Weed closing method for dry paddy field

Abstract

The invention provides a dry land paddy field weed closing method which comprises the following steps: S1, in the middle ten days of April or at least 5 days before paddy rice planting, plowing and preparing land under the conditions of dry soil and clear weather, and removing propagules of perennial weeds in the field; s2, sowing is conducted, wherein the sowing depth is about 5-8 cm; s3, after sowing, spraying a soil sealing herbicide under the condition that a soil layer 2cm away from the soil surface is humid after first effective rainfall; according to the method, the weed control effect can last to the 5-7 leaf stage of rice growth, favorable conditions are created for weed management in the middle and later periods of rice, and the labor input and the use amount of herbicides are remarkably reduced; besides, the method plays an important role in delaying the development of drug resistance of weeds and improving the prevention and control efficiency, and the generation and harm of the weeds in the dry rice field can be effectively controlled only by performing one-time weed prevention and control measures, namely one-time closing and one-time killing, in a later period in an area with a relatively high weed prevention and control level.

Description

Technical Field

[0001] The present invention relates to the fields of plant protection and the application technology of chemical pesticides, and particularly to a method for closing weeds in upland paddy fields. Background Art

[0002] Rice is generally planted on flat lands with relatively rich water resources and irrigation conditions. There are mainly two traditional rice planting methods. One is seedling transplanting, and the other is direct seeding technology. For seedling transplanting, first, seedlings are raised. When the seedlings grow to the 4-5 leaf stage, they are transplanted to the large field. Before transplantation, the land needs to be prepared, pulped, and leveled. After transplantation, a water layer with a height of 5-10 cm is maintained. After rice transplantation, due to the existence of a flooded environment, underwater weeds are difficult to germinate, and their growth is relatively slow after germination. Therefore, the occurrence of weeds is generally light, the harm is light, and the control difficulty is small. Direct seeding technology is a rice planting technology improved to reduce the workload of transplanting rice, mainly including wet direct seeding and dry direct seeding. To improve the emergence rate, generally, pre-germinated seeds are sown. Before sowing using wet direct seeding technology, soil treatment herbicides need to be sprayed on the soil to kill weeds in the field. There are also a large number of dry direct seeding rice areas in the southeastern part of China. The dry direct seeding technology requires simpler operations and further liberates the labor force. In the plots using direct seeding technology, due to sufficient water sources, the rice is sown shallowly and emerges quickly. After the rice emerges, appropriate flooding can be used to control weeds in the field, and the control difficulty of weeds is low.

[0003] The rice dry cultivation technology, as an agricultural innovation technology developed by the research team led by Academician Zhu Youyong of Yunnan Agricultural University, is a cultivation method that, by cultivating drought-tolerant, high-yield, and high-quality rice varieties and through the cultivation and management method of dry seeding and dry management, does not require artificial irrigation throughout the rice production process and entirely relies on natural precipitation. The rice dry cultivation technology represents a brand-new exploration in the field of rice planting. Its varieties are different from upland rice in tropical mountainous areas, and its cultivation techniques are different from those of transplanted rice and direct-seeded rice. With its technical advantages of saving labor, reducing labor intensity, and reducing costs, it has been widely promoted in the areas with abundant precipitation in southern Yunnan and is deeply favored by local farmers. Currently, the annual promotion area has approached 400,000 mu.

[0004] However, compared with traditional rice cultivation and wet direct seeding techniques, dry direct seeding of rice has led to an exacerbation of the weed problem. The main reason is that rice seeding is usually arranged at the end of the dry season before the rainy season arrives. At this time, the timing and intensity of precipitation are greatly affected by the uncertainty of weather conditions. To alleviate the possible water shortage problem after rice emergence, a relatively deep seeding method is usually adopted for rice, with a seeding depth of about 5-8 cm. Due to the early seeding time, large seeding depth, and low soil temperature of rice, the emergence period of rice is prolonged. At the same time, because there are abundant and diverse weed seeds in the plough layer soil, and the germination speed of weed seeds is fast, when the soil surface humidity is suitable, the weed seeds on the soil surface germinate and emerge quickly. If timely and effective control measures are not taken, the rice will face a serious "weed disaster" problem after emergence, which will seriously affect the early growth of rice and become one of the key factors restricting rice yield.

[0005] Since 2016, the experimental cultivation of upland rice has been launched. However, during the first four to five years of its initial promotion, the traditional weed control techniques for transplanted paddy fields were not applicable to upland rice fields. Due to the lack of effective weed management means, paddy fields frequently suffered from weed infestations or phytotoxicity caused by improper use of herbicides, resulting in low rice yields, often less than 300 kg per mu. The weed problem has become one of the key factors restricting the production of upland rice and is also the main obstacle that urgently needs to be overcome during the promotion process.

[0006] Dry cultivation of rice is one of the important strategies for implementing the national food security guarantee law, which is designed for the unique climate and geographical conditions in Yunnan. Upland rice can be planted on dry land without irrigation water, without the need for seedling raising or germination acceleration processes, but directly sowing seeds into the soil using machinery. Since the weeds in dry-seeded fields mainly come from the soil within 2 cm of the surface layer, after rice seeding, the weed seed layer is higher than the rice seed layer, resulting in a faster germination and growth rate of weeds, and the damage degree to rice is also significantly higher than that of traditional transplanted paddy fields.

[0007] It is not suitable to use "water" to manage the weed problem in dry - cultivated paddy fields. Firstly, upland rice is planted on non - irrigated dry land, which is mostly located on the sloping land in mountainous areas, with the slope ranging from 0 degrees to 25 degrees. Secondly, these areas often lack sufficient irrigation water sources. The wet direct - seeding technique, that is, spraying herbicides before sowing and then sowing, is also not applicable to dry - cultivated paddy fields. Wet direct - seeding paddy fields usually adopt broadcast seeding, and the soil is not turned over during sowing, so the weed seeds in the deep soil will not be brought to the surface layer. While dry - cultivated paddy fields use mechanical sowing of dry seeds, and the soil will be disturbed during sowing, resulting in the soil around the sown seeds being turned over. If herbicides are applied before sowing, the originally formed herbicide - closed layer will be destroyed, and the surface soil layer around the seeds will no longer contain herbicides. Dry direct - seeding paddy fields belong to irrigated paddy fields, and water can be released into the field at any time after sowing to increase soil humidity. Spraying herbicides within 1 - 3 days after sowing can effectively control the growth of weed seedlings in paddy fields. Therefore, the current weed - closing techniques applicable to other types of paddy fields are not suitable for dry - cultivated paddy fields of rice.

[0008] The sowing depth of dry - cultivated paddy fields is relatively deep, and it is just during the dry season in Yunnan. The soil is dry, the air humidity is low, and the wind is strong. After sowing rice, weeds will not germinate and emerge for a long time. Spraying soil - closing herbicides 1 - 3 days after sowing has no effect. When the rainy season comes, most of the herbicides in the soil have volatilized or photolyzed, and the previously sprayed soil - closing herbicides basically cannot play a role. Using this soil - closing weeding method in dry - cultivated paddy fields basically has no effect.

[0009] There are significant differences between upland rice cultivation and upland rice widely planted in traditional Yunnan mountainous areas. Upland rice cultivation usually relies on manual broadcast seeding, and the seeds are exposed on the soil surface. Due to the uncertainty of precipitation time in the initial sowing stage, it is difficult for the seeds to germinate or they will die due to drought after germination. In addition, weed seeds are directly broadcast on the soil surface, and the seeds are vulnerable to damage when spraying soil - treatment herbicides. Considering the above factors, the traditional upland rice cultivation method is not applicable to upland rice cultivation.

[0010] Therefore, there is an urgent need for a weed - closing method for dry - cultivated paddy fields of rice that can solve the above problems. Summary of the Invention

[0011] The purpose of the present invention is to provide a weed - closing method for dry - cultivated paddy fields of rice to solve the problems existing in the above - mentioned prior art.

[0012] To achieve the above - mentioned purpose, the present invention provides the following solutions:

[0013] The present invention provides a weed - closing method for dry - cultivated paddy fields of rice, including the following steps:

[0014] S1. In mid - April, or at least 5 days before rice planting, under the condition of dry soil and sunny weather, plow and prepare the land to remove the propagules of perennial weeds in the field;

[0015] S2. Sow the seeds, with the sowing depth being about 5 - 8 cm;

[0016] S3. After sowing, after the first effective precipitation, when the top 2 cm of the soil surface is moist, spray soil - closing herbicide.

[0017] Preferably, in step S1, it further includes: 15 days before plowing, spraying glyphosate on the leaves of perennial weeds.

[0018] Preferably, in step S2, a hand - pushed seeder or a large - scale hill - drop planter is used for sowing.

[0019] Preferably, in step S2, sowing is completed within 5 days after plowing and land preparation.

[0020] Preferably, in step S3, spraying the soil - closing herbicide is completed within 24 hours after rain and is sprayed in the evening without wind.

[0021] Preferably, in step S3, the soil - closing herbicide is a mixed herbicide of 100 mL / mu of 30% propisochlor·butachlor micro - capsule suspension and 100 mL / mu of 330 g / L pendimethalin emulsifiable concentrate.

[0022] Preferably, in step S3, the soil - closing herbicide is a mixed herbicide of 100 mL / mu of 60% butachlor emulsifiable concentrate and 100 mL / mu of 330 g / L pendimethalin emulsifiable concentrate.

[0023] Preferably, in step S3, about 45 L of water is added per mu for using the soil - closing herbicide.

[0024] Preferably, in step S3, a knapsack sprayer and a fan - shaped spray head are used for spraying.

[0025] Preferably, in step S3, the spray angle is between 100 - 110 degrees, and 400 - 100 - micron droplets are used to spray the soil surface, and backward spraying is adopted during spraying.

[0026] The present invention has achieved the following beneficial technical effects compared with the prior art:

[0027] A method for weed control in upland paddy fields provided by the present invention includes the following steps: S1. In mid-April or at least 5 days before rice planting, under the conditions of dry soil and sunny weather, plow and prepare the land to remove the propagules of perennial weeds in the field; S2. Sow seeds, and the sowing depth is about 5-8 cm; S3. After sowing, when the top 2 cm soil layer is moist after the first effective precipitation, spray a soil-sealing herbicide; The above method enables the weed control effect to last until the 5-7 leaf stage of rice growth, creating favorable conditions for weed management in the middle and late stages of rice, significantly reducing labor input and the amount of herbicide used; In addition, this method plays an important role in delaying the development of weed resistance and improving the control efficiency. In areas with a relatively high level of weed control, only one weed control measure, that is, "one sealing and one killing", is required in the later stage to effectively control the occurrence and damage of weeds in upland paddy fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0029] Figure 1 It is a flow chart of a method for weed control in upland paddy fields provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0031] The purpose of the present invention is to provide a method for weed control in upland paddy fields to solve the problems existing in the prior art.

[0032] In order to make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0033] Example 1:

[0034] The discussion on the dryland rice planting technology is significantly different from upland rice widely planted in traditional Yunnan mountainous areas. Upland rice planting usually relies on manual broadcasting, with seeds exposed on the soil surface. Due to the uncertainty of precipitation time in the initial sowing period, it is difficult for seeds to germinate or they may die due to drought after germination. In addition, weed seeds are directly sown on the soil surface, and when spraying soil treatment herbicides, the seeds are vulnerable to damage. Given the above factors, the traditional upland rice planting method is not suitable for dryland rice planting. Therefore, an effective weed control measure must be formulated based on the development characteristics of rice seeds and climatic conditions to ensure high and stable yields of rice.

[0035] This embodiment provides a method for closing weeds in dryland rice fields, as Figure 1 shown, including the following steps:

[0036] S1. In mid-April, or at least 5 days before rice planting, when the soil is dry and the weather is sunny, plow and prepare the land to thoroughly remove the propagules of perennial weeds in the field; since the soil treatment herbicide has limited lethality to perennial weeds, and most foliar treatment herbicides also have unsatisfactory control effects on perennial weeds, this step aims to reduce the harm of weeds after rice planting; plowing the land under dry and sunny weather conditions helps to break up the soil more finely, thereby improving the sowing uniformity of rice and the closing effect of soil treatment herbicides;

[0037] S2. Sow seeds, with the sowing depth being approximately 5 - 8 cm; the 5-cm soil layer has sufficient air and relatively high humidity, which is conducive to the germination and emergence of rice seeds. At the same time, the greater distance between the seeds and the soil surface helps to improve the safety of applying soil closing herbicides to rice;

[0038] S3. After the first effective precipitation after sowing, when the top 2 cm of the soil surface is wet, spray soil closing herbicides; soil treatment herbicides should not be sprayed immediately after sowing, but rather wait for effective precipitation. In spring, the wind is strong and the soil surface dries quickly. In the dry season without precipitation, the water on the soil surface is lost rapidly, and it is difficult for surface weed seeds to germinate; for weed seeds deep in the soil, due to insufficient light, it is also difficult for them to germinate.

[0039] As an implementation method, in step S1, it further includes: 15 days before plowing, spraying glyphosate on the leaves of perennial weeds to reduce the impact of existing perennial weeds in the field.

[0040] As an implementation method, in step S2, a hand-pushed seeder or a large hole seeder is used for sowing to ensure the sowing depth and accuracy.

[0041] As an implementation mode, in step S2, sowing is completed within 5 days after tilling and harrowing the land. After tilling and harrowing the land, it is necessary to wait for about 5 days and it is not advisable to rush sowing. This is to allow the soil to settle fully and ensure the uniformity of sowing depth.

[0042] As an embodiment, in step S3, the spraying of the soil-sealed herbicide is completed within 24 hours after the rain, and is sprayed in the evening without wind. The reason is that the germination of weed seeds requires the completion of the imbibition effect, which takes about 12 hours. 24 hours after the rain, most weeds begin to enter the germination stage, which is the best time for the agent to take effect.

[0043] As an implementation mode, in step S3, the soil-sealed herbicide is a mixed herbicide of 100 mL / mu of 30% butachlor microcapsule suspension and 100 mL / mu of 330 g / L pendimethalin emulsifiable concentrate. The use of a mixed herbicide can expand the weed control spectrum, improve the efficacy, and reduce the amount of herbicide used.

[0044] As an embodiment, in step S3, the soil-sealed herbicide is a mixed herbicide of 100 mL / mu of 60% butachlor emulsifiable concentrate and 100 mL / mu of 330 g / L pendimethalin emulsifiable concentrate.

[0045] Pendimethalin EC is particularly suitable for dryland weed control, and its absorption effect is good; butachlor can maintain a high control effect under heavy rainfall. Pendimethalin and butachlor are mainly effective in controlling grass weeds under drought conditions through bud absorption. Propylene (oxadiazine) is a contact-type broadleaf weed control agent, which has a good control effect on pre-emerged and newly emerged broadleaf weeds. The microcapsule suspension can significantly extend the lasting effect of the herbicide. This formula takes into account a variety of factors and provides an effective weed control solution for dryland rice cultivation.

[0046] As an embodiment, in step S3, the soil-sealed herbicide is diluted with about 45 L of water per acre to ensure uniformity of spraying.

[0047] As an implementation mode, in step S3, the spraying is performed using a backpack sprayer and a fan-shaped spray head. The spray head specifically used for herbicides improves the uniformity of the spray. It is not recommended to use a cone spray head to reduce drift and evaporation.

[0048] As an implementation mode, in step S3, the spray angle is between 100-110 degrees, and 400-100 micron droplets are used to spray the soil surface. Fine droplets are prone to drift hazards, and backward spraying is used when spraying to prevent footsteps from damaging the drug film on the soil surface.

[0049] In the vast areas of southern Yunnan, the temperature is relatively high and precipitation is abundant in summer. By cultivating drought-tolerant rice varieties, dryland planting can be achieved. However, due to the climate characteristics of "distinct dry and wet seasons, synchronous rainfall and heat" in Yunnan, the arrival time of the rainy season varies greatly every year. But to ensure the accumulated temperature for rice production, rice is generally sown at the beginning of May. Since the dry-seeded rice areas are basically in mountainous regions, the unique "night tide" phenomenon in mountainous areas makes the humidity in the soil higher than that on the soil surface. If deep sowing is adopted, even before the real arrival of the rainy season, the evaporation of the mountain soil is less and the dew absorbed by the soil is more, which can ensure the moisture in the deep soil, thus being beneficial to the germination of rice seeds.

[0050] The dry cultivation of rice in Yunnan region makes full use of the geographical and climatic characteristics of this region. The soil surface is dry and the bottom is wet during the planting season, and deep sowing of rice seeds is required to ensure timely germination. However, under dry climate conditions, without effective precipitation, the herbicide on the soil surface is easily volatilized by the strong spring wind, resulting in the loss of drug efficacy. Therefore, the application of soil-sealing herbicides needs to select an appropriate time, usually under the condition of a wet soil surface after rain.

[0051] For the dry direct-seeding paddy fields in the middle and lower reaches of the Yangtze River, due to the long-term flooded state leading to soil compaction, rice seeds are not suitable for deep sowing to avoid affecting the emergence rate. However, the safety of using herbicides under shallow sowing conditions is poor. Coupled with poor soil conditions and large particles, it is difficult for seeds to penetrate deep into the soil in some areas, resulting in easy drying and death of rice after germination, and then serious pond shortage phenomena (the pond shortage rate ranges from 10% to 30%) occur, the field uniformity decreases, the growth of rice is uneven, and the difficulty of weed control increases. This technology aims at the soil characteristics of the mountainous areas in southern Yunnan. By using a seeder or a sowing machine for sowing, deep sowing of seeds, uniform distribution, and soil fragmentation are achieved, thus significantly improving the safety of rice planting and the effectiveness and uniformity of weed control.

[0052] This invention elaborates on the principle and implementation mode of the invention by applying specific examples. The description of the above embodiments is only used to help understand the method and its core idea of the invention; at the same time, for those of ordinary skill in the art, according to the idea of the invention, there will be changes in the specific implementation mode and application scope. In summary, the content of this specification should not be construed as a limitation to the invention.

Claims

1. A method for sealing weeds in dryland rice fields, characterized in that: The following steps are involved: S1. In mid-April, or at least 5 days before rice planting, till the soil when the soil is dry and the weather is clear, and remove the propagules of perennial weeds in the field; S2. Sowing seeds at a depth of about 5-8 cm; S3. After sowing and the first effective rainfall, spray soil-sealing herbicide when the top 2 cm of soil is moist.

2. The method for sealing weeds in dryland rice fields according to claim 1, characterized in that: Step S1 also includes: spraying glyphosate on the leaves of perennial weeds 15 days before tilling the soil.

3. The method for sealing weeds in dryland rice fields according to claim 1, characterized in that: In step S2, sowing is performed using a hand-push seeder or a large-scale hole seeder.

4. The method for sealing weeds in dryland rice fields according to claim 1, characterized in that: In step S2, sowing is completed within 5 days after tilling and preparing the soil.

5. The method for sealing weeds in dryland rice fields according to claim 1, characterized in that: In step S3, the spraying of the soil-sealed herbicide is completed within 24 hours after the rain, and is sprayed in the evening without wind.

6. The method for sealing weeds in dryland rice fields according to claim 1, characterized in that: In step S3, the soil-sealed herbicide is a mixed herbicide of 100 mL / mu of 30% butachlor microcapsule suspension and 100 mL / mu of 330 g / L pendimethalin emulsifiable concentrate.

7. The method for sealing weeds in dryland rice fields according to claim 1, characterized in that: In step S3, the soil-sealing herbicide is a mixed herbicide of 100 mL / mu of 60% butachlor emulsifiable concentrate and 100 mL / mu of 330 g / L pendimethalin emulsifiable concentrate.

8. The method for sealing weeds in dryland rice fields according to claim 1, characterized in that: In step S3, the soil-sealed herbicide is diluted with about 45 L of water per acre.

9. The method for sealing weeds in dryland rice fields according to claim 1, characterized in that: In step S3, the spraying is performed using a backpack sprayer and a fan-shaped spray head.

10. The method for sealing weeds in dryland rice fields according to claim 1, characterized in that: In step S3, the spray angle is between 100 and 110 degrees, and 400-100 micron droplets are used to spray the soil surface, and step-back spraying is used during spraying.

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