Application method of rice nitrogen fertilizer under nitrogen loss condition

Abstract

The invention belongs to the technical field of agricultural planting, and provides an application method of a rice nitrogen fertilizer under a nitrogen loss condition. According to the method, nitrogen deficiency treatment in different tillering stages is set, constant and multiple nitrogen compensation tests are carried out in the subsequent growth stage, the influence of nitrogen deficiency on the rice yield is analyzed, the efficient nitrogen compensation threshold value of indica rice and japonica rice is determined, an important reference basis is provided for nitrogen fertilizer management in rice production, and the method is suitable for large-scale popularization and application. The nitrogen fertilizer utilization efficiency and the rice yield are favorably improved.

Description

Technical Field

[0001] The invention relates to the technical field of agricultural planting, and in particular to a method for applying nitrogen fertilizer to rice under nitrogen deficiency conditions. Background Art

[0002] Nitrogen is an important nutrient for rice growth and development, directly affecting the root growth, microbial community and yield of rice. However, in actual agricultural production, improper nitrogen fertilizer management often leads to problems such as stunted rice growth, low nitrogen utilization efficiency or excessive fertilization. When the nitrogen supply of rice is insufficient during the critical growth period, the yield is often negatively affected.

[0003] As two common rice varieties, indica rice and japonica rice have obvious differences in nitrogen absorption and utilization, especially in root physiology and nitrogen compensation effects. Therefore, the study of effective compensation timing and schemes for nitrogen deficiency is crucial to optimize nitrogen fertilizer use and increase yield. However, there is currently a lack of systematic research on the sensitive period and threshold differences for efficient compensation of nitrogen deficiency in different rice varieties. Therefore, how to manage nitrogen fertilizer to increase rice yield has become an urgent problem for technicians in this field. Summary of the invention

[0004] In view of this, the present invention provides a method for applying nitrogen fertilizer to rice under nitrogen deficiency conditions, which aims to solve the problems of rice growth stunting, low nitrogen utilization efficiency or excessive fertilization caused by existing nitrogen fertilizer management technologies.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] The present invention provides a method for applying nitrogen fertilizer to rice under nitrogen deficiency conditions, comprising the following steps:

[0007] S1, soaking seeds: soaking rice seeds in a mixed solution of fungicide and water for a first time, and then soaking them in water for a second time to obtain soaked seeds;

[0008] S2, raising seedlings: sowing the soaked seeds, and raising seedlings to obtain seedlings;

[0009] S3. Preparation before sowing: including soil pretreatment for barrel planting or soil pretreatment for field planting;

[0010] The steps of soil pretreatment for barrel planting are: drying, crushing and sieving the plough layer soil in sequence, and then putting the plough layer soil into a barrel;

[0011] The steps of field planting soil pretreatment are: deep ploughing, ridge making, and plastic film covering;

[0012] S4. Fertilization: Apply base fertilizer to the planting soil;

[0013] S5, transplanting: pre-flooding the planting soil, and transplanting the rice seedlings obtained in step S2 into the barrel or field in step S4;

[0014] S6. Treatment: When the seedlings enter the tillering stage, apply nitrogen fertilizer again, and apply flower-preserving fertilizer 12 to 15 days before heading until the seedlings complete normal growth.

[0015] Furthermore, in the step S1, the ratio of the amount of rice seeds to the fungicide during the first soaking is 1kg:3-5mL; the mixed solution of the fungicide and water is sufficient to submerge the rice seeds; the fungicide is Liangdun;

[0016] When soaking for the second time, use clean water that is enough to cover the rice seeds.

[0017] Furthermore, in step S1, the first soaking time is 20 to 30 hours, and the second soaking time is 10 to 20 hours.

[0018] Furthermore, in step S2, the specification of the seedling tray for blanket seedling cultivation is 60cm×25cm, and the sowing amount of each seedling tray is 100-120g; after sowing, the seedlings are darkened for 2-3 days.

[0019] Furthermore, in step S3, in the soil pretreatment for barrel planting, the topsoil is 0 to 20 cm thick soil from the paddy field; the particle size of the sieved topsoil is ≤ 0.15 mm; the inner diameter of the barrel bottom is 20 to 25 cm, the outer diameter of the barrel mouth is 28 to 32 cm, and the barrel height is 25 to 30 cm; 14 to 18 kg of topsoil is placed in each barrel.

[0020] Furthermore, in the step S3, in the soil pretreatment for field planting, the tillage depth of deep tillage is 20 to 30 cm; and the treatment steps included in step S3 are repeated at least 3 times.

[0021] Furthermore, in the step S4, in the barrel planting, the base fertilizer includes superphosphate, potassium chloride and nitrogen fertilizer, and the mass ratio of superphosphate, potassium chloride and nitrogen fertilizer is 5-10:1-3:1-3;

[0022] In field planting, the base fertilizer includes superphosphate, potassium chloride and nitrogen fertilizer, and the mass ratio of the superphosphate, potassium chloride and nitrogen fertilizer is 700-800:100-300:10-100.

[0023] Furthermore, in step S5, the pre-flooding treatment step is: flooding the planting soil for two consecutive weeks.

[0024] Furthermore, in step S5, the rice seedlings are transplanted into the field with a planting row spacing of 12 cm×30 cm; and the rice seedlings are transplanted into barrels with 2 to 4 seedlings planted in each barrel.

[0025] Further, in barrel planting, the total amount of nitrogen fertilizer applied per barrel in step S4 and step S6 is 4.5-6 g; the flower-preserving fertilizer includes nitrogen fertilizer and potassium chloride, and the mass ratio of nitrogen fertilizer to potassium chloride is 1:1; between the tillering stage and the completion of the production, the specific scheme of nitrogen fertilizer application is as follows: the amount of nitrogen fertilizer applied per barrel is 0-3 g at the beginning of the tillering stage, the amount of nitrogen fertilizer applied per barrel on the 6th day after the tillering stage is 0-3 g, the amount of nitrogen fertilizer applied per barrel on the 12th day after the tillering stage is 0-3 g, the amount of nitrogen fertilizer applied per barrel on the 18th day after the tillering stage is 0-3 g, the amount of nitrogen fertilizer applied per barrel on the 24th day after the tillering stage is 0-3 g, the amount of nitrogen fertilizer applied per barrel on the 30th day after the tillering stage is 0-3 g, and the amount of nitrogen fertilizer applied per barrel 12-15 days before heading is 1.5 g;

[0026] In field planting, the total amount of nitrogen fertilizer applied in step S4 and step S6 is 180-240 kg·hm -2 ; Flower-protecting fertilizer includes nitrogen fertilizer and potassium chloride, and the mass ratio of nitrogen fertilizer to potassium chloride is 60:150; the specific scheme of nitrogen fertilizer application between tillering stage and completion of growth is as follows: the nitrogen fertilizer application amount at the beginning of tillering stage is 0-120kg·hm -2 , the nitrogen fertilizer application rate on the 6th day after tillering is 0-120 kg·hm -2 , the nitrogen fertilizer application rate on the 12th day after the tillering stage is 0-120 kg·hm -2 , the nitrogen fertilizer application rate on the 18th day after the tillering stage is 0-120 kg·hm -2 , the nitrogen fertilizer application rate on the 24th day after the tillering stage is 0-120 kg·hm -2 , the nitrogen fertilizer application rate on the 30th day after the tillering stage is 0-120 kg·hm -2 , 12 to 15 days before heading, the nitrogen fertilizer application rate is 60 kg·hm -2 .

[0027] It can be seen from the above technical solution that compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] The present invention has achieved remarkable results in the nitrogen deficiency and compensation experiments of indica rice and japonica rice. First, the indica rice variety was treated with double nitrogen compensation 12 days after nitrogen deficiency in the tillering period, and its single plant yield was significantly improved, showing a super compensation effect. Specifically, the 2021 test data showed that the treatment group of Yangxianyou 918 compensated 12 days after nitrogen deficiency had 13.33 effective ears per plant, 182.99 grains per ear, a fruit setting rate of 87.51%, and a single plant yield of 38.58 grams, which was significantly higher than other treatment groups. The 2022 data also supported this conclusion. The single plant yield of the treatment group compensated 12 days after nitrogen deficiency reached 35.95 grams, which also showed the best compensation effect.

[0029] In contrast, the japonica rice variety was subjected to double compensation treatment 18 days after nitrogen deficiency in the tillering stage, and its single plant yield also achieved a significant increase. Data from 2021 showed that the number of effective panicles per plant in the treatment group was 11.00, the total number of grains per panicle was 137.77, the fruit setting rate was 96.19%, and the single plant yield reached 30.48 grams. In the 2022 data, the single plant yield of the double compensation treatment group 18 days after nitrogen deficiency in the tillering stage further increased to 28.71 grams. Compared with other compensation treatment groups, the optimal compensation threshold of japonica rice is delayed compared with indica rice, showing the differences between different varieties under nitrogen deficiency conditions. Therefore, the present invention clarifies the optimal compensation threshold and efficient compensation period of indica rice and japonica rice after nitrogen deficiency, provides an important reference basis for nitrogen fertilizer management in rice production, and helps to improve nitrogen fertilizer utilization efficiency and rice yield. DETAILED DESCRIPTION

[0030] The present invention provides a method for applying nitrogen fertilizer to rice under nitrogen deficiency conditions, comprising the following steps:

[0031] S1, soaking seeds: soaking rice seeds in a mixed solution of fungicide and water for a first time, and then soaking them in water for a second time to obtain soaked seeds;

[0032] S2, raising seedlings: sowing the soaked seeds, and raising seedlings to obtain seedlings;

[0033] S3. Preparation before sowing: including soil pretreatment for barrel planting or soil pretreatment for field planting;

[0034] The steps of soil pretreatment for barrel planting are: drying, crushing and sieving the plough layer soil in sequence, and then putting the plough layer soil into a barrel;

[0035] The steps of field planting soil pretreatment are: deep ploughing, ridge making, and plastic film covering;

[0036] S4. Fertilization: Apply base fertilizer to the planting soil;

[0037] S5, transplanting: pre-flooding the planting soil, and transplanting the rice seedlings obtained in step S2 into the barrel or field in step S4;

[0038] S6. Treatment: When the seedlings enter the tillering stage, apply nitrogen fertilizer again, and apply flower-preserving fertilizer 12 to 15 days before heading until the seedlings complete normal growth.

[0039] In the present invention, in the step S1, the ratio of the amount of rice seeds to the fungicide during the first soaking is 1kg:3-5mL, preferably 1kg:4mL; the mixed solution of the fungicide and water is sufficient to submerge the rice seeds; the fungicide is Liangdun; the concentration of fludioxonil in Liangdun is preferably 25g / L, and the concentration of metalaxyl-M is preferably 37.5g / L;

[0040] When soaking for the second time, use clean water that is enough to cover the rice seeds.

[0041] In the present invention, in step S1, the first soaking time is 20 to 30 hours, preferably 22 to 28 hours, and more preferably 24 to 26 hours; the second soaking time is 10 to 20 hours, preferably 12 to 18 hours, and more preferably 14 to 16 hours.

[0042] In the present invention, in step S2, the specification of the seedling tray for blanket seedling cultivation is 60cm×25cm, and the content of organic matter in the seedling tray is ≥46%, preferably ≥48%, and more preferably ≥50%, so as to ensure the balance of germination rate and seedling growth; the sowing amount of each seedling tray is 100-120g, preferably 105-115g, and more preferably 110g; and the seedlings are darkened for 2-3 days after sowing, preferably 3 days.

[0043] In the present invention, in the step S3, in the soil pretreatment for barrel planting, the topsoil is 0 to 20 cm thick soil of the paddy field, preferably 2 to 16 cm thick soil, and more preferably 5 to 15 cm thick soil; the particle size of the sieved topsoil is ≤0.15 mm, preferably ≤0.14 mm, and more preferably ≤0.12 mm; the inner diameter of the barrel bottom is 20 to 25 cm, the outer diameter of the barrel mouth is 28 to 32 cm, and the barrel height is 25 to 30 cm. The barrel is preferably a plastic barrel, the inner diameter of the barrel bottom is preferably 23 cm, the outer diameter of the barrel mouth is preferably 30 cm, and the barrel height is preferably 27.5 cm; 14 to 18 kg of topsoil is put into each barrel, preferably 15 kg.

[0044] In the present invention, in step S3, in the pretreatment of soil for field planting, the tillage depth of deep tillage is 20 to 30 cm, preferably 22 to 28 cm, and more preferably 24 to 26 cm; the treatment steps included in step S3 are all repeated at least 3 times.

[0045] In the present invention, in step S4, in barrel planting, the base fertilizer includes superphosphate, potassium chloride and nitrogen fertilizer, and the mass ratio of superphosphate, potassium chloride and nitrogen fertilizer is 5-10:1-3:1-3, preferably 6:1.5:1.5;

[0046] In field planting, the base fertilizer includes superphosphate, potassium chloride and nitrogen fertilizer, and the mass ratio of superphosphate, potassium chloride and nitrogen fertilizer is 700-800:100-300:10-100, preferably 750:150:60.

[0047] In the present invention, in step S5, the pre-flooding treatment step is: flooding the planting soil for two consecutive weeks.

[0048] In the present invention, in step S5, the rice is transplanted into the field with a planting spacing of 12 cm×30 cm, one seedling is planted in each hole of indica rice, and two seedlings are planted in each hole of japonica rice; the rice is transplanted into a barrel, 2 to 4 seedlings are planted in each barrel, and preferably 2 holes are planted in each barrel, one seedling is planted in each hole of indica rice, and two seedlings are planted in each hole of japonica rice.

[0049] In the present invention, in barrel planting, the total amount of nitrogen fertilizer applied per barrel in step S4 and step S6 is 4.5-6g, preferably 5-5.5g; the flower-protecting fertilizer includes nitrogen fertilizer and potassium chloride, and the mass ratio of nitrogen fertilizer to potassium chloride is 1:1; between the tillering stage and the completion of the generation, the specific scheme of nitrogen fertilizer application is preferably: the amount of nitrogen fertilizer applied per barrel at the beginning of the tillering stage is 1.5g or 3g; the amount of nitrogen fertilizer applied per barrel on the 6th day after the tillering stage is 1.5g or 3g; the amount of nitrogen fertilizer applied per barrel on the 12th day after the tillering stage is 1.5g or 3g; the amount of nitrogen fertilizer applied per barrel on the 18th day after the tillering stage is 1.5g or 3g; the amount of nitrogen fertilizer applied per barrel on the 24th day after the tillering stage is 1.5g or 3g; the amount of nitrogen fertilizer applied per barrel on the 30th day after the tillering stage is 1.5g or 3g; the amount of nitrogen fertilizer applied per barrel 12-15 days before heading is 1.5g;

[0050] In field planting, the total amount of nitrogen fertilizer applied in step S4 and step S6 is 180-240 kg·hm -2 , preferably 190 to 230 kg·hm -2 , more preferably 200 to 220 kg·hm -2 ; The flower-protecting fertilizer includes nitrogen fertilizer and potassium chloride, and the mass ratio of nitrogen fertilizer to potassium chloride is 60:150; between the tillering stage and the completion of the growth, the specific scheme of nitrogen fertilizer application is preferably: the nitrogen fertilizer application amount at the beginning of the tillering stage is 60kg·hm -2 or 120kg·hm -2 ; The nitrogen fertilizer application rate on the 6th day after tillering is 60kg·hm -2 or 120kg·hm -2 ; The nitrogen fertilizer application rate on the 12th day after the tillering stage is 60kg·hm-2 or 120kg·hm -2 ; The nitrogen fertilizer application rate on the 18th day after the tillering stage is 60 kg·hm -2 or 120kg·hm -2 ; The nitrogen fertilizer application rate on the 24th day after the tillering stage is 60 kg·hm -2 or 120kg·hm -2 ; The nitrogen fertilizer application rate on the 30th day after the tillering stage is 60 kg·hm -2 or 120kg·hm -2 ; Nitrogen fertilizer application rate 12-15 days before heading: 60 kg·hm -2 .

[0051] In the present invention, all nitrogen fertilizers are urea, and the total nitrogen content in the urea is ≥46.0%.

[0052] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0053] Example 1

[0054] S1. Seed soaking: In mid-May, weigh 1 kg of the indica rice variety Yangxianyou 918 and put it into a container, and dilute 4 mL of Liangdun (25 g / L fludioxonil and 37.5 g / L metalaxyl-M) with water until the seeds are submerged. Soak for 24 hours and then soak in clean water for 12 hours to obtain soaked seeds.

[0055] S2. Raising seedlings: Sowing the soaked seeds, raising seedlings in blankets, with a sowing density of 100 g per seedling tray, 8 trays, and darkening for 3 days.

[0056] S3. Preparation before sowing: For barrel planting, choose a plastic barrel with an upper outer diameter of 30 cm, an inner diameter of 23 cm at the bottom, and a height of 27.5 cm. Each barrel should be filled with 15 kg of topsoil. The soil should be the 0-20 cm topsoil of paddy fields that has been naturally dried and crushed with a soil crusher through a 100-mesh sieve. Each treatment should be repeated 3 times, with 10 barrels per repeat.

[0057] S4. Fertilization: Apply basal fertilizers of superphosphate (containing 12% P2O5), 6g of potassium chloride (containing 60% K2O) and 1.5g of urea to each bucket one day before transplanting.

[0058] S5. Transplanting: For two consecutive weeks before transplanting, add water to the bucket to flood it, then plant 2 holes in each bucket, with 1 seedling in each hole.

[0059] S6. Treatment: Apply 1.5 g urea per bucket when entering the tillering stage, and apply 1.5 g urea and 1.5 g potassium chloride per bucket 15 days before heading until the rice matures.

[0060] Example 2

[0061] The method is the same as Example 1, except that in step S6, 3 g of urea is applied to each barrel when the rice enters the tillering stage, and 1.5 g of urea and 1.5 g of potassium chloride are applied to each barrel 15 days before heading until the rice matures.

[0062] Example 3

[0063] The method is the same as Example 1, except that in step S6, 1.5 g of urea is applied to each barrel on the 6th day after the tillering stage, and 1.5 g of urea and 1.5 g of potassium chloride are applied to each barrel 15 days before heading until the rice matures.

[0064] Example 4

[0065] The same as Example 1, except that in step S6, 3 g of urea is applied to each bucket on the 6th day after the tillering stage, and 1.5 g of urea and 1.5 g of potassium chloride are applied to each bucket 15 days before heading until the rice matures.

[0066] Example 5

[0067] The method is the same as Example 1, except that in step S6, 1.5 g of urea is applied to each barrel on the 12th day after the tillering stage, and 1.5 g of urea and 1.5 g of potassium chloride are applied to each barrel 15 days before heading until the rice matures.

[0068] Example 6

[0069] The method is the same as Example 1, except that in step S6, 3 g of urea is applied to each barrel on the 12th day after the tillering stage, and 1.5 g of urea and 1.5 g of potassium chloride are applied to each barrel 15 days before heading until the rice matures.

[0070] Example 7

[0071] The same as Example 1, except that in step S6, 1.5 g of urea is applied to each bucket on the 18th day after the tillering stage, and 1.5 g of urea and 1.5 g of potassium chloride are applied to each bucket 15 days before heading until the rice matures.

[0072] Example 8

[0073] The same as Example 1, except that in step S6, 3 g of urea is applied to each bucket on the 18th day after the tillering stage, and 1.5 g of urea and 1.5 g of potassium chloride are applied to each bucket 15 days before heading until the rice matures.

[0074] Example 9

[0075] The same as Example 1, except that in step S6, 1.5 g of urea is applied to each bucket on the 24th day after the tillering stage, and 1.5 g of urea and 1.5 g of potassium chloride are applied to each bucket 15 days before heading until the rice matures.

[0076] Example 10

[0077] The same as Example 1, except that in step S6, 3 g of urea is applied to each bucket on the 24th day after the tillering stage, and 1.5 g of urea and 1.5 g of potassium chloride are applied to each bucket 15 days before heading until the rice matures.

[0078] Embodiment 11

[0079] The same as Example 1, except that in step S6, 1.5 g of urea is applied to each bucket on the 30th day after the tillering stage, and 1.5 g of urea and 1.5 g of potassium chloride are applied to each bucket 15 days before heading until the rice matures.

[0080] Example 12

[0081] The same as Example 1, except that in step S6, 3 g of urea is applied to each barrel on the 30th day after the tillering stage, and 1.5 g of urea and 1.5 g of potassium chloride are applied to each barrel 15 days before heading until the rice matures.

[0082] Comparative Example 1

[0083] The same as Example 1, except that urea is not added in step S4 and step S6.

[0084] The schemes for applying nitrogen fertilizers in Examples 1 to 12 and Comparative Example 1 are shown in Table 1.

[0085] Table 1 Application scheme of nitrogen fertilizer per barrel for rice

[0086]

[0087] During the rice maturity period, 10 rice ears were repeatedly taken from the barrel-planted rice in each embodiment for seed testing, and the total number of grains per ear, fruit setting rate, thousand-grain weight, and number of effective ears of each sample were recorded. Fruit setting rate of the present invention = number of full grains / total number of grains × 100%, yield per mu = weight of rice in the sample plot / sample plot area × 667; the thousand-grain weight of the present invention was measured using a one-thousandth balance; the harvesting method of the present invention was manual harvesting and mechanical threshing. The test results of different years are shown in Table 2 (2021) and Table 3 (2022).

[0088] Table 2 Differences in yield and composition of Yangxianyou 918 under nitrogen deficiency and compensation treatments (2021)

[0089]

[0090] Table 3 Differences in yield and composition of Yangxianyou 918 under nitrogen deficiency and compensation treatments (2022)

[0091]

[0092]

[0093] Example 13

[0094] The same as Example 1, except that the japonica rice variety Suxiu 867 is used to replace the indica rice variety Yangxianyou 918, and in step S5, 2 seedlings are planted in each hole.

[0095] Embodiment 14

[0096] The same as Example 2, except that the japonica rice variety Suxiu 867 is used to replace the indica rice variety Yangxianyou 918, and in step S5, 2 seedlings are planted in each hole.

[0097] Embodiment 15

[0098] The same as Example 3, except that the japonica rice variety Suxiu 867 is used to replace the indica rice variety Yangxianyou 918, and in step S5, two seedlings are planted in each hole.

[0099] Example 16

[0100] The same as Example 4, except that the japonica rice variety Suxiu 867 is used to replace the indica rice variety Yangxianyou 918, and in step S5, 2 seedlings are planted in each hole.

[0101] Embodiment 17

[0102] The same as Example 5, except that the japonica rice variety Suxiu 867 is used to replace the indica rice variety Yangxianyou 918, and in step S5, 2 seedlings are planted in each hole.

[0103] Embodiment 18

[0104] The same as Example 6, except that the japonica rice variety Suxiu 867 is used to replace the indica rice variety Yangxianyou 918, and in step S5, 2 seedlings are planted in each hole.

[0105] Embodiment 19

[0106] The same as Example 7, except that the japonica rice variety Suxiu 867 is used to replace the indica rice variety Yangxianyou 918, and in step S5, 2 seedlings are planted in each hole.

[0107] Embodiment 20

[0108] The same as Example 8, except that the japonica rice variety Suxiu 867 is used to replace the indica rice variety Yangxianyou 918, and in step S5, 2 seedlings are planted in each hole.

[0109] Embodiment 21

[0110] The same as Example 9, except that the japonica rice variety Suxiu 867 is used to replace the indica rice variety Yangxianyou 918, and in step S5, 2 seedlings are planted in each hole.

[0111] Embodiment 22

[0112] The same as Example 10, except that the japonica rice variety Suxiu 867 is used to replace the indica rice variety Yangxianyou 918, and in step S5, 2 seedlings are planted in each hole.

[0113] Embodiment 23

[0114] The same as Example 11, except that the japonica rice variety Suxiu 867 is used to replace the indica rice variety Yangxianyou 918, and in step S5, 2 seedlings are planted in each hole.

[0115] Embodiment 24

[0116] The same as Example 12, except that the japonica rice variety Suxiu 867 is used to replace the indica rice variety Yangxianyou 918, and in step S5, 2 seedlings are planted in each hole.

[0117] Comparative Example 2

[0118] The same as Example 13, except that urea is not added in step S4 and step S6.

[0119] During the rice maturity period, 10 rice ears were repeatedly taken from the barrel-planted rice for seed testing in each embodiment, and the total number of grains per ear, the fruit setting rate, the thousand-grain weight, and the number of effective ears of each sample were recorded. The fruit setting rate of the present invention = the number of full grains / total number of grains × 100%, the yield per mu = the weight of rice in the sample plot / sample plot area × 667; the thousand-grain weight of the present invention was measured using a one-thousandth balance; the harvesting method of the present invention was manual harvesting and mechanical threshing. The test results of different years are shown in Table 4 (2021) and Table 5 (2022).

[0120] Table 4 Differences in yield and its composition under nitrogen deficiency and compensation treatments of Suxiu 867 (2021)

[0121]

[0122] Table 5 Differences in yield and its composition under nitrogen deficiency and compensation treatments of Suxiu 867 (2022)

[0123]

[0124]

[0125] Different lowercase letters in Tables 2 to 5 indicate that the differences between treatments reached a significant level (p < 0.05). Based on the barrel cultivation test data from 2021 to 2022, it was found that the single-plant yield of Yangxianyou 918 (indica rice) and Suxiu 867 (japonica rice) rice varieties showed a trend of first increasing and then decreasing in the recovery treatment after nitrogen deficit from 0 day at the beginning of tillering to 30 days after tillering.

[0126] The yield per plant of the indica rice variety Yangxian You 918 reached the highest level after the nitrogen deficit was doubled for 12 days during the tillering period (Example 6), which was significantly higher than the doubled recovery treatment after the nitrogen deficit was doubled for 0 days during the tillering period (Example 2), and a super-compensation effect occurred. The reason why the indica rice variety Yangxian You 918 produced a super-compensation effect was mainly due to the high effective panicle per plant, the total number of grains per panicle, and the fruit setting rate. Therefore, the doubled recovery treatment after the nitrogen deficit was doubled for 12 days during the tillering period was the efficient compensation threshold for the indica rice variety Yangxian You 918 to produce a compensation effect.

[0127] The japonica rice variety Suxiu 867 had the highest yield per plant after 18 days of nitrogen deficit during the tillering period (Example 20), which was significantly higher than the double recovery treatment after 0 days of nitrogen deficit during the tillering period (Example 14), and a super-compensation effect occurred. The reason why the japonica rice variety Suxiu 867 produced a super-compensation effect was mainly due to the high number of effective panicles per plant and the total number of grains per panicle. Therefore, the double recovery treatment after 18 days of nitrogen deficit during the tillering period was the efficient compensation threshold for the japonica rice variety Suxiu 867 to produce a compensation effect.

[0128] In 2021, the effective panicle number per plant, total number of grains per panicle, fruit setting rate, 1000-grain weight, and yield per plant of the indica rice variety Yangxianyou 918 (Comparative Example 1) were lower than those of the nitrogen application treatments, among which the effective panicle number per plant, total number of grains per panicle, and yield per plant were significantly lower than those of the nitrogen application treatments. After nitrogen deficiency during the tillering period, the yield per plant of Yangxianyou 918 in the normal and double recovery treatments increased first and then decreased from 0 days at the beginning of tillering to 30 days at tillering. Among them, the yield per plant in the recovery treatment after 24 days of nitrogen deficiency during the tillering period decreased the most compared with the recovery treatment after 18 days of nitrogen deficiency, indicating that 18 days at the tillering period is the nitrogen deficiency threshold for the tillering period. After 18 days of nitrogen deficiency during the tillering period, the effective panicle number per plant in the normal and double recovery treatments decreased the most compared with the recovery treatment at 12 days at the tillering period, decreasing by -2.08% and 7.5%, respectively. The total number of grains per ear in Examples 3, 5, 7, 9, and 11 after nitrogen deficiency recovery increased by -3.60%, 1.33%, 4.38%, 1.28%, and 0.70% respectively compared with Example 1, and the decrease in Examples 7 to 9 was the largest, reaching 3.06%. Example 8 after nitrogen deficiency recovery treatment with double amount decreased by 5.07% compared with Example 6. The nitrogen deficiency period with the largest decrease in fruit set rate in the normal and double amount recovery treatments after tillering of nitrogen deficiency was from 24 days to 30 days after tillering, with decreases of 2.22% and 5.61% respectively.

[0129] It also showed that the yield per plant of Yangxianyou 918 in the double recovery treatment after nitrogen deficiency during tillering period increased by 18.20%, 10.07%, 17.19%, 6.43%, 9.06%, and 7.60% respectively compared with the normal recovery treatment. There was no significant difference in the thousand-grain weight between the normal recovery treatment and the double recovery treatment after nitrogen deficiency during tillering, while the number of effective ears per plant in the double recovery treatment after nitrogen deficiency increased by 13.46%, 5.74%, 9.98%, 0.65%, 9.62%, and 12.22% respectively compared with the normal recovery treatment.

[0130] In 2022, the effective panicle number per plant, total number of grains per panicle, fruit setting rate, 1000-grain weight, and yield per plant of the indica rice variety Yangxianyou 918 (Comparative Example 1) were lower than those of the nitrogen application treatments, among which the effective panicle number per plant and yield per plant were significantly lower than those of the nitrogen application treatments. After nitrogen deficiency during the tillering period, the yield per plant of Yangxianyou 918 in the normal and double recovery treatments increased first and then decreased from 0 days at the beginning of tillering to 30 days at tillering. Among them, the yield per plant in the recovery treatment after 24 days of nitrogen deficiency in the tillering period decreased the most compared with the recovery treatment after 18 days of nitrogen deficiency, indicating that 18 days in the tillering period is the nitrogen deficiency threshold for the tillering period. After 18 days of nitrogen deficiency in the tillering period, the effective panicle number per plant in the normal and double recovery treatments began to decrease compared with the recovery treatment at 12 days in the tillering period, decreasing by 7.89% and 3.07%, respectively. The total number of grains per ear in Examples 3, 5, 7, 9, and 11 after nitrogen deficiency were increased by -4.75%, 7.56%, 0.12%, 1.98%, and -11.75% respectively compared with Example 1, and the decrease from Example 9 to Example 11 was the largest, reaching 13.46%. Example 10 after nitrogen deficiency was reduced by 10.34% compared with Example 8. The nitrogen deficiency period with the largest decrease in the fruiting rate of the normal and double recovery treatments after nitrogen deficiency tillering was from 18d to 24d after tillering, with decreases of 2.66% and 3.93% respectively.

[0131] It also showed that the yield per plant of Yangxianyou 918 in the double recovery treatment after nitrogen deficiency during tillering period increased by 23.88%, 11.47%, 22.28%, 16.38%, 9.88% and 18.92% respectively compared with the normal recovery treatment. There was no significant difference in the thousand-grain weight between the normal recovery treatment and the double recovery treatment after nitrogen deficiency during tillering, while the number of effective ears per plant in the double recovery treatment after nitrogen deficiency increased by 14.22%, 12.07%, 7.89%, 13.53%, 11.11% and 7.50% respectively compared with the normal recovery treatment.

[0132] In 2021, the number of effective panicles per plant, total number of grains per panicle, and yield per plant of the japonica rice variety Suxiu 867 (Comparative Example 2) were lower than those of the nitrogen application treatments, among which the number of effective panicles per plant and yield per plant were significantly lower than those of the nitrogen application treatments. After nitrogen deficiency during the tillering period of Suxiu 867, the yield per plant of the normal and double recovery treatments increased first and then decreased from 0 days at the beginning of tillering to 30 days at tillering. Among them, the yield per plant of the recovery treatment after 24 days of nitrogen deficiency during the tillering period decreased the most compared with the recovery treatment after 18 days of nitrogen deficiency, indicating that 18 days at the tillering period is the nitrogen deficiency threshold for the tillering period. The total number of grains per ear in Examples 15, 17, 19, 21, and 23 after nitrogen deficiency recovery increased by 0.65%, 0.53%, -4.56%, -4.11%, and -16.62% respectively compared with Example 13, and the decrease from Example 21 to Example 23 was the largest, reaching 13.04%. Example 22 after nitrogen deficiency recovery with double amount decreased by 15.29% compared with Example 20. The nitrogen deficiency period with the largest decrease in fruit set rate in the normal and double amount recovery treatments after tillering of nitrogen deficiency was from 24d to 30d of tillering, with decreases of 2.26% and 1.20% respectively.

[0133] It also showed that the yield per plant of Suxiu 867 in the double recovery treatment after nitrogen deficiency during tillering period increased by 15.05%, 4.84%, 13.26%, 23.25%, 2.85%, and 5.28% respectively compared with the normal recovery treatment. There was no significant difference in the thousand-grain weight between the normal recovery treatment and the double recovery treatment after nitrogen deficiency during tillering, while the number of effective ears per plant in the double recovery treatment after nitrogen deficiency increased by 8.58%, 3.30%, 10.34%, 15.79%, 5.40%, and 0.98% respectively compared with the normal recovery treatment.

[0134] In 2022, the effective panicle number per plant, total number of grains per panicle, and yield per plant of the japonica rice variety Suxiu 867 (Comparative Example 2) were lower than those of the nitrogen application treatments, and the effective panicle number per plant and yield per plant were significantly lower than those of the nitrogen application treatments. After nitrogen deficiency in the tillering stage, the yield per plant of Suxiu 867 in the normal and double recovery treatments increased first and then decreased from 0 days at the beginning of tillering to 30 days at tillering. Among them, the yield per plant in the recovery treatment after 24 days of nitrogen deficiency in the tillering stage decreased the most compared with the recovery treatment after 18 days of nitrogen deficiency, indicating that 18 days at the tillering stage is the nitrogen deficiency threshold for the tillering stage. The total number of grains per ear in Examples 15, 17, 19, 21, and 23 after nitrogen deficiency recovery treatment increased by 3.05%, -3.66%, 0.61%, -6.70%, and -6.70% respectively compared with Example 13, and the decrease from Example 19 to Example 21 was the largest, reaching 7.27%. Example 22 after nitrogen deficiency recovery treatment with double amount decreased by 12.63% compared with Example 20. The nitrogen deficiency period with the largest decrease in fruit set rate in the normal and double amount recovery treatments after tillering of nitrogen deficiency was from 18d to 24d of tillering, with decreases of 0.44% and 2.87% respectively.

[0135] It also showed that the yield per plant of Suxiu 867 in the double recovery treatment after nitrogen deficiency during tillering period increased by 24.55%, 7.50%, 12.60%, 16.99%, 12.67% and 12.52% respectively compared with the normal recovery treatment. There was no significant difference in the thousand-grain weight between the normal recovery treatment and the double recovery treatment after nitrogen deficiency during tillering, while the number of effective ears per plant in the double recovery treatment after nitrogen deficiency increased by 7.78%, 4.65%, 12.46%, 13.95%, 11.63% and 6.38% respectively compared with the normal recovery treatment.

[0136] Combining the data from the two years, it can be found that there are differences in the high-efficiency compensation thresholds for indica and japonica rice varieties to produce compensatory effects, and the high-efficiency compensation threshold for japonica rice varieties is delayed.

[0137] Embodiment 25

[0138] S1. Seed soaking: In mid-May, weigh 1 kg of the indica rice variety Yangxianyou 918 and put it into a container, and dilute 4 mL of Liangdun (25 g / L fludioxonil and 37.5 g / L metalaxyl-M) with water until the seeds are submerged. Soak for 24 hours and then soak in clean water for 12 hours to obtain soaked seeds.

[0139] S2. Raising seedlings: Sowing the soaked seeds, raising seedlings in blankets, with a sowing density of 100 g per seedling tray, 50 trays, and darkening for 3 days.

[0140] S3. Preparation before sowing: prepare the field, divide it into small plots and make ridges, cover the ridges with plastic film, and the area of ​​the small plot is 30m 2 (5m×6m).

[0141] S4. Fertilization: Apply basal fertilizer superphosphate (containing 12% P2O5) 750kg·hm2 one day before transplanting -2 , Potassium chloride (containing 60% K2O) 300kg·hm -2 and urea 60kg·hm -2 .

[0142] S5. Transplantation: Transplant the seedlings when they are 20 days old and have three leaves and one heart. Flood the planting soil for two consecutive weeks before transplanting. The spacing between rows and plants is 12cm×30cm, and one seedling is planted in each hole.

[0143] S6, treatment: Apply 60kg·hm2 at the tillering stage -2 urea, and 60 kg hm-15 days before heading. -2 of urea and 150kg·hm -2 of potassium chloride until the rice is ripe.

[0144] Embodiment 26

[0145] Same as Example 25, except that in step S6, 120 kg·hm -2 urea, and 60 kg hm-15 days before heading. -2 of urea and 150kg·hm -2 of potassium chloride until the rice is ripe.

[0146] Embodiment 27

[0147] Same as Example 1, except that in step S6, 60 kg·hm -2 urea, and 60 kg hm-15 days before heading. -2 of urea and 150kg·hm -2 of potassium chloride until the rice is ripe.

[0148] Embodiment 28

[0149] Same as Example 1, except that in step S6, 120 kg·hm -2 urea, and 60 kg hm-15 days before heading. -2 of urea and 150kg·hm -2 of potassium chloride until the rice is ripe.

[0150] Embodiment 29

[0151] Same as Example 1, except that in step S6, 60 kg·hm -2 urea, and 60 kg hm-15 days before heading. -2of urea and 150kg·hm -2 of potassium chloride until the rice is ripe.

[0152] Embodiment 30

[0153] Same as Example 1, except that in step S6, 120 kg·hm -2 urea, and 60 kg hm-15 days before heading. -2 of urea and 150kg·hm -2 of potassium chloride until the rice is ripe.

[0154] Embodiment 31

[0155] Same as Example 1, except that in step S6, 60 kg·hm -2 urea, and 60 kg hm-15 days before heading. -2 of urea and 150kg·hm -2 of potassium chloride until the rice is ripe.

[0156] Embodiment 32

[0157] Same as Example 1, except that in step S6, 120 kg·hm -2 urea, and 60 kg hm-15 days before heading. -2 of urea and 150kg·hm -2 of potassium chloride until the rice is ripe.

[0158] Embodiment 33

[0159] Same as Example 1, except that in step S6, 60 kg·hm -2 urea, and 60 kg hm-15 days before heading. -2 of urea and 150kg·hm -2 of potassium chloride until the rice is ripe.

[0160] Embodiment 34

[0161] Same as Example 1, except that in step S6, 120 kg·hm -2 urea, and 60 kg hm-15 days before heading. -2 of urea and 150kg·hm -2 of potassium chloride until the rice is ripe.

[0162] Embodiment 35

[0163] Same as Example 1, except that in step S6, 60 kg·hm-2 urea, and 60 kg hm-15 days before heading. -2 of urea and 150kg·hm -2 of potassium chloride until the rice is ripe.

[0164] Embodiment 36

[0165] Same as Example 1, except that in step S6, 120 kg·hm -2 urea, and 60 kg hm-15 days before heading. -2 of urea and 150kg·hm -2 of potassium chloride until the rice is ripe.

[0166] Comparative Example 3

[0167] The same as Example 25, except that urea is not added in step S4 and step S6.

[0168] The schemes for applying nitrogen fertilizer in Examples 25 to 36 and Comparative Example 3 are shown in Table 6.

[0169] Table 6 Application scheme for rice field planting

[0170]

[0171] During the rice maturity period, 10 rice ears were repeatedly taken from the field-grown rice in each embodiment for seed testing, and the total number of grains per ear, the fruit setting rate, the thousand-grain weight, and the number of effective ears of each sample were recorded. The fruit setting rate of the present invention = the number of full grains / the total number of grains × 100%, the yield per mu = the weight of rice in the sample plot / the area of ​​the sample plot × 667; the thousand-grain weight of the present invention was weighed using a one-thousandth balance; the harvesting method of the present invention was manual harvesting and mechanical threshing, and the test results are shown in Table 7.

[0172] Table 7 Differences in field yield and its components under nitrogen deficiency and compensation treatments of indica rice

[0173]

[0174] Embodiment 37

[0175] The same as Example 25, except that the japonica rice variety Suxiu 867 is used to replace the indica rice variety Yangxianyou 918, and in step S5, 2 seedlings are planted in each hole.

[0176] Embodiment 38

[0177] The same as Example 26, except that the japonica rice variety Suxiu 867 is used to replace the indica rice variety Yangxianyou 918, and in step S5, 2 seedlings are planted in each hole.

[0178] Embodiment 39

[0179] The same as Example 27, except that the japonica rice variety Suxiu 867 is used to replace the indica rice variety Yangxianyou 918, and in step S5, 2 seedlings are planted in each hole.

[0180] Embodiment 40

[0181] The same as Example 28, except that the japonica rice variety Suxiu 867 is used to replace the indica rice variety Yangxianyou 918, and in step S5, 2 seedlings are planted in each hole.

[0182] Embodiment 41

[0183] The same as Example 29, except that the japonica rice variety Suxiu 867 is used to replace the indica rice variety Yangxianyou 918, and in step S5, 2 seedlings are planted in each hole.

[0184] Embodiment 42

[0185] The same as Example 30, except that the japonica rice variety Suxiu 867 is used to replace the indica rice variety Yangxianyou 918, and in step S5, 2 seedlings are planted in each hole.

[0186] Embodiment 43

[0187] The same as Example 31, except that the japonica rice variety Suxiu 867 is used to replace the indica rice variety Yangxianyou 918, and in step S5, 2 seedlings are planted in each hole.

[0188] Embodiment 44

[0189] The same as Example 32, except that the japonica rice variety Suxiu 867 is used to replace the indica rice variety Yangxianyou 918, and in step S5, 2 seedlings are planted in each hole.

[0190] Embodiment 45

[0191] The same as Example 33, except that the japonica rice variety Suxiu 867 is used to replace the indica rice variety Yangxianyou 918, and in step S5, 2 seedlings are planted in each hole.

[0192] Embodiment 46

[0193] The same as Example 34, except that the japonica rice variety Suxiu 867 is used to replace the indica rice variety Yangxianyou 918, and in step S5, 2 seedlings are planted in each hole.

[0194] Embodiment 47

[0195] The same as Example 35, except that the japonica rice variety Suxiu 867 is used to replace the indica rice variety Yangxianyou 918, and in step S5, 2 seedlings are planted in each hole.

[0196] Embodiment 48

[0197] The same as Example 36, except that the japonica rice variety Suxiu 867 is used to replace the indica rice variety Yangxianyou 918, and in step S5, 2 seedlings are planted in each hole.

[0198] Comparative Example 4

[0199] The same as Example 37, except that urea is not added in step S4 and step S6.

[0200] During the rice maturity period, 10 rice ears were repeatedly taken from the field-grown rice in each embodiment for seed testing, and the total number of grains per ear, the fruit setting rate, the thousand-grain weight, and the number of effective ears of each sample were recorded. The fruit setting rate of the present invention = the number of full grains / the total number of grains × 100%, the yield per mu = the weight of rice in the sample plot / the area of ​​the sample plot × 667; the thousand-grain weight of the present invention was weighed using a one-thousandth balance; the harvesting method of the present invention was manual harvesting and mechanical threshing, and the test results are shown in Table 8.

[0201] Table 8 Differences in field yield and its components of japonica rice under nitrogen deficiency and compensation treatments

[0202]

[0203]

[0204] Different lowercase letters in Tables 7-8 indicate that the differences between the treatments reached a significant level (p < 0.05). It can be seen from Tables 7-8 that the number of effective ears per plant, the total number of grains per ear, the fruit setting rate, the 1000-grain weight, and the yield per plant of Comparative Example 3 of the indica rice variety Yangxianyou 918 were all lower than those of the nitrogen application treatments. Among them, the treatment of Example 29 performed outstandingly in the number of effective ears per plant, which increased by 29.8%, 29.9%, 29.8% and 29.9% respectively compared with Examples 25, 27, 31, 33 and 35. 8.9%, 15.0%, 7.1% and -19.6% respectively; the total number of grains per ear increased by 6.0%, -4.5%, -0.5%, -6.7% and 4.3% respectively; the fruit setting rate increased by 5.6%, 1.1%, -0.3%, 1.8% and 4.8% respectively; the thousand-grain weight increased by 0.6%, 2.1%, 2.4%, 4.6% and 3.4% respectively; the yield per mu increased by 3.6%, 4.3%, 2.4%, 1.8% and 1.8% respectively.

[0205] In addition, the per-acre yield of Example 30 was significantly improved, compared with Example 26, Example 28, Example 32, Example 34 and Example 36, by 1.8%, 4.8%, 1.8%, 3.0% and 4.2% respectively; the total number of grains per ear was increased by 3.7%, 1.6%, -0.7%, 1.7%, -11.1% respectively; the fruit setting rate was increased by 0.8%, 1.7%, 1.0%, 3.3% and 4.5% respectively; and the thousand-grain weight was increased by 2.8%, 5.7%, 2.9%, 9.1% and 8.5% respectively. In summary, 12 days after nitrogen deficiency in the tillering stage of indica rice is the key time for efficient nitrogen compensation, and the double compensation effect is the best.

[0206] Different fertilization treatments of the japonica rice variety Suxiu 867 had significant effects on the number of effective panicles per plant, the total number of grains per panicle, the fruiting rate, the thousand-grain weight and the yield per mu of rice. Compared with Example 38, Example 40, Example 42, Example 46 and Example 48, the yield per mu of Example 44 was increased by 6.3%, 3.7%, 2.5%, 5.7% and 15.3%, respectively, and the number of effective panicles per plant increased by 19.0%, 7.9%, 13.8%, 53.7% and 39.0%, respectively, showing its advantage in significantly promoting rice tillering. However, the total number of grains per panicle decreased by 11.0%, 1.6%, 9.8%, 19.1% and 2.6%, respectively.

[0207] Compared with Example 37, Example 39, Example 41, Example 45 and Example 47, the per-acre yield of Example 43 increased by 2.6%, 1.7%, 1.4%, 3.5% and 9.2% respectively; the number of effective panicles per plant increased by 3.1%, -1.2%, 11.1%, 7.2% and 25.0% respectively; but the total number of grains per panicle decreased by 18.2%, 7.9%, 15.1%, 18.7% and 3.7% respectively, indicating that the treatment of Example 43 may sacrifice some grains while increasing the number of panicles. In general, the fruit set rate and thousand-grain weight remained stable in each treatment, indicating that japonica rice varieties pay more attention to the increase of panicle number and yield on the basis of ensuring grain weight and seed quality. In addition, 18 days after nitrogen deficiency in the tillering stage of japonica rice is the period of efficient nitrogen compensation, and the double compensation effect is significant.

[0208] 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 principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for applying nitrogen fertilizer to rice under nitrogen deficiency conditions, characterized in that: The following steps are involved: S1, soaking seeds: soaking rice seeds in a mixed solution of fungicide and water for a first time, and then soaking them in water for a second time to obtain soaked seeds; S2, raising seedlings: sowing the soaked seeds, and raising seedlings to obtain seedlings; S3. Preparation before sowing: including soil pretreatment for barrel planting or soil pretreatment for field planting; The steps of soil pretreatment for barrel planting are: drying, crushing and sieving the plough layer soil in sequence, and then putting the plough layer soil into a barrel; The steps of field planting soil pretreatment are: deep ploughing, ridge making, and covering with plastic film; S4. Fertilization: Apply base fertilizer to the planting soil; S5, transplanting: pre-flooding the planting soil, and transplanting the rice seedlings obtained in step S2 into the barrel or field in step S4; S6. Treatment: When the seedlings enter the tillering stage, apply nitrogen fertilizer again, and apply flower-preserving fertilizer 12 to 15 days before heading until the seedlings complete normal growth.

2. The method for applying nitrogen fertilizer to rice under nitrogen deficiency conditions according to claim 1, characterized in that: In the step S1, the ratio of rice seeds to fungicide during the first soaking is 1kg:3-5mL; the mixed solution of fungicide and water is sufficient to submerge the rice seeds; the fungicide is Liangdun; When soaking for the second time, use clean water that is enough to cover the rice seeds.

3. The method for applying nitrogen fertilizer to rice under nitrogen deficiency conditions according to claim 2, characterized in that: In step S1, the first soaking time is 20 to 30 hours, and the second soaking time is 10 to 20 hours.

4. The method for applying nitrogen fertilizer to rice under nitrogen deficiency conditions according to any one of claims 1 to 3, characterized in that: In the step S2, the specification of the seedling tray for blanket seedling cultivation is 60cm×25cm, and the sowing amount of each seedling tray is 100-120g; after sowing, the seeds are darkened for 2-3 days.

5. The method for applying nitrogen fertilizer to rice under nitrogen deficiency conditions according to claim 4, characterized in that: In step S3, in the soil pretreatment for barrel planting, the topsoil is 0-20 cm thick soil from paddy fields; the particle size of the sieved topsoil is ≤0.15 mm; the inner diameter of the barrel bottom is 20-25 cm, the outer diameter of the barrel mouth is 28-32 cm, and the barrel height is 25-30 cm; 14-18 kg of topsoil is put into each barrel.

6. The method for applying nitrogen fertilizer to rice under nitrogen deficiency conditions according to claim 2, 3 or 5, characterized in that: In the step S3, in the pretreatment of the soil for field planting, the tillage depth of deep tillage is 20 to 30 cm; the treatment steps included in step S3 are repeated at least 3 times.

7. The method for applying nitrogen fertilizer to rice under nitrogen deficiency conditions according to claim 6, characterized in that: In the step S4, in the barrel planting, the base fertilizer includes superphosphate, potassium chloride and nitrogen fertilizer, and the mass ratio of the superphosphate, potassium chloride and nitrogen fertilizer is 5-10:1-3:1-3; In field planting, the base fertilizer includes superphosphate, potassium chloride and nitrogen fertilizer, and the mass ratio of the superphosphate, potassium chloride and nitrogen fertilizer is 700-800:100-300:10-100.

8. The method for applying nitrogen fertilizer to rice under nitrogen deficiency conditions according to claim 3, 5 or 7, characterized in that: In step S5, the pre-flooding treatment step is: flooding the planting soil for two consecutive weeks.

9. The method for applying nitrogen fertilizer to rice under nitrogen deficiency conditions according to claim 8, characterized in that: In step S5, the rice seedlings are transplanted into the field with a planting row spacing of 12 cm×30 cm; and the rice seedlings are transplanted into barrels with 2 to 4 seedlings planted in each barrel.

10. The method for applying nitrogen fertilizer to rice under nitrogen deficiency conditions according to claim 1, characterized in that: In barrel planting, the total amount of nitrogen fertilizer applied per barrel in step S4 and step S6 is 4.5-6g; the flower-preserving fertilizer includes nitrogen fertilizer and potassium chloride, and the mass ratio of nitrogen fertilizer to potassium chloride is 1:1; the specific scheme of nitrogen fertilizer application between the tillering stage and the completion of the production is as follows: the amount of nitrogen fertilizer applied per barrel is 0-3g at the beginning of the tillering stage, the amount of nitrogen fertilizer applied per barrel on the 6th day after the tillering stage is 0-3g, the amount of nitrogen fertilizer applied per barrel on the 12th day after the tillering stage is 0-3g, the amount of nitrogen fertilizer applied per barrel on the 18th day after the tillering stage is 0-3g, the amount of nitrogen fertilizer applied per barrel on the 24th day after the tillering stage is 0-3g, the amount of nitrogen fertilizer applied per barrel on the 30th day after the tillering stage is 0-3g, and the amount of nitrogen fertilizer applied per barrel 12-15 days before heading is 1.5g; In field planting, the total amount of nitrogen fertilizer applied in step S4 and step S6 is 180-240 kg·hm -2 ; Flower-protecting fertilizer includes nitrogen fertilizer and potassium chloride, and the mass ratio of nitrogen fertilizer to potassium chloride is 150:60; the specific scheme of nitrogen fertilizer application between tillering stage and completion of growth is as follows: the nitrogen fertilizer application amount at the beginning of tillering stage is 0-120 kg·hm -2 , the nitrogen fertilizer application rate on the 6th day after tillering is 0-120 kg·hm -2 , the nitrogen fertilizer application rate on the 12th day after the tillering stage is 0-120 kg·hm -2 , the nitrogen fertilizer application rate on the 18th day after the tillering stage is 0-120 kg·hm -2 , the nitrogen fertilizer application rate on the 24th day after the tillering stage is 0-120 kg·hm -2 , the nitrogen fertilizer application rate on the 30th day after the tillering stage is 0-120 kg·hm -2 , 12 to 15 days before heading, the nitrogen fertilizer application rate is 60 kg·hm -2 .

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