1. A tri-layer biodegradable weed-suppressive mat (100) configured to support direct seeding of aerobic rice onto the soil, the mat (100) comprising: a top layer (102) comprises a perforated hydrophilic biodegradable polymer substrate (108) inoculated with at least one ligninolytic fungus (110) capable of forming a surface-colonizing biofilm that blocks light penetration, and biologically competes with germinating weeds; a middle layer (104) comprising plant-derived biochar (112) impregnated with standardized natural allelopathic extracts (114) configured for controlled release of phenolic compounds that inhibit weed germination without causing rice phytotoxicity; and a bottom layer (106) comprising a biodegradable matrix (116) containing organic acid buffer (118) configured to generate a temporary acidic micro-zone at the soil surface to selectively suppress small-seeded weeds during early establishment.

2. The mat (100) as claimed in claim 1, wherein the biodegradable polymer substrate (108) comprises bacterial cellulose, polylactic acid (PLA), starch-based biopolymer, or combinations thereof.

3. The mat (100) as claimed in claim 1, wherein the allelopathic extract (114) is derived from sorghum, azolla, or other phenolic-rich plant sources.

4. The mat (100) as claimed in claim 1, wherein the ligninolytic fungus (110) is selected from white-rot fungi.

5. The mat (100) as claimed in claim 1, wherein the fungus (110) is selected from Phanerochaete chrysosporium or Trametes versicolor.

6. The mat (100) as claimed in claim 1, wherein perforations comprise 1–5 mm diameter openings spaced to allow rice coleoptile emergence while maintaining at least 70% surface shading.

7. The mat (100) as claimed in claim 1, wherein the organic-acid buffer (118) comprises calcium citrate, magnesium lactate, malic acid, or combinations thereof.

8. The mat (100) as claimed in claim 1, wherein the buffer (118) layer maintains soil-surface pH between 5.4–5.8 for 10–14 days.

9. The mat (100) as claimed in claim 1, wherein the surface-colonizing biofilm colonizes the upper 1–5 mm of soil surface forming a competitive microbial barrier against weed seedlings.

10. A method (300) of suppressing weeds in aerobic rice cultivation, comprising: sowing rice seeds in soil at a depth of approximately 15–25 mm; installing a biodegradable tri-layer myco-allelopathic biofilm mat (100) over the soil surface immediately after sowing; irrigating the field to activate a fungal biofilm layer and an organic-acid buffer layer of the mat (100); suppressing weed germination during a critical early growth period of 0–21 days through combined physical light interception, biological competition, biochemical allelopathic release, and temporary surface pH modification; permitting rice seedlings to emerge through perforations formed in the mat (100); and allowing the mat (100) to biodegrade naturally within approximately 30–40 days after sowing.

Description:FIELD OF DISCLOSURE
[0001] The present disclosure generally relates to purification system, more specifically, relates to tri-layer biodegradable weed-suppressive mat and method thereof based on integrated physical shading, fungal biofilm-mediated biological suppression, biochar-enabled controlled allelopathic release, and temporary pH modulation for weed control in aerobic rice cultivation.
BACKGROUND OF THE DISCLOSURE
[0002] Rice cultivation is increasingly shifting toward aerobic production systems due to water scarcity, rising irrigation costs, and the need for climate-resilient agricultural practices. Unlike conventional flooded rice systems, aerobic rice is grown in non-puddled, well-drained soils without continuous standing water. While this approach significantly reduces water consumption, it creates favorable conditions for aggressive weed proliferation. In the absence of water submergence, weeds emerge simultaneously with rice seedlings and compete intensely for light, nutrients, moisture, and space during the early growth stages.
[0003] Weed competition during the first 2–3 weeks after sowing is particularly critical in aerobic rice systems, often resulting in severe yield losses if not effectively controlled. Farmers primarily rely on pre- and post-emergence herbicides for weed management. However, increasing herbicide resistance, environmental concerns, regulatory restrictions, soil health degradation, and rising chemical input costs have reduced the long-term sustainability of chemical-based solutions. Mechanical weeding methods, while effective to some extent, are labor-intensive, time-consuming, and often impractical during early crop establishment.
[0004] Current weed management practices rely predominantly on chemical herbicides, including pre-emergence and early post-emergence formulations. Although these herbicides can provide short-term control, their effectiveness depends heavily on precise timing, soil moisture conditions, and correct application rates. Repeated and prolonged use has led to the emergence of herbicide-resistant weed biotypes, increased production costs, environmental contamination, and growing regulatory restrictions. Additionally, concerns regarding chemical residues, soil health degradation, and impacts on non-target organisms have raised sustainability issues associated with long-term herbicide dependence.
[0005] Mechanical and manual weeding methods offer alternative control strategies but are labor-intensive, time-consuming, and often impractical during early crop establishment. In dry aerobic soils, mechanical weeders may be less effective due to soil hardness and uneven weed emergence patterns. Physical mulching materials, such as rice straw or plastic films, provide partial light exclusion but lack selectivity, potentially interfering with rice seedling emergence and creating disposal or pest-related concerns. Moreover, these approaches do not integrate biological or biochemical suppression mechanisms and therefore fail to provide synchronized, depth-selective, and time-bound weed control.
[0006] In view of these limitations, there exists a need for a weed management system specifically engineered for aerobic rice ecosystems. Such a system must function immediately after sowing, provide effective suppression during the critical early growth phase, ensure selective crop emergence, minimize environmental impact, and biodegrade without leaving harmful residues.
[0007] The present invention solves the limitations of the prior art by providing a tri-layer biodegradable weed-suppressive mat configured to support direct seeding of aerobic rice onto the soil. The mat provides integrated weed suppression during the critical 0–21 day period when weeds cause the greatest yield loss in aerobic rice, using a combination of physical shading, biological competition, biochemical inhibition, and temporary pH modification.
[0008] Thus, in light of the above-stated discussion, there exists a need for a tri-layer biodegradable weed-suppressive mat.
SUMMARY OF THE DISCLOSURE
[0009] The following is a summary description of illustrative embodiments of the invention. It is provided as a preface to assist those skilled in the art to more rapidly assimilate the detailed design discussion which ensues and is not intended in any way to limit the scope of the claims which are appended hereto in order to particularly point out the invention.
[0010] According to illustrative embodiments, the present disclosure focuses on a tri-layer biodegradable weed-suppressive mat and method thereof which overcomes the above-mentioned disadvantages or provide the users with a useful or commercial choice.
[0011] An objective of the present disclosure is to provide a tri-layer biodegradable weed-suppressive mat and method thereof.
[0012] Another objective of the present disclosure is to suppress weed germination for aerobic rice that functions effectively in the absence of standing water.
[0013] Another objective of the present disclosure is to reduce or eliminate dependence on synthetic herbicides, thereby minimizing environmental contamination, herbicide resistance development, and input costs..
[0014] Another objective of the present disclosure is enable selective crop emergence by incorporating a perforated structure that allows rice coleoptiles to pass through while restricting weed growth at the soil surface.
[0015] Another objective of the present disclosure is to provide a competitive biological barrier using a fungal biofilm that rapidly colonizes the soil surface and occupies the ecological niche exploited by early-emerging weeds.
[0016] Another objective of the present disclosure is to provide controlled release of natural allelochemicals via a biochar-based carrier matrix that suppresses grassy and broadleaf weeds while preventing phytotoxicity to rice.
[0017] Another objective of the present disclosure is to create a temporary surface pH modification zone that selectively inhibits small-seeded weeds without affecting rice seeds placed at deeper sowing depths.
[0018] Yet another objective of the present disclosure is being capable of getting degraded into the soil within 30–40 days, eliminating the need for removal and preventing residual soil pollution.
[0019] In light of the above, in one aspect of the present disclosure, a tri-layer biodegradable weed-suppressive mat configured to support direct seeding of aerobic rice onto the soil is disclosed herein. The mat comprises a top layer comprises a perforated hydrophilic biodegradable polymer substrate inoculated with at least one ligninolytic fungus capable of forming a surface-colonizing biofilm that blocks light penetration, and biologically competes with germinating weeds. The mat includes a middle layer comprising plant-derived biochar impregnated with standardized natural allelopathic extracts configured for controlled release of phenolic compounds that inhibit weed germination without causing rice phytotoxicity. The system also includes a bottom layer comprising a biodegradable matrix containing organic acid buffer configured to generate a temporary acidic micro-zone at the soil surface to selectively suppress small-seeded weeds during early establishment.
[0020] In one embodiment, the biodegradable polymer substrate comprises bacterial cellulose, polylactic acid (PLA), starch-based biopolymer, or combinations thereof.
[0021] In one embodiment, the allelopathic extract is derived from sorghum, azolla, or other phenolic-rich plant sources.
[0022] In one embodiment, the ligninolytic fungus is selected from white-rot fungi.
[0023] In one embodiment, the fungus is selected from Phanerochaete chrysosporium or Trametes versicolor.
[0024] In one embodiment, perforations comprise 1–5 mm diameter openings spaced to allow rice coleoptile emergence while maintaining at least 70% surface shading.
[0025] In one embodiment, the organic-acid buffer comprises calcium citrate, magnesium lactate, malic acid, or combinations thereof.
[0026] In one embodiment, the buffer layer maintains soil-surface pH between 5.4–5.8 for 10 to 14 days.
[0027] In one embodiment, the surface-colonizing biofilm colonizes the upper 1–5 mm of soil surface forming a competitive microbial barrier against weed seedlings.
[0028] In light of the above, in one aspect of the present disclosure, a method of suppressing weeds in aerobic rice cultivation is disclosed herein. The method includes sowing rice seeds in soil at a depth of approximately 15–25 mm. The method includes installing a biodegradable tri-layer myco-allelopathic biofilm mat over the soil surface immediately after sowing. The method includes irrigating the field to activate a fungal biofilm layer and an organic-acid buffer layer of the mat. The method includes suppressing weed germination during a critical early growth period of 0–21 days through combined physical light interception, biological competition, biochemical allelopathic release, and temporary surface pH modification. The method includes permitting rice seedlings to emerge through perforations formed in the mat. The method includes allowing the mat to biodegrade naturally within approximately 30–40 days after sowing.
[0029] These and other advantages will be apparent from the present application of the embodiments described herein.
[0030] The preceding is a simplified summary to provide an understanding of some embodiments of the present invention. This summary is neither an extensive nor exhaustive overview of the present invention and its various embodiments. The summary presents selected concepts of the embodiments of the present invention in a simplified form as an introduction to the more detailed description presented below. As will be appreciated, other embodiments of the present invention are possible utilizing, alone or in combination, one or more of the features set forth above or described in detail below.
[0031] These elements, together with the other aspects of the present disclosure and various features are pointed out with particularity in the claims annexed hereto and form a part of the present disclosure. For a better understanding of the present disclosure, its operating advantages, and the specified object attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated exemplary embodiments of the present disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] To describe the technical solutions in the embodiments of the present disclosure or in the prior art more clearly, the following briefly describes the accompanying drawings required for describing the embodiments or the prior art. Apparently, the accompanying drawings in the following description merely show some embodiments of the present disclosure, and a person of ordinary skill in the art can derive other implementations from these accompanying drawings without creative efforts. All of the embodiments or the implementations shall fall within the protection scope of the present disclosure.
[0033] The advantages and features of the present disclosure will become better understood with reference to the following detailed description taken in conjunction with the accompanying drawing, in which:
[0034] FIG. 1 illustrates a block diagram of a block diagram of a tri-layer biodegradable weed-suppressive mat, in accordance with an exemplary embodiment of the present disclosure, in accordance with an exemplary embodiment of the present disclosure;
[0035] FIG. 2 illustrates a perspective view of a structural design and functional arrangement of the proposed tri-layer biodegradable weed-suppressive mat, in accordance with an exemplary embodiment of the present disclosure; and
[0036] FIG. 3 illustrates a flowchart of method of suppressing weeds in aerobic rice cultivation, in accordance with an exemplary embodiment of the present disclosure.
[0037] The tri-layer biodegradable weed-suppressive mat and method therof is illustrated in the accompanying drawings, which like reference letters indicate corresponding parts in the various figures. It should be noted that the accompanying figure is intended to present illustrations of exemplary embodiments of the present disclosure. This figure is not intended to limit the scope of the present disclosure. It should also be noted that the accompanying figure is not necessarily drawn to scale.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0038] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure.
[0039] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the present disclosure. It may be apparent to one skilled in the art that embodiments of the present disclosure may be practiced without some of these specific details.
[0040] Various terms as used herein are shown below. To the extent a term is used, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[0041] The terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items.
[0042] The terms “having”, “comprising”, “including”, and variations thereof signify the presence of a component.
[0043] Referring now to FIG. 1 to FIG. 3 to describe various exemplary embodiments of the present disclosure. FIG. 1 illustrates a block diagram of a tri-layer biodegradable weed-suppressive mat 100, in accordance with an exemplary embodiment of the present disclosure.
[0044] The mat 100 is configured to support direct seeding of aerobic rice onto the soil, where the absence of standing water leads to severe early weed pressure. The mat 100 is installed immediately after direct seeding and provides integrated, non-chemical weed suppression during the critical early growth period (0–21 days). In aerobic systems, the absence of standing water removes the natural weed suppression effect typically present in flooded rice fields, leading to simultaneous crop–weed emergence and severe early-stage competition.
[0045] The mat 100 includes a top layer 102 comprises a perforated hydrophilic biodegradable polymer substrate 108 inoculated with at least one ligninolytic fungus 110 that blocks light penetration, and biologically competes with germinating weeds. The top layer 102 forms a surface-colonizing biofilm that rapidly colonizes the soil surface under 18–36% moisture, blocks light transmission, and releases oxidative phenolic metabolites that inhibit early weed germination while allowing rice coleoptile emergence through perforations. Uniformly distributed micro-perforations are incorporated into the film to permit selective emergence of rice coleoptiles while maintaining surface coverage sufficient to restrict weed growth.
[0046] In one embodiment of the present invention, the surface-colonizing biofilm colonizes the upper 1–5 mm of soil surface forming a competitive microbial barrier against weed seedlings.
[0047] In one embodiment of the present invention, the biodegradable polymer substrate 108 comprises bacterial cellulose, polylactic acid (PLA), starch-based biopolymer, or combinations thereof.
[0048] Bacterial cellulose is characterized by high purity, nanofibrillar structure, superior tensile strength, and excellent water-holding capacity compared to plant-derived cellulose. Its hydrophilic nature supports moisture retention at the soil–mat interface, which is essential for fungal biofilm activation and sustained metabolic activity.
[0049] Polylactic acid (PLA) is a biodegradable thermoplastic polymer derived from renewable resources such as corn starch or sugarcane. PLA offers good mechanical strength, flexibility, and processability, allowing the film to be manufactured in rollable sheets with precise perforation patterns. It maintains structural integrity during the critical early weed suppression period and undergoes gradual hydrolytic and microbial degradation under field conditions.
[0050] The starch-based biopolymer derived from natural starch sources such as corn, potato, or tapioca. Starch-based polymers are highly biodegradable, cost-effective, and readily available, making them suitable for agricultural field applications. These materials exhibit good soil compatibility and Due to their hydrophilic properties, starch-based substrates facilitate moisture diffusion and support biological activity within the mat.
[0051] In one embodiment of the present invention, the ligninolytic fungus 110 is selected from white-rot fungi 110. The white-rot fungi 110 possess strong ligninolytic enzyme systems, including laccases and peroxidases, which allow them to degrade complex organic polymers and produce oxidative phenolic metabolites. These metabolites have natural inhibitory effects on early weed germination, providing a biochemical mechanism for surface-level weed suppression.
[0052] In one embodiment of the present invention, the fungus 110 is selected from Phanerochaete chrysosporium or Trametes versicolor. Under field moisture conditions of approximately 18–36%, the fungal inoculums become metabolically active and rapidly colonize the underside and surface interface of the film. The fungi 110 form a thin, cohesive mycelial biofilm that extends into the upper 2–4 mm of the soil surface. This rapid colonization enables the fungal network to occupy ecological niches that would otherwise be exploited by germinating weed seedlings.
[0053] The fungi 110 perform multiple functions simultaneously. They establish biological competition at the soil surface, occupying ecological niches that would otherwise be exploited by weed seedlings. Their production of low-dose phenolic metabolites contributes to selective biochemical inhibition of weeds without harming rice seeds sown at deeper levels. Furthermore, the metabolic activity of the fungi 110 facilitates gradual biodegradation of the biopolymer matrix, ensuring that the top layer 102 performs its protective function during the critical 0–21 day weed-free period and then naturally decomposes.
[0054] In one embodiment of the present invention, the perforations comprise 1–5 mm diameter openings spaced to allow rice coleoptiles emergence while maintaining at least 70% surface shading.
[0055] The top layer 102 performs three synchronized actions. First, it provides physical light interception, reducing incident light at the soil surface by more than 90%, thereby suppressing light-sensitive weed seed germination. Second, it establishes biological competition, as the fungal mycelium competes for nutrients and space at the critical soil interface. Third, the fungi 110 produce low concentrations of oxidative phenolic metabolites and ligninolytic enzymes, which create a localized inhibitory microenvironment that interferes with early weed radicle development. These biochemical effects are localized at the soil surface and diminish with depth, ensuring that rice seeds sown at 15–25 mm remain unaffected.
[0056] The perforations in the film are strategically sized and spaced to allow rice coleoptiles to pass through with minimal mechanical resistance. Because rice seeds are placed deeper than most small-seeded weeds, the crop seedlings emerge vertically through the perforations while weed seedlings at the immediate surface encounter shading, biological suppression, and biochemical inhibition. Over time, as soil microbial activity increases and environmental exposure continues, the biopolymer matrix gradually degrades, ensuring that the layer performs its protective function during the critical early growth period and then naturally decomposes without requiring removal.
[0057] Beneath the top layer 102, a middle Layer 104 is provided with the mat 100, comprising a plant-derived biochar 112 impregnated with standardized natural allelopathic extracts 114 configured for controlled release of phenolic compounds that inhibit weed germination without causing rice phytotoxicity.
[0058] The middle Layer 104 is composed of rice husk biochar 112 produced through pyrolysis at a temperature range of 420–480°C. This temperature range is specifically selected to generate a biochar 112 with a moderately high porosity and a BET surface area of approximately 200–350 m²/g. These structural characteristics provide a large internal pore network and extensive adsorption sites, making the biochar 112 suitable as both a carrier and regulator of bioactive compounds.
[0059] Moderately high porosity refers to a material having a well-developed network of internal pores that occupy a significant portion of its volume, allowing it to store and transport substances efficiently. In the case of biochar 112, this means the presence of numerous micro- and mesopores that can hold water, nutrients, and bioactive compounds such as phenolic allelochemicals. The term “moderately high” indicates a balanced pore structure—sufficiently porous to provide high adsorption and controlled-release capacity, yet structurally stable without excessive fragility or pore collapse that can occur at very high carbonization temperatures. This balanced porosity enables the biochar 112 to load natural extracts 114 effectively and release them gradually when exposed to soil moisture.
[0060] BET surface area, measured using the Brunauer–Emmett–Teller (BET) gas adsorption method, quantifies the total surface area available per unit mass of material, including both external surfaces and the internal surfaces within pores. Expressed in square meters per gram (m²/g), a value of 200–350 m²/g means that one gram of biochar 112 possesses an extensive internal surface area equivalent to hundreds of square meters. This high surface area is responsible for the material’s strong adsorption capacity, allowing it to bind, retain, and regulate the release of allelochemicals. The moderately high porosity combined with a substantial BET surface area ensures that the biochar 112 acts as an efficient carrier and self-regulating reservoir, enabling controlled diffusion of weed-inhibiting compounds while preventing phytotoxic accumulation and simultaneously supporting soil moisture retention and microbial activity.
[0061] In one embodiment of the present invention, the allelopathic extract 114 is derived from sorghum, azolla, or other phenolic-rich plant sources. The extract 114 contains approximately 0.6–1.2% total phenolic compounds. These phenolic constituents are known to possess allelopathic properties that inhibit seed germination and early root elongation in many weeds species. By incorporating these extracts 114 into the porous char matrix, the middle layer 104 acts as an allelopathic reservoir positioned directly at the soil surface where weed seeds typically germinate.
[0062] Rice husk is naturally rich in silica, which contributes to improved structural rigidity and stability of the resulting char. This silica content enhances the mechanical integrity of the biochar 112 particles within the mat 100 and helps maintain pore architecture during field exposure. Additionally, utilizing rice husk valorizes agricultural waste, aligning the invention with circular economy principles and reducing raw material costs.
[0063] The specified pyrolysis temperature range of 420–480°C is critical to achieving the desired physicochemical properties. At this moderate temperature range, the biochar 112 develops balanced aromatic carbon structures while retaining sufficient surface functional groups such as carboxyl and hydroxyl moieties. Lower temperatures may result in incomplete carbonization and reduced stability, whereas excessively high temperatures can cause over-carbonization, collapse of micropores, and loss of functional groups, thereby diminishing adsorption capacity and controlled-release performance.
[0064] The controlled release of the middle layer 104 provides moisture when the mat 100 is irrigated after installation, and the moisture diffuses into the biochar 112 pores, gradually mobilizing the adsorbed phenolic compounds. Instead of releasing a high initial dose, the char structure moderates diffusion, providing a sustained low-concentration release over a period of approximately 2–3 weeks. This time window corresponds to the critical weed-free period in aerobic rice systems.
[0065] The high adsorption capacity of the middle layer 104 allows it to re-adsorb excess allelochemicals, thereby preventing the accumulation of phytotoxic concentrations that could harm rice seedlings. Because rice seeds are placed at a deeper sowing depth (15–25 mm), and because the phenolic diffusion gradient decreases with soil depth, the inhibitory effects remain concentrated at the surface zone where weed seeds germinate. In addition to its biochemical role, the biochar 112 also contributes to soil improvement by enhancing moisture retention, increasing cation exchange capacity, and supporting beneficial microbial colonization during degradation.
[0066] The last layer is a bottom layer 106, comprising a biodegradable matrix 116 containing organic acid buffer 118 configured to generate a temporary acidic micro-zone at the soil surface to selectively suppress small-seeded weeds during early establishment. The bottom layer 106 dissolves gradually upon irrigation, ensuring controlled activation rather than immediate release.
[0067] In one embodiment of the present invention, the organic-acid buffer 118 comprises calcium citrate, magnesium lactate, malic acid, or combinations thereof.
[0068] Calcium citrate functions primarily as a mild buffering agent that prevents excessive acidification of the soil surface. Its gradual dissolution profile ensures that the pH reduction remains within a biologically safe range while simultaneously supplying calcium, an essential plant nutrient that supports early root development and cell wall stability.
[0069] Magnesium lactate contributes additional buffering capacity and provides magnesium, a key component of chlorophyll and an important nutrient for plant growth. Magnesium lactate also helps stabilize the acidity level, preventing abrupt pH fluctuations and supporting controlled dissolution dynamics within the layer.
[0070] Malic acid, a naturally occurring organic acid found in many plant tissues, is responsible for the initial rapid but moderate pH reduction upon irrigation. It is biodegradable, soil-compatible, and readily metabolized by soil microorganisms, ensuring no harmful residue accumulation. The buffering salts regulate the acid strength, preventing harmful acidity while maintaining selective suppression.
[0071] In one embodiment of the present invention, the buffer 118 layer maintains soil-surface pH between 5.4–5.8 for 10–14 days.
[0072] When the mat 100 is installed and irrigated, moisture penetrates the starch matrix and initiates slow dissolution of the organic-acid components. This process establishes a mildly acidic microenvironment at the immediate soil–mat 100 interface, reducing the surface pH to approximately 5.4–5.8 for duration of about 10–14 days. The buffering salts (calcium citrate and magnesium lactate) regulate the acidity to prevent excessive pH decline, ensuring that the acidification remains within a biologically tolerable and agronomically safe range.
[0073] This temporary acidic boundary selectively suppresses the germination of many small-seeded weed species that are highly sensitive to surface pH fluctuations during radicle emergence. The lowered pH interferes with enzyme activation, nutrient solubility balance, and early cell elongation processes required for weed seed germination. Because most weed seeds in aerobic rice systems germinate at or very near the soil surface (0–5 mm), they are directly exposed to this modified microenvironment.
[0074] In contrast, rice seeds are sown at a deeper placement of approximately 15–25 mm below the soil surface. At this depth, the buffering effect diminishes significantly due to soil buffering capacity, dilution, and limited downward diffusion of organic acids. As a result, the rice seeds develop under near-normal soil pH conditions and are not adversely affected. After 10–14 days, the organic-acid components are neutralized by soil buffering reactions and microbial activity, restoring the soil surface to its natural pH. The starch carrier then biodegrades, leaving no harmful residues.
[0075] FIG. 2 illustrates a perspective view 200 of a structural design and functional arrangement of the proposed tri-layer biodegradable weed-suppressive mat 100, in accordance with an exemplary embodiment of the present disclosure.
[0076] In 201, the mat 100 in a rolled configuration, demonstrating that the system is flexible, lightweight, and suitable for field-scale deployment immediately after direct seeding. The sheet contains uniform perforations across its surface. These perforations are precisely spaced to allow rice coleoptile emergence, permit gas exchange and moisture movement, and maintain alignment with seed rows (seed-path alignment).
[0077] In 202, the uppermost layer is the perforated fungal biofilm layer, consisting of a hydrophilic biopolymer film such as bacterial cellulose or PLA inoculated with white-rot fungi 110 including Phanerochaete chrysosporium or Trametes versicolor. This layer forms a living biofilm at the soil surface after irrigation, blocks more than 90% of incident light to suppress weed germination, and releases oxidative phenolic metabolites that inhibit early weed growth.
[0078] In 203, the middle allelo-char layer 104 is depicted as a textured or mesh-like structure to indicate its biochar based composition. This layer 104 comprises rice husk biochar 112 impregnated with standardized sorghum or azolla extracts 114 rich in natural phenolic compounds. It acts as a controlled-release biochemical reservoir, gradually diffusing allelochemicals over a 2–3 week period corresponding to the critical weed suppression phase. The porous char matrix 116 regulates release rates and simultaneously adsorbs excess compounds, preventing phytotoxic effects on rice seedlings.
[0079] In 204, the bottom layer 106 represents the dissolvable organic-acid buffer 118 strip embedded in a starch matrix. Upon irrigation, it produces a temporary acidic micro-zone with a surface pH of approximately 5.4–5.8 for 10–14 days. This mild and localized pH reduction selectively inhibits germination of small-seeded weeds positioned near the soil surface while not affecting rice seeds sown deeper at 15–25 mm. The layer gradually dissolves and is neutralized by soil buffering processes, ensuring reversibility and environmental safety.
[0080] FIG. 3 illustrates a flowchart of method of suppressing weeds in aerobic rice cultivation, in accordance with an exemplary embodiment of the present disclosure.
[0081] The method 300 may include the following steps:
[0082] At 302, sowing rice seeds in soil at a depth of approximately 15–25 mm.
[0083] At 304, installing a biodegradable tri-layer myco-allelopathic biofilm mat 100 over the soil surface immediately after sowing.
[0084] At 306, irrigating the field to activate a fungal biofilm layer and an organic-acid buffer 118 layer of the mat 100.
[0085] At 308, suppressing weed germination during a critical early growth period of 0–21 days through combined physical light interception, biological competition, biochemical allelopathic release, and temporary surface pH modification.
[0086] At 312, permitting rice seedlings to emerge through perforations formed in the mat 100.
[0087] At 314, allowing the mat 100 to biodegrade naturally within approximately 30–40 days after sowing.
[0088] The disclosed invention offers several advantages. The invention combines physical light interception, biological competition, biochemical allelopathy, and temporary pH modification within a single biodegradable mat 100, it delivers more reliable and sustained weed suppression compared to conventional single-method approaches. The mat 100 is engineered to function effectively during the critical 0–21 day weed-free period, which is the most sensitive stage for crop–weed competition and yield determination.
[0089] The proposed invention has the ability to reduce or potentially eliminate dependence on synthetic herbicides. Through the use of natural plant extracts 114, fungal bioactivity, and controlled pH modulation, the system minimizes chemical residues, lowers environmental contamination risks, and reduces the likelihood of herbicide resistance development. The perforated biopolymer design ensures selective crop emergence, allowing rice coleoptiles to pass through while restricting weed growth at the soil surface, thereby promoting uniform crop establishment without mechanical obstruction.
[0090] The invention also incorporates a biochar-based allelopathic reservoir that provides controlled release of natural phenolic compounds. The porous structure of the biochar 112 regulates diffusion and re-adsorbs excess allelochemicals, preventing phytotoxicity to rice seedlings. Simultaneously, the organic-acid buffer 118 layer creates a temporary and reversible acidic micro-zone that selectively inhibits small-seeded weeds while remaining safe for rice sown at deeper levels. This targeted and depth-selective action enhances crop safety and system efficiency.
[0091] The proposed invention is biodegradable and soil-compatible, eliminating the need for removal and preventing long-term residue accumulation. The inclusion of rice husk biochar 112 contributes to improved soil moisture retention, enhanced microbial habitat, and better nutrient-holding capacity, while residual calcium and magnesium from the buffer 118 layer support soil fertility. Additionally, the invention reduces labor requirements by minimizing repeated manual or mechanical weeding operations and is designed in a rollable, field-deployable format suitable for large-scale agricultural use.
[0092] While the invention has been described in connection with what is presently considered to be the most practical and various embodiments, it will be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.
[0093] A person of ordinary skill in the art may be aware that, in combination with the examples described in the embodiments disclosed in this specification, units and algorithm steps may be implemented by electronic hardware, computer software, or a combination thereof.
[0094] The foregoing descriptions of specific embodiments of the present disclosure have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present disclosure to the precise forms disclosed, and many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described to best explain the principles of the present disclosure and its practical application, and to thereby enable others skilled in the art to best utilize the present disclosure and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but such omissions and substitutions are intended to cover the application or implementation without departing from the scope of the present disclosure.
[0095] Disjunctive language such as the phrase “at least one of X, Y, Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to present that an item, term, etc., may be either X, Y, or Z, or any combination thereof (e.g., X, Y, and/or Z). Thus, such disjunctive language is not generally intended to, and should not, imply that certain embodiments require at least one of X, at least one of Y, or at least one of Z to each be present.
[0096] In a case that no conflict occurs, the embodiments in the present disclosure and the features in the embodiments may be mutually combined. The foregoing descriptions are merely specific implementations of the present disclosure, but are not intended to limit the protection scope of the present disclosure. Any variation or replacement readily figured out by a person skilled in the art within the technical scope disclosed in the present disclosure shall fall within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.
, Claims:I/We Claim:
1. A tri-layer biodegradable weed-suppressive mat (100) configured to support direct seeding of aerobic rice onto the soil, the mat (100) comprising:
a top layer (102) comprises a perforated hydrophilic biodegradable polymer substrate (108) inoculated with at least one ligninolytic fungus (110) capable of forming a surface-colonizing biofilm that blocks light penetration, and biologically competes with germinating weeds;
a middle layer (104) comprising plant-derived biochar (112) impregnated with standardized natural allelopathic extracts (114) configured for controlled release of phenolic compounds that inhibit weed germination without causing rice phytotoxicity; and
a bottom layer (106) comprising a biodegradable matrix (116) containing organic acid buffer (118) configured to generate a temporary acidic micro-zone at the soil surface to selectively suppress small-seeded weeds during early establishment.
2. The mat (100) as claimed in claim 1, wherein the biodegradable polymer substrate (108) comprises bacterial cellulose, polylactic acid (PLA), starch-based biopolymer, or combinations thereof.
3. The mat (100) as claimed in claim 1, wherein the allelopathic extract (114) is derived from sorghum, azolla, or other phenolic-rich plant sources.
4. The mat (100) as claimed in claim 1, wherein the ligninolytic fungus (110) is selected from white-rot fungi.
5. The mat (100) as claimed in claim 1, wherein the fungus (110) is selected from Phanerochaete chrysosporium or Trametes versicolor.
6. The mat (100) as claimed in claim 1, wherein perforations comprise 1–5 mm diameter openings spaced to allow rice coleoptile emergence while maintaining at least 70% surface shading.
7. The mat (100) as claimed in claim 1, wherein the organic-acid buffer (118) comprises calcium citrate, magnesium lactate, malic acid, or combinations thereof.
8. The mat (100) as claimed in claim 1, wherein the buffer (118) layer maintains soil-surface pH between 5.4–5.8 for 10–14 days.
9. The mat (100) as claimed in claim 1, wherein the surface-colonizing biofilm colonizes the upper 1–5 mm of soil surface forming a competitive microbial barrier against weed seedlings.
10. A method (300) of suppressing weeds in aerobic rice cultivation, comprising:
sowing rice seeds in soil at a depth of approximately 15–25 mm;
installing a biodegradable tri-layer myco-allelopathic biofilm mat (100) over the soil surface immediately after sowing;
irrigating the field to activate a fungal biofilm layer and an organic-acid buffer layer of the mat (100);
suppressing weed germination during a critical early growth period of 0–21 days through combined physical light interception, biological competition, biochemical allelopathic release, and temporary surface pH modification;
permitting rice seedlings to emerge through perforations formed in the mat (100); and
allowing the mat (100) to biodegrade naturally within approximately 30–40 days after sowing.