WO2021002806A1

WO2021002806A1 - Plant growth structure

Info

Publication number: WO2021002806A1
Application number: PCT/SG2020/050381
Authority: WO
Inventors: Tao Xu; Hao Yu; Shengjie BAO
Original assignee: National University Of Singapore
Priority date: 2019-07-03
Filing date: 2020-07-03
Publication date: 2021-01-07

Abstract

Disclosed is a plant growth structure for growing a plant. The plant growth structure comprises a cultivation structure in which the plant is grown, a light source for at least partially illuminating the cultivation structure, and a support 5 frame for supporting the light source at a position relative to the cultivation structure. At least one of the light source and cultivation structure is movably mounted to the support structure to permit relative movement between the light source and cultivation structure, so that the position is adjustable to induce growth of the plant. 10 [Figure 1]

Description

PLANT GROWTH STRUCTURE

Technical Field The present invention relates, in general terms, to a plant growth structure for growing a plant or plants. Embodiments of the present invention relate to plant growth structures that can be used in hydroponic systems.

Background

In general, plants are suited to particular soil types. Traditional strawberry growth, for example, is highly dependent on soil and is limited to growth in temperate geographical regions. Other plants, such as beans, tomatoes and leafy vegetables are similarly pre-disposed to better growth in a particular environment.

Some plants, such as strawberries, are perennial herbs. Since perennial herbs with naturally weather variations in seasons, it can be difficult to promote growth during colder months and to protect plants from excessive sunlight during warmer months.

Strawberries, for example, have high nutritional value, rich flavour and high economic efficiency. However, strawberry cultivation methods are mainly open- air planting and greenhouse cultivation. These methods have poor growth environment controllability, and are often limited to application in temperate regions.

Additionally, traditional strawberry growth methods are highly dependent on land resources. Planting requires a flat surface and a higher terrain than the surrounding area - i.e. strawberries are grown in a peak with a trough on either side, to promote drainage. Cropping in general will, over years, reduce soil fertility and increase pests and diseases. These changes can result in excessive use of pesticides and fertilizers which effect the safety and quality of crops, such as strawberries. Moreover, as strawberry plants are short plants that grow close to ground and rely on stolons for reproduction, planting height and density are typically low. This limits the ability to mechanize and automate strawberry planting.

It would be desirable to overcome or ameliorate at least one of the above- described problems, or at least to provide a useful alternative.

Summary

The present invention provides a plant growth structure for growing a plant, comprising:

a cultivation structure in which the plant is grown;

a lighting device for at least partially illuminating the cultivation structure; and

a support frame for supporting the lighting device at a position relative to the cultivation structure,

wherein at least one of the lighting device and cultivation structure is movably mounted to the support structure to permit relative movement between the lighting device and cultivation structure, so that the position is adjustable to induce growth of the plant. The cultivation structure may be pivotally mounted to the support frame.

The cultivation structure may be moveable along the frame to vary a distance between the lighting device and cultivation structure. The plant growth structure may comprise at least two cultivation structures mounted in spaced relation along the support frame. The plant growth structure may also comprise at least one light source for each cultivation structure, each light source being positioned on the support frame to illuminate a respective one of the cultivation structures.

The cultivation structure may have a cuboid or rectangular volume. The cultivation structure may comprise two plant growth regions separated by an edge, the edge being positioned relative to the lighting device so that light falls on both plant growth regions. Each of the two plant growth regions may be adapted to receive and grow one or more respective plants. The lighting device may be pivotally mounted to the support frame.

The cultivation structure may be moveable along the frame to vary a distance between the lighting device and cultivation structure. The lighting device may be located above the cultivation structure, and is offset to one side.

The relative position of the lighting device and cultivation structure may be adjustable to match a development stage of the plant.

The relative position of the lighting device and cultivation structure may be adjustable to induce a desired growth orientation of the plant. The relative position of the lighting device and cultivation structure may be adjustable to promote growth of fruit by the plant in at an optimum position for harvesting.

The lighting device may comprise a plurality of light sources for illuminating respective regions of the cultivation structure.

The plant growth structure may further comprise an irrigation system. The irrigation system may be a drip irrigation system. The cultivation structure may comprise a drainage port and is mounted so that liquid fed into the cultivation structure from the irrigation system drains towards the drainage port. The cultivation structure may have a longitudinal extent and be tilted along the longitudinal extent, the drainage port being located at a lowermost position of the longitudinal extent. The drainage port may be connected to a reservoir for feeding the irrigation system.

Some embodiments of the present invention provide a specially designed hydroponic structure to reduce soil dependence and labour intensity as well as the reliance on growth in temperate regions. In some embodiments, the plant growth structure or structural unit is one in which the lighting device includes an upper-inclined-side-placed light, the cultivation structure includes cultivation grooves with an inclined angle (e.g. inclined along a longitudinal extent of the cultivation structure), a support frame or support structure, and a dripping irrigation system. In such embodiments, the plant growth structure can effectively induce the upward growth of the plant - e.g. the upward growth of strawberry leaves - and separate fruits from leaves. The integrated design is beneficial for growth environment control for small scale growth and for easy assembly and stacking for large scale growth.

Therefore, embodiments of the present invention provide a specially designed hydroponic setup that can increase planting density and that is upgradable for automatic fruit harvesting.

Embodiments of the present invention are not soil dependent. This reduces the dependence on land requirements and availability, and can effectively reduce the amount of pesticides. For example, pests that would otherwise be borne in soil, or traverse soil to gain access to plants, would effectively be prevented from accessing plant growth in plant growth structures according to embodiments taught herein.

The size of the plant growth structure is small. It is also easy to expand to suit large scale applications and for reasonably high-density planting. The small size also improves growth environment controllability and convenience for promoting use in tropical and other latitude areas - e.g. areas outside those that are considered temperate and naturally suitable for growth of the plant. The inclined cultivation trough and external light source can effectively induce the upward growth of the strawberry leaves and the separation of the fruits from the leaves, thereby facilitating daily management, reducing labor intensity, and providing conditions for automation.

The present invention can used for the large-scale cultivation of strawberry or other plants in hydroponic manner. Brief description of the drawings

Embodiments of the present invention will now be described, by way of non limiting example, with reference to the drawings in which : Figure 1 is a top perspective view of a plant growth structure according to an embodiment of the invention;

Figure 2 is a front view of the plant growth structure of Figure 1;

Figure 3 is a side view of the plant growth structure of Figure 1;

Figure 4 is a partial side view of a cultivation structure and irrigation system ;

Figure 5 is a cross-section view of an alternative embodiment of a cultivation structure; and

Figure 6 is an embodiment of a mounting structure for connecting, for example, the lighting device, cultivation structure and/or irrigation system to the support frame.

Detailed description

The plant growth structures described herein can be used for the cultivation of plants such a strawberry plants, beans, tomatoes, leafy vegetables, others. While the description will be generally cast towards strawberry plant cultivation for the purpose of illustration, the skilled person will understand from the present teachings that the same structure may be employed for the cultivation of other plant varieties.

Figure 1 provides a plant growth structure 100, for growing a plant. The plant growth structure 100 comprises a cultivation structure 102 in which the plant is grown, a lighting device 104 and a support frame 106. The lighting device 104 at least partially illuminates the cultivation structure 102 - for example, the lighting device 104 may be configured to eliminate one end of the cultivation structure 102, or a particular plant on the cultivation structure 102, or the entirety of the cultivation structure 102. The support frame 106 supports the lighting device 104 at a position relative to the cultivation structure 102, to facilitate elimination of the cultivation structure 102 by the lighting device 104.

To induce plant growth, the lighting direction and/or intensity should be adjusted to ensure that it is optimal for the particular type of plant being grown in the plant growth structure 100. In the present embodiments, the lighting device 104 is positioned above and to one side of the cultivation structure 102 (i.e. is offset to one side). Some plants will naturally grow towards the light source of lighting device 104. By placing the lighting device 104 above and to one side of the cultivation structure 102, plants growing in the cultivation structure 102 are encouraged to grow over one side of the cultivation structure 102. In so doing, the fruit borne by those plants is readily accessible for harvesting - e.g. automatic harvesting. To meet the above need, at least one, and in some cases both, of the lighting device 104 and the cultivation structure 102 is movably mounted to the support structure 106 to permit relative movement between the lighting device 104 and the cultivation structure 102. Thus the relative position of the cultivation structure 102 and lighting device 104 can be adjusted to induce plant growth (e.g. plant growth to one side of cultivation structure 102, to facilitate harvesting). The structure or plant growth structure 100 has a unified structural unit comprising support frame 106. The unified structural unit, or support frame 106, can be expanded or duplicated on a large scale from horizontal and vertical. The present support frame 106 is substantially U-shaped, comprising a base 108 and upright support posts 110 at each longitudinally opposite end of the base 108. There may be one or more, and presently there are three, upright support posts 110 at each end of the base 108.

The cultivation structure 102 and lighting device 104 are designed either to fit wholly within the volume 112 of the support frame 106, during use, or to have a length Li that is at most equal to, or just less than, a length L₂ between inwardly facing side 114 of the support posts 110 such that the cultivation structure 102 and lighting device 104 fit between the support posts of a neighbouring, similarly assembled, plant growth structure.

To facilitate stacking, the support frame 106 may have a protrusion or recess on an underside of the base 108 to facilitate engagement with an upper end 116 of a neighbouring, lower support frame in the stack. Alternatively, a plate similar to base 108 may be positioned across the tops of the upper ends 116 of the support frame 106, and be secured by known means (e.g. nut and bolt) to the base of a neighbouring, upper support frame in the stack.

The cultivation structure 102 is tilted. In fact, with concurrent reference to Figures 1 and 4, the cultivation structure 102 is tilted both laterally (Figure 1) and longitudinally (Figure 4 - as indicated by tilt angle a). To facilitate lateral tilt, the cultivation structure 102 is pivotally mounted to the support frame 106. That tilt may be achieved by either providing a cultivation structure 102 with a fixed tilt angle, such that when the cultivation structure 102 is attached to the support frame 106 it will have the fixed tilt angle. This may be achieved by flexible mounts 162. The mounts 162 may comprise a runner, such as runner 126 (see Figure 6), fixed at each opposite end of cultivation structure 102. The runner can then be received in track 124 (see Figure 1) and bolted to the support frame 106 by inserting a bolt through aperture 128. Alternatively, the cultivation structure 102 may be pivotally mounted to the support frame 106. To achieve this, the cultivation structure 102 may comprise an aperture plate 130 (see Figure 6) that is bolted, at any desired tilt angle (about a longitudinal axis X of the cultivation structure 102), to a runner 126 that is in track 124 of the support frame 106. The skilled person will appreciate that many other attachment or mounting systems may be used, all of which are intended to fall within the scope of the present disclosure. The cultivation structure 102 is also moveable along the frame 106 to vary a distance between the lighting device 104 and cultivation structure 102. This can again be achieved by the runner and track mechanism described with reference to Figures 1 and 5, by positioning the runner 126 in the track 124 at the desired distance from lighting device 104.

The cultivation structure 102 may also be tilted (i.e. have an inclined angle) about a lateral axis Y. This can facilitate drainage, as discussed below. To facilitate the tilting, the cultivation structure 102 may be fabricated with a tilt. Alternatively, cultivation structure 102 may be mounted to the support frame 106 by any hinged mechanism, such as hinge 134 shown in Figure 6.

The cultivation structure or tank 102 can therefore fix to or rotate or pivot around the mount or linker (as shown in Figure 6) to fix the cultivation structure 102 in any desired orientation. This can include the ability to be continuously position the cultivation structure 102 across a range of movement, or at discrete positions with the range of movement - e.g. tracks 124 may have pre-drilled bolt holes to which the runner 126 may attach.

The cultivation tank or cultivation structure 102 may have any suitable shape. For example, the cultivation tank 102 may form a cuboid, rectangular prismatic or cylindrical volume or concerns as a tank, with the two holders or mounts (e.g. as shown in Figure 6) at opposite ends thereof. The culture substrate is filled into the container to support the plant growth. Alternatively, the cultivation structure may comprise a frame for retaining or supporting a plant growth mat or fabric. A plant growth structure according to any preceding statement, comprising at least two cultivation structures mounted in spaced relation along the support frame.

The cultivation structure 102 may be one of a plurality of cultivation structures - e.g. two cultivation structures - mounted in spaced relation along the support frame 106. Where the support frame 106 extends vertically, the cultivation structures may be spaced vertically from one another - e.g. the tracks 124 may not be limited to accepting only one runner at a time. The plant growth structure 100 may similarly include the single lighting device 104 for more than one cultivation structure 102, or one or more light sources or devices 104 for each cultivation structure 102, each light source or device 104 being positioned on the support frame 106 to illuminate a respective one of the cultivation structures 102. In one embodiment, each layer (of a stack of structures 100) or each structure 100 can symmetrically hold two cultivation structures 102. The number of layers is determined by the planting needs. For example, there may be two or more cultivation structures 102 supported by the support frame 106

- in other embodiments, there may be more than two cultivation structures 102 in each frame 106. Advantageously, the distance between the cultivation structure 102 and the side placement light device 104 can be easily adjusted to fit the growth of the plant

- e.g. by shifting one of the light device 104 and cultivation structure 102 along respective supports 110 such that the distance is shorter when the plant is small and greater as the plant grows.

Advantageously, in embodiments where the cultivation structure 102 includes, or is, a tank or volume, each tank may be large - e.g. 1.5x0.1x0.1 meters. Each tank contains a drain port or hole 138 at the bottom in the lower side, as shown in Figure 4, for cycling of the water. With further reference to Figure 4, the cultivation structure 102 has a longitudinal extent and is tilted along the longitudinal extent (about axis Y) with the drainage port 138 being located at a lowermost position of the longitudinal extent. Liquid fed into the cultivation structure from the irrigation system, discussed below, drains towards the drainage port. To reuse the liquid, the drainage port may be connected to a reservoir (not shown) for feeding the irrigation system.

With reference to the rectangular cross-section cultivation structure 102 of Figure 1, each cultivation structure 102 will generally include only one growth region. However, a cultivation structure, such as cultivation structure 103, shown in cross-section in Figure 5, may include two plant growth regions separated by an edge. With reference to Figure 5, the cultivation structure 103 is divided into two plant growth regions 142, 144 by wall 146 having top edge 148.

Cultivation structure 103 has been shown with a similar overall rectangular crosds-section to that of cultivation structure 102, to make evident that it can be attached to a frame in the same manner. The growth regions 142, 144 thus each have a triangular cross-section. However, it will be understood the cross- section of any particular cultivation structure may be selected to suit a particular plant, root structure, growth direction, frame construction, and number of growth regions (i.e. one or more growth regions). When disposed in a frame, the edge 148 can therefore be positioned relative to the lighting device so that light from the lighting device falls on both plant growth regions 142, 144. For example, the cultivation structure 103 may be oriented such that wall 146 extends from bottom walls 152 towards a lighting device or light source. Thus, plants can be grown independently in each of the growth regions 142, 144 while being illuminated by the same light source.

The wall 146 may extend all the way down to bottom walls 152 two entirely separate growth region 142 from growth region 144, or may only extend part way down - e.g. to level 150 - such that growth regions 142, 144 can share the same cultivation medium (e.g. soil). As such, the two plant growth regions 142, 144 can be adapted to receive and grow one or more respective plants, of the same type or of different types.

The lighting device or light source structure 104 of the structural unit 100 can facilitate side placement of light source 118. For example, the light source 118 of the lighting device 104 may be positioned closer to one side 120 of the lighting device 104 than the other side 122. The lighting device 104 may alternatively, or in addition, connect to an upright support post 110 that is not centrally disposed (see Figure 1) and thereby be placed to one side of a cultivation structure 102 mounted to a central, or more central, support post 110.

Advantageously, the light source 118 and/or the cultivation tank or cultivation structure 102 are rotated along respective axes Y, Q to ensure the relative angles thereof are adjusted to match different development stages of the plants being cultivated. The positioning of the light source at an angle means plants growing towards the light source may naturally position fruit towards or past the edge of the cultivation structure, thereby facilitating manual or automated harvesting. In addition, the cultivation structure and/or lighting device may be moveable along the support frame to vary the distance between the lighting device and cultivation structure - thus lighting conditions optimum for growth for the particular stage of development of the plant, or desired growth orientation (particularly given the pivotal mounting of the lighting device and/or cultivation structure), can be achieved.

The lighting device 104 may hold a single light source 118 or may be extended, in a known matter in view of present teachings, to hold two or more light sources in order to better cover the plant growing underneath, to illuminate different portions of the cultivation structure 102, or to provide different lighting conditions for different plants. The lighting device 104 may thus comprise a plurality of light sources for illuminating respective regions of the cultivation structure 102. The lighting device 104 may be mounted to the support frame 106 by the same mounting structure (e.g. that shown in Figure 6) as described above in relation to the cultivation structure 102, including all variations of that mounting structure. That mounting structure is generally designated by reference 160. The lighting device 104 can be fixed in position on the support structure or support frame 106 or rotate or pivot around the linker (i.e. runner 136 or assembly 154) between support frame 106. The orientation of the lighting device 104 may be adjusted to match that of the cultivation structure 102 such that the two are in parallel. Alternatively, they may have different orientations. The relative position of the lighting device 104 and cultivation structure 102 is therefore adjustable to promote growth in a desired growth direction, to match the growth stage of the plant or to promote growth of fruit by the plant in at an optimum position for harvesting.

To transfer water and nutrients and irrigation system 156 is provided. The irrigation system 156 is a drip irrigation system. The drippers (one of which is indicated by reference numeral 158) links to the drip irrigation system pipe 160, and are placed near each plant root to convey water and/or nutrients to the vicinity of the roots. Water and/or nutrients are delivered to pipe 160 from a reservoir, in a known manner, connected to extension 162. The drip irrigation pipes 160 are fixed relative to the cultivation structure 102 - e.g. by being attached directly to the cultivation structure 102 in a known manner - or the support frame 106 - e.g. the irrigation system 156 may be attached by runners, such as runners 136 of Figure 6, to the upright posts 110. With further reference to Figure 4, the cultivation structure 102 is mounted so that liquid fed into the cultivation structure 102 from the irrigation system 156 will drain towards the drainage port 138. The cultivation structure 102 is tilted along its longitudinal extent (i.e. direction of axis X-X) such that the drainage port 138 is at the lowermost position of the longitudinal extent of the cultivation structure 102. Liquid delivered from the irrigation system 156 into the higher end of the cultivation structure 102 will therefore naturally drain towards drainage port 138. Liquid collected at the drainage port 138 may be recycled by delivering that liquid back to the reservoir that feeds the irrigation system 156.

It will be appreciated that many further modifications and permutations of various aspects of the described embodiments are possible. Accordingly, the described aspects are intended to embrace all such alterations, modifications, and variations that fall within the spirit and scope of the appended claims or statements.

Throughout this specification and the claims or statements which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Claims

1. A plant growth structure for growing a plant, comprising:

a cultivation structure in which the plant is grown;

wherein at least one of the lighting device and cultivation structure is movably mounted to the support structure to permit relative movement between the lighting device and cultivation structure, so that the position is adjustable to induce growth of the plant.

2. A plant growth structure according to claim 1, wherein the cultivation structure is pivotally mounted to the support frame.

3. A plant growth structure according to claim 1 or 2, wherein the cultivation structure is moveable along the frame to vary a distance between the lighting device and cultivation structure.

4. A plant growth structure according to any preceding claim, comprising at least two cultivation structures mounted in spaced relation along the support frame.

5. A plant growth structure according to any preceding claim, wherein the cultivation structure comprises a cuboid, rectangular prismatic or cylindrical volume.

6. A plant growth structure according to claim 5, wherein the cultivation structure comprises two plant growth regions separated by an edge, the edge being positioned relative to the lighting device so that light falls on both plant growth regions.

7. A plant growth structure according to claim 6, wherein each of the two plant growth regions is adapted to receive and grow one or more respective plants.

8. A plant growth structure according to any preceding claim, wherein the lighting device is pivotally mounted to the support frame.

9. A plant growth structure according to any preceding claim, wherein the lighting device is located above the cultivation structure, and is offset to one side.

10. A plant growth structure according to any preceding claim, wherein the relative position of the lighting device and cultivation structure is adjustable to match a development stage of the plant.

11. A plant growth structure according to any preceding claim, wherein the relative position of the lighting device and cultivation structure is adjustable to induce a desired growth orientation of the plant.

12. A plant growth structure according to claim 11, wherein the relative position of the lighting device and cultivation structure is adjustable to promote growth of fruit by the plant in at an optimum position for harvesting.

13. A plant growth structure according to any preceding claim, wherein the lighting device comprises a plurality of light sources for illuminating respective regions of the cultivation structure.

14. A plant growth structure according to claim 4, further comprising at least one light source for each cultivation structure, each light source being positioned on the support frame to illuminate a respective one of the cultivation structures.

15. A plant growth structure according to any preceding claim, further comprising an irrigation system.

16. A plant growth structure according to claim 15, wherein the irrigation system is a drip irrigation system.

17. A plant growth structure according to claim 15 or 16, wherein the cultivation structure comprises a drainage port and is mounted so that liquid fed into the cultivation structure from the irrigation system drains towards the drainage port.

18. A plant growth structure according to claim 17, wherein the cultivation structure has a longitudinal extent and is tilted along the longitudinal extent, the drainage port being located at a lowermost position of the longitudinal extent.

19. A plant growth structure according to claim 17 or 18, wherein the drainage port is connected to a reservoir for feeding the irrigation system.