A green labor-saving cultivation method for improving soil quality of tropical mango orchard

Abstract

This invention belongs to the field of soil improvement technology, and specifically relates to a green and labor-saving cultivation method for improving soil quality in tropical mango orchards. The core of this invention lies in intercropping a green manure crop with characteristics such as tolerance to paclobutrazol, shade tolerance, heat tolerance, drought tolerance, and tolerance to poor soil conditions between rows in tropical mango orchards. This green manure crop is simple and labor-saving to manage and does not compete with mango trees for water and fertilizer resources. Utilizing the carbon sequestration, fertilization, and water storage functions of this green manure crop, the micro-ecological environment of the tropical mango orchard soil is improved, soil microbial community diversity is restored, and the microbial effect on reducing paclobutrazol residues in the soil is enhanced, thereby improving soil fertility and achieving healthy and sustainable development of orchard soil. Simultaneously, it provides technical support for building a green brand for the tropical early-maturing mango industry, effectively enhancing the brand credibility and product premium of tropical early-maturing mangoes.

Description

Technical Field

[0001] This invention belongs to the field of soil improvement technology, and in particular relates to a green and labor-saving cultivation method for improving soil quality in tropical mango orchards. Background Technology

[0002] In 2024, the main tropical early-maturing mango producing areas in my country had a planting area of ​​1.03 million mu (approximately 65,000 hectares), accounting for about 20% of the national total, with an output value of nearly 5.9 billion yuan. This is a pillar industry for enriching the people and revitalizing villages in tropical regions. External application of paclobutrazol to control shoot growth and promote flowering is a key technology in the cultivation of early-maturing tropical mangoes, used to seize market opportunities. However, in actual production, fruit farmers, in pursuit of earlier market entry, generally adopt a combined application mode of high-dose, high-frequency root zone irrigation and foliar spraying. In high-yield orchards, mature trees receive an average of 30-50g / tree of 15% paclobutrazol in the soil annually, and foliar spraying of 3.0-5.0g / L formulation is applied 15-22 times. The cumulative effect of long-term excessive application results in an average paclobutrazol residue in the surface soil of high-yield orchards reaching as high as 55mg / kg during the fruiting period, more than 15 times the safe threshold for soil microorganisms and tree growth. High paclobutrazol residues reduced soil bacterial populations by 58% and fungal and actinomycete populations by 28%, further weakening the efficiency of soil microorganisms in reducing paclobutrazol residues. Under traditional clean cultivation methods, paclobutrazol's half-life in the soil can reach 114 days. Problems such as declining soil microbial fertility, premature aging of fruit trees, clustered inflorescences, and reduced fruit marketability have become core bottlenecks for the sustainable development of the tropical early-maturing mango industry. Against this backdrop, intercropping green manure crops—which are paclobutrazol-tolerant, shade-tolerant, heat-tolerant, drought-tolerant, and tolerant of poor soil conditions, requiring simple and labor-saving management, and not competing with fruit trees for water and fertilizer resources—better utilizes the carbon sequestration and water storage capacity of green manure crops to improve the soil microecological environment, restore soil microbial community diversity, enhance the microbial capacity to reduce paclobutrazol, improve soil fertility, achieve healthy and sustainable orchard soil, promote the development of a green brand for the tropical early-maturing mango industry, and enhance the brand credibility and premium pricing power of tropical early-maturing mangoes. Summary of the Invention

[0003] The purpose of this invention is to provide a green and labor-saving cultivation method for improving soil quality in tropical mango orchards, so as to restore the diversity of soil microbial communities in orchards with high paclobutrazol residues, improve soil fertility, enhance tree vigor and fruit marketability, reduce management costs, and ultimately achieve healthy and sustainable orchard soil.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution: A green and labor-saving cultivation method for improving soil quality in tropical mango orchards is characterized by intercropping paclobutrazol-tolerant, heat-tolerant, drought-tolerant, barren-tolerant, moderately shade-tolerant, shallow-rooted, high-density root, high ground cover, low-growing, trampling-resistant, and perennial green manure crops between rows of mango orchards, thereby achieving healthy and sustainable soil in tropical dryland mango orchards. Furthermore, the green manure crop mentioned is Bermuda grass (Bermudagrass). Cynodon dactylon (L.) Pers.), the variety is imported from the United States. Savannah ”; Furthermore, the aforementioned " Savannah "The intercropping of Bermuda grass in mango orchards includes the following steps: 3-5 days in advance, spray glufosinate-ammonium between the rows of the tropical mango orchard to quickly kill existing weeds; then, dig trenches every 20cm and sow the seeds in the trenches." Savannah "Plant Bermuda grass seeds and cover them with soil. Before the Bermuda grass coverage is less than 80%, manual weeding is required. Once the coverage is greater than 80%, let it grow naturally." Furthermore, the depth of the trench is 2-3 cm; Furthermore, the " Savannah "Bermudagra seeds are uncoated, shelled seeds." Furthermore, the sowing " Savannah "The best time to plant Bermuda grass seeds is in March and April;" Furthermore, the sowing " Savannah "Bermudagra seeds need to be sown after a concentrated and continuous rainfall of more than 30 mm; Furthermore, the seeds were sown in the trench. Savannah The dosage of Bermuda grass seeds is 8-10g / m³. 2 ; Furthermore, the seeds were sown in the trench. Savannah "The method for sowing Bermuda grass seeds is to thoroughly mix the seeds with the original soil that has passed through a 2mm sieve at a volume ratio of 1:8~10, and then evenly sow them in the furrows." Furthermore, the thickness of the covering soil is 1-2 cm; Furthermore, the aforementioned artificial weeding intervention focuses on removing creeping, parasitic, and invasive weeds and species that grow much faster than bermudagrass, with a frequency of ≤1 time / month and an overall frequency of ≤2 times.

[0005] This invention addresses the high residue stress of paclobutrazol by constructing a complete "grass seed-variety-process" synergistic green remediation system, which has the following advantages: (1) Actively restore soil micro-ecology: Use the root network of bermudagrass to improve the soil environment, activate the microbial population inhibited by paclobutrazol, restore microbial diversity to synergistically dissolve paclobutrazol residue and form a virtuous cycle.

[0006] (2) Significantly reduces management costs and does not compete for water and fertilizer resources: Compared with traditional grass cover that requires regular mowing (2-4 times per year) or weeding, this invention completely eliminates the need for mowing after the bermudagrass coverage reaches the standard. Manual intervention only requires the removal of a few noxious weeds (≤2 times / the entire planting period). Moreover, bermudagrass is a perennial grass, reducing management time by more than 80% and saving labor and pesticide costs. In addition, bermudagrass has a shallow root system and will not compete with fruit trees for water and fertilizer resources.

[0007] (3) Comprehensive improvement of soil fertility and fruit quality: Carbon fixation and fertilization are achieved through the natural decomposition of bermudagrass residues, and water storage and drought resistance are achieved through high coverage and root network, thereby restoring tree health and improving the marketability of mangoes.

[0008] (4) Environmental friendliness and brand support: It adopts bioremediation and natural management without secondary pollution, which is in line with the goal of green agriculture. It can provide key soil management technology support for tropical early-maturing mangoes to obtain green, organic or GAP certification, and enhance market credibility and premium capabilities. Attached Figure Description Figure 1 This is a field effect diagram of the green and labor-saving cultivation method for improving soil quality in tropical mango orchards, as described in this invention. Detailed Implementation

[0009] To make the technical problem to be solved, the technical solution, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention. To demonstrate that the method of this application is superior to conventional methods, the applicant conducted two field trials. Example 1

[0010] This study, conducted at the research base of the South Subtropical Crops Research Institute of the Chinese Academy of Tropical Agricultural Sciences, established an evaluation experiment on suitable intercropping green manure crops in tropical lateritic mango orchards. The experiment ran from March 2018 to March 2019, employing a completely randomized block design with three replicates per treatment, resulting in eight treatments: natural grass cover (with broadleaf floribunda as the pioneer grass), fertile turnip, native bermudagrass, broadleaf grass, cassia seed, and bermudagrass (…). Savannah The intercropping methods include white clover and styloses. Bermuda grass seeds are all uncoated, shelled seeds. Furrows are dug at 20cm intervals, 2-3cm deep. The seeds are then thoroughly mixed with native soil (passed through a 2mm sieve) at a 1:10 volume ratio, and evenly sown between rows. Finally, the seeds are covered with 1-2cm of soil. Specific intercropping methods and growth performance are shown in Table 1.

[0011] Considering that intercropping in tropical mango orchards requires balancing heat tolerance, drought tolerance, a certain degree of shade tolerance, and labor-saving management, while avoiding competition with fruit trees for water and fertilizer resources, native Bermuda grass and " Savannah"Bermudagrass is more suitable, especially..." Savannah "Bermudagrass is the most suitable, requiring no mowing and saving a lot of labor, making it suitable for intensive production. Although Stylosanthes is a high-quality legume forage in tropical regions and is highly adaptable, its tall stature and deep root system require a lot of manpower to mow every year, and it easily competes with trees for water and fertilizer resources, making it unsuitable for intercropping in mango orchards."

[0012] Table 1. Intercropping patterns and adaptability of different green manure crops in mango orchards

[0013] Example 2 This embodiment is based on a long-term, fixed-location experiment of mango orchard cover cropping established at the research base of the South Subtropical Crops Research Institute, Chinese Academy of Tropical Agricultural Sciences. The experiment ran from 2018 to 2025, with mango trees spaced 4 m × 4 m apart. A completely randomized block design was used, including bare-soil cultivation (CT, control) and bermudagrass intercropping (CC, control). Savannah Intercropping with *Cynodon dactylon* and *Stylos lanceolata* was performed, with each treatment replicated four times, and each plot measuring 12 m × 16 m. The CT treatment used a herbicide (glufosinate-ammonium, sprayed at the recommended dose of 200 g / ha) to control weeds between rows. The intercropping method for *Cynodon dactylon* was basically the same as in Example 1, except that the seed dosage was increased to 10 g / m². 2 When sowing, the ratio of seeds to soil should be adjusted to 1:8.

[0014] The experimental area has a tropical monsoon climate. Meteorological monitoring data from 2019 to 2024 show that the average annual temperature is 24.1℃ (±1.3℃) and the annual precipitation is 1558 mm (±218 mm). Rainfall is concentrated from April to October (accounting for 85% of the annual total), and the dry season is from November to March of the following year. The tested soil was a typical lateritic red soil. The basic physicochemical properties of the initial soil layer (0–30 cm) were as follows: pH 4.74 (H2O, 1:2.5), SOC 10.5 g / kg (potassium dichromate oxidation method), TN 0.81 g / kg (Kjeldahl nitrogen determination method), available nitrogen (AN), phosphorus (AP), and potassium (AK) 116.9 mg / kg (alkali hydrolysis diffusion method), 17.0 mg / kg (molybdenum antimony colorimetric method), and 54.0 mg / kg (flame photometry method), respectively. The mechanical composition (hydrometer method) was 42.8% clay (<2 μm), 39.5% silt (2–50 μm), and 17.7% sand (50–2000 μm). The soil texture was classified as loamy clay.

[0015] Comparative test results (1) Improve soil physical and chemical properties, enhance soil nutrient availability, and sequester carbon and enrich soil. Although *Stylosanthes spp.* does not meet the current requirements for green and labor-saving production in mango orchards, it is a leguminous green manure crop with strong adaptability in tropical regions. It can be used as a high-quality forage and has shown good application potential in soil fertility improvement, thus attracting widespread attention. Table 2 shows that compared with the traditional clean cultivation model in orchards, intercropping… Savannah "Bermudagrass can significantly improve soil physical and chemical properties, increase soil nutrient availability, and exert ecological effects of carbon sequestration and fertilization. Moreover, its improvement effect is consistent with that of intercropping with Stylosanthes.

[0016] Table 2. Physicochemical properties of soil in the 0-30 cm depth under different treatments

[0017] Note: Different lowercase letters indicate significant differences (LSD). p <0.05, n = 4), the asterisk represents the significance level: *, p <0.05; **, p <0.01; ***, p <0.001; ns, not significant.

[0018] (2) Significantly improves soil microbial abundance and diversity As shown in Table 3, compared with the clean cultivation treatment, after 4 years of intercropping with "Savannah" bermudagrass (in 2022), both the Chao 1 and Shannon indices in the orchard topsoil significantly increased, and the abundance and diversity of the microbial community were effectively restored. With the extension of the intercropping period, the soil Chao 1 and Shannon indices remained at a high level, and microbial residues also showed significant accumulation characteristics, which can provide a material basis for soil organic carbon sequestration and carbon pool stability, thereby contributing to maintaining soil health and sustainable ecosystem development.

[0019] Table 3. Abundance, diversity, and microbial residue in soil 0-30 cm under different treatments

[0020] Note: Different lowercase letters indicate significant differences (LSD). p <0.05, n = 4), the asterisk represents the significance level: *, p <0.05; **, p <0.01; ***, p <0.001; ns, not significant; Chao 1 represents microbial richness; Shannon represents microbial diversity; carbon from fungal, bacterial, and microbial remains represents the absolute number of microorganisms.

[0021] (3) Significantly enhance the multifunctionality of soil ecosystems Table 4 shows that, compared with the clean cultivation model, intercropping... Savannah "Bermudagrass significantly increased the activity of carbon, nitrogen, and phosphorus cycling-related enzymes in the 0–30 cm soil layer of mango orchards, and the enzyme activity enhancement effect became more stable with the extension of intercropping years. In the topsoil (0–15 cm), the activities of carbon cycling-related enzymes (BG, BX) and carbon acquisition enzymes in the bermudagrass treatment were significantly higher than those in clean cultivation after 4 years of intercropping, and there was no significant difference compared with the Styrax styrax treatment; by 7 years of intercropping, the activities of LAP, NAG, and nitrogen acquisition enzymes in the bermudagrass treatment were significantly higher than those in clean cultivation and Styrax styrax treatment, reflecting its long-term promoting effect on soil nitrogen mineralization. In the deep soil (15–30 cm), the activities of CBH and NAG in the bermudagrass treatment increased significantly after 7 years of intercropping." The annual growth rate was significantly higher than that of the clean cultivation and Styrax styrax treatments, indicating that its deep root characteristics have a more prominent driving effect on carbon decomposition and nitrogen transformation in deep soil. Overall, the activity of soil nutrient acquisition enzymes in the Bermuda grass treatment was comparable to that in the Styrax styrax treatment, and some indicators were even better. It can effectively enhance the multifunctionality of the soil ecosystem and provide a good regulatory effect for maintaining and improving soil fertility in mango orchards.

[0022] Table 4. Enzyme activities related to carbon, nitrogen, and phosphorus cycling in soil at depth 0-30 cm under different treatments

[0023] Note: Soil carbon cycle-related enzymes (BG: β-glucosidase; BX: β-xylosidase; CBH: cellobiase); soil nitrogen cycle-related enzymes (LAP: leucine aminopeptidase; NAG: N-acetyl-β-D-glucosidase); soil phosphorus cycle-related enzymes (ACP: acid phosphatase); C-acq: soil carbon acquisition enzyme activity; N-acq: soil nitrogen acquisition enzyme activity; P-acq: soil phosphorus acquisition enzyme activity; asterisks represent significance levels: *, p <0.05; **, p <0.01; ***, p <0.001; ns, not significant; different letters in the same column indicate significant differences (LSD). p <0.05, n = 4).

[0024] (4) Impact on mango yield and quality As shown in Table 5, intercropping bermudagrass / bermudagrass in orchards does not reduce mango yield and quality.

[0025] Table 5. Mango yield and quality under different treatments (4th year of grass cover, i.e., 2022)

[0026] Note: Different letters in the same column indicate significant differences (LSD). p <0.05, n = 4).

[0027] (5) Saves labor and improves the ecological benefits of mango orchards As shown in Table 6, the clean cultivation treatment required herbicides 4-5 times per year, totaling 31 times over 7 years, while the grass-based treatment only required one application before sowing, resulting in a 96.8% reduction in weeding labor. Styrax intercropping required three harvests per year, in March, June, and October, totaling 21 times over 7 years, with each harvest requiring 1 person-day per mu (approximately 0.067 hectares). In contrast, intercropping with Bermuda grass saved a cumulative 21 person-days per mu over 7 years, resulting in a total labor cost saving of 2520 yuan per mu, averaging 360 yuan per mu per year. Furthermore, the half-life of paclobutrazol in the soil decreased from 103 days under clean cultivation conditions to 75.5 days under Bermuda grass treatment, significantly promoting the degradation efficiency of paclobutrazol in the soil.

[0028] Table 6. Agricultural input costs, management labor, and ecological benefits of different treatments

Claims

1. A green and labor-saving cultivation method for improving soil quality in tropical mango orchards, characterized in that, By intercropping green manure crops that are tolerant to paclobutrazol, heat, drought, and poor soil conditions, moderately shade-tolerant, with shallow and dense root systems, high ground cover, low plant height, strong soil stabilization and fertilization capabilities, do not restrict mango growth, and are resistant to trampling and do not require harvesting for many years, the soil in tropical dryland mango orchards can be kept healthy and sustainable.

2. The green and labor-saving cultivation method for improving soil quality in tropical mango orchards according to claim 1, characterized in that, The green manure crop mentioned is Bermuda grass (Bermudagrass) Cynodon dactylon (L.) Pers.), the variety is imported from the United States. Savannah ".

3. The green and labor-saving cultivation method for improving soil quality in tropical mango orchards according to claim 2, characterized in that, The aforementioned " Savannah "The intercropping of Bermuda grass in mango orchards involves the following steps: 3-5 days in advance, spray glufosinate-ammonium between the rows of the tropical mango orchard to quickly kill existing weeds; then, dig trenches every 20cm and sow the seeds in the trenches." Savannah "Plant Bermuda grass seeds and cover them with soil. Before the Bermuda grass coverage is less than 80%, manual weeding is required. Once the coverage is greater than 80%, let it grow naturally." 4. The green and labor-saving cultivation method for improving soil quality in tropical mango orchards according to claim 3, characterized in that, The depth of the trench is 2-3 cm; The " Savannah "Bermudagra seeds are uncoated, shelled seeds." The sowing Savannah "The best time to plant Bermuda grass seeds is in April and May;" The sowing Savannah "Bermudagra seeds need to be sown after a concentrated and continuous rainfall of more than 30 mm; The sowing in the ditch Savannah The dosage of Bermuda grass seeds is 8-10g / m³. 2 ; The sowing in the ditch Savannah "The method for sowing Bermuda grass seeds is to thoroughly mix the seeds with the original soil that has passed through a 2mm sieve at a volume ratio of 1:8~10, and then evenly sow them in the furrows." The thickness of the covering soil is 1-2 cm; The aforementioned manual weeding intervention focuses on removing creeping, parasitic, and invasive weeds and species that grow much faster than bermudagrass, with a frequency of ≤1 time / month and an overall frequency of ≤2 times.

Images