A method for applying polyglutamic acid to improve water production efficiency of rice

Abstract

The application belongs to the field of water-saving cultivation of rice. Huanghuazhan is used as the material, and two γ-PGA dosages are set under two water management modes of dry-wet alternation (total input water amount is about 1131.33-1152.33 mm) and drought (total input water amount is about 737.00-743.67 mm), wherein a control group is 0 kg hm ‑2 , and a treatment group is 1.0 kg hm ‑2 . The application studies the influence of γ-PGA application on water production efficiency of rice under different water management modes. A method for improving water production efficiency of rice is disclosed, which is characterized by applying 1.0 kg hm ‑2 of the γ-PGA in four times, weighing 0.25 kg hm ‑2 of sodium polyglutamate powder each time, preparing a water solution, preparing on demand, and spraying the solution on the surface layer of soil during the whole field leveling to rice transplanting period, tillering period, jointing period and full heading period, and synchronously with nitrogen fertilizer. The application can effectively improve the water production efficiency of rice.

Description

Technical Field

[0001] This invention belongs to the field of water-saving rice cultivation, specifically relating to a method for improving rice water production efficiency and yield by applying polyglutamic acid (γ-PGA). Background Technology

[0002] Rice is one of my country's most important food crops, with a planting area of ​​approximately 30.1 million hectares in 2021, accounting for about 50% of the world's total. Traditional rice cultivation employs a flood irrigation system, which involves retaining a water layer on raised beds. This system suffers from problems such as frequent irrigation, high water consumption, and low water use efficiency. Agriculture accounts for about 60% of my country's total water consumption, and rice production accounts for about 60% of agricultural water use. However, the utilization rate of agricultural irrigation water is only about 45%, roughly 75% of that in developed countries, indicating significant water waste. Furthermore, unused fertilizers and pesticides flow into natural water bodies with excess irrigation water, causing severe pollution and ecological damage. In recent years, with the gradual deterioration of the ecological environment, agricultural water use has been severely affected. Therefore, researching methods to improve rice water productivity and yield is of significant practical importance for rice production.

[0003] γ-PGA possesses numerous carboxyl and amino functional groups, exhibiting excellent adsorption capacity for water and ions in the soil. This allows for the effective distribution of water and fertilizer around plant roots, leading to greater absorption and utilization, and reducing water and fertilizer loss due to evaporation and seepage. It plays a crucial role in improving water productivity and yield in rice. In water-scarce or low-water areas, the use of γ-PGA can significantly enhance water and fertilizer utilization in rice cultivation. Furthermore, γ-PGA can decompose naturally, generating amino acids, and will not cause secondary pollution to the soil ecosystem. Summary of the Invention

[0004] This invention addresses the problem of low water production efficiency in rice production by proposing a method for improving rice water production efficiency through the application of γ-PGA, thereby achieving the goal of increasing both water production efficiency and yield.

[0005] The technical solution of the present invention is as follows:

[0006] A method for improving rice water productivity by applying γ-PGA under water management patterns of alternating wet and dry periods (total water input approximately 1131.33-1152.33 mm) and drought (total water input approximately 737.00-743.67 mm). The application rate of γ-PGA is 1.0 kg / hm². -2 The technical application solution is as follows:

[0007] 1. Determine the application time of fertilizer and γ-PGA: from land preparation and leveling to rice transplanting, tillering stage, jointing stage, and heading stage.

[0008] 2. The application rate of γ-PGA was determined to be 1.0 kg / hm. -2 .

[0009] 3. γ-PGA application method: Apply at a rate of 1.0 kg / hm². -2 The application rate is divided into 4 applications, each at 0.25 kg / hm². -2 Weigh out the amount of sodium polyglutamate powder, prepare an aqueous solution, and prepare it fresh for use. Apply it to the soil surface at the following stages: before rice transplanting, tillering stage, jointing stage, and heading stage, simultaneously with nitrogen fertilizer.

[0010] 4. Water Management Plan: The alternating wet and dry water management plan involves maintaining a shallow water layer of 3-5 cm on the paddy field from transplanting to the tillering stage. One week before the peak tillering period, drain the field and allow it to dry naturally, then re-water. Repeat this process until two weeks before harvest. The drought water management plan involves maintaining a shallow water layer of 3-5 cm on the paddy field from transplanting to the tillering stage. One week before the peak tillering period, drain the field and allow it to dry and crack, then re-water. Repeat this process until two weeks before harvest.

[0011] Advantages of the present invention

[0012] γ-PGA can promote water transport between soil and rice, improving rice water production efficiency and reducing water loss in paddy fields caused by evaporation and seepage. It effectively improves soil structure, enhances rice's fertilizer utilization efficiency, promotes root and stem development, strengthens lodging resistance, and increases rice yield. The operation method is simple, clean, and environmentally friendly. Attached Figure Description

[0013] Figure 1 The effect of γ-PGA on water production efficiency in rice

[0014] Figure 2 Effects of γ-PGA on rice yield and yield components

[0015] Specific Implementation Cases

[0016] Example 1

[0017] The experimental site is located in Lanjie Village, Huaqiao Town, Wuxue City (115°30′E, 29°55′N). This area belongs to the middle reaches of the Yangtze River rice-growing region, with an altitude of approximately 20 meters. It has a subtropical monsoon climate with an average annual temperature of 16.8℃ and an average annual rainfall of 1278.7-1442.6 mm. The paddy fields are sandy loam, of the stagnant type, with a soil bulk density of 1.12 g / cm³. -3 .

[0018] Field trials were conducted from May to October 2023. Using Huang Huazhan as the research material, two γ-PGA application rates were set under an alternating wet and dry water management model: the control group had a rate of 0 kg / hm². -2The treatment group consisted of 1.0 kg hm -2 Each treatment was repeated 3 times, for a total of 6 cells, each cell area being 20m². 2 (5m × 4m) The plots are divided into sections with ridges and covered with black plastic film. Fertilizers used include compound fertilizer (N:P:K = 24%, N:10%, P₂O₅:14%, K₂O), urea (46.3%, N), superphosphate (12%, P₂O₅), and potassium chloride (60%, K₂O), and nitrogen fertilizer (180 kg / hm²). -2 The fertilizer should be applied according to the ratio of base fertilizer: tillering fertilizer: jointing fertilizer: heading fertilizer = 5:2:1.2:1.8; phosphate fertilizer, potassium fertilizer and compound fertilizer should be applied as base fertilizer once, and urea should be used as top dressing for nitrogen fertilizer.

[0019] Seeds were soaked on May 5, 2023; germinated on May 7; sown on May 9; weeded on June 5; applied base fertilizer on June 6; transplanted on June 7; applied tillering fertilizer on June 22; applied jointing fertilizer on July 23; applied heading fertilizer on August 5; and harvested on September 20. The planting density was 25,000 plants / hm². 2 Two plants per hole, with a row spacing of 15×20cm.

[0020] γ-PGA is prepared using sodium polyglutamate powder at a dosage of 1.0 kg / hm. -2 Divide the fertilizer into four applications. Each time, weigh 2.0g of sodium polyglutamate powder, dissolve it in 500mL of water to make an aqueous solution, transfer it to an electronic sprayer or watering can, and spray it on the soil surface simultaneously with nitrogen fertilizer before transplanting, during the tillering stage, the jointing stage, and the heading stage.

[0021] From land preparation and leveling to rice transplanting, PC pipes and tensiometers are inserted in the center of each plot. The PC pipes, 1.0m long, are used to measure the water level and irrigation volume of each plot. Holes of 75.0cm are evenly drilled and inserted into the ground. During measurement, the distance G1 (H = 25.0 - G1) from the pipe opening to the water surface inside the pipe is measured with a tape measure. The tensiometer is used to measure soil moisture potential. Rainfall data is provided by the local weather station. From rice transplanting to the tillering stage, the plots are irrigated, maintaining a shallow water layer of 3-5cm on the surface. One week before the peak tillering period, the fields are drained and dried, then refilled with water. Once the soil naturally dries and cracks, the water level is controlled at 15-20cm below the surface, with a soil water potential of approximately -15.0kPa. This process is repeated until two weeks before harvest, at which point the fields are drained again. Weed and pest control is carried out using standard methods.

[0022] Rice yield determination: At the rice maturity stage, plant samples were taken at ground level from the center of each plot, at a depth of 3.0m. 2 The grains were dried, hulled, and empty grains were removed. The weight was recorded as M0. The moisture content of the grains was measured, and the average of three measurements was recorded as W. The rice moisture content was converted to 14%, and the actual yield was calculated. The formula is as follows:

[0023] M(kg ha -1 )=M0×(1-W) / (1-14.0%)

[0024] Rice water productivity represents the yield per unit of total water input, where total water input is... Figure 1 This includes irrigation water and rainfall. Calculation formula:

[0025] Rice water production efficiency (kg m -3 = Yield per unit area (kg) / Total water input per unit area (m³) 3 )

[0026] Studies have shown that under alternating wet and dry water management patterns, the application of γ-PGA significantly increased rice water production efficiency by 4.48%. Figure 1 At the same time, it effectively increased rice yield. Figure 2 ).

[0027] Example 2

[0028] The experimental site is located in Lanjie Village, Huaqiao Town, Wuxue City (115°30′E, 29°55′N). This area belongs to the middle reaches of the Yangtze River rice-growing region, with an altitude of approximately 20 meters. It has a subtropical monsoon climate with an average annual temperature of 16.8℃ and an average annual rainfall of 1278.7-1442.6 mm. The paddy fields are sandy loam, of the stagnant type, with a soil bulk density of 1.12 g / cm³. -3 .

[0029] Field trials were conducted from May to October 2023. Using Huang Huazhan as the research material, two γ-PGA application rates were set under a drought water management model: the control group had a rate of 0 kg / hm². -2 The treatment group consisted of 1.0 kg hm -2 Each treatment was repeated 3 times, for a total of 6 cells, each cell area being 20m². 2 (5m × 4m) Fields are divided into sections with ridges and covered with black plastic film. Fertilizers used include compound fertilizer (N:P:K = 24%, N:10%, P₂O₅:14%, K₂O), urea (46.3%, N), superphosphate (12%, P₂O₅), and potassium chloride (60%, K₂O), and nitrogen fertilizer (180 kg / hm²). -2 The fertilizer should be applied according to the ratio of base fertilizer: tillering fertilizer: jointing fertilizer: heading fertilizer = 5:2:1.2:1.8; phosphate fertilizer, potassium fertilizer and compound fertilizer should be applied as base fertilizer once, and urea should be used as top dressing for nitrogen fertilizer.

[0030] Seeds were soaked on May 5, 2023; germinated on May 7; sown on May 9; weeded on June 5; applied base fertilizer on June 6; transplanted on June 7; applied tillering fertilizer on June 22; applied jointing fertilizer on July 23; applied heading fertilizer on August 5; and harvested on September 20. The planting density was 25,000 plants / hm². 2Two plants per hole, with a row spacing of 15×20cm.

[0031] γ-PGA is prepared using sodium polyglutamate powder at a dosage of 1.0 kg / hm. -2 Divide the fertilizer into four applications. Each time, weigh 2.0g of sodium polyglutamate powder, dissolve it in 500mL of water to make an aqueous solution, transfer it to an electronic sprayer or watering can, and spray it on the soil surface simultaneously with nitrogen fertilizer before transplanting, during the tillering stage, the jointing stage, and the heading stage.

[0032] From land preparation and leveling to rice transplanting, a PC pipe and a tensiometer are inserted in the center of each plot. The PC pipe, 1.0m long, is used to measure the water level and irrigation volume of each plot. Holes of 75.0cm are evenly drilled and inserted into the ground. During measurement, the distance G1 (H = 25.0 - G1) from the pipe opening to the water surface inside the pipe is measured with a tape measure. The tensiometer is used to measure soil moisture potential. Rainfall data is provided by the local weather station. From rice transplanting to the tillering stage, the plots are irrigated, maintaining a shallow water layer of 3-5cm on the bed surface. One week before the peak tillering period, the fields are drained and dried, then covered with water. Once the soil naturally dries and cracks, and the soil potential is controlled at around -40.0kPa, it is covered with water again. This process is repeated until two weeks before harvest. During the rainy season, drainage is carried out promptly to keep the bed surface free of standing water. Weed and pest control are carried out using conventional methods.

[0033] Rice yield determination: At the rice maturity stage, plant samples were taken at ground level from the center of each plot, at a depth of 3.0m. 2 The grains were dried, hulled, and empty grains were removed. The weight was recorded as M0. The moisture content of the grains was measured, and the average of three measurements was recorded as W. The rice moisture content was converted to 14%, and the actual yield was calculated. The formula is as follows:

[0034] M(kg ha -1 )=M0×(1-W) / (1-14.0%)

[0035] Rice water productivity represents the yield per unit of total water input, where total water input is... Figure 1 This includes irrigation water and rainfall. Calculation formula:

[0036] Rice water production efficiency (kg m -3 = Yield per unit area (kg) / Total water input per unit area (m³) 3 )

[0037] Studies have shown that under drought water management conditions, the application of γ-PGA significantly increased rice water production efficiency by 3.64%. Figure 1 At the same time, it effectively increased rice yield. Figure 2 ).

Claims

1. A method for improving water use efficiency in rice by applying polyglutamic acid, characterized in that The total input water amount is 1131.33-1152.33mm in the dry-wet alternating moisture management mode and 737.00-743.67mm in the drought moisture management mode, and 1.0kg hm -2 of γ-PGA is applied; the γ-PGA application method is: 0.25kghm -2 of γ-PGA is applied each time, and the γ-PGA is prepared into an aqueous solution, and is prepared on demand, and is sprayed on the soil surface synchronously with nitrogen fertilizer before rice transplanting, at the tillering stage, at the jointing stage, and at the full heading stage.

2. The method for improving water productivity of rice by applying polyglutamic acid according to claim 1, characterized in that: The wet-dry alternating moisture treatment measures are as follows: rice is transplanted to tillering stage, water is introduced to irrigate the plot, the surface is kept with 3.0-5.0 cm shallow water layer, the water is drained to dry the field one week before the tillering peak stage, water is covered, the soil is naturally dried and cracked, the water level is controlled to be 15.0-20.0 cm below the ground surface, the soil water potential is about-15.0 kPa, then water is covered again, and the above process is repeated until two weeks before harvesting; the drought moisture treatment measures are as follows: rice is transplanted to tillering stage, water is introduced to irrigate the plot, the surface is kept with 3.0-5.0 cm shallow water layer, the water is drained to dry the field one week before the tillering peak stage, water is covered, the soil is naturally dried and cracked, the soil potential is controlled to be about-40.0 kPa, water is covered, the above process is repeated until two weeks before harvesting, and the water is drained in time in the rainy season to keep the surface without obvious water.

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