Method for improving soil and water conservation for oil-tea camellia forest on purple soil

Abstract

A method for improving soil and water conservation for an oil-tea camellia forest on purple soil, belonging to the technical field of soil improvement. Leveling, weed control, plowing and fertilizing are performed in an oil-tea camellia forest planting area, and then ryegrass is sowed in the oil-tea camellia forest to form a ryegrass-oil-tea camellia forest intercropping planting mode, thus significantly ameliorating the soil and water loss condition of oil-tea camellia forests on purple soil and enhancing soil and water conservation thereof.

Description

A method for improving soil and water conservation in purple soil camellia forests Technical Field

[0001] This invention belongs to the field of soil improvement technology, specifically relating to a method for improving soil and water conservation in purple soil camellia forests through intercropping ryegrass and camellia oleifera. Background Technology

[0002] Purple soils are soils formed from nutrient-rich sedimentary rocks through rapid physical weathering, and are classified as primary or newly formed soils in the USDA Soil System Classification. These soils primarily originate from purple rocks and are particularly prevalent in the Sichuan Basin of southwestern China, considered the region's most important agricultural soils. Hunan Province has a total of 13,126.8 km² of purple soil. 2 Purple soil accounts for 7.86% of the total land area in China. This purple soil is mainly distributed in the hilly areas of central Hunan, and most of it has been reclaimed as sloping farmland.

[0003] Intercropping is widely used in the mixed cultivation of different plant species within the same plot and at the same growth stage. Intercropping can increase soil surface vegetation cover and extend its duration, thereby significantly reducing the risk of soil erosion. Therefore, intercropping is considered one of the important measures to prevent soil erosion on sloping farmland. As an effective agricultural method, intercropping is crucial for protecting the soil of sloping farmland. By planting different crops, intercropping enhances rainfall interception, promotes rainwater infiltration, and reduces runoff and soil loss. Simultaneously, the root systems of intercropped plants alter soil properties, increasing porosity, reducing bulk density, and enhancing soil aggregate stability, thus protecting the soil, improving water infiltration, and making a positive contribution to sustainable agricultural development.

[0004] Ryegrass is widely used in intercropping systems due to its structural and biological characteristics, while camellia oleifera forests, as a practical woody economic forest, are highly adaptable and suitable for planting on barren land and slopes. Plant roots form a network structure in the soil, which can pull and fix soil particles, impeding runoff and trapping sediment, effectively reducing soil erosion. However, the surface of hilly areas in the south is often bare year-round, and rainfall is abundant, thus facing a serious risk of soil and nutrient loss. To effectively address this situation, it is necessary to combine bioengineering and agricultural measures to work together to better address the problem of soil erosion.

[0005] Summary of the Invention

[0006] This invention provides a planting pattern of intercropping ryegrass and camellia oleifera, which enhances the soil and water conservation capacity of purple soil camellia oleifera forests and effectively alleviates the problem of soil erosion.

[0007] This invention provides a method for improving soil and water conservation in purple soil camellia oleifera forests, the specific steps of which are as follows:

[0008] (1) In mid-May, select the target camellia oleifera forest and ryegrass intercropping area, and carry out leveling, weeding, tilling and fertilization.

[0009] (2) In December, urea was applied to the sample plots. Ryegrass seeds were sown in the camellia oleifera forest, or row sowing was adopted as the preferred sowing method. After sowing, the seeds were covered with soil and watered thoroughly.

[0010] In step (1), the spacing between the trees and rows of the camellia oleifera forest is 2m×3m, and the treatment standard for applying N and P fertilizer is 100kg / ha.

[0011] In step (2), the concentration of urea applied is 100 kg / ha. Ryegrass is sown by broadcasting at a density of approximately 60 plants / m² with a row spacing of 0.3 meters. For row sowing, the row spacing is 15 × 15 cm, and the sowing rate is approximately 1.5 kg / mu.

[0012] The principle of this invention: Ryegrass has a well-developed root system that penetrates deep into the soil, increasing soil structural stability and wind erosion resistance. Through its root system, ryegrass can effectively reduce soil erosion and prevent water loss. Its growth habits enable it to effectively regulate soil moisture. By absorbing and retaining soil moisture, it reduces the impact of rainfall on the soil, helping to maintain soil moisture and water balance. The combination of ryegrass and camellia oleifera creates a more complex ecosystem. Ryegrass provides a protective layer for camellia oleifera forests, reducing surface runoff velocity and helping to mitigate the risk of soil erosion. The intercropping of ryegrass and camellia oleifera effectively enhances the soil and water conservation capacity of purple soil camellia oleifera forests by improving soil structural stability, regulating moisture, and protecting surface cover, significantly reducing the occurrence and impact of soil erosion problems.

[0013] This invention offers the following beneficial effects: The deep root system of ryegrass effectively enhances soil structural stability, reducing the risk of soil erosion and water loss. Especially in purple soil regions, this crop combination significantly reduces the negative impacts of soil erosion, protecting the health of the surface and soil. During the growth of ryegrass, its litter and root residues gradually decompose into organic matter, enriching soil nutrients, improving soil fertility and water retention capacity, which is beneficial for the healthy growth and increased yield of camellia oleifera. The interaction between ryegrass and camellia oleifera can construct a more complex and stable ecosystem, increasing biodiversity and improving the land's ecological environment. This diversified planting method also helps reduce dependence on chemical pesticides and fertilizers, lowering the negative environmental impact of agricultural production. As an intercrop, ryegrass can serve as green manure in camellia oleifera cultivation, not only helping to maintain soil fertility and health but also providing additional economic benefits. For example, ryegrass seeds can be used as animal feed or as green manure for composting, increasing the farm's diversified revenue sources. The intercropping of ryegrass and camellia oleifera not only has significant effects on protecting water and soil resources and improving the ecological environment, but also improves the sustainability and economic benefits of agricultural production, making it an effective agricultural ecosystem management method. Attached Figure Description

[0014] Figure 1 is a schematic diagram of intercropping ryegrass and camellia oleifera forests, monoculture of camellia oleifera forests, and blank control in specific embodiments of the present invention. Detailed implementation method:

[0015] The implementation methods and specific effects of the present invention will be further described below with reference to specific embodiments.

[0016] This invention uses purple soil slope farmland in Changning City, Hengyang City, Hunan Province, China as an example. The main soil type in this area is soil developed from purple sandstone, which belongs to newly formed soil according to the USDA classification system. Camellia oleifera is the dominant vegetation in the study area. Seven-year-old Camellia oleifera forests with uniform growth were selected, and a ryegrass-Camellia oleifera intercropping pattern was adopted to further enhance the soil and water conservation capacity of the purple soil Camellia oleifera forest.

[0017] This invention selects seven-year-old Camellia oleifera forests with relatively uniform growth, and the specific experimental methods are as follows:

[0018] (1) The experimental site was located in Changning City, Hengyang City, Hunan Province, and the experimental forest was a seven-year-old Camellia oleifera forest planted in 2016. Before planting ryegrass, conventional agricultural practices were implemented on the designated land, including leveling, weeding, tilling, and application of N and P fertilizers at a standard of 100 kg / ha.

[0019] (2) Seven-year-old Camellia oleifera monoculture was planted in March 2016, with 1600 one-year-old seedlings per hectare and a plant spacing of 2m × 3m. Intercropping of Camellia oleifera and ryegrass began in December 2022, with specific sowing methods including broadcasting ryegrass seeds at a density of approximately 60 plants / m². 2 The row spacing is 0.3m. Another superior sowing method is row sowing, with a row spacing of 15×15cm and a sowing rate of about 1.5 kg / mu. After sowing, cover the seeds with soil and water thoroughly.

[0020] (3) To verify the positive effect of ryegrass-camellia intercropping on soil and water conservation in purple soil camellia forests, this experiment included an open field control and camellia monoculture for comparison. At the start of the experiment, nine plots were randomly selected to establish runoff plots, including three control plots (open fields) and six seven-year-old camellia monoculture plots. In December 2022, all experimental plots were uniformly treated with urea at a concentration of 100 kg / ha. Management of each runoff plot remained consistent.

[0021] Throughout the runoff monitoring experiment, the average height of ryegrass observed in each runoff plot was approximately 30 cm. Each runoff monitoring plot consisted of a quadrat 5 m wide and 15 m long, with an area of ​​75 m². 2 The number of 7-year-old Camellia oleifera plants in each plot remained relatively consistent at around 15, with fairly uniform growth. The planting method consisted of 3 rows, with 5 plants per row. The row spacing was 0.3m, and the width of each plot was 5m. The runoff plots were constructed using corrosion-resistant plastic partitions. The runoff plots were inclined at 15°, with the catchment ditch located at the base. Surface runoff and subsurface runoff from each plot were channeled into runoff collection bins via PVC pipes.

[0022] Water sampling experiments were conducted from January to July 2023, collecting surface runoff and interflow from nine rainfall events. Two collections were conducted in May, two in June, and one each in the remaining months (January 8, February 6, March 28, April 22, May 5, May 17, June 13, June 20, and July 25, 2023). After each rainfall event, the water volume (in mm) collected in the surface runoff and interflow buckets of each plot was measured. The surface runoff and interflow water samples were settled, filtered, and dried. The sediment content lost with the runoff was measured. If sediment was deposited in the manifold and runoff buckets, it was included in each treatment. The average value was taken as the runoff value and sediment loss value for that plot. The measurement results are shown in Table 1.

[0023] Table 1 Total runoff and soil loss under different treatments

[0024] Note: Different lowercase letters after the data in the same column indicate that the difference is statistically significant (P<0.05).

[0025] The effects of different intercropping treatments on the total annual surface runoff, interflow, and soil loss in Camellia oleifera forests were examined. Both ryegrass-Camellia oleifera intercropping and Camellia oleifera monoculture reduced these losses to some extent. However, the effectiveness of different planting types in controlling runoff and soil loss varied. Overall, ryegrass-Camellia oleifera intercropping was the most effective, with the specific loss distribution being: open field control > Camellia oleifera monoculture > ryegrass-Camellia oleifera intercropping.

[0026] During the observation period from January to July 2023, compared with the open field control, the ryegrass-camellia oleifera intercropping and camellia oleifera monoculture treatments reduced surface runoff by 21.8% and 13.5%, respectively. Ryegrass-camellia oleifera intercropping reduced surface runoff by 9.5% compared with camellia oleifera monoculture. Compared with the open field control, ryegrass-camellia oleifera intercropping and camellia oleifera monoculture treatments reduced interstitial runoff by 50.1% and 30.4%, respectively. Ryegrass-camellia oleifera intercropping reduced interstitial runoff by 27.8% compared with camellia oleifera monoculture. Compared with the open field control, ryegrass-camellia oleifera intercropping and camellia oleifera monoculture reduced soil erosion by 70.1% and 40.4%, respectively. Compared with camellia oleifera monoculture, ryegrass-camellia oleifera intercropping reduced soil erosion by 49.6%.

[0027] Furthermore, surface runoff was significantly higher than interflow in all treatments, with surface runoff accounting for 68.3%–77.1% of the total runoff during the experimental period. This indicates that surface runoff is the primary runoff generation mechanism in the purple sloping farmland of the experimental site during the rainy season. This invention demonstrates that intercropping on purple sloping farmland can reduce surface runoff by 17.0%–37.7% and interflow by 45.0%–64.4%. The planted ryegrass played a significant role in runoff control, and research shows that it can effectively reduce surface runoff, interflow, and soil erosion, thereby improving soil and water conservation capacity.

Claims

1. A method for improving soil and water conservation in purple soil camellia oleifera forests, comprising the following steps: (1) In the area where purple soil camellia forest is planted, leveling, weeding, tilling and fertilizing are carried out. (2) Sow or row sow ryegrass seeds in the camellia oleifera forest. After sowing, cover the seeds with soil and water them thoroughly to form a ryegrass-camellia oleifera intercropping planting pattern.

2. The method for improving soil and water conservation in purple soil camellia forests according to claim 1, characterized in that, In step (1), the spacing between the camellia oleifera trees is 2m × 3m.

3. The method for improving soil and water conservation in purple soil camellia forests according to claim 1, characterized in that, In step (2), ryegrass seeds are sown at a density of approximately 60 plants / m². 2 The row spacing is 0.3m. For row sowing of ryegrass seeds, the row spacing is 15×15cm, and the sowing rate is approximately 1.5 kg / mu.

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