Method for improving ecological environment of citrus orchard by intercropping vicia sativa

Abstract

The invention relates to the technical field of ecological planting, in particular to a method for improving the ecological environment of a citrus orchard through relay intercropping of common vetch. The planting method comprises the following steps: (1) sowing vicia sativa seeds in a citrus garden in late October; (2) applying a phosphorus-potassium fertilizer in the seedling emergence stage of the common vetch; (3) naturally decomposing the vicia sativa plants after the vicia sativa plants are withered; the seeds falling into the soil naturally grow. According to the method, the common vetch is planted in the citrus orchard, the organic matter, total nitrogen and alkali-hydrolyzable nitrogen levels of soil of the citrus orchard can be improved, the urease and cellulase levels of the orchard can be improved, the arsenic content in the soil of the orchard can be reduced, the economic value of the citrus orchard can be improved, the yield and quality of the citrus can be improved, and a basis is provided for ecological green planting of the citrus.

Description

Technical Field

[0001] The invention relates to the technical field of ecological planting, and in particular to a method for improving the ecological environment of a citrus orchard by intercropping peas. Background Art

[0002] With the rapid development of the citrus industry, the drawbacks of traditional citrus orchard cultivation models have gradually emerged. The extensive use of chemical fertilizers and pesticides in traditional citrus cultivation has led to soil compaction, decreased fertility, an imbalance in the soil microbiome, the breeding of pests and diseases, and damage to the orchard's ecological environment, severely impacting citrus yield and quality. This single citrus cultivation model has resulted in poor ecosystem stability and insufficient biodiversity in orchards, making sustainable development difficult.

[0003] Currently, some orchards have begun using intercropping and relay cropping to improve the orchard's ecological environment. However, some intercropping and relay cropping methods do not significantly improve soil fertility, effectively suppressing weeds and reducing pests and diseases. Therefore, a scientific and reasonable relay cropping method is urgently needed to effectively improve the ecological environment of citrus orchards and achieve the green and sustainable development of citrus. Summary of the Invention

[0004] The invention aims to provide a method for improving the ecological environment of a citrus orchard by intercropping peas.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for improving the ecological environment of a citrus orchard by intercropping peas, comprising the following steps:

[0007] (1) In late October, sow the arrow pea seeds in the citrus orchard;

[0008] (2) Apply phosphorus and potassium fertilizers during the emergence stage of arrow pea;

[0009] (3) After the pea plant withers, it will decompose naturally; the seeds that fall into the soil will grow naturally.

[0010] Preferably, the sowing method in step (1) is broadcast sowing or drill sowing;

[0011] No seeds will be sown within a radius of 0.5 to 0.8 m from the vertical projection of the citrus tree crown;

[0012] The furrow depth during row sowing is 2 to 3 cm.

[0013] Preferably, the seed rate during sowing in step (1) is 5.5-6.5 kg / mu.

[0014] Preferably, the phosphorus and potassium fertilizer in step (2) is potassium superphosphate;

[0015] The application amount of the potassium superphosphate is 5 to 8 kg / mu.

[0016] The present invention also provides the application of the method in improving the nutrient content of soil in a citrus orchard;

[0017] The soil nutrients include organic matter, total nitrogen and alkaline-hydrolyzable nitrogen.

[0018] The present invention also provides the application of the method in improving the activity of soil enzymes in citrus orchards;

[0019] The soil enzymes include cellulase and urease.

[0020] The present invention also provides application of the method in reducing the arsenic content in soil of a citrus orchard.

[0021] The present invention also provides application of the method in improving the yield and / or quality of citrus.

[0022] The present invention provides a method for intercropping peas to improve the ecological environment of a citrus orchard. The method comprises the following steps: (1) sowing peas seeds in a citrus orchard in late October; (2) applying phosphorus and potassium fertilizers during the emergence stage of the peas; (3) allowing the peas to wilt and decompose naturally; the seeds that fall into the soil grow naturally. Planting peas in a citrus orchard according to the method of the present invention can increase the levels of organic matter, total nitrogen, and alkaline nitrogen in the soil of the citrus orchard, increase the levels of urease and cellulase in the orchard, reduce the arsenic content in the soil of the orchard, increase the economic value of the citrus orchard, and improve the yield and quality of citrus, providing a basis for the ecological and green cultivation of citrus. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The composition of fungi in the soil of citrus orchards with different treatments;

[0024] Figure 2 is the fungal diversity index in the soil of citrus orchards with different treatments. DETAILED DESCRIPTION

[0025] The present invention provides a method for improving the ecological environment of a citrus orchard by intercropping peas, comprising the following steps:

[0026] (1) In late October, sow the arrow pea seeds in the citrus orchard;

[0027] (2) Apply phosphorus and potassium fertilizers during the emergence stage of arrow pea;

[0028] (3) After the pea plant withers, it will decompose naturally; the seeds that fall into the soil will grow naturally.

[0029] In the present invention, the sowing method in step (1) is broadcast sowing or row sowing;

[0030] No sowing shall be done within a radius of 0.5 to 0.8 m from the vertical projection of the citrus crown; preferably, no sowing shall be done within a radius of 0.6 m from the vertical projection of the citrus crown.

[0031] The furrow depth during row sowing is 2 to 3 cm, preferably 2.5 cm.

[0032] In the present invention, the seed rate during sowing in step (1) is 5.5-6.5 kg / mu, preferably 6.0 kg / mu.

[0033] In the present invention, the phosphorus and potassium fertilizer in step (2) is potassium superphosphate;

[0034] The application amount of the potassium superphosphate is 5-8 kg / mu, preferably 6 kg / mu.

[0035] The present invention also provides the application of the method in improving the nutrient content of soil in a citrus orchard;

[0036] The soil nutrients include organic matter, total nitrogen and alkaline-hydrolyzable nitrogen.

[0037] The present invention also provides the application of the method in improving the activity of soil enzymes in citrus orchards;

[0038] The soil enzymes include cellulase and urease.

[0039] The present invention also provides application of the method in reducing the arsenic content in soil of a citrus orchard.

[0040] The present invention also provides application of the method in improving the yield and / or quality of citrus.

[0041] The solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be understood as limiting the scope of protection of the present invention.

[0042] The citrus orchard described in the embodiments of the present invention is located in Shuangshi Village, Qinglian Town, Jiangyou City, Sichuan Province, covering an area of 20 mu. The citrus varieties in the citrus orchard are Chunjian Papagan, with trees aged 4 years, and a row spacing of 3 meters and a plant spacing of 2.6 meters. The orchard soil is yellow clay with a low organic matter content. Soil nutrient analysis results showed: 12.58g / kg organic matter, 0.9381g / kg total nitrogen, 111.2g / kg alkaline-hydrolyzable nitrogen, 117.98mg / kg available phosphorus, and 316.81mg / kg available potassium.

[0043] The climatic conditions in Shuangshi Village, Qinglian Town, Jiangyou City, Sichuan Province are: an average annual temperature of 16-18°C, an annual precipitation of 800-1200 mm, an altitude of no more than 1500 m, and a frost-free period of at least 280 days. The present invention was tested in 2023-2024, with an average temperature of 16°C, an annual precipitation of 1000 mm, an altitude of 550 m, and a frost-free period of 290 days.

[0044] The peas described in the embodiments of the present invention are sourced from the Sichuan Academy of Agricultural Sciences.

[0045] Example 1

[0046] The experiment adopted a single-factor randomized block design. The experimental site was divided into three treatment groups: the arrow pea group, the clean tillage group (CK1) and the natural grass group (CK2). Each treatment group was replicated three times.

[0047] Select arrow pea seeds with full grains and no diseases and insect pests, dry them for 2 days, and sow them on October 25. The sowing method is row sowing with a furrow depth of 2 cm. Do not sow within a radius of 0.6 m from the vertical projection of the citrus crown. The sowing amount is 6 kg / mu.

[0048] After sowing, water promptly to keep the soil moist to promote germination. During the growing season, water promptly based on weather conditions and soil moisture to avoid drought or waterlogging. Increase watering frequency during droughts, and drain promptly during the rainy season to prevent waterlogging and root rot.

[0049] When the pea seedlings just emerge, apply 6kg / mu of superphosphate.

[0050] The arrow pea grows naturally, and after the plant withers, it decomposes naturally. The seeds that fall into the orchard soil will germinate and grow again in the autumn.

[0051] CK1 manually weeds to ensure there is no vegetation under the orchard trees, and no sowing is carried out.

[0052] The CK2 group did not sow or weed, and allowed the weeds under the orchard to grow naturally.

[0053] Example 2

[0054] The sowing time, seedling emergence time, and the onset of each phenological phase were recorded for the pea group. After the plots were established, the natural height of the plants in each plot was measured five times with a tape measure, and the average height and plant height (vertical height) were calculated. In April 2024, the plant colony height, cover, soil temperature, and humidity in each treatment were investigated. The results are shown in Tables 1 and 2.

[0055] Table 1 Observation results of the phenological period of the growth of the pea in the citrus orchard

[0056]

[0057] Table 2 Plant growth and soil temperature and humidity in citrus orchards of different groups

[0058] Group Plant height (cm) Natural height of colony (cm) Coverage (%) Soil temperature (℃) Soil moisture (%) Arrow pea group 174.11±8.33b 55.33±4.23a 91.67±0.88c 19.00±0.15cd 45.37±1.02ab CK1 0.00±0.00e 0.00±0.00c 0.00±0.00f 20.17±0.09a 37.33±2.39c CK2 25.60±3.53e 22.67±3.06b 83.33±1.67e 19.50±0.15b 38.60±0.56c

[0059] Note: Different lowercase letters indicate significant differences.

[0060] As shown in Tables 1 and 2, the pea grows well in the citrus orchard and can complete the entire growth period normally. In April 2024, the plant height (vertical height), community height, cover, soil moisture and temperature of the pea group were investigated in the orchard. The results showed that the pea can grow to 174.11 cm; the natural grass CK2 group, mainly including Oxalis, wild chrysanthemum, Cynanchum ovata, Alternanthera philoxeroides, etc., has an average height of 25.6 cm, and the community height of the pea is 55.33 cm. The vegetation cover of the pea group is higher than that of the CK2 group. The soil temperature of the pea group is lower than that of the CK1 and CK2 groups, and the soil moisture of the pea group is greater than that of the CK1 and CK2 groups.

[0061] The rapid growth of the pea, with dense branches and leaves, can effectively block sunlight and inhibit weed photosynthesis, thereby suppressing weed growth. This reduces the competition between weeds and citrus trees for nutrients, water, and space, and reduces the cost and labor intensity of weed control in orchards.

[0062] During its growth, the pea plant secretes secondary metabolites that have insect repellent and antibacterial properties, reducing the incidence of pests and diseases in citrus orchards. Furthermore, the plant provides habitats and food sources for beneficial insects in orchards, increasing biodiversity and helping to maintain a balanced ecosystem, further reducing the risk of pests and diseases.

[0063] Example 3

[0064] During the peak flowering period of the pea, grass samples (1 x 1 m) were cut 5 to 10 cm above the ground. The fresh weight of the plants in the small plots was measured and dried to a constant weight. The grass samples were then ground into powder and the contents of crude protein, crude fat, acid detergent fiber (ADF), neutral detergent fiber (NDF), and ash were determined. Crude protein was determined using the Kjeldahl method; fiber was determined using sulfuric acid digestion; crude fat was determined using Soxhlet extraction; and crude ash was determined using the dry pot heating method. The results are shown in Table 3.

[0065] Table 3 Analysis of yield and nutritional components of pea

[0066]

[0067] Table 3 shows that the fresh grass yield of the tested pea grass is 1577.42 kg / mu, and the content of various nutrients is high after drying.

[0068] Example 4

[0069] Soil samples were collected from each experimental group at the peak flowering stage using the five-point mixed sampling method. Samples were shade-dried and sieved. Soil pH, organic matter, total nitrogen, and alkaline-hydrolyzable nitrogen content were measured in each plot. pH was determined using a pH meter, organic matter using the potassium dichromate external heating method, total nitrogen using the Kjeldahl method, and alkaline-hydrolyzable nitrogen using the alkaline diffusion method. The results are shown in Table 4. "Before treatment" refers to the period before planting.

[0070] Table 4 Soil nutrient content under different treatments

[0071] Group pH Organic matter g / kg Total nitrogen g / kg Alkaline nitrogen mg / kg Before treatment 5.67±0.16bc 12.58±0.37ab 0.9381±0.018bc 111.2±2.98ab Arrow pea group 5.83±0.08b 13.57±0.80a 1.001±0.009a 118.3±5.6abc CK1 5.25±0.07c 11.30±0.35b 0.889±0.029c 110.5±1.8abc CK2 5.32±0.13c 11.47±0.90b 0.958±0.008b 113.0±0.7abc

[0072] Table 4 shows that planting pea increased soil pH by 2.82%, organic matter by 7.87%, total nitrogen by 6.71%, and alkaline nitrogen by 6.38% compared to pre-planting levels. All CK1 indicators in the clean tillage treatment decreased compared to pre-planting levels, but the differences were not significant. This indicates that pea significantly increases the nutrient content of citrus orchard soils.

[0073] Example 5

[0074] Soil samples were collected from each experimental group at the peak flowering stage of the pea (Aglaonema truncatum) using a five-point mixed sampling method. The samples were then shade-dried and sieved. The total arsenic content in the soil samples from each plot was determined. The results are shown in Table 5. "Before treatment" refers to the period before planting. Arsenic content was determined using inductively coupled plasma-mass spectrometry.

[0075] Table 5 Effects of different treatments on arsenic content in citrus orchard soil

[0076] Group Total arsenic content mg / kg Before treatment 8.785 Arrow pea group 7.382 CK1 9.515 CK2 11.121

[0077] Table 5 shows that the arsenic content in the soil of the pea plant group decreased by 15.97% compared to pre-treatment levels, while the arsenic content in the soil of the clean-tillage group CK1 and the natural grass-growing group CK2 increased compared to pre-treatment levels. This indicates that pea plant can significantly reduce arsenic levels in citrus orchards.

[0078] Example 6

[0079] Soil enzymes are active substances secreted by plant roots and their residues, soil animals and their remains, and microorganisms in the soil. They are one of the most active organic components in the soil and are important substances involved in soil metabolism. They are biological activity indicators that characterize the cycling status of soil nutrients such as C and N and soil properties. They have been used to evaluate the cycling and transformation of soil nutrients, various agricultural measures, and the effectiveness of fertilizer application.

[0080] Soil samples were collected from the 0-20 cm depth of each experimental group during the peak flowering period of the pea (Argus spp.). The samples were mixed and sampled using the five-point method. The samples were shade-dried and sieved. The cellulase and urease levels in the soil samples from each plot were determined. The results are shown in Table 6. "Before treatment" refers to the period before planting. Cellulase was determined using the dinitrosalicylic acid colorimetric method; urease was determined using the indophenol blue colorimetric method.

[0081] Table 6 Effects of different treatments on enzyme activities in citrus orchard soil

[0082]

[0083]

[0084] Table 6 shows that after planting pea in a citrus orchard, soil urease levels increased by 3.38% and cellulase levels by 9.74% compared to pre-planting levels. The activities of cellulase and urease in the soil were higher in the CK1 group, which was treated with clean tillage, and the CK2 group, which had natural grass growth. This suggests that pea can significantly increase cellulase and urease activities in citrus orchards.

[0085] Example 7

[0086] Soil samples from each experimental group were collected at 0-20 cm depth during the flowering period of the pea. The five-point method was used for mixed sampling. After mixing, impurities such as plant debris and gravel were removed. To prevent sample contamination, the soil samples were disinfected with 75% alcohol before and after each sampling. The samples were placed in sterile bags and brought back to the laboratory in an ice box. They were stored in a -80°C refrigerator for soil microbial DNA extraction and subsequent determination. Soil fungal diversity was detected using ITS rRNA gene high-throughput sequencing technology. The results are as follows. Figures 1-2 shown.

[0087] Figures 1-2 It shows that planting arrow pea in citrus orchards can improve the composition and fungal diversity of soil fungi in citrus orchards.

[0088] Example 8

[0089] By 2023, the citrus orchard, using peas for cultivation, reduced herbicide use, saving 15 yuan per mu (approximately 1500 yuan) in herbicide and manual weeding costs. The orchard also produced 125 kg of seed per mu (approximately 12500 yuan). At 30 yuan per kg, the seed yielded 3,750 yuan per mu (approximately 1,000 yuan). The main costs for peas, including seed, fertilizer, and labor, were 800 yuan, resulting in a 2,950 yuan per mu (approximately 1,000 yuan) return.

[0090] The yield of citrus treated with arrowroot pea in 2023 was 2907 kg / mu, which was 24.55% higher than the yield of 2334 kg / mu of CK1 citrus in clean tillage, and 44.63% higher than the yield of 2010 kg / mu of CK2 citrus in natural grass growth.

[0091] Example 9

[0092] Citrus fruits from the pea-treated group, the clean-tillage group, and the natural grass-grown group were peeled, the pulp removed, and then blended. The juice was extracted using a juicer and filtered through double-layered gauze to remove residue. The sweetness of the fruits from each group was measured using a refractometer. The total acid content of each group was determined using acid-base titration, and the sugar-acid ratio was calculated. The results are shown in Table 7.

[0093] Table 7 Quality of citrus grown in different groups

[0094] Group Sweetness / °Brix Total acid / g / 100mL Sugar-acid ratio Arrow pea group 17.5 0.85 20.59：1 CK1 12.5 0.95 13.16：1 CK2 11.5 0.85 13.53：1

[0095] The sugar-acid ratio of the citrus grown with arrowroot pea is 20.59:1, and the flavor is sweet and slightly sour, with a strong flavor. It is sweeter and has a better flavor than the citrus grown in the clean tillage and natural grass groups.

[0096] As can be seen from the above examples, the present invention provides a method for intercropping peas to improve the ecological environment of a citrus orchard. The method of the present invention comprises the following steps: (1) sowing peas seeds in a citrus orchard in late October; (2) applying phosphorus and potassium fertilizers during the emergence stage of the peas; (3) allowing the peas plants to wither and decompose naturally; the seeds that fall into the soil grow naturally. Planting peas in a citrus orchard according to the method of the present invention can increase the levels of organic matter, total nitrogen, and alkaline nitrogen in the soil of the citrus orchard, increase the levels of urease and cellulase in the orchard, reduce the arsenic content in the soil of the orchard, increase the economic value of the citrus orchard, and improve the yield and quality of citrus, providing a basis for the ecological and green cultivation of citrus.

[0097] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for improving the ecological environment of a citrus orchard by intercropping peas, characterized in that: The steps include: (1) In late October, sow the arrow pea seeds in the citrus orchard; (2) Apply phosphorus and potassium fertilizers during the emergence stage of arrow pea; (3) After the pea plant withers, it will decompose naturally; the seeds that fall into the soil will grow naturally.

2. The method according to claim 1, characterized in that The sowing method in step (1) is broadcast sowing or drill sowing; No seeds will be sown within a radius of 0.5 to 0.8 m from the vertical projection of the citrus tree crown; The furrow depth during row sowing is 2 to 3 cm.

3. The method according to claim 2, characterized in that The seed amount used during sowing in step (1) is 5.5-6.5 kg / mu.

4. The method according to claim 3, characterized in that The phosphorus and potassium fertilizer in step (2) is potassium superphosphate; The application amount of the potassium superphosphate is 5 to 8 kg / mu.

5. Use of the method according to any one of claims 1 to 4 in improving the nutrient content of soil in a citrus orchard; The soil nutrients include organic matter, total nitrogen and alkaline-hydrolyzable nitrogen.

6. Use of the method according to any one of claims 1 to 4 in improving the activity of soil enzymes in citrus orchards; The soil enzymes include cellulase and urease.

7. Use of the method according to any one of claims 1 to 4 for reducing the arsenic content in citrus orchard soil.

8. Use of the method according to any one of claims 1 to 4 in improving the yield and / or quality of citrus.

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