Slope land sweet potato water and soil conservation method and application thereof

Abstract

The present application relates to a kind of hillside sweet potato water and soil conservation method, including S1 variety screening, S2 stereoscopic planting, S3 press vine promotes root, S4 regrowth mowing, S5 winter withering cover, S6 sprout new cycle.Different from prior art, the core of the application selects long vine, high biomass, strong regeneration, tuber dormancy long special sweet potato varieties;In the core area of slope / gradient surface, edge area, slope wall / gradient wall area, it is planted in three-dimensional difference;By artificial press vine, main root anchor rod, fibrous root net bag, adventitious root suture and creeping stem, litter covering "fourfold living anchor structure" are formed;Stalk and leaf are mowed as high-protein feed in growing season;In winter, using natural dead stalk and leaf to build cover layer, realize weed control and in-situ full amount fertilization;Reserve underground tuber as perennial propagule, realize natural germination and system 5 years or more self-maintenance next year.

Description

Technical Field

[0001] This invention relates to the fields of agricultural ecological restoration, soil and water conservation and soil improvement technology, and in particular to a method for soil and water conservation of sweet potatoes on hillsides and its application. Specifically, it relates to a method for constructing a long-term, self-sustaining, and multifunctional soil and water conservation and ecological agriculture synergy system on hillsides (including sloping farmland, barren slopes and terraces) in southern China by utilizing the biological characteristics of perennial sweet potatoes. Background Technology

[0002] The hilly and mountainous areas of southern China, including Jiangxi, Hunan, Guizhou, Guangxi, Fujian, Sichuan, and Chongqing, are regions with severe soil erosion, accounting for approximately 20% to 30% of the total land area affected. The most prominent problems lie on hillsides (including sloping farmland, barren slopes, and terraced fields and their ridges), with the following main issues:

[0003] First, engineering measures are costly and unsustainable. For example, masonry retaining walls and concrete lattice structures require an initial investment of 2,000 to 5,000 yuan per acre. Moreover, these are rigid structures and not well-suited to the ecological environment. After five to ten years, they will fail due to foundation deformation or material aging, making true ecological restoration of the soil impossible.

[0004] Secondly, conventional biological measures are not economically sustainable. Vetiver grass and Amorpha fruticosa hedges can reduce runoff by 21% and produce only 18% of the sediment compared to bare land, so they are effective. However, these are clump-forming grasses or shrubs, only forming linear barriers and not surface cover; the slopes between the hedges will still be eroded by rainwater. More importantly, these plants do not generate direct economic returns, and subsequent pruning and replanting require investment; therefore, less than 30% of farmers are willing to actively maintain them.

[0005] Third, conventional sweet potato cultivation actually exacerbates soil erosion. While sweet potatoes are actually better at protecting the soil than wheat, they are annuals. After the autumn harvest, the soil surface is exposed. This period of exposure during winter and spring coincides with the rainy season in the south, resulting in "soil conservation for half a year, erosion for the other half." Furthermore, the annual tilling and ridging severely damages the soil's aggregate structure, further aggravating erosion.

[0006] Fourth, existing cover crops lack anchoring capabilities. Cover crops like ryegrass are either annuals or biennials, requiring reseeding every year, increasing seed costs and labor costs. Moreover, their root systems are mainly fibrous roots, lacking the deep-rooted ability of taproots and the "stitching" anchoring effect of stolons.

[0007] In summary, existing technologies have failed to address the five key challenges: year-round surface cover, three-dimensional root anchoring, continuous soil carbonization, low maintenance costs, and farmer participation. Therefore, we need a new approach that can transform "ecological governance" into an "ecological industry." Summary of the Invention

[0008] In view of the above problems, this application provides a method for soil and water conservation of sweet potatoes on hillsides, utilizing a specific perennial sweet potato variety and combining a systematic integrated approach of "three-dimensional planting - vine training to promote root growth - regeneration cutting - winter mulching - new growth cycle". The aim is to achieve: ① one-time planting, maintenance-free renewal for more than five years; ② efficient year-round ground cover; ③ formation of a four-dimensional root system soil-stabilizing structure of "anchor rods - netting - stitching - covering"; ④ continuous natural increase in soil organic matter; and ⑤ direct economic returns from the stems and leaves as high-protein feed.

[0009] This application provides a method for soil and water conservation of sweet potatoes on hillsides, including the following steps:

[0010] S1 Variety Selection: Select sweet potato varieties that meet the following characteristics: long vine type, with a vine length of not less than 1.5 meters; strong branching ability, with no less than 8 branches per plant; large stem and leaf biomass, with a fresh weight of more than 2.5 kg per plant; strong stem and leaf regeneration ability, with a regeneration rate of more than 2 cm per day after cutting; long dormancy period of underground tubers, with no dormancy or only shallow dormancy under natural winter conditions in the south, and an overwintering survival rate of not less than 90%; strong spring budding potential of underground tubers, with a budding rate of more than 85%.

[0011] Its long vines are beneficial for quickly covering the ground to suppress weeds and reduce soil erosion; its numerous branches and large stem and leaf growth mean higher biomass production, which can be used for mulching and fertilization after mowing or for feed; its strong regeneration ability ensures continuous coverage after multiple mowings.

[0012] S2 Three-dimensional planting: The sweet potato seedlings selected in S1 are planted in April-May, with a temperature ≥15℃ during the planting period; the hillside is divided into terraced fields and terrace wall areas; the terraced fields include a core planting area and two edge areas near the terrace walls; the core planting area is planted using a wide-row sparse planting method, the edge areas are planted using a double-row dense planting method, and the terrace wall areas are planted using a slanted deep planting method.

[0013] S3 Vine Pressing to Promote Root Development: From June to August, after the sweet potato seedlings' runners reach a length of over 50cm, press the runner segments into the topsoil 3-5cm deep, or cover them lightly with loose soil. This encourages the runner nodes to develop adventitious roots, forming secondary anchorage points. The soil-covered nodes produce a large number of adventitious roots at the designated locations, penetrating vertically or obliquely into different soil depths, forming a living fiber network similar to geocells. This connects the topsoil and subsoil, significantly enhancing the soil's shear resistance. After vine pressing, adventitious root density increased by 343%, average root depth increased by 129%, soil shear strength increased by 70%, and soil disintegration rate decreased by 58%.

[0014] S4 Regeneration Harvesting: From mid-July to mid-November, while ensuring an instantaneous ground cover of no less than 70%, perform 2-4 harvests, leaving a stubble height of 15-20 cm. After each harvest, apply 30-40 kg of N, P, K compound fertilizer per acre to replenish nutrients and maintain vigorous plant growth. Too low a stubble length leads to a prolonged period of bare ground, while too high a stubble length reduces the number of harvests per year and decreases total yield. A stubble height of 15-20 cm represents the optimal balance between ecological safety and economic benefits.

[0015] S5 Winter Mulching: From late November after the first frost until February of the following year, mowing is stopped. After the frost, the above-ground stems and leaves naturally wither and die, forming a 5-10 cm thick dry mulch layer. The resulting mulch layer suppresses weeds, reduces raindrop kinetic energy, and is fully returned to the field for decomposition to improve soil organic matter. It achieves three functions: physical weed suppression (weed reduction ≥70%), in-situ fertilization (full straw return to the field), and winter protection.

[0016] S6 New Growth Cycle: The following spring, the underground tubers naturally sprout and grow new above-ground stems and leaves; and the S3-S6 steps are repeated.

[0017] From the first year onwards, the underground tubers are not harvested, allowing them to remain in the soil as a perennial propagation reservoir. The following spring, the underground tubers naturally sprout, growing new above-ground stems and leaves, completely replacing manual replanting. Once established, this system can be stably maintained for many years without the need for tilling or replanting. Manual management only involves S5 cutting and S3 vine training, with an average of no more than 1.0 man-day per acre (based on 8 hours per day) required for maintenance after planting.

[0018] Furthermore, in the S1 variety selection step, the sweet potato variety meets the requirement of being tolerant to poor soil conditions and is also suitable for barren wastelands and rocky desertification areas. This method can be applied to the red soil hilly areas, purple soil hilly areas, karst rocky desertification areas, abandoned barren hillsides, and the field surfaces and ridges of various terraced fields in southern China.

[0019] Furthermore, in the S1 variety screening step, the sweet potato variety screened is Heshu No. 2. Heshu No. 2 was bred by Handan Hexiatu Seed Industry Co., Ltd. in 2015 using Guangshu 87 for free pollination. It was registered as a non-major crop variety in China in 2022, with registration number: GPD Sweet Potato (2022) 130086. This variety possesses characteristics such as long vines (vine length ≥1.5 m), strong branching ability (≥8 branches / plant), large stem and leaf biomass (fresh weight ≥2.5 kg / plant), strong stem and leaf regeneration ability, long dormancy period of underground tubers, natural overwintering survival rate ≥90% in southern regions, and spring germination rate ≥85%. These characteristics perfectly match the core design of this application, which uses aboveground biomass to provide ecological services and underground tubers as perennial propagation bodies. The long vines are conducive to rapid ground cover to suppress weeds and reduce soil erosion; the large number of branches and the large stem and leaf growth mean higher biomass output, which can be used for mulching or feed after mowing; and the strong regeneration ability ensures continuous coverage after multiple mowings.

[0020] Furthermore, in the S2 three-dimensional planting step, the land is not tilled or prepared during planting, and the original surface vegetation residue is retained. This achieves water and soil conservation, fertilizer and pesticide reduction, labor saving, and yield increase, thus constituting conservation tillage.

[0021] Furthermore, in the S2 three-dimensional planting step, in the core planting area, the plant spacing is 40-50 cm and the row spacing is 60-80 cm; in the edge area, the plant spacing is 25-30 cm and the row spacing is 30-35 cm, arranged in a triangular pattern; in the terrace wall area, seedlings 30-40 cm long are selected and inserted obliquely into the slope wall soil at an angle of 45°-60°, with a soil depth of 15-20 cm and 10-15 cm protruding above the ground.

[0022] Furthermore, in the S2 three-dimensional planting step, sweet potatoes with different leaf colors are mixed in the terrace wall area, forming a colorful ecological slope protection landscape.

[0023] Furthermore, in the S4 regeneration harvesting step, the harvested fresh stems and leaves are used as high-protein green fodder for herbivores such as cattle, sheep, and rabbits. The annual yield of fresh stems and leaves is 3,000-5,000 kg per mu, which can save 400-600 yuan per mu in green fodder costs for herbivores.

[0024] Furthermore, in the S4 regeneration and mowing step, N, P, K compound fertilizer is evenly spread on the terrace surface before rain, and rainwater is used to carry the fertilizer into the rhizosphere soil to promote the development of adventitious roots and the regeneration of stems and leaves.

[0025] Furthermore, in the S6 beginner cycle step, steps S3-S6 are repeated 5-8 times.

[0026] The second aspect of this application also provides the comprehensive application of the hillside soil and water conservation methods described in the first aspect of this application in ecological restoration of soil erosion areas, localized supply of feed for herbivorous livestock, and creation of rural landscapes.

[0027] Unlike existing technologies, this application utilizes a specialized sweet potato variety characterized by long vines, high biomass, strong regeneration, and a long tuber dormancy period. Differential three-dimensional planting is implemented in the core, edge, and slope / terrace wall areas. Artificial vine pressing induces a "four-fold living anchor" structure, consisting of taproot anchors, fibrous root nets, adventitious root sutures, and stolons covered with fallen leaves. Figure 2 As shown; the stems and leaves are cut multiple times during the growing season as high-protein feed; in winter, the naturally dead stems and leaves are used to build a mulch layer to suppress weeds and achieve full fertilization in situ; the underground tubers are retained as perennial propagation bodies to achieve natural germination the following year and self-sustaining the system for more than 5 years.

[0028] This application overcomes three major challenges: ecological measures yield no output, engineering measures are unsustainable, and conventional planting exacerbates soil erosion due to winter and spring exposure. It achieves synergy of "one-time planting, multi-year soil stabilization, feed production, landscape enhancement, and soil carbon increase," reducing soil erosion modulus by >90%, increasing organic matter by >0.4% annually, and producing 3,000-5,000 kg of fresh feed per mu per year. It is applicable to more than 3 million square kilometers of soil erosion areas in southern my country.

[0029] The above description of the invention is merely an overview of the technical solution of this application. In order to enable those skilled in the art to better understand the technical solution of this application and to implement it based on the textual description, and to make the above-mentioned objectives and other objectives, features and advantages of this application easier to understand, the following description is provided in conjunction with the specific embodiments and accompanying drawings of this application. Attached Figure Description

[0030] The accompanying drawings are only used to illustrate the principles, implementation methods, applications, features, and effects of specific embodiments of this application and other related content, and should not be considered as limitations on this application.

[0031] In the accompanying drawings of the instruction manual:

[0032] Figure 1 This is a schematic diagram of the planting zone layout for this application. The core planting area on the terrace is represented by A, which uses wide rows and sparse planting; the edge area is represented by B, which uses double rows and dense planting; and the terrace wall area is represented by C, which uses slanted deep planting (or is paired with colored varieties) in its spatial configuration.

[0033] Figure 2 This is a schematic diagram of the three-dimensional root system structure of the "quadruple living anchor" in this application. The diagram shows the anchoring effect of the main root, the netting effect of the fibrous roots, the suture effect of the adventitious roots of the layered vines, and the covering effect of the stolons and fallen leaves.

[0034] Figure 3 This is a technical flowchart of this application.

[0035] Figure 4 This is a diagram illustrating the soil and water conservation effect of this application. Sweet potatoes are planted on the left and right sides, while the middle side (control) shows severe soil erosion due to the absence of sweet potatoes. Detailed Implementation

[0036] To illustrate the possible application scenarios, technical principles, implementable specific solutions, and achievable objectives and effects of this application in detail, the following description, in conjunction with the listed specific embodiments and accompanying drawings, provides a detailed explanation. The embodiments described herein are merely illustrative of the technical solutions of this application and are therefore intended to limit the scope of protection of this application.

[0037] In this document, the term "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The term "embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment, nor does it specifically limit its independence or connection with other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.

[0038] Unless otherwise defined, the technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the use of related terms herein is merely for the purpose of describing particular embodiments and is not intended to limit this application.

[0039] In the description of this application, the term "and / or" is used to describe the logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and A and B exist simultaneously. Additionally, the character " / " in this document generally indicates that the preceding and following objects have an "or" logical relationship.

[0040] In this application, terms such as “first” and “second” are used only to distinguish one entity or operation from another, and do not necessarily require or imply any actual quantity, hierarchy or order relationship between these entities or operations.

[0041] Unless otherwise specified, the use of terms such as “comprising,” “including,” “having,” or other similar expressions in this application is intended to cover non-exclusive inclusion, which does not exclude the presence of additional elements in a process, method, or product that includes the stated elements, such that a process, method, or product that includes a list of elements may include not only those defined elements but also other elements not expressly listed, or elements inherent to such a process, method, or product.

[0042] As understood in the Examination Guidelines, in this application, expressions such as "greater than," "less than," and "exceeding" are understood to exclude the stated number; expressions such as "above," "below," and "within" are understood to include the stated number. Furthermore, in the description of the embodiments in this application, "multiple" means two or more (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups" and "multiple times," unless otherwise explicitly specified.

[0043] In this embodiment, the natural conditions in southern winter are: average monthly temperature of 8–10℃, minimum temperature not lower than -2℃, and no severe frost.

[0044] In this embodiment, the sweet potato variety meets the requirements for tolerance to poor soil, that is, under the conditions of poor hillside soil with organic matter content of less than 1.0%, available nitrogen of less than 60 mg / kg, available phosphorus of less than 5 mg / kg, and available potassium of less than 40 mg / kg, the sweet potato variety has a stem and leaf growth of not less than 70% of that under fertile soil conditions, an underground tuber yield of not less than 50% of that under fertile soil conditions, and no obvious symptoms of nutrient deficiency.

[0045] This implementation method uses the following approach for sweet potato cultivation, see details below. Figure 3

[0046] S1 variety screening: Heshu No. 2 was selected;

[0047] S2 Three-Dimensional Planting: Planting time is April-May, with a temperature ≥15℃ during planting. No tilling or land preparation is done during planting; existing surface vegetation residue is retained. The hillside is divided into terraced fields and terrace wall areas. The terraced fields include a core planting area and two edge areas near the terrace walls; the remaining areas are the core planting areas. The core planting areas use a wide-row, sparse planting method, with a plant spacing of 40-50 cm and a row spacing of 60-80 cm. The edge areas use a double-row, dense planting method, arranged in a triangular pattern, with a plant spacing of 25-30 cm and a row spacing of 30-35 cm. The terrace wall areas use a slanted, deep planting method, selecting 30-40 cm long seedlings and inserting them obliquely into the slope at a 45°-60° angle, to a depth of 15-20 cm, with 10-15 cm protruding above ground. Specific details are as follows... Figure 1 As shown.

[0048] S3 Vine Pressing to Promote Roots: From June to August, after the sweet potato seedlings' stolons have grown to more than 50cm, press the stolon segments into the top 3-5cm of soil, or cover them lightly with loose soil; this will cause the stolon nodes to produce adventitious roots and form secondary anchoring points.

[0049] S4 Regeneration Harvesting: From mid-July to mid-November, while ensuring an instantaneous ground cover of no less than 70%, perform 2-4 harvests, leaving a stubble height of 15-20 cm. The harvested fresh stems and leaves are used as high-protein green fodder for herbivores such as cattle, sheep, and rabbits. After each harvest, apply 30-40 kg of N, P, K compound fertilizer per acre. Spread the N, P, K compound fertilizer evenly on the terrace surface before rain, utilizing rainwater to carry the fertilizer into the rhizosphere soil, promoting adventitious root development and stem and leaf regeneration.

[0050] S5 Winter mulching: From late November to February of the following year, stop harvesting. After the frost, the above-ground stems and leaves will naturally wither and die, forming a dry mulch layer 5-10 cm thick.

[0051] S6 Sprouting Cycle: The following spring, the underground tubers naturally sprout, growing new above-ground stems and leaves; and the S3-S6 steps are repeated. The S3-S6 steps are repeated 5-8 times.

[0052] Example 1

[0053] This embodiment was conducted in a localized experiment in Xuancheng Township, Changting County, Fujian Province, on typical hillsides (slopes of 15°-25°), including terraced fields and wasteland. A control group was also included. Observations and test results were recorded. The experiment ran from April 2021 to May 2025, using the test variety 'Heshu No. 2'. A randomized block design was employed with three replicates, and each plot was 20 m². 2 .

[0054] The results are shown in Tables 1-4 and 4. Figure 4 ;

[0055] Table 1. Effects of vine layering on root traits and soil shear strength.

[0056]

[0057] As shown in Table 1, after the vine-pressing treatment, the adventitious root density increased by 343%, the average root depth increased by 129%, the soil shear strength increased by 70%, and the soil disintegration rate decreased by 58%, indicating that the adventitious root living fiber network induced by vine-pressing can significantly enhance the soil's shear strength and erosion resistance.

[0058] Table 2. Effects of different stubble heights on regeneration rate and annual biomass.

[0059]

[0060] As shown in Table 2, a stubble height of 15-20 cm resulted in optimal performance, maintaining a ground cover of over 63% during the regeneration period and achieving an annual fresh biomass of 3580-3620 kg / mu. Too low a stubble height led to a prolonged period of exposed soil, while too high a stubble height reduced the number of harvests per year and decreased the total yield. Therefore, a stubble height of 15-20 cm represents the optimal balance between ecological safety and economic benefits.

[0061] Table 3 Tracking of natural sprouting rate of underground tubers in perennial systems

[0062]

[0063] As shown in Table 3, the germination rate remained stable at over 85% for the first three years after establishment, maintaining good coverage function; in the fourth and fifth years, the germination rate remained above 80%, meeting basic coverage requirements. The system can be stably maintained for 5-8 years.

[0064] Table 4. Effects of winter-dried mulch on weed suppression and soil fertility (measured in March of the second year)

[0065]

[0066] As shown in Table 4, the winter mulching treatment reduced weed density by 72.8% in the following spring, increased soil organic matter by 8.1%, total nitrogen by 8.7%, available phosphorus by 14.3%, and soil moisture by 23.5%, achieving triple ecological benefits of weed suppression, fertilization, and moisture retention.

[0067] This application constructs a biomimetic ecosystem centered on "perennial tuberous propagules + highly regenerative stems and leaves + three-dimensional root anchoring structure." This is reflected in:

[0068] 1. Paradigm Innovation

[0069] This invention redefines sweet potato from a "root-harvested food / economic crop" to a "perennial cover plant that serves ecology and animal husbandry through its aboveground biomass," completely overturning its traditional cultivation objectives. This paradigm shift is the most fundamental innovation of this invention, opening up entirely new areas of sweet potato application.

[0070] 2. Mechanism Innovation – “Fourfold Living Anchoring”, such as Figure 2 As shown.

[0071] Anchor effect: The main root (including the obliquely inserted root in zone C) is driven vertically / obliquely deep (up to 60 cm or more) to anchor the deep stable soil.

[0072] Netting effect: The fibrous roots are densely interwoven in the 0-30 cm soil layer, wrapping soil particles and forming stable aggregates.

[0073] Stitching effect: The numerous adventitious roots induced by the layering of the vines penetrate vertically through the topsoil layer, "stitching" the loose topsoil with the underlying compact soil – a unique mechanism that no existing biological measures possess.

[0074] Cover effect: The stolons and litter layer directly reduce the kinetic energy of raindrops and reduce surface splash erosion.

[0075] These four effects work synergistically within the same plant system, constituting the core mechanism advantage that distinguishes this invention from existing technologies such as vetiver hedges and ryegrass mulch.

[0076] 3. Phenological Innovation

[0077] This invention creatively utilizes "natural winter dead mulch" to replace "manual garden cleaning," transforming an "ecological burden" into a "fertilizing and weed-suppressing tool." Traditional practices consider dead stems and leaves as "waste" that needs to be cleaned up, but this invention discovers and utilizes its triple functions of weed suppression, fertilization, and moisture retention, perfectly matching the climate characteristics of southern China, where there is little rain in winter and spring but still erosive rainfall.

[0078] 4. Value Innovation

[0079] By constructing a positive incentive loop of "soil and water conservation → high-yield feed → increased income from livestock farming → farmers' proactive slope protection," the fundamental problem of ecological measures lacking endogenous economic drivers has been solved. The introduction of colorful varieties has opened up a second value transformation path: "ecological governance → landscape creation → rural tourism."

[0080] 5. No-till sustainable innovation

[0081] By preserving the underground tubers as propagation bodies, a "clonal growth"-style self-renewal of the ecosystem is achieved, completely avoiding the drastic release of soil carbon and structural damage caused by annual tillage in conventional annual crop patterns. This is the first creative utilization of the biological characteristics of sweet potatoes.

[0082] 6. Beneficial effects

[0083] Compared with the prior art, this application has the following significant advantages:

[0084] First, the soil and water conservation effect is significant. Vine layering treatment increases soil shear strength by 70% and reduces soil disintegration rate by 58%. Combined with the raindrop energy dissipation effect of the winter cover layer, soil erosion can be reduced by more than 70%. From the second year after planting, the average annual ground cover is ≥85%, and the annual soil erosion modulus drops to 150 t / (km²). 2 •a) or below (more than 95% reduction compared to bare land).

[0085] Secondly, the system has a strong self-sustaining ability. The natural germination rate of underground tubers remains above 84% within 5 years, achieving 5-8 years without the need for replanting, thus avoiding the soil carbon pool release problem caused by annual tilling in the traditional annual planting model.

[0086] Third, ecological and economic benefits are synergistic. Each mu (unit of land area) can yield 3580-3620 kg of fresh stems and leaves annually, which can be used as high-protein green fodder, forming a positive incentive cycle of "soil and water conservation → feed production → increased livestock income". The average cost of feed is reduced by 400-600 yuan per mu, and the colorful terraced fields can boost regional tourism revenue.

[0087] Fourth, maintenance costs are significantly reduced. No tilling, annual replanting, or additional fertilization is required (the fallen leaves themselves enrich the soil), weeding frequency is reduced by more than 70%, and the average annual maintenance man-days are only 1.0 man-day per acre. The overall cost over 5 years is more than 85% lower than that of engineering measures.

[0088] Fifth, soil quality continues to improve. Each year, 500-800 kg / mu of dry matter is restored in situ through litter, the organic matter content in the 0-20cm soil layer increases by an average of 0.4%-0.6% annually, and the content of water-stable aggregates in the soil increases by more than 30%.

[0089] Example 2: Ecological restoration and synergistic application of grass planting and livestock raising in typical red soil hilly terraced fields in Jiangxi (2020–2025)

[0090] Example 2 was set in the terraced fields of the red soil erosion area in Guanxi Town, Taihe County, Jiangxi Province (slope 10°–20°, soil type is typical red soil, pH 4.8–5.2).

[0091] Five treatments were set up with four replicates: CK1 bare ground control, CK2 vetiver hedge, CK3 conventional sweet potato planting (autumn harvest), and T1 the method of this application (slanted deep planting using Heshu No. 2 + colored sweet potato mixed planting).

[0092] Planting should be done according to the steps in May 2020. Harvest once each in July, August and September (leaving a stubble of 18 cm). Apply 35 kg of compound fertilizer per mu before rain after each harvest. Feed the fresh stems and leaves to local goats. Stop harvesting after the frost in November and let it wither and cover itself naturally.

[0093] The main results are as follows:

[0094] Soil erosion modulus: T1 treatment decreased to 386 t / km in the first year. 2 •a (92.5% lower than bare land), stabilized at 260 t / km from the second year onwards. 2 • Below a (reduced by more than 95% compared to bare land), significantly better than vetiver grass (reduction rate of 82%-85%) and conventional sweet potato autumn harvest (reduction rate of 48%-51%).

[0095] Ground cover: The T1 treatment achieved an average of 66.4% in the first year, 76.5% in the second year, and 82.5% in the third year, achieving "efficient coverage throughout the year." Conventional sweet potatoes, however, experience a sharp drop in coverage to 32% after the autumn harvest in November, with the winter and spring exposure period coinciding with the rainy season in southern China.

[0096] Soil organic matter: The cumulative increase rate of T1 treatment over 3 years was 57.0%, while that of conventional sweet potato in autumn was only 14.0%, vetiver grass was 23.3%, and bare land was 9.3%.

[0097] Root distribution: Through vine pressing management, the dry weight of sweet potatoes is increased by 57%-72% compared with conventional sweet potatoes, and the maximum root depth is extended from 38 cm to 52-55 cm.

[0098] Weed suppression: In the third year, the dry weight of weeds in the T1 treatment was reduced by 91.4% compared with bare land and by 69.1% compared with vetiver.

[0099] Perennial germination rate: 92% in the second year, 96% in the third year, and still 91% in the fifth year. The system can be maintained for more than 5 years without replanting.

[0100] Fresh stem and leaf yield: The T1 treatment yielded 4,800 kg per mu in the third year, which can meet the green fodder needs of 3 goats for 150 days.

[0101] Verification of rice crop after cropping: The yield of rice grown without chemical fertilizers in the following spring reached 93.8%-97.1% of that of conventionally fertilized fields, confirming the efficient nutrient return effect of the winter-dried mulch layer.

[0102] Farmers' willingness to participate increased from 22% before implementation to 89% after implementation.

[0103] Example 3: Slope management in moderately desertified karst areas of Guizhou

[0104] Example 3 was conducted on a rocky desertification slope in Huajiang Town, Guanling County, Anshun City, Guizhou Province (bedrock exposure rate approximately 30%, soil layer thickness <30 cm, slope 15°-25°). Four treatments were set up with three replicates: CK1 natural recovery, CK2 traditional maize planting, CK3 conventional sweet potato planting (autumn harvest), and T (the method described in this example, using 'Heshu No. 2' + local purple-leaf variety for deep, oblique planting).

[0105] The procedure for this application is as follows: planting in fish-scale pits, with a focus on deep, slanted planting in area C. Harvest once each in July, August, and September (leaving a stubble of 15-18 cm). Apply 30 kg of compound fertilizer per mu before rain after each harvest.

[0106] Main results:

[0107] Vegetation coverage: The average annual coverage of treatment T reached 73.3% in the third year, with a peak of 92% in September.

[0108] Soil erosion modulus: Treatment T decreased to 210 t / km² in the third year. 2 •a, a reduction of 93.8% compared to natural recovery and 95.4% compared to traditional corn planting.

[0109] Soil organic matter: The cumulative increase rate of T treatment over 3 years was 74.2%, while natural restoration decreased by 6.5% and traditional maize planting decreased by 12.9%.

[0110] Perennial germination rate: 88% in the second year and still 83% in the fifth year.

[0111] Fresh stem and leaf yield: 2850-3780 kg per mu per year, which can meet the roughage needs of one local yellow cattle for about 6 months.

[0112] Finally, it should be noted that although the above embodiments have been described in the text and drawings of this application, this should not limit the scope of patent protection of this application. Any technical solutions that are based on the essential concept of this application and utilize the content described in the text and drawings of this application, resulting in equivalent structural or procedural substitutions or modifications, as well as the direct or indirect application of the technical solutions of the above embodiments to other related technical fields, are all included within the scope of patent protection of this application.

Claims

1. A method for soil and water conservation of sweet potatoes on hillsides, characterized in that, Includes the following steps: S1 Variety Selection: Select sweet potato varieties that meet the following characteristics: long vine type, with a vine length of not less than 1.5 meters; strong branching ability, with no less than 8 branches per plant; large stem and leaf biomass, with a fresh weight of more than 2.5 kg per plant; strong stem and leaf regeneration ability, with a regeneration rate of more than 2 cm per day after cutting; long dormancy period of underground tubers, which, under natural winter conditions in the south, do not go dormant or only have shallow dormancy, with an overwintering survival rate of not less than 90%; strong spring budding potential of underground tubers, with a budding rate of more than 85%. S2 Three-dimensional planting: The sweet potato seedlings selected in S1 are planted in April-May, with a temperature ≥15℃ during the planting period; the hillside is divided into terraced fields and terrace wall areas; the terraced fields include a core planting area and two edge areas near the terrace walls; the core planting area is planted using a wide-row sparse planting method, the edge areas are planted using a double-row dense planting method, and the terrace wall areas are planted using a slanted deep planting method. S3 Vine Pressing to Promote Roots: From June to August, after the sweet potato seedlings' stolons have grown to more than 50cm, press the stolon segments into the top 3-5cm of soil, or cover them lightly with loose soil; this will cause the stolon nodes to produce adventitious roots and form secondary anchoring points. S4 Regeneration Harvesting: From mid-July to mid-November, while ensuring that the instantaneous surface coverage is not less than 70%, carry out 2-4 harvests, leaving a stubble height of 15-20 cm; after each harvest, apply 30-40 kg of N, P, K compound fertilizer per mu; S5 Winter mulching: From late November to February of the following year, stop harvesting. After the frost, the above-ground stems and leaves will naturally wither and die, forming a dry mulch layer 5-10 cm thick. S6 New Growth Cycle: The following spring, the underground tubers naturally sprout and grow new above-ground stems and leaves; and the S3-S6 steps are repeated.

2. The soil and water conservation method according to claim 1, characterized in that, In the S1 variety screening step, the sweet potato variety meets the requirement of being tolerant to poor soil conditions.

3. The soil and water conservation method according to claim 1 or 2, characterized in that, In the S1 variety screening step, the sweet potato variety screened is Heshu No.

2.

4. The soil and water conservation method according to claim 1, characterized in that, In the S2 three-dimensional planting step, the land is not tilled or prepared during planting, and the original surface vegetation residue is retained.

5. The soil and water conservation method according to claim 1, characterized in that, In the S2 three-dimensional planting step, in the core planting area, the plant spacing is 40-50 cm and the row spacing is 60-80 cm; in the edge area, the plant spacing is 25-30 cm and the row spacing is 30-35 cm, arranged in a triangular pattern; in the terrace wall area, seedlings 30-40 cm long are selected and inserted obliquely into the slope wall soil at an angle of 45°-60°, with a soil depth of 15-20 cm and 10-15 cm exposed above the ground.

6. The soil and water conservation method according to claim 1, characterized in that, In the S2 three-dimensional planting step, sweet potatoes with different leaf colors are mixed in the terrace wall area.

7. The soil and water conservation method according to claim 1, characterized in that, In the S4 regeneration harvesting step, the harvested fresh stems and leaves are used as high-protein green fodder for herbivores.

8. The soil and water conservation method according to claim 1, characterized in that, In the S4 regeneration and mowing step, N, P, K compound fertilizer is evenly spread on the terrace surface before rain, and rainwater is used to carry the fertilizer into the rhizosphere soil to promote the development of adventitious roots and the regeneration of stems and leaves.

9. The soil and water conservation method according to claim 1, characterized in that, In the S6 beginner cycle step, steps S3-S5 are repeated 5-8 times.

10. The application of the method according to any one of claims 1-9 in ecological restoration of soil erosion areas, feed supply for herbivorous livestock, or creation of rural landscapes.

Images