Improved gleying rice field wetting planting method

Abstract

The invention discloses an improved gleying rice field wetting planting method, which comprises the following steps: firstly, carrying out pretreatment on a rice field, carrying out field flattening and soil preparation before ditching, then digging side ditches and central ditches which are communicated with each other around and in the center of the gleying rice field to form a drainage network, carrying out deep ploughing after drainage, and uniformly spreading a high-stability organic fertilizer; selecting a rice variety according to characteristics of a producing area, and performing treatment and germination acceleration on seeds; sowing after determining the sowing time according to the plot characteristics, the climate and the variety characteristics, and enabling the soil moisture to be 60-100% WHC in the growth period of the rice by virtue of the established drainage network; chemical fertilizer and organic fertilizer are applied as base fertilizer in rice planting, and the chemical fertilizer is dressed in the growing period; and returning the straws to the field after harvesting. By optimizing and innovating early-stage treatment, water management and other links of the rice field, the soil environment of the gleying rice field is improved, the adaptability of the rice to the bad environment is improved, high-yield, high-quality and efficient planting of the rice is achieved, and meanwhile the benign development of a soil ecosystem is promoted.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural planting, and more specifically, to an improved moist planting method for gley paddy fields. Background Art

[0002] A gley paddy field refers to a paddy field affected by groundwater or waterlogging, where the soil is in a water-saturated state and in a strong reduction state, forming a blue-gray gley horizon. The main reasons for its formation include poor drainage, such as in areas like depressions, small plains, and valley bottomlands; excessive water caused by water conservancy projects, such as leakage of dams and canals around ditches and reservoirs, emergence of groundwater, non-separation of drainage and irrigation, and cross-irrigation; and overcultivation. For example, the promotion of triple-cropping rice in the south has increased the multiple cropping index, thickened and compacted the plow sole, which hinders water and air permeability, and is also related to the heavy soil texture and high organic matter content.

[0003] There are many problems in gley soil, such as more reducing harmful substances, cold soil properties, weak biological activities, inhibited organic matter mineralization, which easily lead to the stagnant growth of rice seedlings in paddy fields, and ultimately result in late maturity and low yield, seriously affecting the yield and quality of rice and restricting the development of agriculture. Therefore, an effective improved planting method is needed to solve the problems of gley paddy fields. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide an improved moist planting method for gley paddy fields. By optimizing and innovating links such as pre-treatment of paddy fields, water management, and application of highly stable organic fertilizers, the soil environment of gley paddy fields is improved, the adaptability of rice to adverse environments is enhanced, high-yield, high-quality, and efficient planting of rice is achieved, and at the same time, the healthy development of the soil ecosystem is promoted.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] An improved moist planting method for gley paddy fields, comprising the following steps:

[0007] Step 1: Pre-treatment of paddy fields

[0008] Level the gley paddy field and then dig side ditches around the gley paddy field. The depth of the side ditches is controlled at 40 - 50 cm, and the width is 20 - 25 cm. Dig a central ditch in the middle of the paddy field. The depth of the central ditch is 20 - 30 cm, and the width is 10 - 15 cm. The side ditches and the central ditch are interconnected to form a drainage network. After drainage, conduct deep plowing and evenly spread highly stable organic fertilizer at a dosage of 40 t / ha;

[0009] Step 2: Variety selection and seed treatment

[0010] Select rice varieties according to the characteristics of the production area. 3-5 days before sowing, on a sunny day, spread the seeds thinly and dry them for 1-2 days. After drying, select the seeds with brine to remove empty and shriveled grains and impurities. After soaking and disinfecting the seeds, take them out, wash them, and soak the disinfected seeds in clean water for 2-4 days, changing the water 1-2 times a day. After the soaking is over, take out the seeds, drain the water, wrap them with a damp cloth, and place them in an environment of 30-35°C for germination. When more than 80% of the seeds show white tips, they can be sown.

[0011] Step 3: Sowing

[0012] Determine the sowing time according to the characteristics of the plot, climate, and variety characteristics. Adopt the direct seeding method, evenly spread the germinated seeds, and after sowing, cover the seeds with fine soil with a covering thickness of 0.5-1.0 cm, and gently press to make the seeds in close contact with the soil.

[0013] Step 4: Water management

[0014] Relying on the drainage network established in Step 1, the soil moisture during the rice growth season is between 60-100% WHC.

[0015] Step 5: Fertilization management

[0016] Apply chemical fertilizers and organic fertilizers as basal fertilizers, and top-dress chemical fertilizers during the growth period.

[0017] Step 6: Harvesting

[0018] Harvest after the crop is mature, and return the straw to the field.

[0019] Preferably, the slope of the field surface for leveling the field in Step 1 is required to be 1 / 10000-1 / 20000, and the tillage depth for deep tillage is 25-40 cm. Break the plow sole, enhance soil aeration, improve soil structure, and promote the oxidation and decomposition of reducing toxic substances in the soil.

[0020] Preferably, the high-stability organic fertilizer in Step 1 is granulated organic fertilizer, and the application rate is 40 t / ha. Improve soil structure, increase soil nutrients, promote microbial metabolism, prevent rapid loss of soil organic carbon after drainage, and enhance soil fertility.

[0021] Preferably, the selection of rice varieties in Step 2 is specifically as follows:

[0022] Double-cropping rice production area: For early rice, select conventional early rice, and for late rice, select deep-rooted late rice;

[0023] Rice-rape rotation production area: Select deep-rooted giant rice for rice.

[0024] Preferably, in Step 2, the disinfection is carried out by soaking in a strong chlorine dioxide solution with a mass fraction of 0.3%-0.5% for 12-24 h.

[0025] Further, the sowing in step three is specifically as follows:

[0026] Double-cropping rice production area: The early rice is sown when the daily average temperature is stable above 12°C, and the late rice is sown in a timely manner after the early rice is harvested.

[0027] Rice - rapeseed rotation production area: The rice is sown in the middle and late May.

[0028] The seeding rate is 1.5 - 2.0 kg / mu.

[0029] Further, the fertilization management in step five is specifically as follows:

[0030] Double-cropping rice production area: In both the early and late rice seasons, the inorganic fertilizer is applied at a rate of 10 kg N / mu, calculated by N. The base fertilizer and two top dressings are applied in three times at a ratio of 5:3:2. Among them, the base fertilizer is a nitrogen, phosphorus, and potassium compound fertilizer (15 - 15 - 15), and both top dressings are urea; the application rate of organic fertilizer is 10 t / ha / y and is applied as the base fertilizer in the early rice season.

[0031] Late rice + rapeseed planting pattern:

[0032] In the rice planting season, the application rate of chemical fertilizer is calculated at 6 kg N / mu, calculated by N. The ratio of base fertilizer to top dressing is 5:1. Among them, the base fertilizer is a nitrogen, phosphorus, and potassium compound fertilizer (15 - 15 - 15), and the top dressing is urea.

[0033] Rapeseed season: The application rate of chemical fertilizer is calculated at 14 kg N / mu, calculated by N. The ratio of base fertilizer to top dressing is 9:5. Among them, the base fertilizer is a nitrogen, phosphorus, and potassium compound fertilizer (15 - 15 - 15), and the top dressing is urea.

[0034] Increase the application of organic fertilizer, and the application rate is 40 t / ha, which is applied only once as the base fertilizer in the first-year rice planting season.

[0035] Further,

[0036] In the double-cropping rice production area: The two top dressings are respectively the tillering fertilizer and the panicle fertilizer. The organic fertilizer is attached cow dung, and the organic carbon and total nitrogen contents are 32.4% and 1.4% respectively.

[0037] In the late rice + rapeseed planting pattern: In the rice planting season, the top dressing is carried out at the tillering stage, and in the rapeseed season, the top dressing is carried out at the green-reverting stage.

[0038] Further, in the late rice + rapeseed planting pattern, the organic fertilizer uses granulated organic fertilizer.

[0039] Preferably, in the double-cropping rice production area, milk vetch is planted as green manure during the winter fallow period after the late rice harvest.

[0040] Through the above technical solutions, compared with the prior art, the present invention discloses an improved moist planting method for gley paddy fields, having the following beneficial effects:

[0041] The technical solution of the present invention, through treatment measures such as deep plowing, spreading soil conditioners, and arranging drainage systems in the pre-treatment, effectively improves the soil structure of the gley paddy field, reduces the content of reducing toxic substances in the soil, adjusts the soil pH, and creates a good soil environment for rice growth;

[0042] The technical solution of the present invention selects suitable rice varieties for different planting areas, scientifically treats the seeds, and combines reasonable sowing methods and water and fertilizer management, improving the adaptability of rice to the adverse environment of the gley paddy field, promoting the root development, tillering and grain filling of rice, and ensuring the growth and yield formation of rice;

[0043] The planting method of the present invention can achieve high-yield, high-quality and efficient planting of rice in the gley paddy field, improve the physical and chemical properties of the soil, and achieve the improvement of the gley paddy field at low cost and high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] 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 for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0045] Figure 1 For the change of rice yield under the conventional paddy field improvement in Test Example 1;

[0046] Figure 2 For the change of rice plant growth under the conventional paddy field improvement in Test Example 1;

[0047] Figure 3 For the change of the traits of the underground and above-ground parts of rice plants under the conventional paddy field improvement in Test Example 1;

[0048] Figure 4 For the change of soil Eh in the early and late rice seasons under the conventional paddy field improvement in Test Example 1;

[0049] Figure 5 For the change of soil iron ion concentration under the conventional paddy field improvement in Test Example 1;

[0050] Figure 6 For the change of soil available nutrients under the conventional paddy field improvement in Test Example 1;

[0051] Figure 7 For the change of soil Eh and ferrous content of upland rice under the moist planting improvement in Test Example 2;

[0052] Figure 8For the changes in soil bulk density and compactness of the upland rice profile under the improved wet planting in Test Example 2;

[0053] Figure 9 For the changes in soil organic carbon and total nitrogen of the upland rice profile under the improved wet planting in Test Example 2;

[0054] Figure 10 For the changes in available nutrients of the upland rice profile under the improved wet planting in Test Example 2;

[0055] Figure 11 For the changes in soil microbial biomass carbon and nitrogen of the upland rice profile under the improved wet planting in Test Example 2;

[0056] Figure 12 For the changes in soil microbial biomass carbon and nitrogen in the rhizosphere and non-rhizosphere soils of upland rice under the improved wet planting in Test Example 2. Detailed implementation manners

[0057] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0058] Step 1: Pre-treatment of paddy field

[0059] Level the paddy field with gleying, and the slope of the field surface is required to be 1 / 10000 - 1 / 20000. Then, dig side ditches around the gleying paddy field. The depth of the side ditches is controlled at 40 - 50 cm, and the width is 20 - 25 cm. Dig a center ditch in the middle of the paddy field. The depth of the center ditch is 20 - 30 cm, and the width is 10 - 15 cm. The side ditches and the center ditch are interconnected to form a drainage network. After drainage, conduct deep plowing with a depth of 25 - 40 cm. After deep plowing, evenly spread high-stability organic fertilizer (granulated organic fertilizer) at a rate of 40 t / ha per mu;

[0060] Step 2: Variety selection and seed treatment

[0061] Select rice varieties according to the characteristics of the production area. For early rice in double-cropping rice production areas, select conventional early rice, and for late rice, select deep-rooted late rice; for rice in rice-rape rotation production areas, select deep-rooted giant rice; 3 - 5 days before sowing, choose a sunny day to spread the seeds thinly and dry them for 1 - 2 days. After sun drying, select seeds with brine to remove empty and shriveled grains and impurities. Soak the seeds in a strong chlorine dioxide solution with a mass fraction of 0.3% - 0.5% for 12 - 24 h for disinfection and then fish them out and wash them. After disinfection, soak the seeds in clean water for 2 - 4 days, changing the water 1 - 2 times a day. After the soaking is over, fish out the seeds and drain the water, wrap them with a wet cloth, and place them in an environment of 30 - 35 °C for germination. Sowing can be carried out when more than 80% of the seeds show white tips;

[0062] Step 3: Sowing

[0063] Determine the sowing time according to the plot characteristics, climate and variety characteristics.

[0064] Double-cropping rice production area: For early rice, sow when the daily average temperature is stable above 12°C; for late rice, sow in a timely manner after the early rice is harvested.

[0065] Rice-rape rotation production area: Sow rice in the middle and late May.

[0066] The seeding rate is 1.5 - 2.0 kg / mu. Adopt the direct seeding method, evenly spread the germinated seeds, and after sowing, cover the seeds with fine soil, with a covering thickness of 0.5 - 1.0 cm, and gently press to make the seeds in close contact with the soil.

[0067] Step 4: Water management

[0068] Relying on the drainage network established in Step 1, the soil moisture during the rice growth season is between 60 - 100% WHC.

[0069] Step 5: Fertilization management

[0070] Apply chemical fertilizers and organic fertilizers as basal fertilizers, and top-dress chemical fertilizers during the growth period.

[0071] Among them,

[0072] Double-cropping rice: In both the early and late rice seasons, the application rate of chemical fertilizers is 10 kg N / mu of inorganic fertilizers. Calculated by N, the basal fertilizer and two top-dressings are applied in three times at a ratio of 5:3:2. Among them, the basal fertilizer is a nitrogen, phosphorus and potassium compound fertilizer (15-15-15), and the two top-dressings (tiller fertilizer and panicle fertilizer) are both urea; the organic fertilizer uses decomposed cow dung, with an application rate of 10 t / ha / y, and the organic carbon and total nitrogen contents are 32.4% and 1.4% respectively, and it is applied as a basal fertilizer in the early rice season.

[0073] Late rice + rape planting mode:

[0074] During the rice planting season, the application rate of chemical fertilizers is calculated at 6 kg N / mu and applied in two times. Calculated by N, the ratio of basal fertilizer to top-dressing is 5:1. Among them, the basal fertilizer is a nitrogen, phosphorus and potassium compound fertilizer (15-15-15), and the top-dressing (tiller fertilizer) is urea.

[0075] Rape season: The application rate of chemical fertilizers is calculated at 14 kg N / mu and applied in two times. Calculated by N, the ratio of basal fertilizer to top-dressing is 9:5. Among them, the basal fertilizer is a nitrogen, phosphorus and potassium compound fertilizer (15-15-15), and the top-dressing (green-recovery period) is urea.

[0076] Increase the application of highly stable organic fertilizers. Adopt granulated organic fertilizers, with an application rate of 40 t / ha, and apply them only once as basal fertilizers in the first-year rice planting season.

[0077] Step Six: Harvesting

[0078] After the crops are mature, they are harvested and the straw is returned to the field. In the double-cropping rice production area, milk vetch is planted as green manure during the winter fallow period after the late rice harvest.

[0079] The following uses relevant test examples to illustrate the advancement of the improvement of the technical solution of the present invention.

[0080] The test area is located in Shanghuashan Village, Kaihui Town, Changsha County, Changsha City (113°19′8.81″N, 28°32′33.5″E), which is located in the hilly area in the northeast of Hunan Province. This area is a typical double-cropping area (rice-rape, double-cropping rice), with a subtropical monsoon climate. Rainfall is concentrated in summer, with an annual precipitation of 1000 - 1500 mm and an average annual temperature of 17.2°C. This area belongs to a typical hilly and low-lying waterlogged area, with a high groundwater level and heavy soil. The soil has poor drainage all year round, a high content of soil reducing substances, and belongs to a severely gleyed paddy field, with a proportion of low-yield fields exceeding 70%.

[0081] In the following tests, the relevant index determination and analysis are specifically as follows:

[0082] I. Determination and analysis of upland rice yield and its component factors

[0083] Determination of upland rice yield: In the mature season of upland rice, randomly select 1 2m×2m quadrat in each test plot to harvest upland rice, thresh and weigh it, record the total fresh weight of grains within 4m 2 After drying, calculate the moisture content of upland rice (converted to a moisture content of 13.5%), and calculate the upland rice yield of each test treatment based on the fresh weight of grains and the moisture content.

[0084] Determination of upland rice yield component factors: Randomly select 20 hill plants in different test plots to investigate and record their effective panicle numbers and effective tiller numbers; select 5 hill plants with uniform growth, place them in a net bag and bring them back to the laboratory. The rice panicles are blanched in an oven at 105°C for 30 min and dried to a constant weight at 75°C, record the number of grains per panicle, thresh, use a winnowing machine to separate the filled grains and empty grains of the rice grains of 5 hill plants, record the number of filled grains and empty grains, and randomly select 1000 plump grains for weighing, which is the 1000-grain weight (converted to the mass with a moisture content of 13.5%); the seed setting rate of upland rice is the ratio of the number of filled grains to the total number of grains of 5 hill plants.

[0085] II. Determination and analysis of key gley indexes of paddy soil

[0086] The key gleying indicators of paddy soil include: soil redox potential, ferrous iron, ferric iron, total iron, total amount of reducing substances, and amount of active reducing substances, etc. All are determined by general methods, referring to "Methods for Agricultural Chemical Analysis of Soils". The soil redox potential is determined by the potentiometric method, the ferrous iron, ferric iron, and total iron in the soil are determined by the spectrophotometer method, and the total amount of reducing substances in the soil is determined by the potassium dichromate oxidation method. Specifically, weigh 10 g of fresh soil into a conical flask, add 200 ml of aluminum sulfate extractant and extract for 5 min, then filter. Then add potassium dichromate and sulfuric acid (1:1) and heat in a water bath. After cooling, add o-phenanthroline and titrate with ferrous sulfate solution. The end point of titration is when the solution changes from yellow through green to brownish red. Calculate the total amount of reducing substances. The amount of active reducing substances in the soil is determined by the potassium permanganate titration method. The soil extraction steps are the same as those for the total amount of reducing substances. After extraction, add sulfuric acid (1:1) and titrate with a calibrated potassium permanganate solution at room temperature until the solution turns slightly red and does not fade for 30 s as the end point of titration. At the same time, set a blank control to calculate the active reducing substances.

[0087] III. Determination and Analysis of Basic Physicochemical and Biological Property Indicators of Soil

[0088] Soil physicochemical properties are used to characterize the changes in soil fertility under the enhanced input of organic materials. The main physicochemical indicators include: soil compaction, soil bulk density, soil organic carbon (SOC), total nitrogen in soil (TN), ammonium nitrogen in soil (NH4 +- N), nitrate nitrogen in soil (NO 3- -N), dissolved organic carbon (DOC), Olsen P in soil, microbial biomass carbon (MBC) in soil, and microbial biomass nitrogen (MBN) in soil. They are determined by general methods, specifically referring to "Methods for Agricultural Chemical Analysis of Soils". Soil compaction is directly determined by a compaction meter, soil bulk density is determined by the core method, soil organic carbon and total nitrogen in soil are determined by a carbon-nitrogen analyzer, and the determination of microbial biomass carbon and nitrogen in soil adopts the chloroform fumigation-potassium sulfate-extraction method. The carbon and nitrogen contents are determined using a continuous flow analyzer. Calculate the microbial biomass carbon and nitrogen in soil according to the conversion coefficients K EC =0.45, K EN =0.54.

[0089] Experimental Example 1

[0090] Research on the conventional paddy field cultivation technology of deep ditch drainage combined with organic fertilizer application in gleyed paddy fields:

[0091] Five treatments were set up in this experiment, including four experimental treatments of deep ditch drainage, combined application of organic and inorganic fertilizers and rice variety combinations, and a control treatment (CK) without deep ditches. Among them, T1 was conventional double-cropping rice + conventional chemical fertilizers, T2 was conventional double-cropping rice + conventional chemical fertilizers + organic fertilizer input, T3 was conventional early rice + deeply plowed late rice + conventional chemical fertilizers, T4 was conventional early rice + deeply plowed late rice + conventional chemical fertilizers + organic fertilizer input. The specific experimental treatments are shown in Table 1. Conventional chemical fertilizers refer to applying inorganic fertilizers at 10 kg N per mu in both the early and late rice seasons, and applying them in three times according to the ratio of 5:3:2. Among them, the basal fertilizer is compound fertilizer, and the latter two top dressings are both urea. The organic fertilizer used is decomposed cow dung, and its organic carbon and total nitrogen contents are 32.4% and 1.4% respectively, which are applied as basal fertilizer in the early rice season and input once a year. The conventional early rice variety is Kenyou 1683, the conventional late rice is Taiyou 390, and the deep-rooted late rice variety is Y Liangyou 911. Deep ditch drainage refers to drainage in the form of double ditch matching, with the side ditch depth of 40-50 cm, width of 20-25 cm, the center ditch depth of 20-30 cm, and width of 10-15 cm. All fields were rotary plowed before rice planting, and the whole amount of straw was returned to the field after harvest. Chinese milk vetch was planted as green manure during the winter fallow period.

[0092] Table 1 Experimental treatments of conventional paddy field improvement technology for reducing potential waterlogging obstacle factors

[0093]

[0094]

[0095] The specific results are as follows:

[0096] 1.1 Effects of conventional paddy field cultivation combined with deep ditch drainage and organic fertilizer application on the improvement of gley paddy fields and the enhancement of production capacity

[0097] 1.1.1 Effects of conventional paddy field improvement on rice yield and its component factors

[0098] After two years of field experiments, it was found that deep ditch drainage significantly increased rice yield ( Figure 1 ). Under the condition of deep ditch drainage, the average yield of early rice in the experimental plots was 482.2 kg per mu, which was 53.7% higher than that of CK without deep ditches (313.8 kg per mu). Similarly, the yield of late rice was 514.5 kg per mu, an increase of 15.1% compared with the control (446.9 kg per mu). Under the conventional paddy field improvement technology, the combination of deep-rooted late rice and organic fertilizer application had the most obvious effect on increasing rice yield. Although the rice variety and organic fertilizer application in the early rice season had no obvious effect on increasing rice yield ( Figure 1), however, the average yield of the deep-rooted rice variety in the late rice season was 548.9 kg / mu, which was 14.3% higher than that of the conventional late rice variety (average 480.1 kg / mu). The yield increase of the deep-rooted late rice combined with the application of organic fertilizer (T4) was also as high as 27.6% compared with the conventional treatment (T1).

[0099] Deep ditch drainage significantly improved the underground and above-ground biological traits of rice Figure 2 ). Comparing the traits of the above-ground and underground parts of rice at the early rice harvest stage, it can be seen that the effective tiller number and plant height of the organic-inorganic combined application treatment were both greater than those of the inorganic fertilizer treatment, but the root length was the opposite, indicating that the application of organic manure in the early rice season mainly promoted the growth of the above-ground part of rice Figure 3 ). Therefore, under the conventional paddy cultivation mode, the effect of combining the cultivation of deep-rooted rice with the application of organic fertilizer is the most obvious. It can promote the increase of above-ground biomass of rice, thereby improving the soil structure and increasing the rice yield.

[0100] 1.1.2 Influence of conventional paddy cultivation improvement on soil redox status

[0101] The deep ditch drainage measure can effectively improve the redox state of the waterlogged paddy field. Compared with the control, the soil Eh increased by 9.1 mV and 20.6 mV (the negative value decreased) at the seedling stage and tillering stage of early rice respectively under the deep ditch drainage measure, and the soil Eh increased by 49.2 mV and 35.6 mV at the seedling stage and tillering stage of late rice respectively Figure 4 ).

[0102] The average ferrous ion concentration in the experimental plots at the tillering stage and heading stage of early rice was 309.1 mg / kg and 260.6 mg / kg respectively, both lower than 327.7 mg / kg and 344.8 mg / kg of the control Figure 5 ). It shows that deep ditch drainage can reduce the content of ferrous ions in the soil. However, the content of ferrous ions in the T2 and T4 treatments showed a greater value than that in the T1 and T3 treatments numerically, which was consistent with the Eh measurement results, indicating that the rice variety affects the soil iron ion concentration.

[0103] 1.1.3 Influence of conventional paddy cultivation improvement on soil nutrient dynamics

[0104] The variability of the available nutrient content in the soil at different times was relatively large. Compared with the control treatment (CK), the cultivation of deep-rooted rice + organic-inorganic combined application (T4) significantly increased the DOC content at each stage of early rice, indicating that the comprehensive improvement technology had the best effect on improving the soil dissolved organic carbon. The application of organic fertilizer showed an overall trend of increasing the available P in the soil at the seedling stage and tillering stage of early rice Figure 6 ).

[0105] Experimental Example 2

[0106] Research on wet planting technology of deep ditch drainage combined with organic fertilizer application in submerged rice fields:

[0107] This experiment set up 4 treatments, including: T1 (conventional upland rice-rapeseed + normal organic fertilizer); T2 (giant rice-rapeseed + normal organic fertilizer); T3 (conventional upland rice-rapeseed + granulated high-amount organic fertilizer); T4 (giant rice-rapeseed + granulated high-amount organic fertilizer). Each treatment was set up with 3 replicates, totaling 12 experimental plots. The specific experimental treatments are shown in Table 2. Deep ditch drainage refers to double-ditch drainage, with a side ditch depth of 40-50cm and a width of 20-25cm, and a center ditch depth of 20-30cm and a width of 10-15cm. Soil moist planting needs to be controlled by combining soil depth and shallow ditch to ensure that the rice growing season remains moist and the soil moisture is between 60-100% WHC. Conventional dry rice season: 10kgN / mu, applied three times, the three fertilizer ratios are 5:3:2 (in terms of N), the base fertilizer is compound fertilizer, and the two topdressings are urea; Giant rice season: 6kgN / mu, applied twice, the base fertilizer and topdressing ratio is 5:1 (in terms of N). Rapeseed season: 14kgN / mu, applied twice, the base fertilizer and topdressing ratio is 9:5 (in terms of N). Normal organic fertilizer (10t / ha) is applied once a year, and granulated high-volume organic fertilizer is only applied once in the first year, and no longer applied afterwards. The conventional dry rice variety is Jieyou 804, the giant rice variety is Giant Rice No. 6, and the rapeseed variety is Sunshine 131.

[0108] Table 2 Experimental treatment of rice field waterlogging obstacle factors reduction and wet planting improvement technology

[0109] Treatment Organic fertilizer input Planting pattern Engineering measures T1 10 t / ha (per year) Conventional upland rice - rapeseed Deep ditch drainage T2 10 t / ha (per year) Deep - rooted giant rice - rapeseed Deep ditch drainage T3 40 t / ha (in the first year) Conventional upland rice - rapeseed Deep ditch drainage T4 40 t / ha (in the first year) Deep - rooted giant rice - rapeseed Deep ditch drainage

[0110] The specific results are as follows:

[0111] 2.1 Effects of wet planting combined with deep ditch drainage and organic fertilizer application on the improvement and productivity enhancement of latent rice fields

[0112] 2.1.1 Effects of wet planting improvement on rice yield and its components

[0113] Under the wet planting mode, high-amount organic fertilizer intensive input significantly increased the yield of upland rice, but did not significantly increase the yield of giant rice (Table 3). The conventional upland rice yield in the T3 treatment was 20.1t / ha (1340kg / mu), while the conventional upland rice yield in the T1 treatment was 18.2t / ha (1213kg / mu), an increase of 10.5%. However, high-amount organic fertilizer input reduced the yield of giant rice. Combined with the yield factor analysis, it was found that the number of grains per panicle of giant rice was significantly higher than that of conventional upland rice, but because its fruit set rate and effective panicle number were significantly lower than those of conventional upland rice, the yield of giant rice was significantly lower than that of conventional upland rice. Due to the low planting density and pests and diseases of giant rice, further improvement is needed.

[0114] Table 3 Changes in upland rice yield and its component factors under wet planting improvement

[0115]

[0116]

[0117] Deep-rooted crops (giant rice) have outstanding growth advantages compared with conventional upland rice. Under both high and normal levels of organic fertilizer input, the effective tiller numbers of giant rice are significantly higher than those of conventional upland rice (p<0.05) (Table 4). The effective tiller numbers of giant rice in treatments T2 and T4 are as high as 22.2 and 22.7 respectively, while those of upland rice in treatments T1 and T3 are only 14.6 and 17.0, with the highest increase rate reaching 55.5%. Similarly, giant rice is also significantly higher than conventional upland rice in terms of crop plant height and root length. The plant height of giant rice generally exceeds 210 cm, while that of conventional upland rice is only about 130 cm, with a difference of 80 cm between the two. The root lengths of giant rice in treatments T2 and T4 are as high as 21.9 cm and 20.0 cm respectively, which are significantly higher than the root lengths of conventional upland rice in T1 and T3, showing great potential for expanding the soil layer and increasing its capacity, opening up new ideas for soil improvement.

[0118] Table 4 Changes in upland rice growth under wet planting improvement

[0119]

[0120] 2.1.2 Effects of wet planting improvement on soil redox status

[0121] The combination of deep ditch drainage measures and wet planting has a highly significant impact on soil reduction status ( Figure 7 ). The soil Eh of the CK treatment in the conventional paddy field is less than 10 mV, while the soil Eh is increased to above 600 mV through the deep ditch + wet planting method. Further analysis found that the effect of high levels of organic fertilizer (T3 and T4) input on enhancing soil Eh is stronger than that of normal levels of organic fertilizer (T1 and T2), indicating that enhanced input of organic fertilizer is beneficial to plant growth, increasing the oxygen secretion ability of rice roots, thereby improving soil Eh and the soil redox properties.

[0122] Similar conclusions were also found for the content of soil ferrous ions, that is, the combination of deep ditch drainage measures and wet planting significantly reduced the soil ferrous content and improved the soil redox characteristics ( Figure 7 ). The soil Fe 2+ concentration in the CK treatment of the conventional paddy field is higher than 4 cmol / kg, while the soil Eh is reduced to below 2 cmol / kg through the deep ditch + wet planting method, with a reduction rate exceeding 50%. However, the effects of high levels of organic fertilizer (T3 and T4) input and normal levels of organic fertilizer (T1 and T2) on soil Fe 2+ are not significant.

[0123] 2.1.3 Effects of Moist Planting Improvement on Soil Structure

[0124] Significantly enhanced input of organic materials has remarkably improved the plough layer structure. Whether for conventional upland rice or giant rice cultivation, the soil bulk density and soil compactness under enhanced input of organic fertilizers are significantly lower than those under normal input of organic fertilizers ( Figure 8 ). It is worth noting that the improvement effect of the deep-rooted giant rice - enhanced input of organic materials (T4) on soil structure is the strongest under the moist planting mode. The soil compactness of T1, T2, and T3 treatments are 3.94 KPa, 3.85 Kpa, and 3.71 Kpa respectively, all significantly higher than that of the T4 treatment (3.59 Kpa).

[0125] 2.1.4 Effects of Moist Planting Improvement on Soil Organic Carbon and Total Nitrogen

[0126] Soil samples were collected from the 0 - 10 cm, 10 - 20 cm, and 20 - 30 cm soil layers to analyze the distribution of soil organic carbon and total nitrogen in the soil profile. The results show that with the increase of soil depth, the soil organic carbon and total nitrogen show a downward trend, and the enhanced input of organic fertilizers also increases the contents of soil organic carbon and total nitrogen, which is most obvious in the 10 - 20 cm plough layer ( Figure 9 ). Under the enhanced input of organic fertilizers, the soil organic carbon content in the 10 - 20 cm plough layer is as high as 24.6 g / kg, higher than that of the treatment with normal application of organic fertilizers (20.6 g / kg), with an increase of 19.4%. Similarly, the total nitrogen contents in the 10 - 20 cm plough layer under the enhanced input of organic fertilizers and normal application of organic fertilizers are 2.13 g / kg and 2.47 g / kg respectively, with a difference of 0.33 g / kg between them.

[0127] 2.1.5 Effects of Moist Planting Improvement on Soil Available Nutrients

[0128] The distribution results of soil available nutrients in the soil profile (0 - 10 - 20 - 30 cm) show that with the increase of soil depth, soil DOC, NH4 + , NO3 - and Olsen P all show a downward trend ( Figure 10 ). This is similar to the distribution law of soil total index profiles. However, the improvement of available nutrients in the profile soil under the enhanced input of organic fertilizers is not obvious, and the variation of available nutrients in the field is relatively large.

[0129] 2.1.6 Effects of Moist Planting Improvement on Soil Microbial Biomass Carbon and Nitrogen

[0130] The distribution results of soil microbial biomass carbon and nitrogen in the soil profile (0 - 10 - 20 - 30 cm) also show that with the increase of soil depth, both soil microbial biomass carbon and nitrogen show a downward trend ( Figure 11) It is worth noting that the enhanced input of organic fertilizer increased the contents of soil microbial biomass carbon and nitrogen, especially in the 10-20 cm plough layer soil. In the 10-20 cm hot zone of upland rice roots, microbial activity was strong, and the microbial turnover process promoted the accumulation and retention of nutrients, thus showing higher contents of soil organic carbon and nitrogen.

[0131] The results of microbial carbon and nitrogen in the rhizosphere and non-rhizosphere soils of wetland-grown upland rice also supported the above conclusion. The deep-rooted giant rice enhanced the rhizosphere effect of the soil ( Figure 12 ). The microbial biomass carbon in the rhizosphere soil was 1446.0 mg / kg and 1462.9 mg / kg in treatments T1 and T3, respectively, while it was as high as 1636.8 mg / kg and 1585.5 mg / kg in treatments T2 and T4, respectively, with an increase of 8.4-13.2%. The microbial biomass nitrogen in the rhizosphere soil was 87.3 mg / kg and 83.9 mg / kg in treatments T1 and T3, respectively, while it was as high as 101.5 mg / kg and 108.7 mg / kg in treatments T2 and T4, respectively, with an increase of up to 29.6%.

[0132] To sum up, through two years of field experiments, it was found that the deep-ditch drainage measure could effectively improve the redox status of gley paddy fields, reduce the ferrous ion content in the soil, and significantly increase the yields of early rice and late rice. Under the condition of deep-ditch drainage, the average yield of early rice was 482.2 kg / mu, which was 53.7% higher than that of the control treatment without digging deep ditches. The average yield of late rice was 514.5 kg / mu, which was also 15.1% higher than that of the control. The application of constant amount of organic fertilizer significantly increased the soil microbial biomass carbon and nitrogen and promoted the formation of rice grains. Generally speaking, the combined effect of deep-ditch drainage + planting deep-rooted rice and applying organic fertilizer was the most obvious. It promoted the increase of rice yield by improving the redox status (Eh and ferrous content) and soil structure of paddy fields.

[0133] The previous research results found that although the deep-ditch de-gleying treatment was carried out, the phenomenon of anti-gley still occurred during the seedling and tillering stages of rice under the conventional flooding cultivation mode. Therefore, in this study, a wet cultivation mode with optimized regulation of soil moisture was further adopted, and its improvement effect on soil gleying obstacles was more significant than that of the conventional flooding cultivation with deep ditches. The Eh of conventional paddy field soil was less than 10 mV, while the Eh of the soil was increased to more than 600 mV by the deep-ditch + wet cultivation method. Moreover, the combined input of deep-rooted crops and high amount of organic fertilizer had a stronger effect on improving soil fertility than the constant amount of organic fertilizer. It promoted the accumulation and retention of soil nutrients by improving the soil structure and stimulating the microbial activity in the rhizosphere hot zone, and thus improved the soil fertility and crop yield. All in all, the comprehensive improvement technology of deep-ditch drainage, application of highly stable organic fertilizer and wet cultivation can mutatively improve the redox status of the soil, promote the growth of above-ground biomass of rice and increase crop yield, and is expected to completely solve the problems of the plough layer soil obstacles in waterlogged paddy fields.

[0134] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the various embodiments, reference can be made to each other. The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An improved method for wet cultivation of gleyed paddy fields, characterized in that, It includes the following steps: Step 1: Pre-treatment of paddy fields Level the paddy fields with gleyic soil. The slope of the field surface is required to be 1 / 10000 - 1 / 20000. Then, dig side ditches around the gleyic paddy fields. The depth of the side ditches is controlled at 40 - 50 cm, and the width is 20 - 25 cm. Dig a central ditch in the middle of the paddy field. The depth of the central ditch is 20 - 30 cm, and the width is 10 - 15 cm. The side ditches and the central ditch are interconnected to form a drainage network. After drainage is completed, conduct deep plowing and evenly spread high-stability organic fertilizer. Step 2: Variety selection and seed treatment Select rice varieties according to the characteristics of the production area. 3 - 5 days before sowing, choose a sunny day to spread the seeds thinly and sun-dry them for 1 - 2 days. After sun-drying, select seeds with brine to remove empty and shriveled grains and impurities. Soak the seeds in disinfectant and then fish them out and wash them. After disinfection, soak the seeds in clean water for 2 - 4 days, changing the water 1 - 2 times a day. After the soaking is over, fish out the seeds, drain the water, wrap them with a damp cloth, and place them in an environment of 30 - 35 °C for germination. Wait until more than 80% of the seeds show white tips before sowing. Step 3: Sowing Determine the sowing time according to the characteristics of the plot, climate, and variety characteristics. Adopt the direct seeding method and evenly spread the germinated seeds. After sowing, cover the seeds with fine soil, with a covering thickness of 0.5 - 1.0 cm, and gently press to make the seeds in close contact with the soil. Step 4: Water management Relying on the drainage network established in Step 1, during the rice growth season, the soil moisture is between 60 - 100% WHC. Step 5: Fertilization management Apply chemical fertilizers and organic fertilizers as base fertilizers, and top-dress chemical fertilizers during the growth period. Step 6: Harvesting Harvest after the crops are mature, and return the straw to the field.

2. The improved method for wet cultivation of gley paddy fields according to claim 1, characterized in that, In Step 1, the slope of the field surface for leveling is required to be 1 / 10000 - 1 / 20000, and the depth of deep plowing is 25 - 40 cm.

3. An improved method for wet cultivation of gley paddy fields according to claim 1, characterized in that, The high-stability organic fertilizer mentioned in Step 1 is granulated organic fertilizer, and the application rate is 40 t / ha.

4. The improved method for wet cultivation of gley paddy fields according to claim 1, characterized in that, The specific selection of rice varieties in Step 2 is as follows: Double-cropping rice production area: For early rice, select conventional early rice; for late rice, select late rice with deep roots. Rice - rapeseed rotation production area: Select deep-rooted giant rice for rice.

5. A modified method for wet cultivation of gley paddy fields according to claim 1, characterized in that, In Step 2, the disinfection is carried out by soaking in a strong chlorine essence solution with a mass fraction of 0.3% - 0.5% for 12 - 24 h.

6. The improved method for wet cultivation of gley paddy fields according to claim 4, characterized in that The specific sowing in Step 3 is as follows: Double-cropping rice production area: Sow early rice when the average daily temperature is stable above 12 °C, and sow late rice in time after the early rice is harvested. Rice - rapeseed rotation production area: Sow rice in the middle and late May. The seeding rate is 1.5 - 2.0 kg / mu.

7. An improved method for wet cultivation of gley paddy fields according to claim 4, characterized in that, The specific fertilization management in Step 5 is as follows: Double-cropping rice production area: In both the early and late rice seasons, apply inorganic fertilizers at a rate of 10 kg N / mu in terms of N. The base fertilizer and two top-dressings are applied in three times in a ratio of 5:3:

2. Among them, the base fertilizer is a nitrogen, phosphorus, and potassium compound fertilizer (15 - 15 - 15), and both top-dressings are urea; the application rate of organic fertilizer is 10 t / ha / y, and it is applied as a base fertilizer in the early rice season. Late rice + rapeseed planting mode: During the rice planting season, the application rate of chemical fertilizer is calculated at 6 kg N / mu in terms of N. The ratio of the base fertilizer to the top-dressing is 5:

1. Among them, the base fertilizer is a nitrogen, phosphorus, and potassium compound fertilizer (15 - 15 - 15), and the top-dressing is urea. Rapeseed season: The chemical fertilizer application rate is calculated at 14 kg N per mu, based on N. The ratio of basal fertilizer to top dressing is 9:

5. The basal fertilizer is a nitrogen-phosphorus-potassium compound fertilizer (15-15-15), and the top dressing is urea. Increase the application of organic fertilizer, with an application rate of 40 t / ha, which is applied only once as basal fertilizer in the first-year rice planting season.

8. A modified method for wet cultivation of gley paddy fields according to claim 7, characterized in that In the double-cropping rice production area: The two top dressings are tillering fertilizer and panicle fertilizer respectively. The organic fertilizer is attached cow dung, and the organic carbon and total nitrogen contents are 32.4% and 1.4% respectively. In the late rice + rapeseed planting mode: During the rice planting season, top dressing is carried out at the tillering stage, and during the rapeseed season, top dressing is carried out at the green-recovery stage.

9. An improved method for wet cultivation of gley paddy fields according to claim 8, characterized in that, In the late rice + rapeseed planting mode, granulated organic fertilizer is used as the organic fertilizer.

10. A modified method for wet cultivation of gley paddy fields according to claim 4, characterized in that, In the double-cropping rice production area, milk vetch is planted as green manure during the winter fallow period after the late rice harvest.

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