Cultivation method for improving intercropping nitrogen fixation efficiency

Abstract

The invention belongs to the field of cultivation, and particularly relates to a cultivation method for improving intercropping nitrogen fixation efficiency, which is characterized in that intercropping or intercropping is carried out by cultivating leguminous plants under plum trees; when the plum tree is the Shengxue Perot plum tree, intercropping soybeans, or intercropping vicia sativa; when the plum trees are giant early plum trees, intercropping soybeans; when the plum trees are purple plums, intercropping soybeans. According to the method, the plum trees are intercropped with leguminous plants, so that the nitrogen fixation efficiency can be improved. By interplanting the vicia sativa with the Shenxue Perot plum trees, soil nutrients can be improved, and high-quality optimized plum fruits and soybeans can be obtained. By adopting the mode of interplanting soybeans in the Shengxue Perot plum trees and the giant early plum trees, plum fruits which are rich in nutrient substances and good in flavor can be harvested. The mode of adding the selenium-rich fertilizer is adopted, so that selenium-rich plums can be harvested in the mode of interplanting the soybeans on the purple pennisetum hydridum trees. When the plum trees and the soybeans are intercropped or relay-intercropped, the use amount of decomposed organic fertilizer can be reduced and the nitrogen fixation effect can be improved by applying the slow-release agent.

Description

Technical Field

[0001] The present invention relates to the field of cultivation techniques, and particularly relates to a cultivation method for improving the nitrogen fixation efficiency of intercropping and relay cropping. Background Art

[0002] Plums belong to the Rosaceae family among dicotyledonous plants. As a major province for plum cultivation, Sichuan currently has more than a dozen varieties that have been planted on a large scale, including Qingcui Plum, Honey Plum, Juzao Plum, Crispy Plum, Apple Plum, etc. At the same time, there are also some newly cultivated varieties such as Zihuang and Shengxuepo.

[0003] Compared with high-input agriculture, intercropping and relay cropping improve the stability of the total annual output of low-input systems. At the same time, intercropping and relay cropping have great potential, and the complementary effects between crops can be used to achieve long-term productivity improvement.

[0004] Currently, there is little research on the intercropping of plums with leguminous plants. For example, "A Method for Intercropping Plums and Grapes" disclosed in Publication No. CN108370790A, "A Method for Intercropping Zhui Plums in a Tea Garden" disclosed in Publication No. CN117378422A, "A Method for Intercropping Golden Buds and Plum Trees" disclosed in Publication No. CN110622753A, "A Method for Intercropping Pseudostellaria heterophylla under Honey Plum Forests" disclosed in Publication No. CN106797778A, "A Method for Intercropping Plum Trees and Loquats" disclosed in Publication No. CN105010066A, "A Method for Intercropping Plum Trees and Watermelons" disclosed in Publication No. CN108781977A, "A Method for Intercropping Panax notoginseng under Plum Forests" disclosed in Publication No. CN107258830A, etc.

[0005] The influence of intercropped crops is not limited to soil nutrients, and may also involve the mutual relationships between crops. The competitive, synergistic or symbiotic relationships between different crops may lead to varying degrees of influence, and may change the quality of plum fruits.

[0006] Therefore, in the present invention, different intercropping patterns will be explored, including intercropping experiments between different varieties of plums and different leguminous plants, aiming to explore the effects of intercropping leguminous crops on the quality of plum fruits and the content of soil nutrients, and obtain a more optimized agricultural production model.

[0007] Based on this, the present invention is proposed. Summary of the Invention

[0008] The purpose of the present invention is to provide a cultivation method for improving the nitrogen fixation efficiency of intercropping and relay cropping to solve the above problems. The specific technical solution is as follows: A cultivation method for improving the nitrogen fixation efficiency of intercropping and relay cropping, which is carried out by intercropping or relay cropping leguminous plants under plum trees; When the plum tree is a Shengxuepo plum tree, intercropping or relay cropping with soybeans; Or, When the plum tree is the Shengxuepo plum tree, intercrop or relay interplant with common vetch; Or, When the plum tree is the Juzao plum tree, intercrop or relay interplant with soybean; Or, When the plum tree is the Zihuang plum tree, intercrop or relay interplant with soybean.

[0009] Furthermore, when the plum tree is the Shengxuepo plum tree or the Juzao plum tree, the method for intercropping the plum tree and soybean includes the following steps: Step 1: Select plum trees with a distance of more than 80 cm between the drip lines of the crowns of two rows in the orchard for intercropping; Step 2: When choosing to sow spring soybean, the sowing period is from the middle and late March to the early April when the soil temperature is stable above 12 °C; When choosing to sow summer soybean, the sowing period is from the middle of June to the early July; Step 3: Apply soil fertilizer, foliar topdressing, and weed control to the intercropped plum trees and soybeans; Step 4: Control diseases and pests using insecticides, fungicides, and biological control agents.

[0010] Furthermore, in Step 2, the planting density of soybean is: the average row spacing is 30 - 40 cm, the plant spacing is 15 - 25 cm, and the distance between the sowing belt of the soybean edge row and the drip line of the plum tree crown is not less than 30 cm.

[0011] Furthermore, in Step 3, from late September to late October, 1 ton of decomposed organic fertilizer per mu of orchard is used as the base fertilizer, and both the inter-row and the tree basin are deeply plowed by 15 - 25 cm in combination with applying the base fertilizer; 5 - 7 days before sowing soybean, 10 - 25 kg of nitrogen, phosphorus, and potassium balanced compound fertilizer is applied to each mu of soybean planting belt, and then the inter-row of the plum tree is plowed and leveled 1 - 2 times, with a plowing depth of 20 cm, and the leveling range does not exceed the drip line of the fruit tree crown.

[0012] Furthermore, in Step 3, when the gramineous weeds are in the 2 - 4 leaf stage and the broad-leaved weeds are 3 - 5 cm in height, use acifluorfen sodium aqueous solution, quizalofop-p-ethyl emulsifiable concentrate, or acifluorfen to conduct whole-orchard weed control.

[0013] Furthermore, in Step 4, the insecticide is acetamiprid or lambda-cyhalothrin, the fungicide is thiophanate-methyl or hexaconazole, and the biological control agent is selected as Bacillus subtilis.

[0014] Furthermore, when the plum tree is the Zihuang plum tree, relay interplant with soybean; during the relay interplanting period, from late September to late October, 1 ton of decomposed organic fertilizer mixed with selenium-rich fertilizer per mu of orchard is used as the base fertilizer, and the incorporation amount of the selenium-rich fertilizer is 5% of the mass of the decomposed organic fertilizer, and the selenium-rich fertilizer is amino acid chelated selenium fertilizer or humic acid selenium fertilizer.

[0015] Further, in step 3, from late September to late October, 750 kg of decomposed organic fertilizer is used as base fertilizer per mu of orchard, and the inter-row and tree trays are both deep-turned 15-25 cm in combination with base fertilizer application; and trenches are also dug at the tree trays and slow-release agents are applied, with the amount of slow-release agents being 50 kg / mu; 5 to 7 days before soybean sowing, apply 10 to 25 kg of balanced nitrogen, phosphorus and potassium compound fertilizer per acre of soybean planting belt, then plow and prepare the land between the rows of plum trees 1 to 2 times, with a plowing depth of 20 cm. The land preparation range should not exceed the drip line of the fruit tree crown.

[0016] Furthermore, the preparation method of the sustained-release agent is: The sludge, ferric molybdate and water are mixed and injected into a sealed electrolytic chamber, and the mixture in the electrolytic chamber is subjected to high-voltage pulse discharge. The sludge and ferric molybdate generate mud under the action of the liquid-electric effect. The mud is poured out and filtered, and the filter cake is baked at 180-185° C. for 55 minutes to obtain the sustained-release agent.

[0017] Furthermore, the mass ratio of sludge to ferric molybdate in the electrolytic chamber is 11:5, the initial material-liquid ratio in the electrolytic chamber is 1:7, the voltage of the high-voltage pulse discharge is 20 kV, the pulse width is 850 ns, and the discharge is performed 150 times.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. Interplanting white clover, soybean, arrow pea, glossy purple vetch and crimson clover with Saint-Shepard plum trees can improve the efficiency of nitrogen fixation.

[0019] 2. Interplanting soybeans with Saint Shepard plum trees can harvest soybean byproducts with high economic value. Interplanting arrow peas with Saint Shepard plum trees can not only improve soil nutrients but also obtain high-quality optimized plum fruits and soybeans.

[0020] 3. The technical effects of interplanting soybeans with specific varieties of plum trees are different. By interplanting soybeans with Saint Sheperd Plum Trees and Giant Early Plum Trees, you can harvest plums that are rich in nutrients and have good flavor. During the soil and fertilizer management period, by adding selenium-rich fertilizers, you can harvest selenium-rich plums by interplanting soybeans with Purple Emperor Plum Trees. The selenium content in selenium-rich plums is 7-11 times that of other interplanted varieties.

[0021] 4. When intercropping or relay-cropping plum trees with soybeans, use a slow-release agent made from silt, ferric molybdate and water through the liquid-electric effect. It can slowly release organic iron and molybdenum salts in the soil. During soil and fertilizer management, by digging trenches in the tree pits and applying slow-release agents, the amount of decomposed organic fertilizer can be reduced by 1 / 4, and the nitrogen fixation effect will be significantly improved. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below through specific examples.

[0023] The following detailed description of the embodiments of the present application is not intended to limit the scope of the present application claimed, but merely represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts fall within the scope of protection of the present application.

[0024] Example 1 1. Test materials Plant samples: 20 fruits were randomly picked from each plot in the test field. After picking, the fruits were packed in foam boxes and ice bags and immediately transported back to the laboratory to measure the fruit quality indicators.

[0025] Soil samples: One soil sample of 0 - 20 cm was collected from each sampling point, brought back to the laboratory to air dry, remove impurities and grind, and then passed through 0.25 mm and 1 mm sieves for standby.

[0026] 2. Test sites In the test base, five leguminous plants, namely white clover, soybean, common vetch, purple sericea lespedeza, and crimson clover, were intercropped with 4 - year - old Shenxuepo plum trees in the field.

[0027] 3. Test design The test adopted a randomized block design, with a total of 5 intercropping treatments and 1 control (CK), totaling 6 treatments. Among them, Treatment 1: Shenxuepo plum trees intercropped with white clover (plum - white clover); Treatment 2: Shenxuepo plum trees intercropped with soybean (plum - soybean); Treatment 3: Shenxuepo plum trees intercropped with common vetch (plum - common vetch); Treatment 4: Shenxuepo plum trees intercropped with purple sericea lespedeza (plum - purple sericea lespedeza); Treatment 5: Shenxuepo plum trees intercropped with crimson clover (plum - crimson clover); Control (CK): no crop intercropping (single - planted plum). Each treatment had 3 replicates, totaling 18 test plots.

[0028] 4. Index determination Soil indicators: The determination of organic matter was measured by the potassium dichromate volumetric method (external heating method), total nitrogen and available nitrogen were measured by the alkaline diffusion method, total phosphorus was determined by the molybdenum antimony anti - colorimetric method after digestion with perchloric acid and sulfuric acid, available phosphorus was determined by the molybdenum antimony anti - colorimetric method after extraction with hydrochloric acid - sulfuric acid, and total potassium and available potassium were measured by the flame photometer method.

[0029] Fruit indicators: The fresh fruit weight of single fruits was weighed with a Liping electronic scale with an accuracy of 0.01 and the average value was taken. The soluble solids were measured by a hand - held digital refractometer to determine the soluble solids content, and the results were expressed as %.

[0030] 5. Results and analysis 5.1. Effect of intercropping leguminous plants on the fruit quality of plums Table 1

[0031] As shown in Table 1, compared with single-plant plum, interplanting white clover will increase plum fruit weight; but the soluble solids and ascorbic acid content in plum fruit are not significantly different from those in CK; but the total acid is significantly lower than that in CK, down 0.81kg -1 ·g. When plums were interplanted with soybeans, the fruit weight was increased and the increase was greater than that of interplanted with white clover, but there was no significant difference; the soluble solids and ascorbic acid in the fruit increased, and the total acid decreased, but there was no significant difference. When plums were interplanted with arrowroot peas, the fruit weight was greatly increased and there was a significant difference, increasing by 19.5g; the soluble solids and ascorbic acid in the fruit increased, and the total acid decreased, but there was no significant difference. When plums were interplanted with glossy-leaved purple vetch, the fruit weight increased by 16.5g and there was a significant difference, but the increase was weaker than that of arrowroot peas, the soluble solids and ascorbic acid in the fruit increased, and the total acid decreased, but there was no significant difference. When plums were interplanted with red clover, the fruit weight increased by 19g and there was a significant difference, the soluble solids and ascorbic acid in the fruit increased, and the total acid decreased, but there was no significant difference.

[0032] 5.2 Effects of intercropping on soil nutrients Table 2 Effects of interplanting different crops on soil total nutrient content

[0033] As shown in Table 2, for organic matter, the organic matter content of the five intercropping patterns was significantly higher than that of CK, indicating that the organic matter content in the soil increased when plums were intercropped with different leguminous crops. The soil organic matter content of the five intercropping patterns was as follows: pea> white clover> glossy purple vetch> soybean> crimson clover; among them, the organic matter content of pea intercropping was the highest, which increased by 14.75kg compared with CK. -1 ·g. For total nitrogen, the total nitrogen content of the five intercropping patterns was significantly higher than that of CK, indicating that the total nitrogen content in the soil was increased by intercropping plums with different leguminous crops. The total nitrogen content of the soil in the five intercropping patterns was as follows: soybean> arrow pea> white clover> crimson clover> glossy purple vetch. Among them, soybean had the highest total nitrogen content, which was increased by 0.0685kg compared with CK. -1 ·g. For total phosphorus, the soil total phosphorus content of the five intercropping patterns was higher than that of CK, but there was no significance in two intercropping patterns; among them, plum and white clover, glossy purple flower vetch, and crimson clover were significant, and the soil total phosphorus content of plum and crimson clover intercropping increased the most, increasing by 0.0315%. For total potassium, plum intercropping white clover, arrow pea, and crimson clover were lower than CK but not significantly, plum intercropping soybean was lower than CK and significant, and plum intercropping glossy purple flower vetch was higher than CK but not significantly; this shows that intercropping soybean can significantly reduce the soil total potassium content, which can be reduced by 0.15%.

[0034] Table 3 Effects of Intercropping Different Crops on the Content of Available Nutrients in Soil

[0035] As can be seen from Table 3: For available phosphorus, the available phosphorus contents of the 5 intercropping patterns are all higher than that of CK. Among them, there are significant differences in 3 patterns, and the available phosphorus contents are in the order of: Trifolium incarnatum > Vicia sativa > Vicia villosa Roth. The available phosphorus content of the intercropping of plum and Trifolium incarnatum increased by 12.55 kg -1 ·g, and there are no significant differences in the other two groups. For available potassium, only 1 of the 5 intercropping patterns is lower than CK, which is the intercropping pattern of plum and Vicia villosa Roth, but there is no significant difference; the other patterns are all higher than CK, but there are only two groups with significant differences. Among them, the intercropping pattern of plum and Vicia sativa has the highest increase, which is 17 kg -1 ·g. For hydrolyzable nitrogen, the 5 intercropping patterns are all higher than CK, and all show significant differences; the intercropping pattern of plum and Trifolium incarnatum has the highest increase, which is 49.5 kg -1 ·g.

[0036] From the above research, it can be seen that after intercropping 5 leguminous plants, the fruit weights of Santaixue plum trees are all higher than the control (CK); in addition, no matter which leguminous plant is intercropped, compared with single-planted plum, the soluble solids in its fruits are increased, the total acid is overall reduced and the ascorbic acid is increased. It can be seen that intercropping Santaixue plum trees with leguminous plants can effectively improve the fruit quality of plums. Among them, the single fruit weight of the fruits obtained under the intercropping pattern of plum-Vicia sativa is the highest. In addition, intercropping soybeans can not only harvest the original plums, but also harvest soybeans, with higher product richness and economic benefits. Thus, it can be seen that all five leguminous plants are suitable for intercropping between plum trees.

[0037] All 5 intercropping patterns significantly increased the content of soil hydrolyzable nitrogen, that is, improved the nitrogen fixation efficiency. Among them, the contents of soil organic matter, available phosphorus, available potassium and hydrolyzable nitrogen were significantly increased under the intercropping pattern of plum-Vicia sativa. The increase of these soil available nutrients can promote plant growth, thus contributing to obtaining high-quality fruits.

[0038] In summary, all five leguminous plants are suitable for intercropping between plum trees. Plum-soybean is an intercropping pattern that can harvest soybean by-products. Plum-Vicia sativa is an optimized fruit-legume intercropping pattern that can not only improve soil nutrients but also obtain high-quality fruits.

[0039] Example 2 Cultivation method of intercropping Step 1: Select an orchard suitable for intercropping The distance between the drip lines of the crowns of two rows of fruit trees reaches more than 80 cm.

[0040] Step 2: Sow soybeans 2.1 Sowing date Spring soybeans can be sown earlier, from mid-to-late March to early April, when the soil temperature is stable at above 12°C, and sowing can be carried out in time according to the soil moisture conditions; the sowing period of summer soybeans can be delayed appropriately, from mid-June to early July, and sowing should be carried out in time after the early and mid-maturing fruit tree varieties intercropped are harvested, taking advantage of the soil moisture conditions after rain.

[0041] 2.2 Planting density The average row spacing of soybeans is about 30~40cm, and the plant spacing is about 15~25cm. The specific number of sowing rows depends on the row spacing of fruit trees: the distance between the soybean side row sowing belt and the drip line of the fruit tree crown should not be less than 30cm.

[0042] Sow 4 to 5 seeds in each hole and cover with 3 to 5 cm of fine soil after sowing. For soybeans sown in artificial holes, thin out the seedlings once before the single leaf unfolds to the first compound leaf unfolds, remove weak seedlings, diseased seedlings, small seedlings and miscellaneous seedlings, and select 2 to 3 healthy seedlings in each hole.

[0043] Step 3: Soil and fertilizer management From late September to late October, use 1 ton of decomposed organic fertilizer as base fertilizer per acre of orchard, and apply base fertilizer between rows and tree circles to deep plow 15-25cm; 5-7 days before soybean sowing, apply 10-25kg of nitrogen, phosphorus and potassium (15‒15‒15) balanced compound fertilizer per acre of bean planting belt, and then plow and prepare the land between the rows of fruit trees 1-2 times, with a plowing depth of about 20cm, to evenly mix the soil and fertilizer, and harrow the soil. The land preparation range should not exceed the drip line of the fruit tree crown.

[0044] The flowering and grain-filling period of soybeans combined with the seed and fruit development period of deciduous fruit trees are both critical periods that require nutrient supplementation. At this time, two foliar topdressings can be carried out throughout the garden.

[0045] When grass weeds are in the 2-4 leaf stage and broad-leaved weeds are 3-5 cm tall, use soybean-specific herbicides (such as fomesafen aqueous solution, quizalofop-PhD emulsifiable concentrate or fomesafen, etc.) to weed the entire garden.

[0046] Step 4: Pest and disease control Aphids, Spodoptera litura, Concha peach borer, etc. are common pests of fruit trees and soybeans. They can be controlled by insecticides, fungicides, biological control agents, etc.; insecticides include acetamiprid, chlorflucythrinate, etc., fungicides include methyl thiophanate, hexaconazole, etc., and biological control agents include Bacillus subtilis, which can be used commonly between fruit trees and soybeans (for specific pesticide use, please refer to the provisions of GB / T 8321 and NY / T 1276).

[0047] Comprehensive control can be carried out three times with fruit trees, during the 3-4 leaf stage, flowering stage, and grain filling stage of soybean seedlings. At other times, control can be carried out separately according to the disease conditions and needs of fruit trees and soybeans.

[0048] Example 3 1. The experiment adopted a randomized block design, with a total of 7 intercropping experimental groups and 7 control groups, totaling 14 groups. Among them, in experimental group 1, Shenxuepo plum trees were intercropped with soybeans (Shenxuepo - soybean); in control group 1, only Shenxuepo plum trees were planted. In experimental group 2, Zihuang plum trees were intercropped with soybeans (Zihuang - soybean); in control group 2, only Zihuang plum trees were planted. In experimental group 3, Qingcui plum trees were intercropped with soybeans (Qingcui - soybean); in control group 3, only Qingcui plum trees were planted. In experimental group 4, Fengtang plum trees were intercropped with soybeans (Fengtang - soybean); in control group 4, only Fengtang plum trees were planted. In experimental group 5, Juzao plum trees were intercropped with soybeans (Juzao - soybean); in control group 5, only Juzao plum trees were planted. In experimental group 6, Su plum trees were intercropped with soybeans (Su - soybean); in control group 6, only Su plum trees were planted. In experimental group 7, Pingguo plum trees were intercropped with soybeans (Pingguo - soybean); in control group 7, only Pingguo plum trees were planted. Each treatment was replicated 3 times, totaling 42 experimental plots.

[0049] 2. During the soil fertility management period, that is, from late September to late October, 1 ton of decomposed organic fertilizer mixed with selenium - rich fertilizer per mu of orchard was used as the base fertilizer. The incorporation amount of selenium - rich fertilizer was 5% of the mass of the decomposed organic fertilizer. The selenium - rich fertilizer was amino acid chelated selenium fertilizer or humic acid selenium fertilizer.

[0050] 3. The hydride generation - atomic fluorescence spectrometry was used to determine the selenium content in plum fruits.

[0051] 4. The experimental results are shown in Table 4: Table 4

[0052] As can be seen from Table 4, intercropping leguminous plants with plum fruit trees can improve the nitrogen - fixation efficiency. However, for different varieties of plum trees, when intercropping different leguminous plants, even when adding selenium - rich fertilizer during fertilization, the competition and absorption of selenium elements between different varieties of plum trees and different varieties of leguminous plants are different, with huge differences; in addition, the competition and absorption of nutrients in the soil between different varieties of plum trees and different varieties of leguminous plants are different, resulting in huge differences in the nutrients and flavors in plum fruits (a high content of soluble solids in fruits is positively correlated with a high sugar accumulation).

[0053] Therefore, considering the nutrients and flavors in plum fruits, it is preferably to adopt the method of intercropping Shenxuepo plum trees with soybeans and intercropping Juzao plum trees with soybeans. Considering the selenium content in plum fruits, it is preferably to adopt intercropping Zihuang plum trees with soybeans.

[0054] Example 4 In step 3 of Example 2, during the soil fertility management period, trenches were dug at the tree trays and slow - release agents were applied. The amount of decomposed organic fertilizer used could be reduced by 1 / 4 (the actual fertilization amount was 750 kg), and the application amount of the slow - release agent was 50 kg / mu.

[0055] Preparation method of the sustained-release agent: Method 1: Mix sludge, iron molybdate and water, and then inject the mixture into a sealed electrolysis chamber. The mass ratio of sludge to iron molybdate is 11:5. Apply high-voltage pulsed discharge to the mixture in the electrolysis chamber. Under the action of the liquid-electric effect, sludge and iron molybdate generate mud material. The initial liquid-solid ratio in the electrolysis chamber is 1:7. The voltage of the high-voltage pulsed discharge is 20 kV, the pulse width is 850 ns, and the discharge is carried out 150 times. Pour out the mud material and filter it. Bake the filter cake at 180 - 185 °C for 55 min to obtain the sustained-release agent.

[0056] When a pulsed high voltage is applied to a pair of electrodes placed in a liquid, the electrode gap is instantaneously broken down, generating a strong arc spark discharge, and a series of significant physical, chemical, biological, and mechanical effects occur. This process is called the liquid-electric phenomenon. Its occurrence chamber can utilize an existing electrolysis chamber, but no electrolysis reaction occurs in the electrolysis chamber.

[0057] The sludge in the pond uses various physical and chemical effects generated by the liquid-electric effect to destroy the structure of flocs and other organic matters in the sludge. In addition, it can also cause a series of decomposition reactions of iron molybdate, and at the same time react with the organic matter in the sludge to generate corresponding molybdenum salts and iron salts. Most of the organic molybdenum salts and iron salts contained in the finally filtered filter cake are slightly soluble. After subsequent high-temperature baking, they combine with the loose and porous sludge. When soaked in water, they can be slowly released for a long time.

[0058] The sludge treated by the liquid-electric effect can be used as a medium for rhizobia to colonize after absorbing water.

[0059] The elements necessary for rhizobia mainly include iron, molybdenum, phosphorus, calcium, magnesium, etc. These elements play a key role in the nitrogen fixation process. Therefore, adding the sustained-release agent can promote the growth and reproduction of rhizobia, thereby significantly improving the nitrogen fixation efficiency.

[0060] Method 2: Mix sludge, iron molybdate and water to make a slurry. The mass ratio of sludge to iron molybdate is 11:5. Bake the slurry at 180 - 185 °C for 55 min to obtain the sustained-release agent.

[0061] Method 3: Mix sludge, iron molybdate and water to make a slurry. The mass ratio of sludge to iron molybdate is 11:5. After the slurry is dried, calcine it at 750 - 760 °C for 30 min and then crush it to obtain the sustained-release agent.

[0062] Method 4: Bake the sludge at 180 - 185 °C for 55 min to obtain the sustained-release agent.

[0063] The total nitrogen measurement is the same as that in Example 2.

[0064] Pour 2 kg of the slow-release agent into a flower pot (with air holes of 1 cm in diameter at the bottom). Water it 3 times a day, with 500 mL of water each time. Keep watering for 30 days, and measure the contents of iron and molybdenum elements released by the slow-release agent before watering and after 30 days. Sampling method: Take 2 g of the slow-release agent, pour it into a test tube, add 5 mL of deionized water to the test tube, shake it for 30 min, filter it, and take the filtrate to complete the sampling. The measurement method for the iron element content in the sample adopts the "spectrophotometry" (such as the "o-phenanthroline colorimetry"), and the measurement method for the molybdenum element content adopts the "thiocyanate photometry".

[0065] The test results are shown in Table 5: Table 5

[0066] As can be seen from Table 5, the slow-release agent can release for a long time in moist soil, and the released organic iron and molybdenum salts are beneficial to the growth and reproduction of rhizobia nearby, significantly improving the nitrogen fixation effect.

[0067] However, when treating sludge and iron molybdate by direct mixing or calcination, a large amount of organic molybdenum salts and iron salts that can be absorbed by plants and rhizobia cannot be generated, which is not very helpful for nitrogen fixation.

[0068] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0069] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A cultivation method for improving nitrogen fixation efficiency of intercropping, characterized in that: intercropping or relay cropping by planting leguminous plants under plum trees; When the plum trees are Sheperd Plums, intercrop or interplant with soybeans; or, When the plum trees are St. Shepherd's Plum trees, intercrop or interplant with arrow peas; or, When the plum trees are giant early plum trees, intercrop or interplant with soybeans; or, When the plum trees are Purple Emperor plum trees, soybeans are intercropped or interplanted.

2. A cultivation method for improving nitrogen fixation efficiency of intercropping according to claim 1, characterized in that: When the plum tree is a Saint Shepherd plum or a Giant Early plum, the intercropping method of the plum tree and soybean includes the following steps: Step 1: Select two rows of plum trees in the orchard with a distance of more than 80 cm between the drip lines of the crowns for intercropping; Step 2: When choosing spring soybean sowing, the sowing period is from mid-to-late March to early April, when the soil temperature is stable above 12°C; When choosing summer soybeans for sowing, the sowing period is from mid-June to early July; Step 3, applying soil fertilization, foliar topdressing and weeding to the intercropped plum trees and soybeans; Step 4: Use pesticides, fungicides, and biological control agents to control pests and diseases.

3. A cultivation method for improving nitrogen fixation efficiency of intercropping according to claim 3, characterized in that: In step 2, the planting density of soybeans is: average row spacing 30~40cm, plant spacing 15~25cm, and the distance between the soybean side row sowing belt and the drip line of the plum tree crown is not less than 30cm.

4. A cultivation method for improving nitrogen fixation efficiency of intercropping according to claim 3, characterized in that: In step 3, from late September to late October, use 1 ton of decomposed organic fertilizer as base fertilizer per acre of orchard, and apply base fertilizer to deep plow 15-25 cm between rows and tree pits; 5-7 days before soybean sowing, apply 10-25 kg of nitrogen, phosphorus and potassium balanced compound fertilizer per acre of soybean planting belt, and then plow and till the land between the rows of plum trees 1-2 times, with a plowing depth of 20 cm. The land preparation range should not exceed the drip line of the fruit tree crown.

5. A cultivation method for improving nitrogen fixation efficiency of intercropping according to claim 3, characterized in that: In step 3, when grass weeds are in the 2-4 leaf stage and broad-leaved weeds are 3-5 cm tall, use fomesafen aqueous solution, quizalofop-PhD emulsifiable concentrate or fomesafen to weed the entire garden.

6. A cultivation method for improving nitrogen fixation efficiency of intercropping according to claim 3, characterized in that: In step 4, the insecticide is acetamiprid or chlorfenapyr, the fungicide is methyl thiophanate or hexaconazole, and the biological control agent is Bacillus subtilis.

7. The cultivation method for improving nitrogen fixation efficiency of intercropping according to claim 1, characterized in that: When the plum trees are purple emperor plum trees, soybeans are intercropped; during the intercropping period, from late September to late October, 1 ton of decomposed organic fertilizer mixed with selenium-rich fertilizer is used as base fertilizer per acre of orchard. The amount of selenium-rich fertilizer added is 5% of the mass of the decomposed organic fertilizer. The selenium-rich fertilizer is amino acid chelated selenium fertilizer or humic acid selenium fertilizer.

8. The cultivation method for improving nitrogen fixation efficiency of intercropping according to claim 2, characterized in that: In step 3, from late September to late October, 750 kg of decomposed organic fertilizer is used as base fertilizer per mu of orchard, and the inter-row and tree trays are both deep-turned 15-25 cm in combination with base fertilizer; in addition, trenches are opened at the tree trays and slow-release agents are applied, with the amount of slow-release agents being 50 kg / mu; 5 to 7 days before soybean sowing, apply 10 to 25 kg of balanced nitrogen, phosphorus and potassium compound fertilizer per acre of soybean planting belt, then plow and prepare the land between the rows of plum trees 1 to 2 times, with a plowing depth of 20 cm. The land preparation range should not exceed the drip line of the fruit tree crown.

9. A cultivation method for improving nitrogen fixation efficiency of intercropping according to claim 8, characterized in that: The preparation method of the sustained-release agent is: The sludge, ferric molybdate and water are mixed and injected into a sealed electrolytic chamber, and the mixture in the electrolytic chamber is subjected to high-voltage pulse discharge. The sludge and ferric molybdate generate mud under the action of the liquid-electric effect. The mud is poured out and filtered, and the filter cake is baked at 180-185° C. for 55 minutes to obtain the sustained-release agent.

10. A cultivation method for improving nitrogen fixation efficiency of intercropping according to claim 9, characterized in that: The mass ratio of sludge to ferric molybdate in the electrolytic chamber is 11:5, the initial material-liquid ratio in the electrolytic chamber is 1:7, the voltage of the high-voltage pulse discharge is 20 kV, the pulse width is 850 ns, and the discharge is performed 150 times.

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