A method for synergistically turning over chemical fertilizers and green manure in yellow mud fields of early rice

Abstract

The present invention provides a method for cooperatively turning over chemical fertilizers and green manures in yellow mud fields of early rice. The method specifically discloses the concept of cooperatively turning over early rice base fertilizers and Chinese milk vetch under flooding conditions, which accelerates the decomposition rate of the Chinese milk vetch and greatly shortens the turning over time of the Chinese milk vetch, thereby increasing the time for the Chinese milk vetch to absorb and utilize CO2 in the air, shortening the CO2 and CH4 emission time of the Chinese milk vetch during the turning over period, slowing down the greenhouse effect, saving the number of fertilizations, and saving labor. Under the premise of maintaining stable rice yield, the content of amylopectin, protein and amino acids in rice is increased, and the quality of rice is improved.

Description

Technical Field

[0001] The invention belongs to the field of rice formula fertilization production, and particularly relates to a method for cooperatively turning over chemical fertilizers and green manure in yellow mud fields of early rice. Background Art

[0002] At present, the existing milk vetch turning technology mainly uses milk vetch alone or combined with rice straw to turn the rice fields. The turning period is long, usually more than half a month, resulting in large amounts of CO2 and CH4 emissions from rice fields, exacerbating the greenhouse effect. Relevant research has found that compared with the control without turning milk vetch, turning milk vetch at 15,000, 30,000, and 45,000 kg·hm -2 The average CO2 emission rates of the treated soils increased by 7.67, 12.48, and 20.54 mg·kg, respectively. -1 ·d -1 The average CH4 emission rates increased by 0.04, 0.09, and 0.21 mg·kg, respectively. -1 ·d -1 In addition, many rice fields in Fujian Province are located in hilly and mountainous areas with large terrain variations and large spatial variations in soil fertility, resulting in large differences in the amount of fresh milk vetch grass between different plots. The amount of milk vetch turned over is closely related to the time of turning over. If the amount of milk vetch turned over is too large and the turning over time is too short, then the oxygen consumption during the decomposition process will be too high, causing the redox potential of the paddy field soil to drop and producing a large amount of Fe 2+ , hydrogen sulfide, organic acids and other reducing toxic substances, causing rice seedling stunting. On the contrary, if the interval between turning over the milk vetch and transplanting early rice is too long, the large amount of nutrients released by the early decomposition of the milk vetch cannot be absorbed and utilized by the seedlings in time, resulting in nutrient loss and poor growth of the seedlings. At the same time, it causes a large amount of CO2 and CH4 emissions, which is not conducive to mitigating climate warming and increasing rice production. Therefore, creating a method for turning over and utilizing milk vetch suitable for rice fields in mountainous areas of Fujian Province is an inevitable trend in the development of modern agriculture. In early rice production, how to determine the optimal turning amount of milk vetch and the interval between turning over the milk vetch and transplanting early rice are key issues that need to be urgently addressed in the process of planting and utilizing milk vetch in double-season rice areas in Fujian Province.

[0003] The present study found that the independently bred new milk vetch line 84(8)7-1-1 (tentatively named 'Minzi No. 8') combined with chemical fertilizers and synergistic turning under flooding conditions can promote a two-stage stimulation effect on nitrogen in paddy soil, that is, the application of milk vetch green manure and different amount of fertilizers to the soil produces a positive and violent stimulation effect before 20 days of cultivation, promoting the growth of soil ammonium nitrogen (NH4 + -N) is released rapidly and in large quantities, and the positive excitation effect slows down rapidly after 20 days. + -N release decreases ( Figure 1 The cytochrome oxidase activity in the roots of double-season early rice plants is strong at the seedling stage, so the NH4 +-N is more than nitrate nitrogen (NO3 - -N), and this NH4 + The dominant role of -N nutrition is more obvious in the tillering stage. Combined with the fertilizer requirement of the early growth and development of double-season early rice and the research findings of this application, "NH4 + -N release characteristics", boldly proposed "a new concept of delaying the turning period of milkvetch green manure under flooding conditions and moving the application time of base fertilizer to simultaneous application", which can promote the release of soil NH4 + -N release, timely meet the double-season early rice in the seedling and tillering stages of NH4 + -N is in high demand.

[0004] The soil used in this application belongs to the percolation-type yellow mud paddy soil, which is one of the medium-low yield fields with a wide distribution in the rice-growing areas of southern China, with an area of ​​about 1.4×10 4 hm 2 , there are obstacle factors such as thinness, stickiness, and drought. Therefore, scientific planting and utilization of milk vetch green manure can improve the quality of paddy field soil and increase the yield of yellow mud field rice. This application studies the effects of different milk vetch turning amounts, milk vetch turning and early rice transplanting intervals on yellow mud field soil fertility, rice yield and quality under the management measures of reducing chemical fertilizers through orthogonal experiments and comparative experiments, in order to obtain high-yield and high-quality rice while simultaneously improving the fertility of double-season rice soil in yellow mud field, reducing CO2 and CH4 greenhouse gas emissions, improving nitrogen fertilizer utilization efficiency, achieving reduced chemical fertilizer application, and promoting farmers to increase production and income, thereby constructing a resource-saving and environmentally friendly double-season early rice milk vetch turning technology. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for cooperatively turning over chemical fertilizers and green manures in yellow mud fields of early rice.

[0006] Existing milk vetch turning and tamping technology often uses milk vetch alone or in combination with rice straw. The decomposition rate of milk vetch is slow, and the tamping time is long, generally more than 15 days, which prolongs the tamping time and shortens the growing period of milk vetch, which is not conducive to carbon sequestration and emission reduction in double-season rice fields. In addition, most rice-growing areas in Fujian Province are located in mountainous and hilly areas, and the spatial variation of fertility between fields is large, resulting in large differences in the amount of milk vetch turning and tamping. The amount of milk vetch turning and tamping is related to the length of the milk vetch turning period and the amount of chemical fertilizer reduction. However, in reality, the amount of milk vetch turning and tamping, the turning period, and the amount of chemical fertilizer reduction are mostly based on experience or single-factor experiments, and can no longer meet the needs of the large spatial variation of fertility between rice fields in mountainous areas of Fujian Province. The present application found that the synergistic plowing of astragalus combined with chemical fertilizers can significantly promote the positive excitation effect of soil nitrogen compared to plowing astragalus alone. Therefore, in the experimental design, the concept of synergistic plowing of base fertilizer and astragalus under flooding conditions was innovatively proposed, which accelerated the decomposition rate of astragalus and greatly shortened the plowing time of astragalus, thereby increasing the time for astragalus to absorb and utilize CO2 in the air, shortening the CO2 and CH4 emission time during the plowing period of astragalus, slowing down the greenhouse effect, saving the number of fertilizations, and saving labor. At the same time, the present application uses an orthogonal experimental design to quantitatively study the amount of astragalus plowing, plowing time, and chemical fertilizer reduction, which can better meet the actual needs of large spatial variation in fertility between rice fields in mountainous areas of Fujian Province, and proposes a synergistic plowing method of chemical fertilizers and green manures in yellow mud fields of early rice. This method has developed key technologies such as delayed sowing time of double-season early rice milk vetch, delayed turning during the flowering period, and forward shifting of base fertilizer. It integrates the "delayed turning during the flowering period of milk vetch and forward shifting of base fertilizer to simultaneous turning, which accelerates the decomposition of milk vetch plants, promotes the positive stimulation effect of soil nitrogen, and increases the NH4 + A precise tillage method for the new double-season early rice milk vetch line 'Minzi 8' focuses on "delaying the tillage period for milk vetch, moving base fertilizer application forward, and shifting tillering fertilizer application backward." Based on the fertility characteristics of yellow mud paddies, this method adopts the principle of "front-load fertilizer, mid-stage fertilizer control, and back-stage fertilizer promotion" to meet the nutrient needs of early rice during the two peak fertilizer-demanding periods of tillering and young panicle differentiation, thereby improving fertilizer use efficiency. Therefore, compared with traditional milk vetch tillage techniques, this combined tillage method of milk vetch and chemical fertilizers delays tillage during peak flowering, prolongs the time milk vetch absorbs and utilizes atmospheric CO2, and shortens CO2 and CH4 emissions from paddy soils. This method provides a reference for achieving the coordinated development of increasing yield and quality of double-season early rice in southern China while reducing greenhouse gas emissions from rice paddies.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for cooperatively turning over chemical fertilizers and green manures in yellow mud fields of early rice, comprising the following steps:

[0009] 1.1 Milk vetch (Astragulus sinicus L.) varieties

[0010] The local variety 'Min Zi No. 8' which has not been approved for suitable planting areas shall be given priority and shall be verified by regional suitability tests of 2 planting cycles (2 years or more).

[0011] 1.2 Seed quality

[0012] Milk vetch seeds should meet the requirements for field seeds in GB 8080.

[0013] 1.3 Seed treatment

[0014] Sun-drying the seeds. Before sowing, choose a sunny day and sun-dry the seeds for 2 to 3 days.

[0015] Rub the seeds. Add the milk vetch seeds to 4% to 8% salt water at 45-62°C, stir and mix evenly, let it stand for 4-8 minutes, remove the floating diseased seeds and shriveled seeds, and then immerse the milk vetch seeds in a mixture of wood ash, ammonium chloride and water at a ratio of 1:0.2-0.5:9-15 at 45-62°C. Stir and soak for 14-18 hours, then drain.

[0016] Inoculate with rhizobia. If you are planting Chinese milk vetch for the first time or in an area where it has not been planted for many years, you should inoculate with Chinese milk vetch rhizobia. The quality of the rhizobia should meet the requirements of NY410.

[0017] Phosphate fertilizer should be mixed with seeds. If conditions permit, calcium magnesium phosphate fertilizer 225-300 kg·hm2 can be used for milk vetch green manure seeds. -2 Mix well and sow seeds.

[0018] 1.4 Seeding

[0019] 1.4.1 Seeding rate

[0020] The sowing amount of astragalus per hectare is 22.5 to 37.5 kg.

[0021] 1.4.2 Seeding Time

[0022] The sowing time of Chinese milk vetch is early October.

[0023] 1.4.3 Seeding method

[0024] Milk vetch is usually sown under rice 10-15 days before rice harvest. When there is no water on the field surface and water in the drainage ditch, the milk vetch seeds are evenly spread on the field surface to complete the sowing of milk vetch.

[0025] 2 Field management

[0026] 2.1 Ditching

[0027] After the late rice harvest, furrows should be dug as soon as possible, with a width and depth of approximately 20 cm. Depending on the size of the field, dig a perimeter ditch around the field first. Then, dig trenches every 5 to 8 meters in a well-shaped pattern. For smaller fields, dig trenches in a cross-shaped pattern. Ensure that the trenches are connected to the field's water outlet.

[0028] 2.2 Moisture Management

[0029] During the growth period of Chinese milk vetch, the field surface should be kept moist but not flooded.

[0030] When drought causes many fine cracks to appear on the field surface and the soil becomes hard, timely irrigation with "running water" (a method of flooding, quickly irrigating and draining to moisten the field surface); when there is heavy rain, timely ditches should be cleared and waterlogged.

[0031] 2.3 Fertilization

[0032] If conditions permit, base fertilizer can be applied.

[0033] 2.3.1 Base fertilizer

[0034] Base fertilizer is usually phosphate fertilizer, which is applied before sowing. For fields that have been mixed with phosphate fertilizer, base fertilizer is not required. The base fertilizer dosage for planting leguminous milk vetch is 15-30 kg·hm2 of phosphate fertilizer (P2O5). -2 .

[0035] 2.3.2 Topdressing

[0036] During the rapid growth period of milk vetch from mid-February to early March, if the growth is weak, 30-45 kg·hm2 of nitrogen fertilizer (N) can be applied. -2 Potash fertilizer (K2O) 30-45 kg·hm -2 .

[0037] 2.4 Pest and disease management

[0038] When pests and diseases occur seriously, timely prevention and control measures should be taken. The selection of pesticides should comply with the provisions of GB 4285 and GB 8321, especially those that are safe for bees.

[0039] In winter rice fields, the main diseases and pests of leguminous green manure include sclerotinia disease, powdery mildew, aphids, thrips, leaf miners, etc.

[0040] For the control of sclerotinia rot, refer to NY / T 794; for the control of powdery mildew and downy mildew, refer to NY / T 2702. For the control of aphids and thrips, refer to NY / T 2994; for the control of leafminer, refer to NY / T 2158.

[0041] 3 Turn over the fertile fields

[0042] 3.1 The period of resurgence

[0043] In double-season rice fields, the leguminous astragalus green manure is turned over during the peak flowering period (March to early April), usually 4 to 7 days before transplanting early rice.

[0044] 3.2 Green manure composting time

[0045] In rice fields where rice seedlings are transplanted, the green manure should be fermented for about 4 to 7 days.

[0046] 3.3 Turnover volume

[0047] For low-fertility rice fields, the full amount of rice should be returned to the field. For medium- and high-fertility rice fields, the amount of rice turning and compaction depends on the situation, with a slightly higher amount for medium-fertility and a slightly lower amount for high-fertility, ranging from 22.5 to 37.5 t·hm -2 High fertility is based on the amount of milk vetch turning 22.5t·hm -2 The time of turning over and pressing is 4 days before rice planting. The amount of fertilizer used for turning over and pressing is in accordance with the requirements of T1 treatment, or the amount of turning over and pressing of astragalus is 37.5t·hm -2 The time of turning and compacting is 4 days before rice planting, and the amount of chemical fertilizer used for turning and compacting is in accordance with the requirements of T2 treatment; the amount of turning and compacting of Chinese milk vetch is 37.5t·hm -2 It was determined that the time for turning over the soil was 7 days before rice planting, and the amount of fertilizer used for turning over the soil was in accordance with the requirements of T4 treatment.

[0048] 3.4 Turnover method

[0049] Use wet tillage and shallow retting. That is, when the milk vetch flowers are in full bloom, water the field until the surface water level reaches 1.2-2.5 cm. Then mechanically plow the milk vetch to a depth of 15-20 cm. The plowing quality should meet the requirements of NY / T 742 and NY / T 499. Allow the milk vetch to ret for 4-7 days. Continue irrigating the field until the surface water level reaches 3-4.5 cm. Remember to apply basal fertilizer while plowing.

[0050] If conditions permit, apply lime at 750 kg / hm2 before turning over the soil. -2 .

[0051] 3.5 Fertilizer application methods

[0052] For double-season early rice, nitrogen fertilizer is applied at a ratio of 3:2 of base fertilizer: ear fertilizer, phosphorus fertilizer is applied as a one-time base fertilizer for early rice, and potassium fertilizer is applied at a ratio of 1:1 of base fertilizer: ear fertilizer.

[0053] Furthermore, the nitrogen fertilizer in step (3.5) is urea, the phosphorus fertilizer is superphosphate, and the potash fertilizer is potassium chloride. Effective tillering; tillering nitrogen fertilizer is applied later together with ear fertilizer, and precise turning and reducing emissions technology.

[0054] Furthermore, the ratio of base fertilizer to panicle fertilizer for early rice in step (3.5) is 3:2. Based on the fertility characteristics of yellow mud fields, the principle of "heavy fertilizer in the early stage, control in the middle stage, and promote fertilizer in the late stage" is adopted to meet the nutritional needs of early rice during the two peak fertilizer demand periods of tillering and panicle differentiation, thereby improving fertilizer utilization efficiency.

[0055] The advantages of the present invention are:

[0056] Based on the discovery that the combined use of green manure and chemical fertilizer produces a strong positive nitrogen-stimulating effect on the soil, this invention proposes a novel concept for the coordinated tumbling of basal and green manures before transplanting double-season early rice. This concept also integrates the results of our research team's long-term experiments in optimizing fertilization for double-season early rice by increasing potassium and reducing nitrogen and phosphorus, as well as long-term tumbling experiments with Chinese milk vetch in the region. The results suggest a method for synergistic tumbling of chemical and green manures in yellow mud fields of early rice, based on the following principles: reduced chemical fertilizer dosage, the interval between tumbling Chinese milk vetch and early rice transplanting, and the amount of green manure tumbling. Furthermore, the Chinese milk vetch used in the experiment was 'Min Zi No. 8,' a new variety independently bred by the Soil and Fertilizer Research Institute of the Fujian Academy of Agricultural Sciences. It exhibits distinctive characteristics as a research material, including tolerance to low phosphorus levels, high yield, early growth, and strong adaptability.

[0057] Compared with the traditional milk vetch turning technology, this application proposal proposes to turn over the base fertilizer and green manure in coordination before transplanting the double-season early rice under flooded conditions. This can not only reduce the number of fertilization times, but also accelerate the decomposition of the milk vetch plants, delay the turning time during the flowering period of the milk vetch, increase the planting time of the milk vetch, and prolong the time for the milk vetch to absorb and utilize CO2 in the atmosphere, while shortening the emission time of CO2 and CH4 in the paddy soil, which is beneficial to carbon sequestration and emission reduction in the double-season early rice paddies. In addition, the relationship between the turning amount, turning time and fertilizer reduction of the milk vetch was comprehensively considered and tested. The test results can better meet the characteristics of large spatial variations in fertility between rice fields in the mountainous areas of Fujian. It is a variable amount of precise coordinated turning over of chemical fertilizers and green manures in yellow mud fields of early rice. While maintaining high yield and high quality of rice, it can also save fertilizer and reduce emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 The total nitrogen stimulation effect (A) and net nitrogen stimulation effect (B) of paddy field soil under different milk vetch incorporation; Note: M, milk vetch incorporation; MC 100 , returning astragalus to the field + full amount of fertilizer; MC 80 , returning Chinese milk vetch to the field + reducing chemical fertilizer by 20%. Different lowercase letters indicate significant differences among different treatments (P<0.05), the same below.

[0059] Figure 2Figure 3 shows the yield (A), fat (B), starch (C), protein (D) and amino acid (E, F) contents of potted rice under different astragalus incorporation treatments. Different lowercase letters outside brackets indicate significant differences among different treatments, and different lowercase letters within brackets indicate significant differences among different growth periods (P<0.05).

[0060] Figure 3 Changes in chlorophyll content in potted rice under different conditions of returning astragalus to the field.

[0061] Figure 4 Changes in nitrogen, phosphorus and potassium transport coefficients of potted rice plants under different astragalus return conditions. DETAILED DESCRIPTION

[0062] A method for cooperatively turning over chemical fertilizers and green manures in yellow mud fields of early rice, comprising the following steps:

[0063] (1) Milk vetch sowing and water management

[0064] Milk vetch should be sown under rice 10-15 days before rice harvest. When there is no water on the field surface and water in the drainage ditch, the milk vetch seeds should be evenly spread on the field surface to complete the sowing of milk vetch. During the growth period of milk vetch, the field surface should be kept moist but not flooded.

[0065] (2) Overturning

[0066] For double-cropping rice fields, the leguminous milk vetch green manure should be turned over 4-7 days before transplanting the early rice seedlings. At the same time, it is necessary to ensure that the milk vetch is in full bloom at the time of turning over. The specific turning over operation includes: when the milk vetch is in full bloom, irrigate the field to a water level of 1.2-2.5 cm, and apply lime at a rate of 750 kg·hm -2 Then mechanically plow the milk vetch to a depth of 15 to 20 cm, allow the milk vetch to ferment for 4 to 7 days, continue to irrigate the field until the water level is 3 to 4.5 cm, and then transplant early rice; pay attention to applying early rice base fertilizer while plowing.

[0067] Furthermore, the amount of turning over of milk vetch is 1500~2500kg·667m -2 .

[0068] Furthermore, nitrogen fertilizer for double-season early rice is applied at a mass ratio of 3:2 of base fertilizer: ear fertilizer, phosphorus fertilizer is applied as a one-time base fertilizer for early rice, and potassium fertilizer is applied at a mass ratio of 1:1 of base fertilizer: ear fertilizer.

[0069] Furthermore, the total dosage of nitrogen, phosphorus, and potassium fertilizers for double-season early rice formula is 8.00, 1.73, and 6.60 kg·667 m -2 After turning over the Chinese milk vetch, reduce the amount of chemical fertilizer applied by 10-30% according to this formula.

[0070] Furthermore, the nitrogen fertilizer is urea, the phosphorus fertilizer is superphosphate, and the potash fertilizer is potassium chloride.

[0071] Furthermore, tillering nitrogen fertilizer is applied later together with ear fertilizer.

[0072] To make the above features and advantages of the present invention more clearly understood, the following embodiments are given for detailed description. Unless otherwise specified, the methods of the present invention are all conventional methods in the art.

[0073] Example 1

[0074] (1) Research plan

[0075] 1 Experimental design

[0076] The soil type is yellow mud field. The parent material is low hill slope sediment. The experiment started in 2022 and used L9 orthogonal experimental design and comparative experiment. The orthogonal experimental factors and levels are detailed in Table 1. Each treatment was replicated three times, with a total of 30 plots. The plots were arranged in completely randomized blocks. The plot area was 15m 2 Small ridges with film-coated insulation were set up between plots, with a height of 20 cm, to reduce water and fertilizer cross-fertilization and lateral seepage between plots. Each plot was irrigated with a single row to avoid cross-irrigation and cross-drainage. Protective rows were set up outside the plots. Each plot was accurately marked and positioned. The nitrogen, phosphorus, and potassium fertilizer dosages for the double-season early rice formula were 8.00, 1.73, and 6.60 kg / 667 m2, respectively. -2 The nutrient content of Chinese milk vetch dry matter is OC 397.6g·kg -1 、N 23.9g·kg -1 、P2O52.2 g·kg -1 、K2O 16.4g·kg -1 , with a moisture content of 82.9%. All phosphorus fertilizer was used as base fertilizer; 60% of the total nitrogen fertilizer was used as base fertilizer, and 40% was used as ear fertilizer during the initial stage of ear differentiation; 50% of the potassium fertilizer was used as base tillering fertilizer, and 50% was used as ear fertilizer during the ear differentiation stage. In addition, the conventional fertilizer treatment in the comparative experiment used 9.10, 1.97, and 3.73 kg / 667 m3 of nitrogen, phosphorus, and potassium fertilizers, respectively. -2 All phosphate fertilizers were used as base fertilizers, 60% nitrogen fertilizers and 40% potassium fertilizers were applied as base fertilizers, and 40% nitrogen fertilizers and 60% potassium fertilizers were applied as topdressing during the tillering period. Chemical fertilizers were urea (N 46%), superphosphate (P 5%) and potassium chloride (K 12%). The milk vetch variety used for the test was 'Min Zi No. 8', which was planted in the original field and turned over during the flowering period (March to April). The field was irrigated during turning over, with a water layer depth of 1 to 2 cm. Lime 25 to 40 kg / 667 m was applied during turning over. -2. Use 20cm×40cm sample plots to take samples from each plot, carefully dig out the roots of the milk vetch, wash them with water on site, and weigh them. Calculate the fresh grass yield of the milk vetch in each plot, remove the excess milk vetch from the original field, and supplement the insufficient part with external sources. Irrigate in time after plowing to accelerate the decomposition rate of the milk vetch. Turn the milk vetch into the soil layer and press it as tightly as possible to make it fully contact with the soil. Do not expose the milk vetch stubble. At the same time, combine the application of early base fertilizer for early rice to accelerate the decomposition and rot of the milk vetch, reduce the negative effects of harmful substances produced during the decomposition of green manure on the seedlings, improve the conversion rate of green manure, and ensure that the fertilizer effect is exerted in time. The early season rice variety tested is conventional rice 78-30. There are 418 seedlings in each plot, with a row spacing of 20cm×23cm, and the harvest is in late July each year.

[0077] Table 1 Orthogonal test L9(3 3 ) The interval between turning over the astragalus and transplanting the early rice, the amount of green manure turning over and the amount of chemical fertilizer reduction in each treatment

[0078]

[0079] Table 2 Changes in nitrogen, phosphorus and potassium nutrient contents in potted rice plants under different conditions of returning astragalus to the field

[0080]

[0081]

[0082] Table 3 Changes in soil chemical properties of potted rice fields under different conditions of returning astragalus to the field

[0083]

[0084]

[0085] Note: Different letters outside the brackets between different treatments in the same column indicate significant differences in Duncan's multiple comparisons (P < 0.05); different letters in the brackets between different rice growth stages in the same column indicate significant differences in Duncan's multiple comparisons under the same treatment.

[0086] Depend on Figure 2It can be seen that compared with the T0 treatment, the rice yield of the T2 and T4 treatments increased by 5.5% and 1.3%, respectively, while the rice yield of the T1, T3, T5, T6, T7, T8 and T9 treatments decreased by 0.3%, 23.1%, 19.4%, 7.0%, 24.1%, 5.5% and 14.4%, respectively, but the differences did not reach statistical significance (P>0.05). Compared with T0 treatment, the fat content of rice in T1, T2, T3, T4, T5, T6, T7 and T8 treatments increased by 6.3, 5.9, 3.7, 1.9, 0.7, 1.0, 1.4 and 1.1 times, respectively, while that in T9 treatment decreased by 0.4 times; the amylopectin content of rice in T1, T2, T3, T4, T5, T6, T7 and T8 treatments increased by 8.4%, 12.6%, 5.1%, 11.6%, 9.8%, 8.5%, 3.1% and 6.4%, respectively, while that in T9 treatment decreased by 1.1%. Compared with the T0 treatment, the protein content of rice in the T1, T2, T3, T4, T5, T6, T7, T8 and T9 treatments increased by 16.5%, 1.2%, 18.9%, 14.9%, 23.5%, 15.3%, 23.9%, 10.6% and 15.1%, respectively. Compared with T0 treatment, the amino acid content of rice in T1, T2, T3, T4, T5, T6, T7 and T9 treatments increased by 0.4%, 8.7%, 21.4%, 24.6%, 8.9%, 8.4%, 20.9% and 4.7%, respectively, and the non-essential amino acid content increased by 2.7%, 10.7%, 26.1%, 28.2%, 10.8%, 7.6%, 23.6% and 6.4%, respectively, while the amino acid and non-essential amino acid contents in T8 treatment decreased by 3.9%; compared with T0 treatment, except for T1 and T8 treatments, the essential amino acid content of rice in T2, T3, T4, T5, T6, T7 and T9 treatments increased by 6.2%, 15.8%, 20.3%, 6.5%, 9.4%, 17.6% and 2.7%, respectively. Among them, compared with the T0 treatment, the phenylalanine content of rice in the T2, T3, T4, T5, T6, T7 and T9 treatments increased by 12.5%, 17.8%, 21.5%, 11.2%, 7.8%, 19.4% and 4.2%, respectively, while that in the T1 and T8 treatments decreased by 1.0% and 3.5%, respectively; the isoleucine content of rice increased by 17.4%, 18.7%, 24.2%, 10.7%, 11.5%, 21.6% and 2.2%, respectively, while that in the T1 and T8 treatments decreased by 1.0% and 2.2%, respectively. Compared with the T0 treatment, except for the T8 treatment, the essential amino acid contents of rice in the T1, T2, T3, T4, T5, T6, T7 and T9 treatments increased by 0.7%, 15.3%, 19.3%, 22.5%, 12.1%, 11.4%, 22.4% and 6.1%, respectively.Compared with T0, the methionine content of rice in treatments T3, T4, T5, T6, T7, T8, and T9 increased by 13.7%, 29.2%, 7.2%, 24.4%, 19.9%, and 7.1%, respectively, while it decreased by 8.5% and 60.7%, respectively, in treatments T1 and T2. Compared with T0, the valine content of rice in treatments T3, T4, and T7, with the exception of treatment T2, increased by 13.7%, 29.2%, and 7.2%, respectively, while it decreased by 16.7%, 7.2%, 3.7%, 11.9%, and 7.7%, respectively, in treatments T1, T5, T6, T8, and T9. Compared with T0, the threonine content of rice in treatments T1, T2, T3, T4, T6, T7, and T9 increased by 8.6%, 11.8%, 29.6%, 14.0%, 13.8%, 4.3%, and 3.3%, respectively, while it decreased by 10.9% and 20.0%, respectively, in treatments T5 and T8. Compared with T0, the lysine content of rice in treatments T1, T2, T3, T4, T5, T6, T7, T8, and T9 increased by 37.8%, 46.3%, 38.7%, 46.4%, 27.6%, 25.7%, 36.1%, 10.6%, and 27.7%, respectively.

[0087] Depend on Figure 3 It can be seen that during the tillering stage, compared with the T0 treatment, the chlorophyll content of rice leaves in the T1, T2, T3, T4, T5, T6, T7, T8, and T9 treatments increased by 50.8%, 39.9%, 35.1%, 38.9%, 29.0%, 20.5%, 43.7%, 23.2%, and 25.7%, respectively. During the grain filling stage, compared with the T0 treatment, the chlorophyll content of rice leaves in the T1, T2, T3, T4, T5, T6, T7, T8, and T9 treatments increased by 59.3%, 79.2%, 73.6%, 131.4%, 72.9%, 35.6%, 74.5%, 4.9%, and 30.6%, respectively. It can be seen that the treatment containing astragalus maintained a high chlorophyll content in rice leaves during the rice maturity period, especially the T4 treatment maintained a high chlorophyll content in rice leaves during the rice tillering and filling stages.

[0088] Depend on Figure 4Compared with T0, the nitrogen transport coefficients of rice plants in the T2, T3, T4, T5, T6, and T7 treatments increased by 2.2%, 25.7%, 10.7%, 11.9%, 0.9%, and 1.7%, respectively, while those in the T1, T8, and T9 treatments decreased by 2.6%, 0.8%, and 16.5%, respectively. Compared with T0, the phosphorus transport coefficients of rice plants in the T3, T4, and T5 treatments increased by 7.3%, 4.4%, and 2.2%, respectively, while those in the T1, T2, T6, T7, T8, and T9 treatments decreased by 1.8%, 4.5%, 6.5%, 2.5%, 1.7%, and 11.6%, respectively, not reaching statistically significant differences (P>0.05). Compared with the T0 treatment, the potassium transport coefficients of rice plants increased by 12.6%, 9.9%, 21.9%, 18.0%, 16.3%, 12.9%, 13.2%, and 12.7% in the T1, T3, T4, T5, T6, T7, T8, and T9 treatments, respectively, with the exception of the T2 treatment. This suggests that tumbling practices involving Chinese milk vetch generally prioritize the transport of nitrogen and potassium to the grain, a storage organ, improving rice quality, with the T4 treatment being particularly effective. Compared with treatment T0, the nitrogen content of rice grains in treatments T1, T2, T3, T4, T5, T6, T7, T8, and T9 increased by 1.6%, 6.6%, 19.4%, 10.3%, 17.0%, 7.5%, 15.8%, 2.0%, and 6.1%, respectively, and the potassium content of rice grains increased by 13.1%, 1.6%, 10.8%, 20.8%, 25.4%, 19.9%, 10.3%, 15.1%, and 18.6%, respectively. However, there was no significant difference in phosphorus content among the tested rice grains (P>0.05) (Table 2).

[0089] Table 3 shows that soil acidification improved over time. During the rice maturity stage, compared with treatment T0, soil pH values ​​in paddy fields increased by 4.7%, 4.9%, 6.3%, 7.0%, 3.3%, 0.9%, 8.5%, 3.3%, and 2.5% in treatments T1, T2, T3, T4, T5, T6, T7, T8, and T9, respectively. During the tillering stage, compared with the T0 treatment, the soil organic matter content of paddy fields in T1, T2, T3, T4, T5, T6, T7, T8 and T9 treatments increased by 0.6%, 8.0%, 6.3%, 7.9%, 10.8%, 2.8%, 5.1%, 3.6% and 8.1%, respectively; during the maturity stage, compared with the T0 treatment, the soil organic matter content of paddy fields in T1, T2, T3, T4, T5, T7 and T8 treatments increased by 5.1%, 8.1%, 5.5%, 3.0%, 10.4%, 4.3% and 5.8%, respectively, while the soil organic matter content of paddy fields in T6 and T9 treatments decreased by 0.5% and 3.7%, respectively. During the tillering stage, compared with the T0 treatment, the total nitrogen content of the paddy soil in the T2, T4, T5, T6, T7, T8 and T9 treatments, except for the T1 and T3 treatments, increased by 7.1%, 4.0%, 7.1%, 1.0%, 5.1%, 5.1% and 5.1%, respectively; during the maturity stage, compared with the T0 treatment, the total nitrogen content of the paddy soil in the T1, T2, T3, T4, T5, T7 and T8 treatments increased by 6.4%, 6.4%, 6.4%, 3.2%, 5.3%, 2.1% and 5.3%, respectively, while the total nitrogen content of the soil in the T6 and T9 treatments decreased by 1.1% and 3.2%, respectively. Compared with T0, total potassium content in paddy soils under treatments T1, T2, T3, T4, T5, T6, T7, T8, and T9 increased by 5.5%, 22.5%, 30.0%, 8.2%, 12.1%, 11.8%, 20.5%, 2.6%, and 2.1% at the tillering stage. Compared with T0, total potassium content in paddy soils under treatments T1, T2, T3, T4, T5, T6, T7, T8, and T9 increased by 8.2%, 1.1%, 10.4%, 7.9%, 0.5%, 5.9%, 6.0%, 5.2%, and 3.7%, respectively. However, there were no significant differences in total phosphorus content among the treatments at the maturity stage. In addition, there was no significant difference in soil organic matter between the tillering stage and the maturity stage; except that the total nitrogen content in the paddy field soil of T5, T7, and T9 treatments was significantly lower in the maturity stage than in the tillering stage (P<0.05), there was no significant difference among other treatments.During the tillering stage, compared with the T0 treatment, the alkaline-hydrolyzable nitrogen content of the paddy soil in the T1, T2, T3, T4, T5, T7, T8 and T9 treatments increased by 7.0%, 23.6%, 40.2%, 14.7%, 7.5%, 2.5%, 13.3% and 23.4%, respectively, while that of the T6 treatment decreased by 5.6%; during the maturity stage, compared with the T0 treatment, the alkaline-hydrolyzable nitrogen content of the paddy soil in the T2, T3, T4, T5, T6, T7, T8 and T9 treatments increased by 1.7%, 23.0%, 28.2%, 20.7%, 24.7%, 33.7%, 22.5% and 35.4%, respectively, while that of the T1 treatment decreased by 16.9%. During the tillering stage, compared with the T0 treatment, the total potassium content of the paddy soil in the T1, T2, T3, T4, T5, T6, T7, T8 and T9 treatments increased by 77.8%, 186.3%, 220.6%, 59.2%, 105.8%, 40.2%, 118.4%, 23.3% and 12.7%, respectively; during the maturity stage, compared with the T0 treatment, the total potassium content of the paddy soil in the T1, T2, T3, T4, T5, T6, T7, T8 and T9 treatments increased by 11.4%, 4.7%, 2.5%, 4.8%, 16.0%, 20.6%, 4.5%, 9.3% and 9.1%, respectively.

[0090] In summary, compared with farmers' customary fertilization treatment T0, treatments T1, T2, or T4 are ideal for turning and compacting milk vetch in Huangni paddy fields. These methods can reduce nitrogen fertilizer application by 20% to 40%, phosphorus fertilizer application by 20% to 40%, increase soil pH by 4.7% to 7.0%, organic matter content by 0.6% to 8.0%, increase leaf chlorophyll content by 38.9% to 131.4% during the critical growth period of rice, increase rice nitrogen content by 1.6% to 10.3%, and rice potassium content by 1.6% to 20.8%. Turning and compacting duration can also be shortened by 8 to 11 days. Conversely, shortening the turning and compacting duration prolongs the milk vetch's growth period, increasing its absorption and utilization of CO2, reducing CO2 and CH4 greenhouse gas emissions from turning and compacting, and thus helping to mitigate the greenhouse effect in Huangni early rice fields. On the premise of maintaining stable and high yield, the amylopectin content of rice in T1, T2 and T4 treatments increased by 8.4%, 12.6% and 11.6% respectively, the protein content increased by 16.5%, 18.9% and 14.9% respectively, and the amino acid content increased by 0.4%, 8.7% and 24.6% respectively.

[0091] It can be seen that the present invention comprehensively considers the quantitative relationship between the three factors of the turning amount, turning time and chemical fertilizer dosage of the Chinese milk vetch, creates a method for the coordinated turning of chemical fertilizers and green manures in yellow mud fields of early rice, and applies it to potted experiments. The test results confirm that the coordinated turning of chemical fertilizers and green manures in yellow mud fields of early rice can improve the soil fertility level of rice fields, enhance the photosynthetic function of rice leaves, and achieve good effects of reducing emissions, reducing weight, stabilizing yields and improving quality.

[0092] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A method for cooperatively compacting chemical fertilizers and green manure in yellow mud fields of early rice, characterized in that: The following steps are involved: (1) Milk vetch sowing and water management Milk vetch should be sown under rice 10-15 days before rice harvest. When there is no water on the field surface and water in the drainage ditch, the milk vetch seeds should be evenly spread on the field surface to complete the sowing of milk vetch. During the growth period of milk vetch, the field surface should be kept moist but not flooded. (2) Overturning For double-cropping rice fields, the leguminous milk vetch green manure should be turned over 4-7 days before transplanting early rice, and it is necessary to ensure that the milk vetch is in full bloom at the time of turning over. The specific turning over operation includes: when the milk vetch flowers are in full bloom, irrigate the field to a water level of 1.2-2.5 cm, and apply lime at 750 kg / hm2. 2 Then, the milk vetch is mechanically turned over to a depth of 15 to 20 cm, and the milk vetch is allowed to ferment for 4 to 7 days. Water is then continuously irrigated to a water level of 3 to 4.5 cm, and then early rice is transplanted. Note that early rice base fertilizer should be applied while turning over. The amount of turning over of Chinese milk vetch is 1500~2500 kg / 667 m 2 ; For double-season early rice, nitrogen fertilizer should be applied at a base fertilizer: ear fertilizer mass ratio of 3:2, phosphate fertilizer should be applied as a base fertilizer for early rice at one time, and potash fertilizer should be applied at a base fertilizer: ear fertilizer mass ratio of 1:

1. The total dosage of nitrogen, phosphorus, and potassium fertilizers for double-season early rice is 8.00, 1.73, and 6.60 kg / 667 m, respectively. 2 After turning over the Chinese milk vetch, reduce the amount of chemical fertilizer applied by 10-30% according to this formula; The nitrogen fertilizer is urea, the phosphorus fertilizer is superphosphate, and the potash fertilizer is potassium chloride; The nitrogen fertilizer for tillering should be applied later together with the ear fertilizer.

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