Method for reducing nitrogen and phosphorus nutrient loss for camellia oleifera forest on purple soil

Abstract

The present invention belongs to the technical field of soil improvement. Disclosed in the present invention is a method for reducing nitrogen and phosphorus nutrient loss for a Camellia oleifera forest on purple soil. In the present invention, agricultural measures such as leveling, weed control and plowing are performed in a Camellia oleifera forest planting area, and then Lolium multiflorum is planted in a target area, so as to form a Lolium multiflorum-Camellia oleifera intercropping mode. The method of the present invention can remarkedly ameliorate loss of nitrogen and phosphorus nutrients in purple soil, and improve the soil fertility and ecological health of purple soil slope cultivated land.

Description

Method for reducing nitrogen and phosphorus nutrient loss in purple soil camellia sinensis plantation TECHNICAL FIELD

[0001] The application belongs to the technical field of soil improvement, and particularly relates to a method for reducing nitrogen and phosphorus nutrient loss in purple soil camellia sinensis plantation through ryegrass and camellia sinensis intercropping. BACKGROUND

[0002] Purple soil slope farmland is an important farmland resource in China. Because the soil-forming parent material is mostly loose and porous purple sand shale, and combined with long-term high-intensity reclamation and repeated planting, the soil and water loss is serious, and the ecological environment is extremely severe. Nitrogen (N) and phosphorus (P) are important nutrient elements. Severe soil and water loss in the purple soil region can cause N and P loss, reduce soil fertility, and limit the growth of vegetation in the region.

[0003] The intercropping method can significantly improve the degree of ground cover. This management method not only significantly reduces the flow of surface runoff and interflow, but also effectively reduces the amount of nitrogen and phosphorus nutrients lost with runoff. Compared with single planting structure, reasonable intercropping and interplanting measures show obvious superiority. These measures not only promote the absorption of nitrogen, phosphorus and other nutrients by crops, but also significantly improve the utilization efficiency of fertilizers and reduce the loss of nitrogen and phosphorus nutrients. This is of great significance to the protection of soil fertility and environmental sustainability.

[0004] Camellia sinensis is an agricultural economic crop. Its root system is developed, which can effectively fix soil and reduce nutrient loss. At the same time, through the action of rhizosphere microorganisms, it promotes the circulation of nutrients in the soil, thereby maintaining soil fertility and health. Ryegrass (Lolium multiflorum) is a common grass family plant. Its root system can effectively fix soil, reduce soil and water loss and soil erosion, and provide organic matter to soil during growth and decomposition, increase soil organic matter content, and promote soil fertility improvement. Adopting the intercropping mode of ryegrass and camellia sinensis plantation can effectively intercept nitrogen and phosphorus nutrients, prevent their loss, and thus improve soil fertility and promote crop growth.

[0005] SUMMARY

[0006] The present application provides a planting mode of ryegrass and camellia sinensis intercropping, which reduces the loss of nitrogen and phosphorus nutrients in purple soil camellia sinensis plantation and effectively alleviates the problem of soil fertility decline.

[0007] The present application provides a method for reducing nitrogen and phosphorus loss in purple soil camellia sinensis plantation, and the specific steps are as follows:

[0008] (1) Select the target camellia sinensis plantation monoculture planting area, and implement conventional agricultural measures, including leveling, leveling, weeding, and plowing.

[0009] (2) In December, spread or drill ryegrass seeds in the camellia forest, cover with soil, and irrigate with timed watering.

[0010] In step (1), the camellia forest is a seven-year-old camellia forest, and the plant spacing of the camellia forest is 2m x 3m.

[0011] In step (2), the ryegrass seeding method is scattering, the density is about 60 plants per square meter, and the row spacing is 0.3 meters. The row spacing of the drilling method is 15 x 15 cm, and the seeding amount is about 1.5 kg per mu.

[0012] Principle of the application:

[0013] The growth of ryegrass forms a dense ground cover that significantly reduces the direct impact of rainfall on the soil surface. When rain falls on the ryegrass cover, most of the water is absorbed and buffered, reducing the risk of soil erosion. This ground cover not only reduces soil erosion, but also effectively reduces the opportunity for nitrogen and phosphorus to be carried away with the water flow. Its root system improves soil structure, increases soil permeability and water retention capacity, reducing the risk of nitrogen and phosphorus being carried away by water flow; in addition, the decomposition of ryegrass litter and roots increases soil organic matter, improving soil fertility and nutrient retention capacity. Through ground cover, soil structure improvement, organic matter increase, and nutrient cycling, intercropping ryegrass with camellia forest can effectively reduce the loss of nitrogen and phosphorus in purple soil, thereby improving soil fertility and ecological health.

[0014] The application has the following beneficial effects:

[0015] The combination of camellia forest with intercropping crops such as ryegrass significantly improves the economic benefits of purple soil. The root system of camellia tree improves soil structure and increases soil organic matter, while the root system of ryegrass enhances soil water holding capacity and reduces fertilizer demand. This model improves the yield of camellia trees and intercropping crops, thereby increasing overall economic benefits. In addition, vegetation cover reduces soil erosion and erosion, reduces repair costs, and prolongs the effective service life of the land. The combination of camellia forest and intercropping crops also brings multiple sources of income, including camellia fruit, tea oil and ryegrass feed, enhancing the economic stability of farmers. Improved soil quality reduces nitrogen and phosphorus loss, reduces environmental governance costs, increases land market value, and supports long-term economic benefits. This model not only improves productivity, but also realizes sustainable development of agriculture. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is the change of surface runoff N loss amount in different treatments in the specific implementation example of the application.

[0017] Figure 2 is the change of interflow N loss amount in different treatments in the specific implementation example of the application.

[0018] Figure 3 is a change of P loss amount of different treatments of surface runoff in the embodiment of the present application.

[0019] Figure 4 is a change of P loss amount of different treatments of soil runoff in the embodiment of the present application. DETAILED DESCRIPTION

[0020] The present application reduces the problem of nitrogen and phosphorus loss of purple soil by using the method of ryegrass-camellia oleifera intercropping. The implementation and specific effects of the present application will be further described below in combination with specific examples.

[0021] The present application takes the purple soil slope farmland in Changning City, Hengyang City, Hunan Province, China as an example, and the dominant vegetation in this area is camellia oleifera. A seven-year-old camellia oleifera forest with consistent growth vigor is selected, and a ryegrass-camellia oleifera intercropping planting mode is adopted to improve the soil fertility and effectively reduce the problem of nitrogen and phosphorus loss of purple soil slope farmland.

[0022] The present application selects a camellia oleifera forest planting area with consistent growth vigor, and the specific implementation method is as follows:

[0023] (1) The test area is located in Changning City, Hengyang City, Hunan Province, and the test forest is a seven-year-old camellia oleifera forest planted in 2016. The planting spacing of the camellia oleifera forest is 2m x 3m. Before planting ryegrass, routine agricultural measures are carried out on the slope farmland in the target area, including leveling, weeding, plowing, etc.

[0024] (2) In December, camellia oleifera and ryegrass intercropping is carried out, and the specific sowing method includes broadcasting ryegrass seeds with a density of about 60 plants / m 2 , and the row spacing is 0.3m. A more optimal sowing method is strip sowing with a row spacing of 15x15cm and a sowing amount of about 1.5kg per mu. After sowing, the seeds are covered with soil and fully watered.

[0025] (3) In order to verify the improvement effect of ryegrass-camellia oleifera intercropping on the nitrogen and phosphorus loss of purple soil, this test increases the bare land control and camellia oleifera monocropping for comparison.

[0026] Under the condition that the altitude, orientation, slope, soil type and other site background conditions are roughly similar, 9 runoff plots are established for the 3 measures selected (bare land, camellia oleifera monocropping and ryegrass-camellia oleifera intercropping).

[0027] The average height of ryegrass observed in each runoff plot was approximately 30 cm throughout the runoff monitoring experiment. Each runoff monitoring plot was a quadrat with a width of 5 m and a length of 15 m. The number of Camellia oleifera trees in each plot was maintained at approximately 15, and the growth was relatively consistent. The planting pattern was 3x5. The row spacing was 0.3 m, and the width of each plot was 5 m. The runoff plots were constructed using corrosion-resistant plastic partitions. The runoff plots were inclined at an angle of 15°, and the convergence ditch was located at the base. The surface runoff and interflow of each plot were directed into the runoff collection barrels through PVC pipes.

[0028] The water sampling experiment was conducted from January 2023 to July 2023, and a total of 9 rainfall events were selected to collect the generated surface runoff and interflow. Among them, 2 times were collected in May, 2 times in June, and 1 time in each of the remaining months (January 8, 2023, February 6, 2023, March 28, 2023, April 22, 2023, May 5, 2023, May 17, 2023, June 13, 2023, June 20, 2023, and July 25, 2023, respectively). After each rainfall event, 3 water samples were collected from each runoff collection barrel for analysis of N and P concentrations. The water samples in the runoff collection barrels were thoroughly mixed, and 500 mL of sample was quickly transferred to a labeled polyethylene bottle. These samples were sent to the laboratory, stored at 4°C, and analyzed within 48 hours.

[0029] A portion of the water samples were analyzed using the molybdenum blue colorimetric method and potassium persulfate oxidation method to determine the total nitrogen (TN) and total phosphorus (TP) in the stock solution; another portion of the water samples was filtered through a 0.45 μm filter membrane, and the AutoAnalyzer-3 flow analyzer was used to determine the soluble nitrogen (DN), nitrate nitrogen (NO 3- -N), ammonium nitrogen (NH 4+ -N), soluble phosphorus (DP), and phosphate (PO 4- -P) contents. Particulate nitrogen (PN) was calculated by determining the difference between TN and DN, and particulate phosphorus (PP) was calculated by determining the difference between TP and DP.

[0030] As shown in FIG. 1, the N loss in surface runoff under different treatments was mostly in the order of bare land control > Camellia oleifera monoculture > ryegrass intercropping. The TN, DN, and NO 3- -N loss was in the order of bare land control > Camellia oleifera monoculture > ryegrass intercropping, and the NH 4+ -N loss was mostly in the order of bare land control > Camellia oleifera monoculture > ryegrass intercropping, but in event 6, it was in the order of Camellia oleifera monoculture > bare land control > ryegrass intercropping. The PN loss was mostly in the order of bare land control > Camellia oleifera monoculture > ryegrass intercropping, but in event 5, it was in the order of ryegrass intercropping > bare land control > Camellia oleifera monoculture. Overall, the effect of intercropping on the loss of various forms of nitrogen in surface runoff was greater than that of Camellia oleifera monoculture.

[0031] As shown in Figure 2, different treatments on the loss of nitrogen in the soil of the runoff mostly showed that the bare land control > Camellia oleifera monoculture > ryegrass intercropping. Among them, the loss of TN and PN showed that the bare land control > Camellia oleifera monoculture > ryegrass intercropping, and the loss of DN mostly showed that the bare land control > Camellia oleifera monoculture > ryegrass intercropping, and in events 7 and 8, it showed that Camellia oleifera monoculture > bare land control > ryegrass intercropping. In event 7, the total loss of DN in intercropping and monoculture increased.

[0032] Therefore, on the purple soil slope farmland, different treatments on the loss of nitrogen in the surface runoff mostly showed that the bare land control > Camellia oleifera monoculture > ryegrass intercropping. Intercropping ryegrass can change the soil structure and water migration to affect nitrogen loss, especially on the purple soil slope farmland, which plays a great role in alleviating the loss of nitrogen (N) in surface runoff and soil runoff in Camellia oleifera forest.

[0033] As can be seen from Figure 3, different treatments on the loss of phosphorus (TP, DP, PO 4- -P and PP) in the surface runoff mostly showed that the bare land control > Camellia oleifera monoculture > ryegrass intercropping. In Figure 4, the loss of PO 4- -P in the soil runoff of the three treatments was relatively large. Different treatments on the loss of phosphorus (TP, DP, PO 4- -P and PP) in the soil runoff showed that the bare land control > Camellia oleifera monoculture > ryegrass intercropping.

[0034] In this test, purple soil showed high soil porosity due to its unique soil structure. When this soil is covered with green manure, its water storage and conservation capacity is significantly enhanced. This change not only helps to maintain soil moisture, but also effectively slows down the downward migration speed of phosphorus, thereby achieving the goal of reducing the loss of phosphorus in the soil runoff. Therefore, combined with the actual situation of purple soil slope farmland, intercropping ryegrass has become an effective agricultural practice. This not only can improve the soil nutrient status, but also can significantly reduce the loss of nutrients, thereby improving the agronomic utilization rate of fertilizers and providing strong support for the sustainable development of agricultural production.

Claims

1. A method for reducing nitrogen and phosphorus nutrient loss in a Camellia oleifera forest in purple soil, comprising the following steps: (1) In the planting area of the Camellia oleifera forest in purple soil, leveling, weeding, plowing and fertilizing are carried out. (2) In the Camellia oleifera forest, ryegrass seeds are sown or sowed, and after sowing, the seeds are covered with soil and fully watered to form a ryegrass-Camellia oleifera forest intercropping planting mode.

2. The method for improving water and soil conservation of a Camellia sinensis plantation in purple soil according to claim 1, characterized in that, In step (1), the spacing between Camellia oleifera trees is 2m x 3m.

3. The method for improving water and soil conservation of a purple soil Camellia sinensis plantation according to claim 1, characterized in that, In step (2), the ryegrass seeds are sown at a density of about 60 plants per square meter 2 with a row spacing of 0.3 m. The ryegrass seeds are sown in rows with a spacing of 15 x 15 cm at a seeding rate of about 1.5 kg per mu.

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