FIG. 1G, each of the air cells 20 comprise a frustoconical wall 21, an open top 22, and an open bottom 23, the open bottom 23 acting as a port through which water may drain and the air cell 20 may be ventilated, and at which roots growing out of the EllePots into the air cell 20 may be air pruned. To efficiently guide roots toward the open bottom 23, the frustoconical wall 21 has an interior angle of decline of e, which may be in a range of about 110 to about 130, as illustrated in FIG. 1G. The frustoconical wall 21 also comprises four equidistantly-spaced oblong side ports 24, through which water may drain and the air cell 20 may be ventilated, and at which roots growing out of the EllePots into the air cell 20 may be air pruned.
(40) The propagation tray 10 comprises four substantially open sides 16, 17, 18, 19, which provide virtually uninhibited air flow among the EllePots throughout the tray 20. Less than about 10%, for example about 2-10%, of the surface area of the EllePots is in contact with the tray 20 providing roots with the opportunity to grow substantially without defects caused by tray structure, and providing maximal air contact for air-root pruning of roots growing out of the EllePots.
(41) With reference to FIG. 2A and FIG. 2B, a second embodiment of a propagation tray 50 is the same as the propagation tray of FIG. 1A, except that frustoconical air cells 60 (only one shown) each comprise four open-edged generally rectangular side ports 64 (only one shown in FIG. 2A) equidistantly located around a frustoconical side wall 61 of the air cell 60 and connected at a bottom wall 65 surrounding a bottom port 63 of the air cell 60. The four side ports 64 wrap around a bottom edge 66 of the air cell 60 to also form ports in the bottom wall 65 of the air cell 60. A top plate 51 and a bottom plate 52 are spaced apart by a sufficient distance that EllePots 53 (only one shown) inserted though top apertures in the top plate 51 are loosely held within top apertures while being retained proximate bottoms of the EllePots 53 in corresponding bottom apertures in the bottom plate 52. Small amounts 54 of the EllePots 53 extend through the bottom apertures so that the bottoms of the EllePots 53 are supported on inner surfaces of the side walls 61 of the frustoconical air cells 60 associated with and disposed below the bottom apertures.
(42) With reference to FIG. 3A, FIG. 3B, FIG. 3C and FIG. 3D, a third embodiment of a propagation tray 100 comprises a rectangular top plate 101 vertically spaced apart from a rectangular bottom plate 102, the top plate 101 comprising a first 84 array of 32 apertures 103 (only one labeled) concentrically aligned with a second 84 array of 32 apertures 104 (only one labeled) in the bottom plate 102. Design of the plates 101, 102, the apertures 103, 104 and air cells 120 (only one labeled) are otherwise the same as in the propagation tray 10 described above, except for the way in which the tray 100 and the plates 101, 102 are supported. In the tray 100, the top and bottom plates 101, 102 are connected to each other at four corners by four struts 131, which are part of the same monolithic molded piece of material of which the bottom plate 102 is made. The top plate 101 is removably fitted, for example snap fitted, on to the struts 131 at a top of the struts 131. The bottom plate 102 is supported on a rectangular base 105 formed of four walls joined at corners 135, the base 105 and the bottom plate 102 formed in the same monolithic molded piece of material. The base 105 has a height sufficient to provide a suitable air space under the air cells 120 to permit drainage and air-root pruning at the bottoms of the air cells 120. The four walls of the base 105 each have single large apertures 106 so that at least 90% of the surface area of the four walls is open to permit air to flow freely under the bottom plate 102 and air cells 120. Likewise, at least 90% of the surface area of the sides of the tray 100 between the top plate 101 and the bottom plate 102 is open to permit air to flow freely in the gap between the plates 101, 102.
(43) With reference to FIG. 4A, FIG. 4B, FIG. 4C, FIG. 4D and FIG. 4E, a fourth embodiment of a propagation tray 200 comprises a single molded monolithic piece of plastic. The propagation tray 200 comprises a substantially square top plate 201 vertically spaced apart from a substantially square bottom plate 202 by four struts 232, one strut 232 at each corner of the propagation tray 200. The top plate 201 comprises a first 55 array of 25 apertures 203 (only one labeled) concentrically aligned with a second 55 array of 25 apertures 204 (only one labeled) in the bottom plate 202. The apertures 203 may have substantially the same diameters as the apertures 204, which can be seen in FIG. 4B illustrating the concentric apertures 203, 204 as viewed from the top of the tray 200.
(44) The top and bottom plates 201, 202 are spaced apart by a sufficient distance that EllePots (not shown) inserted though the apertures 203 in the top plate 201 are loosely held within the apertures 203 while being loosely retained proximate bottoms of the EllePots in the apertures 204. Small amounts of the EllePots extend through the apertures 204 so that the bottoms of the EllePots are supported on inner surfaces of frustoconical walls 221 of frustoconical air cells 220 (only one labeled) associated with and disposed below the apertures 204.
(45) The frustoconical air cell 220 comprises the wall 221, an open top, and an open bottom, the open bottom acting as a port through which water may drain and the air cell 220 may be ventilated, and at which roots growing out of the EllePots into the air cell 220 may be air pruned. The wall 221 also comprises four equidistantly-spaced open-edged side ports 224 (only one labelled) through which water may drain and the air cell 220 may be ventilated, and at which roots growing out of the EllePots into the air cell 220 may be air pruned. The four side ports 224 in a given air cell 220 are open spaces between four tab-like bottom portions 223 (only one labelled) of the wall 221, bottom edges of the four tab-like bottom portions 223 being unattached to each other by virtue of the bottom of the air cell 220 being open.
(46) The propagation tray 200 comprises four legs 231 depending downwardly from the four corners of the bottom plate 202. The legs 231 support the propagation tray 200 on a surface such that the bottoms of the air cells 220 are raised sufficiently above the surface to permit virtually uninhibited air flow beneath the air cells 220. The propagation tray 200 further comprises four substantially open sides 206, 207, 208, 209, which provide virtually uninhibited air flow among the EllePots throughout the tray 220. The open sides 206, 207, 208, 209 are spaces defined by outer edges of the top and bottom plates 201, 202 and the struts 232. Less than about 10%, for example about 2-10%, of the surface area of the EllePots is in contact with the tray 220 providing roots with the opportunity to grow substantially without defects caused by tray structure, and providing maximal air contact for air-root pruning of roots growing out of the EllePots.
(47) With particular reference to FIG. 4D and FIG. 4E, the propagation tray 200 is designed to be stacked in a plurality of stacked propagation trays, which for simplicity is illustrated in FIG. 4D and FIG. 4E as a stack 250 of two propagation trays, an upper tray 200a and a lower tray 200b. To facilitate stacking, the top plate 201 of the propagation tray 200 may comprise a raised perimetrical upper edge 241 within which the legs 231 of another propagation tray may be contained. As shown in FIG. 4D and FIG. 4E, the legs 231 of the upper tray 200a are supported on the top plate 201 of the lower tray 200b inside the raised perimetrical upper edge 241 of the lower tray 200b to reduce the possibility of relative lateral movement between the upper and lower trays 200a, 200b. The legs 231 of the propagation tray 200 are offset inwardly from the open sides of the propagation tray 200. The inward offset permits the legs 231 of the upper tray 200a to rest on the top plate 201 of the lower tray 200b inside the perimetrical upper edge 241 of the lower tray 200b. The height of the perimetrical upper edge 241 may be sufficient to inhibit lateral movement of the upper tray 200a on the lower tray 200b to form a stable stack 250, while permitting the trays to be stacked and deliberately unstacked without undue difficulty.
(48) With reference to FIG. 5A, FIG. 5B, FIG. 5C, FIG. 5D and FIG. 5E, a fifth embodiment of a propagation tray 300 comprises two molded pieces of plastic. One piece of the propagation tray 300 comprises a substantially square top plate 301. The other piece of the propagation tray 300 comprises a substantially square bottom plate 302 with four vertically extending struts 332, one strut 332 at each corner of the bottom plate 302. The struts 332 support a raised perimetrical upper edge 341 on which the top plate 301 may be supported to be vertically spaced apart from bottom plate 302. The top plate 301 comprises four inwardly extending raised lips 349 at each of the corners of the top plate 301, which provide raised surfaces on which a grower may conveniently grip the top plate 301 to lift the top plate 301 off the upper edge 341 or lower the top plate 301 on to the upper edge 341. In this manner, the top plate 301 may be separable from the bottom plate 302 to facilitate loading and unloading of EllePots (not shown) in the tray 300.
(49) The top plate 301 comprises a first 55 array of 25 apertures 303 (only one labeled) concentrically aligned with a second 55 array of 25 apertures 304 (only one labeled) in the bottom plate 302 when the top plate 301 is supported on the upper edge 341. The apertures 303 may have substantially the same diameters as the apertures 304, which can be seen in FIG. 5B illustrating the concentric apertures 303, 304 as viewed from the top of the tray 300.
(50) The top and bottom plates 301, 302 are spaced apart by a sufficient distance that EllePots inserted though the apertures 303 in the top plate 301 are loosely held within the apertures 303 while being loosely retained proximate bottoms of the EllePots in the apertures 304. Small amounts of the EllePots extend through the apertures 304 so that the bottoms of the EllePots are supported on inner surfaces of four downwardly extending tabs 323 (only one labeled) which form wall-like structures of frustoconical air cells 320 (only one labeled) associated with and disposed below the apertures 304.
(51) The frustoconical air cell 320 comprises the tabs 323, an open top, and an open bottom, the open bottom acting as a port through which water may drain and the air cell 320 may be ventilated, and at which roots growing out of the EllePots into the air cell 320 may be air pruned. The four tabs 323 of one air cell 320 are separated by four equidistantly-spaced open-edged side ports 324 (only one labelled) through which water may drain and the air cell 320 may be ventilated, and at which roots growing out of the EllePots into the air cell 320 may be air pruned. The four side ports 324 in a given air cell 320 are open spaces between the four tabs 323, bottom edges of the four tabs 323 being unattached to each other by virtue of the bottom of the air cell 320 being open.
(52) The propagation tray 300 comprises four legs 331 depending downwardly from the four corners of the bottom plate 302. The legs 331 support the propagation tray 300 on a surface such that the bottoms of the air cells 320 are raised sufficiently above the surface to permit virtually uninhibited air flow beneath the air cells 320. The propagation tray 300 further comprises four substantially open sides 306, 307, 308, 309, which provide virtually uninhibited air flow among the EllePots throughout the tray 320. The open sides 306, 307, 308, 309 are spaces defined by outer edge of the bottom plate 302, the perimetrical upper edge 341 and the struts 332. Less than about 18%, for example about 10-16%, of the surface area of the EllePots is in contact with the tray 320 providing roots with the opportunity to grow substantially without defects caused by tray structure, and providing maximal air contact for air-root pruning of roots growing out of the EllePots.
(53) The bottom plate 302 is further provided with irrigation holes 345 (only one labeled) situated between the apertures 304 holding the EllePots, which permit drainage of water from through the bottom plate 302 to both irrigate the regions around air cells 320 and reduce pooling of water on the bottom plate 302. Furthermore, as best seen in FIG. 5D, an underside of the bottom plate 302 comprises integrally molded longitudinal and transverse ribs 347 (one longitudinal rib labeled and one transverse rib labeled) that provide structural strength to reduce deformation (e.g. bowing) of the bottom plate 302 due to the weight of the EllePots. The ribs 347 are situated between the air cells 320 and have a sufficiently thin and narrow profile to prevent contact with or otherwise interfere with the air cells 320 or the EllePots in the air cells 320.
(54) A plurality of propagation trays 300 may be stacked in a manner similar to the propagation tray 200 described above.
(55) The effect of a propagation tray of the present invention (RootSmart Tray) on various growing parameters of various species of woody perennials was compared to the effect of commercially available propagations trays (Solid-walled Tray and Porous-walled Tray). FIG. 6, FIG. 7, FIG. 8, FIG. 9 and FIG. 10 are graphs depicting the results.
(56) FIG. 6A, FIG. 6B and FIG. 11 show the effect on root deformation. FIG. 6A, FIG. 6B and FIG. 11 reveal that the propagation tray of the present invention (RootSmart Tray) significantly reduces root deformities in three commercially relevant species that present production challenges, quaking aspen (Populus tremuloides), red oak (Quercus rubra) and red maple (Acer rubrum). The Solid-walled Tray possesses no air-root pruning features (i.e. the substrate is in direct contact with the cell walls on all sides), whereas the Porous-walled Tray is designed for minimal contact between the substrate and the container but has four vertical structures in the cells. With respect to the Porous-walled tray, where the vertical structures are present and the growing media makes contact with plastic of the tray, root deflections occur and root deformities develop. The root dry weights of the quaking aspen and red maple seedlings grown in the RootSmart Tray of the present invention were significantly less with respect to root deformations that developed than the root dry weight grown in the Solid-walled Tray. The root dry weight of the red oak seedlings grown in the RootSmart Tray of the present invention was significantly less with respect to root deformations that developed than the root dry weight grown in the Solid-walled Tray and the Porous-walled Tray.
(57) FIG. 7 shows the effect on root dry weight (g) per total root length (cm). The RootSmart Tray also demonstrated significantly greater root dry weight to root length ratio for quaking aspen compared to the Solid-walled Tray. This is particularly important for a species like quaking aspen that is notoriously challenging to grow because of the vigor of the root systems, which can quickly outgrow the plug volumes resulting in diving or circling roots. As indicated in FIG. 7, root dry weight of the seedlings in the RootSmart Tray were the most balanced in terms of root architecture when compared to the Solid-walled Tray which had long thin roots that dive to the bottom of the container.
(58) The propagation tray of the present invention also outperformed an air-pruning tray that was identified as the best tree seedling plug tray commercially available in terms of above-ground growth parameters, i.e. the Porous-walled Tray, (FIG. 8, FIG. 9 and FIG. 10). The growth parameters are presented as by-volume because the substrate volume of the commercial tray (Porous-walled Tray) is significantly more than the substrate volume of the tray of the present invention (RootSmart Tray). Red maple seedlings grown in the RootSmart Tray performed significantly better with respect to TCSA and height (FIG. 8B). Quaking aspen seedlings grown in the RootSmart Tray performed significantly better with respect to trunk cross sectional area (TCSA) (FIG. 9A), height (FIG. 9B) and leaf area (FIG. 9D). Red oak seedlings grown in the RootSmart Tray performed significantly better with respect to TCSA (FIG. 10A), leaf dry weight (FIG. 10C) and leaf surface area (FIG. 10D).
(59) FIG. 12 depicts the percentages of red maple, red oak and quaking aspen seedlings that were found to have root deformities present, and of those seedlings, what proportion of root dry weight was deformed. Statistical analysis revealed that the RootSmart Tray had significantly fewer defects than the Solid-walled tray for red maple and quaking aspen, and significantly fewer defects than both the Solid-walled Tray and Porous-walled Tray for red oak.
(60) FIG. 13, FIG. 14, FIG. 15, FIG. 16 and FIG. 17 show the results of tests involving propagation trays of the present invention comprising bottom plates having air cells designed with three different angles (110, 120 and 130) and four different levels of openness (25%, 35%, 40% and 45%) in order to determine the best combination that would reduce root deflections at the base of Ellepots. Statistical analysis compared the tray types with equivalent angles (110), but varying levels of openness (25%, 35% and 45%), in addition to similar levels of openness (40% and 45%) and varying angles (110, 120 and 130). A RootSmart Tray in which the air cells have an angle of about 110 and an openness of about 45% resulted in the least amount of root deformities in red oak seedlings when compared against air cells with similar openness, as well as with similar angles, at a 95% confidence interval. However, when compared against all other air cells, results were not significantly different at a 95% confidence interval.
(61) It is apparent from these experiments that the propagation tray of the present invention provides significantly better results than commercially successful propagation trays of the prior art.
(62) The novel features will become apparent to those of skill in the art upon examination of the description. It should be understood, however, that the scope of the claims should not be limited by the embodiments, but should be given the broadest interpretation consistent with the wording of the claims and the specification as a whole.
