A slow-release mixed fertilizer suitable for increasing yield and reducing emission of early rice with machine transplanting in low latitude areas

Abstract

This invention discloses a slow-mixed fertilizer suitable for increasing yield and reducing emissions in machine-transplanted early rice in low-latitude regions. It consists of the following parts by weight: 4-6 parts sulfur-coated urea and 4-6 parts 2-month resin-coated urea. The invention also discloses the application of this slow-mixed fertilizer in early rice production, with fertilization carried out simultaneously with rice transplanting. The slow-mixed fertilizer is applied directly to the base of the seedlings at a depth of 5 cm and 3-5 cm in the soil. This invention's slow-mixed fertilizer can increase yield, nitrogen fertilizer use efficiency, and reduce greenhouse gas emissions. Compared with conventional high-yield, multi-stage fertilization, the application of this invention's slow-mixed fertilizer increases rice yield by 7.5%-7.8%, increases nitrogen fertilizer use efficiency by 30.5%-44.5%, reduces global warming potential by 12.8%-27.5%, and reduces greenhouse gas emission intensity by 19.3%-32.7%.

Description

Technical Field

[0001] This invention belongs to the fields of fertilizer production and rice cultivation, and relates to a slow-mixed fertilizer suitable for increasing yield and reducing emissions of machine-transplanted early rice in low-latitude regions. Specifically, it relates to a slow-mixed fertilizer that is specifically suitable for machine-transplanted early rice in low-latitude regions and has the function of increasing yield and reducing emissions. Background Technology

[0002] Double-cropping rice is the main planting pattern in low-latitude regions (30°N–30°S). For a long time, in pursuit of high yields, production has generally suffered from problems such as frequent fertilization, large amounts of fertilizer, and high labor costs, resulting in high production costs, low fertilizer utilization, and numerous negative effects such as non-point source pollution and greenhouse gas emissions. With the promotion of mechanized rice transplanting technology, the planting efficiency of early rice in low-latitude regions has significantly improved. However, the compatibility between traditional fertilization methods and mechanized production is becoming increasingly prominent, gradually becoming a technical bottleneck restricting the large-scale production of mechanized early rice in low-latitude regions.

[0003] Applying nitrogen fertilizer is one of the effective measures to promote rice growth and increase yield, but it also increases greenhouse gas emissions from paddy fields. Specifically, nitrogen fertilizer promotes the input of root exudates and plant residues, increasing the abundance of methanogenic bacteria, inhibiting the activity of methanogenic bacteria, and promoting methane production. Simultaneously, as nitrogen is a direct substrate for nitrous oxide formation, applying nitrogen fertilizer, while increasing nitrous oxide production in paddy fields, also promotes the proliferation of nitrifying bacteria, accelerating NH4+ production. + Oxidized to NO2 - This, in turn, promotes the production of nitrous oxide.

[0004] Coated controlled-release fertilizers, as an important carrier of single-application fertilization technology in paddy fields, can effectively reduce the number of fertilizations, fertilizer application rates, production costs, and greenhouse gas emissions from paddy fields. Numerous studies have shown that the "single-peak" nitrogen release curve of a single coated controlled-release fertilizer is insufficient to meet the nitrogen requirements of rice during the tillering and panicle differentiation to heading stages, and nitrogen supply is redundant during a single key growth stage, leading to significant nitrogen loss in paddy fields. Furthermore, machine-transplanted early rice in low-latitude regions exhibits a temperature characteristic of low temperatures before and high temperatures after the jointing stage. Low temperatures before the jointing stage are detrimental to seedling greening and tillering, while high temperatures after the jointing stage are detrimental to rice growth and grain filling. The release rate of slow-release fertilizers is affected by temperature; the higher the temperature, the faster the release. Currently, the nitrogen release from a combination of urea and coated controlled-release fertilizers cannot simultaneously address both the tillering promotion before the jointing stage and the negative impact of high temperatures after the jointing stage on rice growth. Therefore, there is an urgent need for a highly efficient and environmentally friendly slow-release fertilizer specifically for machine-transplanted early rice in low-latitude regions. Summary of the Invention

[0005] This invention aims to address the problems in mechanized early rice production in low-latitude regions, where existing nitrogen fertilizer management schemes cannot meet the nutrient requirements of crops at different growth stages. Excessive nitrogen fertilizer application can lead to fertilizer waste, increased greenhouse gas emissions, and the unsuitability of ordinary fertilizers for mechanized rice fertilization. Based on the nitrogen requirements of rice at different growth stages, this invention provides a slow-mixed fertilizer prepared by blending sulfur-coated urea with 2-month resin-coated urea. This slow-mixed fertilizer is suitable for mechanized early rice in low-latitude regions, with fertilization and transplanting occurring simultaneously. The slow-mixed fertilizer is applied directly to the seedlings at a depth of 3-5 cm and 5 cm from the root zone, improving rice yield and nitrogen fertilizer utilization efficiency while reducing greenhouse gas emissions from paddy fields.

[0006] The present invention solves the above problems through the following technical solutions:

[0007] A slow-mixed fertilizer suitable for increasing yield and reducing emissions of machine-transplanted early rice in low-latitude regions is composed of the following parts by weight of sulfur-coated urea and 2-month resin-coated urea: 4-6 parts sulfur-coated urea and 4-6 parts 2-month resin-coated urea.

[0008] As a preferred technical solution of the slow-mixed fertilizer of the present invention, the slow-mixed fertilizer is composed of the following parts by weight of sulfur-coated urea and 2-month resin-coated urea: 4.8-5.5 parts of sulfur-coated urea and 4.8-5.5 parts of 2-month resin-coated urea.

[0009] As a further preferred technical solution of the slow-mixed fertilizer of the present invention, the slow-mixed fertilizer is composed of the following parts by weight of sulfur-coated urea and 2-month resin-coated urea: 5.0 parts of sulfur-coated urea and 5.0 parts of 2-month resin-coated urea.

[0010] The sulfur-coated urea is a slow-mixed fertilizer with a nitrogen mass percentage of 35% to 37%.

[0011] Preferably, the sulfur-coated urea is a slow-release fertilizer with a nitrogen mass percentage of 37%.

[0012] The 2-month resin-coated urea is a controlled-release fertilizer with a nitrogen mass percentage of 40% to 45% and a nutrient supply period of 2 months or a fertilizer effect period of 60 days.

[0013] Preferably, the 2-month resin-coated urea is a controlled-release fertilizer with a nitrogen mass percentage of 43% and a nutrient supply period of 2 months or a fertilizer effect period of 60 days.

[0014] Another object of the present invention is to provide a method for preparing the slow-mixed fertilizer, comprising: thoroughly stirring and mixing sulfur-coated urea and 2-month resin-coated urea according to the formula.

[0015] The slow-mixed fertilizer is suitable for machine-transplanted early rice in low-latitude regions. When applied according to the local conventional nitrogen application rate, it can significantly reduce greenhouse gas emissions from paddy fields while increasing rice yield and nitrogen fertilizer absorption and utilization rate.

[0016] The low-latitude region referred to is the region between 30°N and 30°S.

[0017] Another object of the present invention is to provide the application of the slow-mixed fertilizer, which is suitable for increasing yield and reducing emissions of machine-transplanted early rice in low-latitude regions, in early rice production.

[0018] Preferably, the slow-mixed fertilizer is applied to machine-transplanted early rice in low-latitude regions.

[0019] Preferably, the nitrogen application rate of the slow-mixed fertilizer is the same as the local conventional nitrogen application rate.

[0020] Preferably, the application of the slow-mixed fertilizer is carried out simultaneously with rice transplanting, and the slow-mixed fertilizer is applied directly to the seedlings at a depth of 3-5 cm and 5 cm from the root zone.

[0021] Specifically, the application includes: applying the slow-mixed fertilizer according to the local nitrogen application rate, with the application of the slow-mixed fertilizer being carried out simultaneously with rice transplanting, and the slow-mixed fertilizer being applied directly to the seedlings at a depth of 3-5 cm and 5 cm from the root zone.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) This invention makes full use of the nutrient demand pattern of rice in tropical regions and the nitrogen release characteristics of coated urea. It mixes sulfur-coated urea with resin-coated urea with a fertilizer effect period of 2 months or 60 days to prepare a slow-mixed fertilizer. In terms of controlled release time, it provides a new possibility for achieving synchronous "double peak" nitrogen supply for rice. The "multi-stage and rapid" release mode of sulfur-coated urea and the "precise and long-lasting" release mode of resin-coated urea are theoretically more in line with the nitrogen absorption pattern of rice during the tillering stage and after jointing. One application of fertilizer can well meet the nutrient demand of rice, solve the key problem of one application of fertilizer in low latitude regions, and greatly reduce fertilizer production costs and labor costs.

[0024] (2) The slow-mixed fertilizer of the present invention can improve yield, nitrogen fertilizer use efficiency and reduce greenhouse gas emissions. Compared with conventional high-yield multi-application fertilization, the application of the slow-mixed fertilizer of the present invention increases rice yield by 7.5% to 7.8%, increases nitrogen fertilizer use efficiency by 30.5% to 44.5%, reduces global warming potential by 12.8% to 27.5%, and reduces greenhouse gas emission intensity by 19.3% to 32.7%. Attached Figure Description

[0025] Figure 1 Rice yields under different treatments at different ecological sites.

[0026] Figure 2 GWPs were treated differently at different ecological sites.

[0027] Figure 3 GHGIs with different treatments at different ecological sites. Detailed Implementation

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

[0029] Example 1

[0030] Preparation of slow-mixed fertilizer suitable for machine-transplanted early rice in low-latitude regions

[0031] The sulfur-coated urea and the 2-month resin-coated urea were thoroughly mixed at a mass ratio of 5:5 to obtain a slow-release fertilizer. The sulfur-coated urea was a slow-release fertilizer with a nitrogen mass percentage of 37%, and the 2-month resin-coated urea was a controlled-release fertilizer with a nitrogen mass percentage of 43% and a nutrient supply period of 2 months.

[0032] Example 2

[0033] From March to July 2024, the inventors conducted field trials at the Shanggao Rice Science and Technology Courtyard (114.92E, 28.22N) in Yichun City, Jiangxi Province; the trial variety was Xiangzaoxian 45.

[0034] From January to April 2024, the inventors conducted field trials at the Batou Comprehensive Experimental Base (109.14E, 18.39N) in Yazhou District, Sanya City, Hainan Province; the tested variety was Jingjingxiang No. 8.

[0035] Each ecological site was set up with three treatments: treatment group, control group 1, and control group 2.

[0036] Treatment group: The slow-mixed fertilizer used in Example 1 for machine-transplanted early rice in low-latitude regions was applied. The nitrogen fertilizer application rate was the same as the local nitrogen application rate (Table 1). At the same time as transplanting, the slow-mixed fertilizer was applied in one go to a depth of 3-5 cm in the soil and 5 cm from the base of the seedlings using a side-deep fertilization machine. The phosphorus and potassium fertilizer application rates were the same as the local application rates, applied as a single basal application. Alternating wet and dry water management was adopted, and the management of diseases, pests, and weeds was the same as that of high-yield areas in the region.

[0037] Control group 1: Urea (46%) was used as the test nitrogen source. The amount of nitrogen applied was the same as that of the treatment group. Conventional high-yield fertilizer was applied manually in multiple applications. The fertilizer was applied three times in the ratio of base fertilizer: tillering fertilizer: panicle fertilizer (4:3:3). The amount of phosphorus and potassium fertilizer was the same as that of the treatment group. The fertilizer was applied as a base fertilizer in one application.

[0038] Control group 2: No nitrogen fertilizer was applied, and all other conditions were the same as the treatment group.

[0039] Table 1. Rice varieties and local fertilizer application rates in different ecological locations

[0040]

[0041] The experimental results of the treatment group, control group 1, and control group 2 were measured.

[0042] (1) Determination of actual rice yield: At the rice maturity period, 100 holes were actually cut at the center of each of the three treatment plots. After drying, the grain quality and moisture content were measured, and then the actual yield was calculated at 13.5%.

[0043] (2) Biomass determination: At the rice maturity period, 3 plants were taken as a sample for each treatment, and the samples were repeated 3 times. The panicle and stem were separated, blanched at 105℃ for 30 minutes, and then dried at 70℃ to constant weight. The dry weight of the panicle and the total dry weight of the stem and leaves were obtained.

[0044] (3) Determination of plant nitrogen content: The dried samples of each treatment were crushed and the nitrogen content of the spike and stems and leaves was determined by Kjeldahl method.

[0045] (4) Greenhouse gas measurement: The static chamber-gas chromatography method was used to measure the concentration of CO2 and CH4 in the paddy field every 7 days after rice transplanting. The cumulative greenhouse gas emissions during the entire growth period were calculated based on the greenhouse gas concentration.

[0046] Calculation formula:

[0047] Nitrogen fertilizer use efficiency (NUE) = (Nitrogen uptake in the nitrogen-applied area - Nitrogen uptake in the control area) / Nitrogen application rate × 100%;

[0048] In the formula, the nitrogen application zone refers to the treatment group and control group 1; the blank zone refers to control group 2.

[0049]

[0050] In the formula, f represents the total emissions of different greenhouse gases during the entire rice growing season. Since the CO2 fixed by crop photosynthesis returns to the atmosphere as CO2 from respiration, agriculture is generally considered a zero-cycle system for CO2. Therefore, the calculation of greenhouse gas emissions per unit area in this invention only considers the two main greenhouse gases, CH4 and N2O.

[0051]

[0052] In the formula, Y represents the total yield of rice.

[0053] Table 2. Effects of slow-mixed fertilizers on nitrogen accumulation and nitrogen uptake (NUE) in rice.

[0054]

[0055] The experimental results showed that in the field trial in Jiangxi Province, the rice yield of the treatment group was 7693.11 kg·ha. -1 It was significantly higher than the control group 2's 4146.9 kg·ha -1 Compared with control group 1, 7139.9 kg·ha -1 In field trials in Hainan Province, the rice yield of the treatment group was 6899.31 kg·ha. -1 The concentration was significantly higher than that of control group 2, which was 2513.7 kg·ha. -1 Compared with control group 1, 6420.5 kg·ha -1 ( Figure 1 ).

[0056] The results of stage nitrogen accumulation and NUE (Table 2) showed that the total nitrogen accumulation and NUE of the treatment groups were significantly higher than those of the control group. Compared with control group 1, the stage nitrogen accumulation of the treatment groups was significantly increased. In addition, the NUE of the treatment groups in Jiangxi Province and Hainan Province were 49.2% and 44.9%, respectively, which were increased by 30.5% and 44.5%, respectively, indicating that a single application of the slow-mixed fertilizer of this invention can better meet the nitrogen requirements of rice throughout its entire growth period. In addition, analysis of GWP and GHGI revealed that ( Figure 2 , Figure 3 Compared with control group 1, the GWP of the Jiangxi Province and Hainan Province treatment groups decreased by 12.8% and 27.5% respectively, and the GHGI decreased by 19.3% and 32.7% respectively, indicating that a single application of the slow-mixed fertilizer of this invention can effectively reduce greenhouse gas emissions from rice.

[0057] In summary, applying a slow-mixed fertilizer consisting of sulfur-coated urea and 2-month resin-coated urea at a mass ratio of 5:5 in a single application to machine-transplanted early rice in low-latitude regions can significantly reduce total greenhouse gas emissions while increasing yield and nitrogen fertilizer utilization efficiency. This is a cost-effective, efficiency-enhancing, and environmentally friendly nitrogen fertilizer management method.

Claims

1. A slow-mixed fertilizer suitable for increasing yield and reducing emissions of machine-transplanted early rice in low-latitude regions, characterized in that: It is composed of the following parts by weight of sulfur-coated urea and 2-month resin-coated urea: 4-6 parts sulfur-coated urea and 4-6 parts 2-month resin-coated urea; wherein the sulfur-coated urea is a slow-mixed fertilizer with a nitrogen mass percentage of 37%; and the 2-month resin-coated urea is a controlled-release fertilizer with a nitrogen mass percentage of 43% and a nutrient supply period of 2 months or a fertilizer effect period of 60 days.

2. The slow-mixed fertilizer for increasing yield and reducing emissions of machine-transplanted early rice in low-latitude regions according to claim 1, characterized in that: It consists of the following parts by weight of sulfur-coated urea and 2-month resin-coated urea: 4.8 to 5.5 parts of sulfur-coated urea and 4.8 to 5.5 parts of 2-month resin-coated urea.

3. The slow-mixed fertilizer for increasing yield and reducing emissions of machine-transplanted early rice in low-latitude regions according to claim 2, characterized in that: It consists of the following parts by weight of sulfur-coated urea and 2-month resin-coated urea: 5.0 parts sulfur-coated urea and 5.0 parts 2-month resin-coated urea.

4. A method for preparing a slow-mixed fertilizer as described in claim 1, suitable for increasing yield and reducing emissions of machine-transplanted early rice in low-latitude regions, characterized in that: include: The sulfur-coated urea and 2-month resin-coated urea were thoroughly stirred and mixed according to the formula to obtain the final product.

5. The application of the slow-mixed fertilizer of claim 1, which is suitable for increasing yield and reducing emissions of machine-transplanted early rice in low-latitude regions, in early rice production.

6. The application according to claim 5, characterized in that: The slow-mixed fertilizer is applied to machine-transplanted early rice in low-latitude regions.

7. The application according to claim 5, characterized in that: The nitrogen application rate of the slow-mixed fertilizer shall be in accordance with the local conventional nitrogen application rate.

8. The application according to claim 5, characterized in that: The application of the slow-mixed fertilizer is carried out simultaneously with rice transplanting. The slow-mixed fertilizer is applied directly to the seedlings at a depth of 3-5 cm and 5 cm from the root zone.

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