A foliar fertilizer for improving the yield of rice and the quality of rice straw and a preparation method thereof

Abstract

The present application belongs to the technical field of rice fertilizer, and particularly relates to a foliar fertilizer for improving the yield of rice straw and the feeding quality of rice straw and a preparation method thereof. The foliar fertilizer comprises the following components in parts by weight: 3-8 parts of sodium alginate, 2-5 parts of compound amino acid, 0.1-0.5 parts of organic silicon additive, 0.1-0.5 parts of potassium dihydrogen phosphate, 2-10 parts of pyruvic acid and 100 parts of solvent. In the preparation process, the sodium alginate, the compound amino acid, the potassium dihydrogen phosphate and the pyruvic acid are mixed, and the organic silicon additive is added before use, so as to avoid the gelation caused by the long-time contact between the organic silicon additive and the high-concentration sodium alginate in the mother liquor. Through the research on the relationship between the nutritional components of the foliar fertilizer and the yield of rice straw and the feeding quality of rice straw, the suitable nutritional components and the matching are selected, so that the yield of rice straw is improved and the feeding quality of the harvested rice straw is ensured.

Description

Technical Field

[0001] This invention belongs to the field of rice fertilizer technology, specifically relating to a foliar fertilizer for improving rice straw yield and straw feed quality, and its preparation method. Background Technology

[0002] Globally, approximately 975 million tons of rice straw are produced annually, with my country producing around 190 million tons. The main methods of disposal are returning it to the field, collecting it for compost, or burning it. Meanwhile, there is a shortage of roughage to varying degrees worldwide; and in some agricultural areas of my country, forage production competes with food crops for land. Utilizing rice straw as feed not only helps reduce resource waste and environmental pollution but also alleviates the conflict between forage production and food security.

[0003] However, rice straw is low in digestible feed components such as crude protein (CP), soluble carbohydrates (WSC), and starch, while it is high in fibrous materials (such as neutral detergent fiber (NDF) and acid detergent fiber (ADF)) and has a dense and complex structure, making it difficult for animals to degrade and digest. Therefore, improving the feed quality of rice straw through cultivation techniques and increasing its feed utilization rate, while ensuring normal rice production, is an effective way to resolve the above contradictions.

[0004] Several rice foliar fertilizers have been reported in the prior art. For example, CN120483796A discloses a rice foliar fertilizer containing chitin derivatives, compound amino acids, sodium alginate, potassium silicate, and other components, mainly used to increase the β-glucan content in rice. CN103524236A discloses a foliar fertilizer rich in seaweed extract and amino acid chelated trace elements. However, the above-mentioned existing foliar fertilizers are all mainly aimed at promoting rice growth or improving rice quality, and no foliar fertilizer products have been found that systematically improve the quality of rice straw for feed, such as crude protein content, fiber content, and starch content.

[0005] Therefore, developing a foliar fertilizer that can effectively improve the quality of rice straw for feed while increasing the yield of rice straw is of great practical significance and application value. Summary of the Invention

[0006] To address the technical problem that existing rice foliar fertilizers cannot improve the feed quality of rice straw, this invention provides a foliar fertilizer and its preparation method for improving rice straw yield and feed quality. By studying the relationship between the nutrient components of the foliar fertilizer and the quality of the rice straw, and selecting appropriate nutrient components and ratios, it is possible to both increase rice yield and ensure the feed quality of harvested rice straw.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A foliar fertilizer for improving rice straw yield and forage quality is characterized in that the foliar fertilizer comprises the following components by weight: 3-8 parts sodium alginate, 2-5 parts compound amino acids, 0.1-0.5 parts organosilicon adjuvant, 0.1-0.5 parts potassium dihydrogen phosphate, 2-10 parts pyruvic acid, and 100 parts solvent.

[0009] Inventive Concept: As mentioned in the background section, existing research on rice foliar fertilizers focuses on improving rice yield and quality, with little research on regulating the feed quality of rice straw. The regulatory role of active components in foliar fertilizers on the accumulation of key feed components in rice straw is not yet fully understood. The inventors of this application noted that since foliar fertilizers can alter the nutrient accumulation pattern in the aboveground parts of rice, the nutrient content of straw, as a major component of aboveground biomass at harvest, must also be subject to the differentiated regulation of nutrient ratios by foliar fertilizers. Therefore, researching the impact of the nutrient composition and content of foliar fertilizers on the feed value of straw has become crucial.

[0010] Further research by the inventors of this application revealed that enhanced photosynthetic carbon assimilation capacity signifies an increase in the overall carbon skeleton synthesis of the plant. Increased antioxidant enzyme activity helps delay functional leaf senescence and prolongs the transport and distribution time of photosynthetic products to various sink organs (including the stem). The combined effects of these two aspects may jointly promote the accumulation of structural carbohydrates, non-structural carbohydrates, and nitrogen-containing compounds in the stem, thus positively impacting the nutritional value of straw for feed while simultaneously increasing rice yield. Foliar fertilizer treatment significantly increased the chlorophyll content of rice leaves, and the green retention advantage in the later stages of growth provides a photosynthetic basis for grain filling and nutrient accumulation. In summary, the core mechanism by which foliar fertilizer delays chlorophyll degradation in the later stages of growth is that exogenous nutrients or active substances, after absorption by the leaves, directly participate in or indirectly regulate the metabolic balance between chlorophyll synthesis and decomposition, prolonging the functional period of photosynthetic organs. The differences in the effects of different types of foliar fertilizers depend on their nutrient ratios, active ingredients, and interaction characteristics with the crop genotype. Spraying foliar fertilizer to delay leaf senescence is an important way to increase the CP content of rice straw.

[0011] Therefore, the inventors of this application selected sodium alginate, compound amino acids, organosilicon adjuvants, potassium dihydrogen phosphate, and pyruvic acid in the foliar fertilizer formulation. Sodium alginate, a natural polysaccharide, can assist in chelating trace elements and forming a breathable film, facilitating nutrient entry into rice. Simultaneously, sodium alginate provides organic nutrients; an appropriate ratio of organic and inorganic fertilizers can synergistically improve leaf photosynthetic rate and nitrogen fertilizer agronomic utilization rate. Compound amino acids can be directly absorbed by leaves, quickly replenishing nitrogen sources and organic nutrients, promoting photosynthesis. At the same time, some amino acids participate in osmotic regulation, helping rice cope with adversity, acting as a fast-acting nitrogen source, trace element carrier, and adversity regulator. The controlled-release compound amino acids, when properly blended, can meet the nutrient needs of rice throughout its entire growth period, indirectly ensuring the continuous and efficient operation of the photosynthetic system. Under abiotic stress, the compensatory effect of foliar regulation on photosynthetic performance is more pronounced. Organosilicon adjuvants can reduce the surface tension of the solution, promoting the spread and penetration of foliar fertilizer on rice leaves, increasing the absorption area, and helping nutrients enter the leaves. Meanwhile, rice, as a silicon-loving crop, benefits from silicon, which forms silicified cell walls, strengthens stems, thickens the epidermis, enhances disease and pest resistance, improves plant type, and increases light energy utilization. Potassium dihydrogen phosphate (KH2PO4) is a high-purity, highly soluble binary phosphorus and potassium fertilizer, a classic component of foliar fertilizers. Rice has critical phosphorus requirements during the tillering, booting, and grain-filling stages. KH2PO4 can supplement potassium, strengthen stems, increase grain size, regulate stomatal opening and closing, and activate enzymes, enhancing stress resistance, promoting the translocation of photosynthetic products to grains, increasing thousand-grain weight and seed setting rate, strengthening stem toughness, reducing lodging, and forming a synergistic effect with amino acids, making it a core mineral nutrient source. In this invention, because rice leaves contain a large number of silicon cells and waxes and are highly hydrophobic, a high proportion of sodium alginate is used as the main component to improve the adhesion and duration of the foliar fertilizer. The addition of pyruvate to the foliar fertilizer promotes carbon metabolism, increasing straw yield and the quality of rice straw forage.

[0012] Furthermore, the complex amino acid includes two or three of glutamic acid, glycine, and aspartic acid.

[0013] Furthermore, the organosilicon additive is potassium silicate or polyether-modified trisiloxane. In this invention, potassium silicate also serves as a silicon nutrient supplement. Polyether-modified trisiloxane offers superior spreading and penetration. In practical applications, the choice can be made based on cost, compatibility, and target effect.

[0014] Furthermore, the foliar fertilizer has a pH of 5-8, preferably 5.5-6.5. In this invention, excessively high or low pH values ​​can affect the absorption of nutrients by rice and may also harm the rice plants. Within the preferred weakly acidic range, silicic acid and amino acids can be stabilized, and the absorption efficiency of phosphorus and potassium can be improved.

[0015] A method for preparing a foliar fertilizer to improve the yield and quality of rice straw for feed includes the following steps: Step 1: Dissolve sodium alginate and compound amino acids separately to prepare sodium alginate solution and compound amino acid solution; Step 2: Dissolve potassium dihydrogen phosphate and pyruvic acid, and after complete dissolution, add sodium alginate solution and compound amino acid solution to them, and mix evenly under continuous stirring to prepare a mixed solution; Step 3: Dilute the mixed solution, and after dilution, add organosilicon adjuvant solution under stirring to obtain working solution, and add pH adjuster to adjust the pH of working solution to obtain foliar fertilizer spray solution.

[0016] Furthermore, in step one, the concentration of the sodium alginate solution is 20-25% (w / v), and the concentration of the composite amino acid solution is 20-30% (w / v).

[0017] Furthermore, in step two, the final concentration of sodium alginate in the mixed solution is 3-8% (w / v), the final concentration of the complex amino acids is 2-5% (w / v), the final concentration of potassium dihydrogen phosphate is 0.1-0.5% (w / v), and the final concentration of pyruvate is 2-10% (w / v).

[0018] Furthermore, in step three, the mixed solution is diluted by 500 to 600 times, and the concentration of the organosilicon additive solution is 1 to 10% (w / v).

[0019] Furthermore, the pH adjuster is a citric acid or phosphoric acid solution.

[0020] Beneficial effects:

[0021] The foliar fertilizer provided by this invention can effectively increase the content of digestible components such as crude protein, soluble sugars, and starch in rice straw, while reducing the content of difficult-to-digest and degrade components such as NDF and ADF. This invention involves spraying the foliar fertilizer during the later stages of rice growth, which prolongs the functional period of leaves, thereby increasing chlorophyll content and thus crude protein content. The extended leaf functional period also increases the storage of redundant photosynthetic products in the stems and leaves during the later stages of growth, thus increasing the content of soluble sugars and starches. Although cellulose, lignin, and other plant "skeleton" components mainly accumulate during the vegetative growth period, their percentage content is reduced due to the increased content of crude protein, starch, and soluble sugars. Therefore, the foliar fertilizer provided by this invention can significantly improve the straw feed quality and rice straw yield of both glutinous and japonica rice, achieving the goal of "improved straw quality + increased rice straw yield." Furthermore, the foliar fertilizer of this invention has significant quality improvement and yield-increasing effects on both glutinous and japonica rice. The application time is chosen to be 2-3 weeks after rice flowering, in the evening on a rainless day. The operation is simple and suitable for large-scale application. The cost of the foliar fertilizer of this invention is only about 3 yuan per acre, while the cost of drone spraying is about 20 yuan. The income from the increased rice yield alone is about 200 yuan, not including the value of the improved straw production. The increased income significantly exceeds the expenditure. In contrast, the cost of commercially available foliar fertilizers is as high as 40 yuan per acre, far exceeding that of this invention, and their effect on improving straw production is significantly lower than that of the foliar fertilizer provided by this invention. Detailed Implementation

[0022] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the specific implementation methods according to the present invention will be described in detail below with reference to embodiments and experimental examples.

[0023] Example 1

[0024] This embodiment provides a foliar fertilizer for improving rice straw yield and forage quality. The foliar fertilizer comprises the following components by weight: 5 parts sodium alginate, 3 parts compound amino acids, 0.1 parts organosilicon adjuvant, 0.3 parts potassium dihydrogen phosphate, 5 parts pyruvic acid, and 100 parts solvent. The organosilicon adjuvant is potassium silicate, the compound amino acids are glutamic acid, glycine, and aspartic acid prepared in a mass ratio of 1:1:1, and the solvent is purified water or softened water to avoid gelation of sodium alginate caused by calcium and magnesium ions.

[0025] This embodiment also provides a method for preparing a foliar fertilizer to improve the yield and feed quality of rice straw, including the following steps:

[0026] Step 1: Dissolve sodium alginate and compound amino acids separately to prepare sodium alginate solution and compound amino acid solution;

[0027] Specifically, weigh 5g of sodium alginate, add 25ml of softened water at 40℃, and stir while adding to allow it to swell and dissolve completely, resulting in a viscous sodium alginate solution for later use.

[0028] Weigh 3g of the compound amino acid, add 15ml of softened water at room temperature, and stir until completely dissolved to obtain a compound amino acid solution for later use.

[0029] Step 2: Dissolve potassium dihydrogen phosphate and pyruvic acid. After complete dissolution, add sodium alginate solution and compound amino acid solution and mix evenly with continuous stirring to form a mixed solution.

[0030] Specifically, weigh 0.3g of potassium dihydrogen phosphate and 5g of pyruvate, dissolve them together in 10ml of softened water, and stir until completely dissolved. Transfer the sodium alginate solution, the compound amino acid solution, and the potassium dihydrogen phosphate / pyruvate mixed solution to the same 100ml volumetric flask. Rinse each dissolving container separately with a small amount of soft water, transferring the rinsing solution into the flask. Finally, add soft water to bring the total volume to 100ml, shake thoroughly, and the mixed solution is obtained. The final concentrations of sodium alginate, compound amino acids, potassium dihydrogen phosphate, and pyruvate in the mixed solution are 5% (w / v), 3% (w / v), 0.3% (w / v), and 5% (w / v).

[0031] Step 3: Dilute the mixed solution, add the organosilicon adjuvant solution while stirring to obtain the working solution, and add pH adjuster to adjust the pH of the working solution to obtain the foliar fertilizer spray solution.

[0032] Specifically, take 10 ml of the above mixed solution and slowly pour it into 5 L of soft water to dilute it 500 times, stirring until homogeneous. While stirring vigorously, slowly add potassium silicate solution dropwise to the diluted solution. The potassium silicate solution contains 0.1 g of potassium silicate, with a volume of 5 ml. Given the strong alkalinity of potassium silicate, to avoid gelation caused by prolonged contact with high-concentration sodium alginate in the mother liquor, potassium silicate is not added to the above mixed solution but is added as a separate component when preparing the working solution just before use. This sequence ensures that potassium silicate is instantly dispersed in a large amount of water, avoiding localized over-alkalinity, thereby effectively protecting the structural stability of sodium alginate and amino acids.

[0033] After preparing the solution as described above, use pH test paper to check the pH value, ensuring it remains between 5 and 8. A pH that is too high or too low will affect nutrient absorption and may even harm the plant. If the pH is too high, add a few drops of citric acid or phosphoric acid solution to adjust it to the optimal foliar absorption range of slightly acidic (5.5-6.5). This not only stabilizes potassium silicate but also amino acids and improves the absorption efficiency of phosphorus and potassium. The working solution in the sprayer is the final foliar spray solution. The actual usage concentrations of each component in this working solution are precisely as follows: sodium alginate: 100 ppm, compound amino acids: 60 ppm, potassium dihydrogen phosphate: 6 ppm, pyruvic acid: 100 ppm, and potassium silicate: 2 ppm.

[0034] Example 2

[0035] This embodiment provides a foliar fertilizer for improving rice straw yield and forage quality. The foliar fertilizer comprises the following components by weight: 5 parts sodium alginate, 3 parts compound amino acids, 0.1 parts organosilicon adjuvant, 0.3 parts potassium dihydrogen phosphate, 2 parts pyruvic acid, and 100 parts solvent. The organosilicon adjuvant is potassium silicate, the compound amino acids are glutamic acid, glycine, and aspartic acid prepared in a 1:1:1 mass ratio, and the solvent is purified water or softened water to avoid gelation of sodium alginate caused by calcium and magnesium ions. Other preparation steps are the same as in Example 1.

[0036] Example 3

[0037] This embodiment provides a foliar fertilizer for improving rice straw yield and forage quality. The foliar fertilizer comprises the following components by weight: 5 parts sodium alginate, 3 parts compound amino acids, 0.1 parts organosilicon adjuvant, 0.3 parts potassium dihydrogen phosphate, 8 parts pyruvic acid, and 100 parts solvent. The organosilicon adjuvant is potassium silicate, the compound amino acids are glutamic acid, glycine, and aspartic acid prepared in a mass ratio of 1:1:1, and the solvent is purified water or softened water to avoid gelation of sodium alginate caused by calcium and magnesium ions. Other preparation steps are the same as in Example 1.

[0038] Comparative Example 1

[0039] The difference between this comparative example and Example 1 is that pyruvic acid was not added to the foliar fertilizer. All other steps are the same as in the example.

[0040] Comparative Example 2

[0041] The difference between this comparative example and Example 1 is that a commercial foliar fertilizer containing amino acids was used. The fertilizer is available in 500g bottles, diluted 800 times with water, and applied at a rate of 2000g per acre.

[0042] The foliar fertilizers prepared in Examples 1-3 and Comparative Example 1 were diluted with 100 ml of water to make 50 L of diluted solution before being sprayed. Examples 1-3, Comparative Example 1, Comparative Example 2, and a blank control (sprayed with water) were set up for fertilization. Each group included two rice varieties: conventional japonica rice Nanjing 46 and glutinous rice Zhennuo 29, with three experimental plots for each variety, each plot measuring 1.5 m × 1.5 m. The spraying volume for Examples 1 and Comparative Example 1 was 500 ml of diluted solution per experimental plot. The spraying volume for the blank control was 500 ml of water per experimental plot.

[0043] Foliar fertilizer should be sprayed 2 weeks and 3 weeks after rice flowering, under the condition of spraying in the evening on a rainless day.

[0044] After the rice matures normally, the yield of rice grains and straw, as well as the feed quality of the straw, are measured to evaluate the yield and quality of the rice. The grain-to-straw ratio is measured simultaneously at harvest. The feed quality of the harvested straw is evaluated by measuring the content of soluble carbohydrates (WSC), starch, neutral detergent fiber (NDF), acid detergent fiber (ADF), and crude protein (CP).

[0045] The experimental results are shown in the table below:

[0046] Table 1. Effects of different treatments on the feed quality of glutinous rice straw.

[0047]

[0048] Results analysis:

[0049] The CP content of rice straw in Comparative Example 1 and Example 1 was 9.08% and 9.45%, respectively, which were 57.2% and 63.6% higher than that of the control (5.78%), respectively, and the differences were highly significant (P<0.01). The CP of Comparative Example 2 was 8.50%, which was significantly lower than that of the two self-developed formulations (P<0.05).

[0050] In Example 1, the NDF (54.80%) and ADF (32.74%) were the lowest among all treatments, decreasing by 5.2% and 1.7% respectively compared to the control (CK). The significant reduction in NDF (P<0.05) indicates a decrease in straw cell wall content and improved animal digestibility. In contrast, Comparative Example 1 (NDF 62.50%) and Comparative Example 2 (NDF 59.74%) had higher fiber content than the control (CK), indicating lower feed value.

[0051] There was no significant difference in WSC content among the treatments (F=5.10, P>0.05), but the WSC content in Example 1 (10.77%) was higher than that in CK (10.40%) and Comparative Example 2 (9.86%). WSC is a substrate for silage fermentation, and the slightly higher WSC content in Example 1 is beneficial to silage quality.

[0052] Example 1 showed the highest starch content (4.77%), which was 15.5% higher than Comparative Example 2 (4.13%) (P<0.05) and 4.8% higher than CK (4.55%) (not significant). Starch is an energy storage substance in rice straw, and its increased content means an increase in the metabolizable energy value of the rice straw.

[0053] The straw feed quality traits of Example 2 were lower than those of Example 1, while the straw feed quality traits of Example 3 were not significantly different from those of Example 1 (P>0.05), but both Examples 2 and 3 were significantly higher than the comparative example (P<0.05).

[0054] Example 1 achieved a treatment that simultaneously provided "high protein, low fiber, and high energy," resulting in the optimal overall quality of the rice straw for feed. Comparative Example 1, while having a high protein content, had excessively high fiber content, limiting its feed value. Comparative Example 2 showed poor quality of glutinous rice straw for feed.

[0055] Table 2. Effects of different treatments on the feed quality of japonica rice straw.

[0056]

[0057] Results analysis: Example 1 showed the highest CP content (5.05%), which was 16.5% higher than the control (4.33%) and significantly better than all other treatments (P<0.05). Comparative Example 1 (4.87%) and Comparative Example 2 (4.87%) showed no significant difference, but were both significantly higher than the control (CK).

[0058] Unlike glutinous rice, the NDF and ADF in the straw of japonica rice in Comparative Example 2 were the lowest, decreasing by 7.2% and 10.2% respectively compared to the control (CK), with significant differences (P<0.05). The NDF (65.02%) and ADF (40.95%) in Example 1 were in the middle, significantly lower than the control but higher than Comparative Example 2. Comparative Example 1 was the next best.

[0059] Comparative Example 2 (WSC) showed the highest rate (6.83%), which was 34.1% higher than the control (CK) and significantly higher than other treatments (P<0.05). Example 1 (5.52%) and Comparative Example 1 (5.26%) showed no significant difference from the control (CK) (5.10%).

[0060] The starch content of Example 1 (4.18%) and Comparative Example 2 (3.91%) was significantly higher than that of CK (3.05%) (P<0.05), and the starch content of Example 1 was significantly higher than that of Comparative Example 2 (P<0.05), with increases of 36.8% and 27.9%, respectively. Comparative Example 1 (3.48%) was in the middle range.

[0061] The straw feed quality traits of Example 2 were lower than those of Example 1, while the straw feed quality traits of Example 3 were not significantly different from those of Example 1 (P>0.05), but both Examples 2 and 3 were significantly higher than the comparative example (P<0.05).

[0062] Example 1 ranked first in both CP and starch, the two most important energy / protein indicators, achieving an improved quality of rice straw feed with "high protein + high starch". Comparative Example 2 had advantages in reducing fiber and increasing WSC, but its CP and starch were not as good as Example 1.

[0063] Table 3 Comparison of feed quality of glutinous rice and japonica rice straw

[0064]

[0065] Results analysis: The CP, WSC, and starch contents of glutinous rice straw were 71.5%, 75.0%, and 23.3% higher than those of japonica rice, respectively, while the NDF and ADF were 10.1% and 16.4% lower, respectively. All indicators showed significant or highly significant differences among varieties. Glutinous rice straw performed better; from the perspective of roughage grading, glutinous rice straw (CP > 8%, NDF < 60%) has reached the standard for medium to high quality roughage.

[0066] Table 4. Sensitivity of two types of rice to foliar fertilizer treatment

[0067]

[0068] Results Analysis: Further comparison of the sensitivity of the two rice varieties to foliar fertilizer treatment showed that glutinous rice showed a CP increase of 63.6% under Example 1, which was 3.9 times that of japonica rice (16.5%); while japonica rice showed a starch increase of 36.8% under Example 1, which was 7.7 times that of glutinous rice (4.8%). This indicates that glutinous rice straw CP is more sensitive to exogenous foliar fertilizer, while japonica rice straw starch responds more strongly to exogenous regulation.

[0069] Table 5. Effects of different treatments on glutinous rice yield (mean ± standard deviation, kg / mu)

[0070]

[0071] Results Analysis: Table 5 shows that different treatments significantly affected the fresh straw yield, dry matter yield, and rice yield of glutinous rice. Example 1 showed the highest fresh straw yield (4929.68 kg / hm²), a 14.7% increase compared to Control Example 2, significantly higher than both CK and Control Example 2 (P<0.05); Control Example 1 (4551.68 kg / hm²) showed no significant difference compared to other treatments. Regarding dry matter yield, Example 1 showed the highest (1509.86 kg / hm²), significantly higher than all other treatments (P<0.01). Example 1 also showed the highest rice yield (1870.44 kg / hm²), a 6.9% increase compared to CK, significantly higher than both CK and Control Example 2 (P<0.05); Control Example 1 (1842.46 kg / hm²) showed a 5.3% increase compared to CK, but the difference was not statistically significant. This indicates that Example 1 had the most stable yield-increasing effect on glutinous rice.

[0072] Table 6. Effects of different treatments on japonica rice yield (mean ± standard deviation, kg / hm²)

[0073]

[0074] Results Analysis: Table 6 shows that all treatments had highly significant effects on the yield indicators of japonica rice (P<0.01). Comparative Example 2 showed the highest fresh grass yield (4589.54 kg / hm²), an increase of 26.0% compared to the control (CK), significantly higher than other treatments (P<0.01). There was no significant difference between Comparative Example 1 and Example 1, both significantly higher than the control (CK). The trend of dry matter yield was consistent with that of fresh grass, with Comparative Example 2 showing the highest yield, followed by Comparative Example 1 and Example 1. Comparative Example 1 showed the highest rice yield (1734.12 kg / hm²), an increase of 27.8% compared to the control (CK), significantly higher than all other treatments (P<0.01). There was no significant difference between Example 1 (1673.32 kg / hm²) and Comparative Example 2 (1637.90 kg / hm²), but both were significantly higher than the control (yield increases of 23.4% and 20.8%, respectively).

[0075] The results indicate that Comparative Example 2 significantly promoted vegetative growth in japonica rice, but its rice yield increase was lower than that of Comparative Example 1 and Example 1, suggesting that its assimilates were allocated more to the stems and leaves than to the grains. Comparative Example 1 showed a clear advantage in promoting efficient translocation of assimilates to the grains, achieving the highest rice yield among all treatments.

[0076] Table 7 Effects of different treatments on the cereal-to-straw ratio

[0077]

[0078] Results Analysis: The grain-to-straw ratio (rice yield / dry matter yield) reflects the efficiency of assimilate distribution to grains. Table 7 shows that in japonica rice, Comparative Example 1 had the highest grain-to-straw ratio (1.292), an increase of 11.8% compared to the control (CK) (1.156), indicating that Comparative Example 1 significantly promoted the translocation of assimilates from stems and leaves to grains; Example 1 was second highest (1.269), while Comparative Example 2 (1.151) was basically the same as the control. In glutinous rice, the differences in grain-to-straw ratio among treatments were small, with Comparative Example 1 being slightly higher (1.303). Although Comparative Example 2 had the largest biomass, its grain-to-straw ratio did not increase, indicating that its yield increase mainly came from vegetative expansion rather than an increase in the harvest index; while Comparative Example 1 (especially japonica rice) significantly increased the grain-to-straw ratio, demonstrating the advantage of "source-sink coordination".

[0079] Three weeks after rice flowering, the foliar fertilizer of Example 1 (5% sodium alginate + 3% compound amino acids (30ml solution) + 0.1% organosilicon adjuvant (potassium silicate) + 0.3% potassium dihydrogen phosphate + 5% pyruvic acid) was sprayed at a rate of 296ml per mu, which significantly improved the straw feed quality and rice yield of glutinous rice and japonica rice. Among them, glutinous rice straw feed quality showed the best overall performance: CP reached 9.45% (63.6% higher than CK), NDF decreased to 54.80% (5.2% lower than CK), starch reached 4.77% (15.5% higher than Comparative Example 2), and rice yield increased by 6.9%, achieving the win-win goal of "improved straw feed quality + increased rice straw yield". The cost of foliar fertilizer per mu (approximately 0.067 hectares) is about 3 yuan, while the cost of drone spraying is about 20 yuan. The income from the increased rice yield alone is about 200 yuan, not including the rice straw production that improves feed quality. Therefore, the increased income significantly exceeds the expenditure. The cost of commercial foliar fertilizer per mu is 40 yuan, which is much higher than in Example 1, and its effect on improving rice straw production is significantly lower than in Example 1.

[0080] In summary, the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A foliar fertilizer for improving rice straw yield and forage quality, characterized in that, The foliar fertilizer comprises the following components by weight: 3-8 parts sodium alginate, 2-5 parts compound amino acids, 0.1-0.5 parts organosilicon adjuvant, 0.1-0.5 parts potassium dihydrogen phosphate, 2-10 parts pyruvic acid, and 100 parts solvent.

2. The foliar fertilizer for improving rice straw yield and forage quality according to claim 1, characterized in that, The complex amino acid includes two or three of the following: glutamic acid, glycine, and aspartic acid.

3. The foliar fertilizer for improving rice straw yield and forage quality according to claim 1, characterized in that, The organosilicon additive is potassium silicate or polyether-modified trisiloxane.

4. The foliar fertilizer for improving rice straw yield and forage quality according to claim 1, characterized in that, The pH of the foliar fertilizer is 5-8.

5. The method for preparing the foliar fertilizer for improving rice straw yield and forage quality according to any one of claims 1 to 4, characterized in that, Includes the following steps: Step 1: Dissolve sodium alginate and compound amino acids separately to prepare sodium alginate solution and compound amino acid solution respectively; Step 2: Dissolve potassium dihydrogen phosphate and pyruvic acid. After complete dissolution, add sodium alginate solution and compound amino acid solution to the solution and mix evenly with continuous stirring to prepare a mixed solution; Step 3: Dilute the mixed solution. After dilution, add organosilicon adjuvant solution while stirring to obtain working solution. Add pH adjuster to adjust the pH of working solution to obtain foliar fertilizer spray solution.

6. The method for preparing the foliar fertilizer for improving rice straw yield and forage quality according to claim 5, characterized in that, In step one, the concentration of the sodium alginate solution is 20-25% (w / v), and the concentration of the compound amino acid solution is 20-30% (w / v).

7. The method for preparing foliar fertilizer to improve rice straw yield and forage quality according to claim 6, characterized in that, In step two, the final concentration of sodium alginate in the mixed solution is 3-8% (w / v), the final concentration of compound amino acids is 2-5% (w / v), the final concentration of potassium dihydrogen phosphate is 0.1-0.5% (w / v), and the final concentration of pyruvic acid is 2-10% (w / v).

8. The method for preparing foliar fertilizer to improve rice straw yield and forage quality according to claim 7, characterized in that, In step three, the mixed solution is diluted by 500 to 600 times, and the concentration of the organosilicon additive solution is 1 to 10% (w / v).

9. The method for preparing foliar fertilizer to improve rice straw yield and forage quality according to claim 8, characterized in that, In step three, the pH adjuster is citric acid or phosphoric acid solution.

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