Simple and efficient rice one-time fertilization method based on soil available potassium level

Abstract

The invention belongs to the field of rice fertilization, and discloses a simple and efficient one-time rice fertilization method based on soil available potassium level, which comprises the following steps: measuring the available potassium content of plough layer soil of a target field; selecting a slow mixed fertilizer according to the content of available potassium in plough layer soil: when the content of available potassium is lower than 150mg / kg, selecting a high-potassium-ratio slow mixed fertilizer with the mass percent of K2O not lower than 10%; and when the content of available potassium is higher than or equal to 150mg / kg, selecting a low-potassium-ratio slow-mixing fertilizer with the mass percent of K2O being lower than 10%. Through precise matching of soil potassium with a slow-mixing fertilizer formula and combination of one-time basal application, fine soil preparation, precise ear fertilizer diagnosis and other technologies, synchronous supply of nutrients in the whole growth period of rice is realized, the fertilization frequency is remarkably reduced, the nitrogen fertilizer utilization rate and yield are improved, and the method has the advantages of labor saving, high efficiency and environmental protection.

Description

Technical Field

[0001] This invention belongs to the field of rice fertilization and relates to a simple and efficient one-time fertilization method for rice based on the available potassium level in the soil. In particular, it relates to a simple and efficient one-time fertilization method for rice that accurately selects slow-release fertilizer for paddy fields based on the available potassium content in the soil. Background Technology

[0002] Rice, as one of the world's most important food crops, directly impacts food security and agricultural economic benefits through its yield and quality. Fertilizer management is a key factor influencing rice quality and yield during rice cultivation. Traditional fertilization methods typically involve multiple applications of fertilizer at different growth stages, such as basal fertilizer, tillering fertilizer, and panicle fertilizer. However, this requires farmers to enter the field repeatedly, increasing labor and time costs. Furthermore, traditional methods are prone to fertilizer loss, volatilization, or fixation, especially nitrogen fertilizer, leading to low utilization rates, resource waste, and environmental pollution. Rice has different nutrient requirements at different growth stages, and multiple applications cannot precisely match these requirements, potentially resulting in insufficient or excessive nutrient supply, affecting rice quality and yield.

[0003] Slow-release fertilizers, by controlling the nutrient release rate, can reduce the number of fertilizations and improve fertilizer utilization to some extent. Existing slow-release fertilizer technologies have achieved some success in increasing rice yields, but the same slow-release fertilizer formula shows significant differences in field performance across different regions, indicating unstable yield and quality improvement effects. In-depth analysis by the inventors revealed that soil nutrient differences are one of the key factors causing these differences, with the impact of available potassium content being more pronounced in saline-alkali areas. In soils with low available potassium content, using slow-release fertilizers with low potassium ratios may limit yield increases; while in soils rich in available potassium, using slow-release fertilizers with high potassium ratios may lead to resource waste or even poor results. Therefore, the interaction between soil potassium status and fertilizer potassium ratio cannot be ignored. There is an urgent need for a simple, efficient, and single-application fertilization method that couples soil potassium indicators with the selection of slow-release fertilizer formulas. Summary of the Invention

[0004] Through multi-point comparative experiments on soils with varying available potassium contents (ranging from approximately 80 to 250 mg / kg), the inventors discovered a significant interaction between soil available potassium content and the yield-increasing effect of slow-release fertilizers with different potassium ratios. Data analysis showed that when the soil available potassium content was below 150 mg / kg, applying high-potassium slow-release fertilizers could increase nitrogen fertilizer utilization by an average of 5–10 percentage points, resulting in a significant yield increase (>5%). Conversely, when the soil available potassium content was above or equal to 150 mg / kg, the soil's own potassium supply basically met the needs of rice; continuing to apply high-potassium formulas not only failed to further increase yield but also led to a decline in economic benefits due to nutrient imbalance and increased costs.

[0005] The purpose of this invention is to provide a simple and efficient one-time fertilization method for rice based on the soil's available potassium content level and combined with slow-mixed fertilizer technology. This method allows for the precise selection of the optimal slow-mixed fertilizer for rice in a specific area, which can reduce the number of fertilizations and lower labor costs, while accurately matching the nutrient requirements of rice to maximize fertilizer benefits and provide technical support for high-efficiency and high-quality rice production.

[0006] The objective of this invention is achieved through the following technical solutions:

[0007] A simplified and efficient single-application fertilization method for rice based on soil available potassium levels includes: determining the available potassium content in the topsoil of the target field; selecting a slow-release fertilizer based on the available potassium content in the topsoil: when the available potassium content is below 150 mg / kg (defined as low-potassium soil), a high-potassium slow-release fertilizer with a K2O mass percentage of not less than 10% is selected; when the available potassium content is above or equal to 150 mg / kg (defined as high-potassium soil), a low-potassium slow-release fertilizer with a K2O mass percentage of less than 10% is selected.

[0008] Generally, the available potassium content in the topsoil of the target field is measured before rice sowing, when no base fertilizer has been applied.

[0009] The nitrogen release characteristics of slow-release fertilizer are synchronized with the nitrogen requirements of high-yield and high-quality rice in the local area. It requires uniform grain shape, appropriate hardness, low moisture absorption, and prevention of floating, and is suitable for single basal application.

[0010] The mass ratio of nitrogen (N), phosphorus (P2O5), and potassium (K2O) in the high-potassium slow-mixed fertilizer is (30-33):(6-8):(10-12).

[0011] Preferably, the mass ratio of nitrogen, phosphorus, and potassium in the high-potassium slow-mix fertilizer is 30:6:12.

[0012] The mass ratio of nitrogen (N), phosphorus (P2O5), and potassium (K2O) in the low-potassium slow-mixed fertilizer is (32-34):(6-10):(6-8).

[0013] Preferably, the mass ratio of nitrogen, phosphorus, and potassium in the low-potassium slow-mix fertilizer is in the range of 32:10:6.

[0014] The nitrogen application rate of the slow-mixed fertilizer is 65% to 80% of the local conventional nitrogen application rate.

[0015] Fertilization method: Apply slow-mixed fertilizer once during paddy field preparation, and mix the fertilizer with the soil in the 0-20cm depth of the cultivated land through mechanical plowing or tilling to achieve uniform fertilization.

[0016] Preferably, the need for panicle fertilizer is diagnosed based on leaf color during the 3-leaf stage of rice: if the leaf color is significantly lighter (the top 4 leaves are lighter than the top 3 leaves), then 3 kg of nitrogen fertilizer per mu should be applied for indica rice and no more than 5 kg of nitrogen fertilizer per mu should be applied for japonica rice; if the leaf color is normal (the top 4 leaves are similar in color to the top 3 leaves), then panicle fertilizer is not required.

[0017] Another object of the present invention is to provide a low-potassium slow-mixed fertilizer suitable for rice cultivation in soils with high potassium content. The low-potassium slow-mixed fertilizer is composed of the following components in parts by weight: 20-22 parts sulfur-coated urea, 46-48 parts 90-day resin-coated urea, 20-22 parts resin-coated diammonium phosphate, and 10-12 parts resin-coated potassium chloride.

[0018] Preferably, the low-potassium slow-mix fertilizer is composed of the following components in parts by weight: 21 parts sulfur-coated urea, 47 parts 90-day resin-coated urea, 22 parts resin-coated diammonium phosphate, and 10 parts resin-coated potassium chloride.

[0019] The sulfur-coated urea is a slow-release fertilizer with a nitrogen content of 37% by mass.

[0020] The 90-day resin-coated urea is a controlled-release fertilizer with a nitrogen content of 43% by mass and a fertilizer effect period of 90 days.

[0021] The resin-coated diammonium phosphate is a controlled-release fertilizer with a nitrogen content of 18% and a P2O5 content of 46%.

[0022] The resin-coated potassium chloride is a controlled-release fertilizer with a K2O content of 56% by mass.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] This invention achieves simultaneous nutrient supply throughout the entire rice growth cycle by precisely matching soil potassium with a slow-mixed fertilizer formula, combined with one-time basal application, meticulous land preparation, and accurate diagnosis of panicle fertilization techniques. This significantly reduces the number of fertilization applications, improves nitrogen fertilizer utilization and yield, and has the advantages of being labor-saving, highly efficient, and environmentally friendly. Specifically:

[0025] (1) Current rice production mainly relies on water-soluble quick-acting fertilizers. Even if the fertilizer is applied to the soil through rotary tillage, it will be lost due to drainage. This invention reduces the amount of nitrogen applied and spreads the slow-mixed fertilizer evenly on the surface of the field before tillage. The slow-mixed fertilizer is then mixed into the soil through rotary tillage, achieving the effect of deep fertilization. No additional topdressing is needed in the later stages, and the utilization rate of nitrogen fertilizer is improved.

[0026] (2) This invention reduces the number of fertilizations by applying slow-release fertilizer in a single application, thereby lowering labor and time costs and achieving a simple and efficient fertilization model. The nutrient release characteristics of the slow-release fertilizer are synchronized with the nutrient requirements of rice growth, meeting the nutrient needs of rice throughout its entire growth period. In addition, leaf color diagnosis technology accurately determines whether additional panicle fertilizer is needed at the three-leaf stage from the top of the rice plant, further optimizing nutrient supply.

[0027] (3) This invention is the first to use the available potassium content in the soil as the core decision indicator for selecting slow-release fertilizer formulations, solving the problem of unstable fertilizer effects caused by different soil potassium background values, and ensuring that the selected formulation can fully realize its potential for increasing yield and improving quality. At the same time, this method is simple to operate and easy to promote. Only a routine soil available potassium test is required to make a scientific decision, which is easy for agricultural technicians and growers to master and apply, realizing the implementation of precision agriculture. Detailed Implementation

[0028] The technical solution of the present invention will be further described below through specific embodiments.

[0029] Test varieties: Local conventional varieties.

[0030] Before rice sowing, the soil physicochemical properties at different ecological sites were measured without the application of basal fertilizer, as shown in Table 1.

[0031] Table 1. Soil physicochemical properties at different ecological sites

[0032]

[0033] The conventional high-yield nitrogen application rate in Hongze is 24.43 kg N / mu, and the conventional high-yield nitrogen application rate in Lianyungang is 25.9 kg N / mu.

[0034] The nutrients in large-particle urea, sulfur-coated urea, 60-day resin-coated urea, 90-day resin-coated urea, resin-coated diammonium phosphate, resin-coated potassium chloride, and potassium chloride are as follows:

[0035] The nitrogen content in large-particle urea is 46% by mass, and the particle diameter is 2-5 mm.

[0036] Sulfur-coated urea is a slow-release fertilizer with a nitrogen content of 37% by mass.

[0037] The 60-day resin-coated urea is a controlled-release fertilizer with a nitrogen content of 43% by mass and a fertilizer effect period of 60 days.

[0038] The 90-day resin-coated urea is a controlled-release fertilizer with a nitrogen content of 43% by mass and a fertilizer effect period of 90 days.

[0039] The resin-coated diammonium phosphate is a controlled-release fertilizer with a nitrogen content of 18% and a P2O5 content of 46%.

[0040] The resin-coated potassium chloride is a controlled-release fertilizer with a K2O content of 56%.

[0041] Potassium chloride is in crystalline form, and the mass percentage of K2O is 60%.

[0042] Example 1

[0043] High-potassium slow-release fertilizer is composed of the following components in parts by weight: 6 parts granular urea, 20 parts sulfur-coated urea, 20 parts 60-day resin-coated urea, 20 parts 90-day resin-coated urea, 13 parts resin-coated diammonium phosphate, 16 parts potassium chloride, and 5 parts resin-coated potassium chloride. The nutrient ratio of the high-potassium slow-release fertilizer is 30:6:12 (referring to the mass ratio of N:P2O5:K2O).

[0044] Fine land preparation techniques: Appropriate tillage methods are adopted based on crop rotation and soil properties. Generally, sandy soil is tilled 1-2 days before transplanting, loam soil 2-3 days before transplanting, and clay soil 3-4 days before transplanting. Mechanical tillage depth should be 15-20cm, ensuring a level field surface free of weeds, debris, and crop residue, with a height difference of no more than 3cm within the field. Before transplanting, mud slurry needs to settle to achieve clear water and mud, without sedimentation or hardening, and with a water depth of 1-3cm on the field surface.

[0045] Centralized seedling cultivation technology: The dry-seedling and micro-spraying seedling cultivation technology is used to cultivate seedlings evenly and uniformly. The seedlings are upright with green leaves, thick and flat stem base with elasticity, and roots are firmly coiled. The soil thickness of the coiled roots is 2-2.3cm. When the seedlings are transported, the seedling blocks do not deform or break, and the seedlings are not damaged.

[0046] Fertilization method: When preparing paddy fields, use a fertilizer spreader to evenly spread the slow-mixed fertilizer on the field surface in one go, and then mechanically till the land to a depth of about 12cm to achieve uniform fertilization.

[0047] Nitrogen fertilizer application rate: The nitrogen application rate of slow-mixed fertilizer is 80% of the local conventional nitrogen application rate.

[0048] If field diagnosis is performed during the three-leaf stage, and the leaf color is normal (i.e., the top 4 leaves are similar in color to the top 3 leaves), then no additional fertilizer is needed.

[0049] Water management and precision irrigation techniques: moist irrigation during the transplanting and greening period; for fields where straw is returned to the field, ensure the field is exposed after planting; dry the field promptly from the ineffective tillering period to the early jointing stage; alternate between dry and wet irrigation from jointing to maturity; and prevent premature dehydration and premature aging in the later grain-filling stage.

[0050] Green prevention and control technology: Adhere to the principle of "prevention first and comprehensive control", and use agricultural control, physical control, biological control, ecological regulation and the scientific, rational and safe use of pesticides to control diseases, pests and weeds.

[0051] Example 2

[0052] The low-potassium slow-release fertilizer is composed of the following components in parts by weight: 21 parts sulfur-coated urea, 47 parts 90-day resin-coated urea, 22 parts resin-coated diammonium phosphate, and 10 parts resin-coated potassium chloride. The nutrient ratio of the low-potassium slow-release fertilizer is 32:10:6 (referring to the mass ratio of N:P2O5:K2O).

[0053] The fertilization method, nitrogen fertilizer application rate, and water management are the same as in Example 1.

[0054] Comparative Example 1

[0055] Basal fertilizer was applied one day before rice seedling transplanting, urea was applied one week after transplanting as tillering fertilizer, and urea was applied again as panicle fertilizer at the three-leaf stage from the top. The ratio of basal fertilizer, tillering fertilizer, and panicle fertilizer was 4:3:3, all applied manually to the soil surface. The nitrogen application rate was the local standard high-yield nitrogen application rate. Water management was the same as in Example 1.

[0056] Experimental results determination: The actual plot area was measured at maturity, and the yield was measured by harvesting machine. The moisture content was determined and converted according to the standard moisture content of 14.5% to obtain the yield (Table 2).

[0057] Nitrogen content determination in plants: After drying and pulverizing the samples from each treatment, the nitrogen content of the aboveground plants was determined by the Dumas combustion method.

[0058] Nitrogen fertilizer uptake and utilization rate (NUE) = (Nitrogen uptake in the nitrogen application area - Nitrogen uptake in the blank area) / Nitrogen application amount × 100% (Table 3).

[0059] The blank area represents the treatment without nitrogen fertilizer, while the phosphorus and potassium fertilizers and other measures are the same as those in control example 1.

[0060] Table 2. Effects of fertilization methods on rice yield

[0061]

[0062] Table 3. Nitrogen fertilizer use efficiency and economic benefits under different fertilization methods

[0063]

[0064] This invention provides a simplified and efficient single-application fertilization method for rice based on soil available potassium levels. By accurately matching a specialized slow-release fertilizer formula to the soil's available potassium content, and combining this with supporting technologies such as single-application basal application, meticulous land preparation, and precise diagnosis of panicle fertilizer application, it achieves simultaneous nutrient supply throughout the entire rice growth cycle. Experimental results show that this method significantly reduces the number of fertilizations and labor costs while effectively improving rice yield and nitrogen fertilizer utilization: In low-potassium soils in Hongze, the application of a high-potassium formula (Example 1) resulted in a yield of 8722.5 kg / hm². 2 Compared with conventional fertilization, this method increased yield by 5.54%; in the high-potassium soil of Lianyungang, Example 2 achieved even better yield and efficiency. This method effectively solves the problem of unstable fertilizer effect caused by differences in soil potassium background, and has significant advantages such as increased yield and quality, labor saving and high efficiency, and environmental friendliness, providing technical support for the precise implementation of simplified and efficient fertilization technology for rice.

Claims

1. A simple and efficient single-application fertilization method for rice based on soil available potassium levels, characterized in that: include: Determine the available potassium content in the topsoil of the target field; select slow-release fertilizers based on the available potassium content in the topsoil: when the available potassium content is less than 150 mg / kg, select a high-potassium slow-release fertilizer with a K2O mass percentage of not less than 10%; when the available potassium content is greater than or equal to 150 mg / kg, select a low-potassium slow-release fertilizer with a K2O mass percentage of less than 10%.

2. The simplified and efficient single-application fertilization method for rice according to claim 1, characterized in that: The mass ratio of nitrogen, phosphorus and potassium in the high-potassium slow-mix fertilizer is (30-33):(6-8):(10-12).

3. The simplified and efficient single-application fertilization method for rice according to claim 1 or 2, characterized in that: The mass ratio of nitrogen, phosphorus, and potassium in the high-potassium slow-mix fertilizer is 30:6:

12.

4. The simplified and efficient single-application fertilization method for rice according to claim 1, characterized in that: The mass ratio of nitrogen, phosphorus and potassium in the low potassium slow-mix fertilizer is (32-34):(6-10):(6-8).

5. The simplified and efficient single-application fertilization method for rice according to claim 1 or 4, characterized in that: The mass ratio of nitrogen, phosphorus, and potassium in the low-potassium slow-mix fertilizer is 32:10:

6.

6. The simplified and efficient single-application fertilization method for rice according to claim 1, characterized in that: The nitrogen application rate of the slow-mixed fertilizer is 65% to 80% of the local conventional nitrogen application rate.

7. The simplified and efficient single-application fertilization method for rice according to claim 1, characterized in that: Fertilization method: Apply slow-mixed fertilizer once during paddy field preparation, and mix the fertilizer evenly with the soil in the 0-20cm depth of the cultivated land by mechanical plowing or turning.

8. A low-potassium slow-release fertilizer suitable for rice cultivation in soils with high potassium content, characterized in that: The low-potassium slow-mix fertilizer is composed of the following components in parts by weight: 20-22 parts sulfur-coated urea, 46-48 parts 90-day resin-coated urea, 20-22 parts resin-coated diammonium phosphate, and 10-12 parts resin-coated potassium chloride.

9. The low-potassium slow-mix fertilizer according to claim 8, characterized in that: It is composed of the following components in parts by weight: 21 parts sulfur-coated urea, 47 parts 90-day resin-coated urea, 22 parts resin-coated diammonium phosphate, and 10 parts resin-coated potassium chloride.

10. The low-potassium slow-mix fertilizer according to claim 8 or 9, characterized in that: The sulfur-coated urea is a slow-release fertilizer with a nitrogen content of 37% by mass; the 90-day resin-coated urea is a controlled-release fertilizer with a nitrogen content of 43% by mass and a fertilizer effect period of 90 days; the resin-coated diammonium phosphate is a controlled-release fertilizer with a nitrogen content of 18% by mass and a P2O5 content of 46% by mass; and the resin-coated potassium chloride is a controlled-release fertilizer with a K2O content of 56% by mass.

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