A method for controlling weeds by direct seeding of rice paddies after flooding

Abstract

This invention belongs to the field of crop cultivation technology, specifically relating to a method for controlling weeds by direct seeding of rice in flooded fields. The method includes the following steps: (1) variety selection, (2) land preparation and leveling, (3) application of base fertilizer, (4) deep sowing, (5) flooding and weeding, (6) assisted weeding, and (7) conventional cultivation management. This invention utilizes direct seeding of rice in flooded fields to achieve the purpose of controlling weeds. It avoids environmental pollution caused by excessive application of herbicides and reduces production costs.

Description

Technical Field

[0001] This invention relates to the field of crop cultivation technology, and in particular to a method for controlling weeds by direct seeding of rice in flooded fields. Background Technology

[0002] Weeds in paddy fields compete with rice for space, sunlight, water, fertilizer, air, and heat, weakening the rice plants' photosynthesis and leading to poor growth, reduced yield, and lower quality. Many weeds also serve as intermediate or overwintering hosts for rice diseases and pests, potentially inducing or exacerbating their damage. In rice cultivation, weeds include grasses and sedges. Grasses begin to cause damage in the early stages of rice growth, while sedges and other weeds begin to cause damage in the middle stages. *Echinochloa crus-galli* proliferates rapidly in alternating wet and dry conditions, while *Potamogeton crispus* and algae tend to cause damage in older paddy fields with deeper water. Weeds from the Asteraceae, Scrophulariaceae, Polygonaceae, and Plantagoaceae families also cause damage along field edges and dikes. To avoid the impact of weeds on rice growth, farmers usually spray herbicides or weed manually. However, the excessive use of herbicides can cause environmental pollution and may also affect rice, leading to reduced rice yields. Furthermore, long-term use of herbicides can cause weeds to develop resistance. Manual weeding, on the other hand, requires a lot of labor and is therefore costly.

[0003] Chinese patent application number 201911406844.5, entitled "A herbicide-free direct seeding method for rice", discloses a herbicide-free direct seeding method for rice. Although it adopts the technical solution of direct seeding rice in flooded conditions, the technical solution of this patent does not solve the technical problem of low germination rate of ordinary rice varieties that are not tolerant to flooding in flooded direct seeding. Summary of the Invention

[0004] In view of the technical problems in existing technologies, such as long-term application of herbicides polluting the environment, weeds developing herbicide resistance, high labor costs of manual weeding, and low rice seedling emergence rate when directly planting rice in flooded areas, the purpose of this invention is to provide a method for controlling weeds by planting rice in deep water, which can significantly inhibit weed growth while reducing costs and not polluting the environment.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for controlling weeds by direct seeding of rice in flooded fields includes the following steps:

[0007] (1) Land preparation and leveling: Prepare the land so that the height difference between the fields does not exceed 2cm, dig sowing furrows with a depth of 1-1.5cm and ensure that the sowing furrows do not collapse within 5 days; make field ridges with a height greater than 15cm;

[0008] (2) Base fertilizer application: Apply base fertilizer at a depth of 4.5-5.5cm from the sowing furrow, with a depth of more than 10cm;

[0009] (3) Deep sowing: Sow rice seeds in the sowing furrow, bury the seeds in the soil, and ensure that the surface of the field is flat and no seeds are exposed.

[0010] (4) Flooding and weeding: After sowing, shallow irrigation is carried out at intervals of 24-48 hours. Water is released into the field every 2-3 days to maintain a water depth of 5-8 cm. 7-10 days after flooding irrigation, during the rice seed germination and seedling emergence period, the field is drained and exposed for 48-72 hours. After the exposure period ends, the field is immediately re-watered to a water depth of 8-10 cm. Water is added into the field every 3-5 days or when the water level is below 5 cm to maintain a water depth of 7-10 cm until the seedlings are ready to be dried.

[0011] Preferably, the rice seeds used in step (3) are water-resistant rice seeds, and more preferably LS128 rice seeds.

[0012] Preferably, the base fertilizer in step (2) is a compound fertilizer, wherein N:P2O5:K2O = 15:15:15, and the dosage is 550-600 kg / hm. 2 .

[0013] Preferably, the sowing density of water-resistant rice seeds in step (3) is 160-195 seeds / m2.

[0014] In step (4), when draining the paddy field, apply a mixture of copper sulfate and plant growth regulator to the areas in the paddy field where moss is dense.

[0015] Preferably, the copper sulfate mixture comprises copper sulfate and finely crushed wet soil, with the amount of copper sulfate being 3.00-3.25 kg / hm². 2 The amount of finely crushed alluvial soil used is 150-180g / hm. 2 .

[0016] Preferably, the plant growth regulator is fulvic acid, and the dosage is 15-20 kg / mu.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) From rice sowing to harvest, direct seeding with floodwater can effectively suppress weed growth, avoid the use of conventional herbicides on the market, and reduce environmental pollution. Applying deep base fertilizer can not affect seed germination, but at the same time provide the nutrients needed for the later growth of rice. During the later growth stage of the seed, short-term exposure of the soil can promote the growth of rice roots.

[0019] (2) Applying copper sulfate can effectively inhibit the growth of moss in paddy fields. The biological weed control fertilizer humic acid is natural and pollution-free and will not affect the ecological environment.

[0020] (3) In the flooding and weeding step, shallow irrigation is carried out 24-48 hours after sowing. During the germination and seedling stage of rice seeds, the field is drained and exposed for 48-72 hours. These operations not only enable the present invention to have good weeding effect on both flood-tolerant and flood-intolerant rice varieties. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0022] All conventional rice varieties used in the following examples were obtained through conventional channels. For the source of the LS128 rice variety, please refer to the Genetic Resource Source Disclosure Registration Form. The selection criteria for water-tolerant rice seeds were: emergence rate > 50% on day 11 after waterlogging treatment; emergence rate > 80% on day 15; average seedling length > 15cm on day 15; average number of roots > 5; maximum root length > 5cm.

[0023] Example 1

[0024] A method for controlling weeds by direct seeding of rice in flooded fields includes the following steps:

[0025] (1) Land preparation and leveling: Select fields with smooth and convenient water inlet and drainage, flat terrain, and uniform fertility; prepare the land with a height difference of 2cm, open sowing furrows with a depth of 1cm and ensure that the sowing furrows do not collapse within 5 days; make field ridges with a height greater than 15cm.

[0026] (2) Base fertilizer application: Apply base fertilizer at a depth of more than 10 cm, 4.5 cm away from the sowing furrow; the base fertilizer is a compound fertilizer with N:P2O5:K2O = 15:15:15, and the application rate is 550 kg / hm. 2 ;

[0027] (3) Deep sowing: Sow rice seeds in the sowing furrows, burying them in the soil to a depth of 0.5 cm, ensuring the field surface is flat and no seeds are exposed; the sowing density of rice seeds is 160 seeds / m². 2 50 barnyard grass seeds, and 0.163g and 0.295g of Echinochloa crus-galli seeds were sown in equal portions.

[0028] (4) Flooding and weeding: After sowing, shallow irrigation is carried out at intervals of 24 hours. Water is released into the field every 2 days to maintain a water depth of 5cm. 7 days after flooding irrigation, during the rice seed germination and seedling emergence period, the field is drained and exposed for 48 hours. After the exposure period ends, the field is immediately re-watered to a water depth of 8cm. Water is added into the field every 3 days or when the water level is lower than 5cm to maintain a water depth of 7cm until the seedlings are ready to be dried.

[0029] (6) Conventional cultivation management: Other management shall be in accordance with conventional cultivation management.

[0030] Example 2

[0031] A method for controlling weeds by direct seeding of rice in flooded fields includes the following steps:

[0032] (1) Land preparation and leveling: Select fields with convenient water inlet and drainage, flat terrain, and uniform fertility; prepare the land with a height difference of 1cm, open sowing furrows with a depth of 1.2cm and ensure that the sowing furrows do not collapse within 5 days; make field ridges with a height greater than 15cm.

[0033] (2) Base fertilizer application: Apply base fertilizer at a depth of more than 10 cm, 5.0 cm away from the sowing furrow; the base fertilizer is a compound fertilizer with N:P2O5:K2O = 15:15:15, and the application rate is 600 kg / hm. 2 ;

[0034] (3) Deep sowing: Sow rice seeds in the sowing furrows, burying them in the soil to a depth of 0.6 cm, ensuring the surface of the field ridges is flat and no seeds are exposed; the sowing density of rice seeds is 180 seeds / m². 2 50 barnyard grass seeds, and 0.163g and 0.295g of Echinochloa crus-galli seeds were sown in equal portions.

[0035] (4) Flooding and weeding: After sowing, shallow irrigation is carried out at intervals of 48 hours. Water is released into the field every 2.5 days to maintain a water depth of 7cm. Eight days after flooding irrigation, during the rice seed germination and seedling emergence period, the field is drained and exposed for 60 hours. After the exposure period ends, the field is immediately re-watered to a water depth of 9cm. Water is added into the field every 4 days or when the water level is lower than 5cm to maintain a water depth of 9cm until the seedlings are ready to be dried.

[0036] (5) Assisted weed control: During the open field period, apply a mixture of copper sulfate and plant growth regulator to areas of dense moss in the paddy field; the copper sulfate mixture includes copper sulfate and finely crushed moist soil, and the amount of copper sulfate used is 3.25 kg / hm. 2 The amount of finely crushed alluvial soil used is 180g / hm. 2 The plant growth regulator is fulvic acid, and the dosage is 17 kg / mu.

[0037] (6) Conventional cultivation management: Other management shall be in accordance with conventional cultivation management.

[0038] Example 3

[0039] A method for controlling weeds by direct seeding of rice in flooded fields includes the following steps:

[0040] (1) Land preparation and leveling: Select fields with convenient water inlet and drainage, flat terrain, and uniform fertility; prepare the land with a height difference of 0.5cm, open sowing furrows with a depth of 1.5cm and ensure that the sowing furrows do not collapse within 5 days; make field ridges with a height greater than 15cm.

[0041] (2) Base fertilizer application: Apply base fertilizer at a depth of more than 10 cm, 5.5 cm away from the sowing furrow; the base fertilizer is a compound fertilizer with N:P2O5:K2O = 15:15:15, and the application rate is 580 kg / hm. 2 ;

[0042] (3) Deep sowing: Sow rice seeds in the sowing furrows, burying them in the soil to a depth of 0.8 cm, ensuring the surface of the field ridges is flat and no seeds are exposed; the sowing density of rice seeds is 195 seeds / m². 2 50 barnyard grass seeds, and 0.163g and 0.295g of Echinochloa crus-galli seeds were sown in equal portions.

[0043] (4) Flooding and weeding: After sowing, shallow water irrigation is carried out at 30-hour intervals, and water is released into the field every 3 days to maintain a water depth of 8cm; 10 days after flooding irrigation, during the rice seed germination and seedling emergence period, the field is drained and exposed for 72 hours; after the exposure period ends, the field is immediately re-watered to a water depth of 10cm, and water is added into the field every 5 days or when the water level is lower than 5cm to maintain a water depth of 10cm until the seedlings are ready to be dried.

[0044] (5) Assisted weed control: During the open field period, apply a mixture of copper sulfate and plant growth regulator to areas of dense moss in the paddy field; the copper sulfate mixture includes copper sulfate and finely crushed moist soil, and the amount of copper sulfate used is 3.0 kg / hm. 2 The amount of finely crushed alluvial soil used is 170g / hm. 2 The plant growth regulator is fulvic acid, and the dosage is 20 kg / mu.

[0045] (6) Conventional cultivation management: Other management shall be in accordance with conventional cultivation management.

[0046] The difference between Comparative Example 1 and Example 1 is that no flooding treatment was performed, and normal water management was used.

[0047] Test case

[0048] (1) Test scheme

[0049] The seeds of rice varieties Zhongjiazao 17, Luliangyou 996, Wuyou Huazhan, Huanghuazhan, Meixiangzhan, Longliangyou Huazhan, and LS128 were tested in the field according to the methods described in Example 1 and Comparative Example 1.

[0050] (2) Recording data

[0051] After 25 days, the plants were removed, and the seedling length, root length, emergence rate, total dry matter weight (sterilized at 105℃ for 30 minutes and then dried at 80℃), maximum root length per plant, number of roots per plant, and average total stem width of 10 plants were recorded for each rice variety under the methods of Examples 1-3 and Comparative Example 1. Additionally, the presence of weeds was observed.

[0052] (3) The test results are shown in Table 1 and Table 2.

[0053] Table 1. Measurement results of rice plants grown using the methods of Example 1 and Comparative Example 1.

[0054]

[0055]

[0056] Table 2. Measurement results of rice plants grown using the methods of Example 1 and Comparative Example 1.

[0057]

[0058] Rice plants of the following varieties—Zhongjiazao 17, Luliangyou 996, Wuyou Huazhan, Huanghuazhan, Meixiangzhan, Longliangyou Huazhan, and LS128—were planted using the methods described in Examples 1-3 and Comparative Example 1. The plants were harvested 25 days later.

[0059] The results showed that the seedling indicators of LS128 rice variety were significantly higher than those of conventional varieties under direct seeding and flooding conditions, indicating that the selected material could suppress weeds and ensure its own growth under flooded seedling conditions.

[0060] Under flooded conditions, the growth of weeds was significantly inhibited in rice varieties such as Zhongjiazao 17, Luliangyou 996, Wuyou Huazhan, Huanghuazhan, Meixiangzhan, Longliangyou Huazhan, and LS128. This resulted in a growth potential difference between rice and weeds after drainage, ensuring the competitive advantage of rice in terms of temperature, light, and water in the field ecological environment. However, under direct seeding flooded conditions, the seedling length, root length, emergence rate, total dry matter weight, maximum root length per plant, number of roots per plant, and total stem width of 10 plants were all lower in Zhongjiazao 17, Luliangyou 996, Wuyou Huazhan, Huanghuazhan, Meixiangzhan, and Longliangyou Huazhan compared to conventional cultivation treatment.

Claims

1. A method for preventing and controlling weeds by using rice water-logging direct seeding, characterized in that, The method comprises the following steps: (1) field leveling: field leveling, the height difference of the field is not more than 2 cm, the seeding ditch is opened, the seeding ditch is 1-1.5 cm deep and does not collapse within 5 days; the ridge is made, and the height of the ridge is greater than 15 cm; (2) base fertilizer application: the base fertilizer is applied at a distance of 4.5-5.5 cm from the seeding ditch, and the application depth is greater than 10 cm; (3) deep seeding: the submergence-tolerant rice seeds are seeded in the seeding ditch, the seeds are collapsed into the soil, the seeds are buried in the soil by 0.5-0.8 cm, and the surface of the field is ensured to be flat and no seed is exposed; (4) Watering for weeding: shallow irrigation is carried out 24-48 hours after sowing, and water is drained into the field every 2-3 days to maintain a water depth of 5-8 cm; 7-10 days after the watering, the rice seeds germinate and sprout, and the field is drained for 48-72 hours; at the time of draining the field, copper sulfate mixture and plant growth regulator are sprayed on the dense green algae in the rice field; the copper sulfate mixture includes copper sulfate and fine and moist soil, the amount of copper sulfate is 3.00-3.25 kg / hm 2 , the amount of fine and moist soil is 150-180 g / hm 2 ; the plant growth regulator is fulvic acid, and the amount is 15-20 kg / acre; immediately after the field is drained, the water is replenished to a water depth of 8-10 cm in the rice field, and the water level is replenished into the field every 3-5 days or when the water level is lower than 5 cm, and the water depth is maintained at 7-10 cm until the seedlings are dried.

2. The method of claim 1, wherein, The base fertilizer in step (2) is compound fertilizer, wherein N:P2O5:K2O=15:15:15, and the amount is 550-600 kg / hm 2 .

3. The method of claim 1, wherein, The submergence-tolerant rice seeds are LS128 rice seeds.

4. The method of claim 3, wherein, The sowing density of the submergence-tolerant rice seeds is 160-195 grains / m 2 .

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