Environment-responsive intelligent controlled-release organic fertilizer and preparation method thereof

Abstract

The present application relates to an environment-responsive intelligent controlled-release organic fertilizer and a preparation method thereof, and belongs to the technical field of composite organic fertilizer. In order to solve the problem that the traditional soil improvement method cannot simultaneously improve the efficiency of phosphorus supply and the soil, the present application provides a preparation method of an environment-responsive intelligent controlled-release organic fertilizer. The method comprises the following steps: crushing and drying agricultural and forestry waste, and then placing the waste in a calcium source compound solution to complete preloading; drying and grinding to obtain a preloaded sample; pyrolyzing the preloaded sample in an inert atmosphere to obtain calcium-modified biochar; mixing the calcium-modified biochar with a phosphorus-containing solution to perform adsorption, thereby obtaining phosphorus-loaded biochar; and mixing the phosphorus-loaded biochar with peat and a binder, and then granulating and forming to obtain the organic fertilizer. The organic fertilizer has the environment-responsive characteristic, can adapt to the growth of crops in a three-stage phosphorus release mode, can reduce phosphorus fixation, can improve the soil structure, can stabilize the soil pH, and can improve the differentiation of the micro-niche ecological niche of the soil.

Description

Technical Field

[0001] This invention belongs to the field of compound organic fertilizer technology, and particularly relates to an environmentally responsive intelligent controlled-release organic fertilizer and its preparation method. Background Technology

[0002] Under the dual pressures of surging global food demand and excessive land reclamation, soil fertility degradation has become a core issue restricting sustainable agricultural development. While traditional phosphate fertilizer improvement technologies can quickly replenish soil phosphorus, they are caught in a dilemma where synergistic effects between phosphorus supply efficiency enhancement and soil improvement are difficult to achieve.

[0003] The adsorption characteristics of soil phosphorus determine that its availability is regulated by three factors: organic matter content, clay ratio, and pH value. Organic matter, as the main phosphorus adsorbent, increases available phosphorus by 5 mg / kg for every 0.5% increase in its content. However, high organic matter input is often accompanied by short-term mineralization, leading to the destruction of soil aggregate structure. Excessive application of phosphate fertilizer can cause the formation of a phosphate precipitation layer on the surface of soil clay particles. Although this increases the concentration of available phosphorus in the short term, it blocks soil pore connectivity, leading to the risk of compaction. This vicious cycle of phosphorus saturation and structural deterioration is particularly pronounced when the pH value deviates from the range of 5.5–7.0.

[0004] Phosphate fertilizer application has a dual impact on soil microorganisms. On the one hand, appropriate amounts of phosphorus can promote the reproduction of phosphorus-solubilizing microorganisms and enhance the mineralization capacity of organic phosphorus; on the other hand, excessive phosphorus input can inhibit the activity of nitrogen-fixing bacteria and mycorrhizal fungi, leading to obstruction of carbon and nitrogen cycles. Long-term field trials showed that soils treated with 150 kg / ha of P2O5 annually for three consecutive years experienced a 37% decrease in microbial biomass carbon and a 22% decrease in the diversity index of phosphorus-solubilizing bacteria communities compared to the control. This degradation of microbial function not only weakens the soil's self-sustaining fertility but also indirectly reduces the effective conversion rate of phosphorus by decreasing organic matter decomposition products.

[0005] There is a fundamental contradiction between crop growth cycles and phosphorus release rates. While fast-acting phosphate fertilizers can meet the critical nutrient requirements of crops, over 70% of them are fixed or leached during the same season. Slow-release phosphate fertilizers, although extending the phosphorus supply cycle, struggle to precisely match peak crop nutrient demands. Field monitoring shows that treatments using slow-release formulations such as ammonium polyphosphate only increase crop phosphorus uptake by 12% compared to ordinary superphosphate, while soil phosphorus residues increase by 31%. This phenomenon of delayed phosphorus supply and residue accumulation is further amplified in crop rotation systems, leading to the dual risks of phosphorus supply disruptions and environmental pollution for subsequent crops. Summary of the Invention

[0006] To address the problems of slow phosphorus release, low utilization rate, and difficulty in simultaneously improving soil structure associated with conventional organic fertilizers, this invention provides an environmentally responsive intelligent controlled-release organic fertilizer and its preparation method.

[0007] The technical solution of the present invention:

[0008] A method for preparing an environmentally responsive intelligent controlled-release organic fertilizer includes the following steps:

[0009] Step 1: After crushing and drying agricultural and forestry waste, the crushed material is placed in a calcium source compound solution, stirred to complete the pre-loading, dried and ground to obtain a pre-loaded sample.

[0010] Step 2: Pyrolyze the obtained pre-loaded sample under an inert atmosphere to obtain calcium-modified biochar;

[0011] Step 3: Mix the obtained calcium-modified biochar with a phosphorus-containing solution for adsorption to obtain phosphorus-loaded biochar;

[0012] Step 4: Mix the obtained phosphorus-loaded biochar with peat and air dry to obtain organic fertilizer.

[0013] Furthermore, the agricultural and forestry waste mentioned in step one is straw waste, shell waste, wood waste, or agricultural product processing residue waste; the particle size of the crushed material is 80 mesh.

[0014] Furthermore, the calcium source compound solution in step one is a calcium gluconate solution, the mass ratio of the pulverized material to calcium gluconate is 1:2~5; the pre-loading temperature is 40~60℃, the pre-loading stirring speed is 180rpm, and the pre-loading time is 12~24h.

[0015] Furthermore, the drying temperature in step one is 105°C, and the particle size of the preloaded sample obtained by grinding is 80 mesh.

[0016] Furthermore, the inert atmosphere in step two is a nitrogen atmosphere, the heating rate of the pyrolysis is 5℃ / min, the pyrolysis temperature is 200~400℃, and the pyrolysis time is 1~2h.

[0017] Furthermore, the phosphorus-containing solution in step three is a potassium dihydrogen phosphate solution with a concentration of 100~200 mg P / L, and the mass-volume ratio of the calcium-modified biochar to the phosphorus-containing solution is 0.1g:30mL~0.1g:50mL.

[0018] Furthermore, the adsorption temperature in step three is 25°C, the stirring speed during adsorption is 200 rpm, and the adsorption time is 24 h.

[0019] Furthermore, the mass ratio of phosphorus-loaded biochar to peat in step four is 1.8:5.

[0020] Furthermore, in step four, the air-drying temperature is controlled at 20–25°C, and the air-drying time is 48 hours.

[0021] An environmentally responsive intelligent controlled-release organic fertilizer prepared by the method described in this invention.

[0022] The beneficial effects of this invention are:

[0023] This invention constructs a chelate adsorption biphase system of peat and phosphorus-loaded biochar, effectively reducing phosphorus fixation and improving phosphorus storage efficiency. Simultaneously, relying on an environmentally responsive intelligent controlled-release mechanism, it achieves on-demand phosphorus supply. The composite structure formed by peat fibers and phosphorus-loaded biochar particles significantly improves soil pore connectivity and aeration. Combined with the dynamic pH buffering effect of peat and phosphorus-loaded biochar, it stabilizes the soil pH within the optimal range for crop growth. From phosphorus activation and soil structure improvement to acid-base balance regulation, it achieves synergistic enhancement of multiple soil functions, resolving the contradiction between phosphorus adsorption and fixation and soil structure improvement.

[0024] This invention utilizes an alternating aerobic and anaerobic microenvironment constructed through the pores of phosphorus-loaded biochar and the gaps between peat fibers to promote the coexistence of aerobic phosphate-solubilizing bacteria and anaerobic nitrogen-fixing bacteria, thus optimizing the soil microbial community structure. A gradient carbon source supply system ensures the sustainability of microbial activity. Its unique three-stage phosphorus release model and rhizosphere triggering mechanism precisely match the phosphorus requirements of crops, achieving spatiotemporal coupling of phosphorus supply and demand. The environmentally responsive intelligent controlled release can sense environmental signals such as rhizosphere exudates, rapidly activating peat-ferric phosphate inclusions, significantly increasing the phosphorus concentration in the rhizosphere microdomain within a short period, forming a positive feedback loop of phosphorus demand and release, significantly improving nutrient utilization efficiency and the nutrient supply capacity of the crop rhizosphere microdomain.

[0025] This invention uses agricultural and forestry waste biochar and waste peat as raw materials, employing low-temperature pyrolysis and granulation processes. This reduces production costs while achieving compatibility between the organic fertilizer and existing agricultural machinery, significantly improving field application efficiency. At the crop growth level, this organic fertilizer not only activates available phosphorus and potassium in the soil, driving aboveground growth and root development, but also alleviates salt-alkali stress through sodium fixation, enhancing the plant's ion-selective absorption capacity. Environmentally responsive intelligent controlled-release technology further improves resource utilization efficiency and reduces the risk of nutrient loss, ultimately creating a synergistic effect in saline-alkali land restoration and crop yield increase, possessing both ecological benefits and production application value. Attached Figure Description

[0026] Figure 1 The image shows a comparison of the germination of soybeans in five groups on the third day of planting in a pot experiment. A represents Group 1 of Example, B represents Group 2 of Example, C represents Group 3 of Example, D represents the control group, and E represents the peat moss group.

[0027] Figure 2 The image shows a comparison of the germination of soybeans in five groups on the 7th day of planting in a pot experiment. A represents Group 1 of Example, B represents Group 2 of Example, C represents Group 3 of Example, D represents the control group, and E represents the peat moss group.

[0028] Figure 3 The images show a comparison of the growth of soybean plants in five groups on day 14 of a pot experiment. A shows the overall growth of soybean plants, B shows the leaf area of ​​soybean canopy, and C shows the root morphology of soybeans.

[0029] Figure 4 A comparison of the total length of soybean plants in five groups of potted plants after sampling on day 21.

[0030] Figure 5 A comparison of the total fresh weight of soybean plants in five groups of potted plants after sampling on the 21st day of planting.

[0031] Figure 6 A comparison of the total dry weight of soybean plants in five groups of potted plants after sampling on the 21st day of planting.

[0032] Figure 7 A comparison chart of the total potassium ion content of soybean plants in five groups of soybean plants after sampling on the 21st day of planting in a pot experiment.

[0033] Figure 8 A comparison of potassium ion migration index of soybean plants in five groups of potted plants after sampling on day 21 of planting.

[0034] Figure 9 A comparison chart of the total sodium ion content of soybean plants in five groups of soybean plants after sampling on the 21st day of planting in a pot experiment.

[0035] Figure 10 A comparison of sodium ion migration index of soybean plants in five groups of potted plants after sampling on day 21 of planting.

[0036] Figure 11 Na, the soil sample from soybean plants in five potted experimental groups, harvested on day 21 after planting. + / K + Comparison chart;

[0037] Figure 12 Comparison of root system architecture of soybean plants in five groups of potted plants after sampling on day 21.

[0038] Figure 13 A comparison chart of potassium ion content in the soil of five groups of soybean plants after sampling on day 21 of the pot experiment.

[0039] Figure 14 A comparison chart of sodium ion content in the soil of five groups of soybean plants after sampling on day 21 in a pot experiment.

[0040] Figure 15 The soil Na content of the five groups of soybeans in the pot experiment was collected on the 21st day after planting. + / K + Comparison chart;

[0041] Figure 16 A comparison chart of available phosphorus content in the soil of five groups of soybean plants after sampling on day 21 of the pot experiment.

[0042] Figure 17 A comparison chart of available potassium content in the soil of five groups of soybean plants after sampling on day 21 of the pot experiment.

[0043] Figure 18 A comparison chart of total phosphorus content in soil samples taken from five groups of soybean plants on day 21 of a pot experiment.

[0044] Figure 19 A comparison of the total potassium content of the soil samples from the five groups of soybean plants in a pot experiment, taken on the 21st day after planting.

[0045] Figure 20 A comparison chart of the total potassium content of soybeans in five groups of soybeans after sampling on day 21 of the pot experiment.

[0046] Figure 21 This is a comparison chart of the total phosphorus content of soybeans in five groups of soybeans after sampling on day 21 of the pot experiment. Detailed Implementation

[0047] The technical solution of the present invention will be further described below with reference to embodiments, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention. In the following embodiments, the process equipment or apparatus not specifically specified are all conventional equipment or apparatus in the art. Unless otherwise specified, the raw materials used in the embodiments of the present invention are all commercially available; unless otherwise specified, the technical means used in the embodiments of the present invention are all conventional means well known to those skilled in the art.

[0048] Example 1

[0049] This invention provides a method for preparing an environmentally responsive intelligent controlled-release organic fertilizer, comprising the following steps:

[0050] Step 1: Crush wheat straw to 80 mesh, dry it at 105℃ to obtain crushed material, add 1g of crushed material and 2g of calcium gluconate to 80mL of water, preload it at 60℃ and stirring speed of 180rpm for 24h, dry it at 105℃, and grind it to 80 mesh to obtain preloaded sample.

[0051] Step 2: Place the obtained preloaded sample in a tube furnace and heat it to 400℃ at a heating rate of 5℃ / min under a nitrogen atmosphere. Pyrolyze for 2 hours to obtain calcium-modified biochar.

[0052] Step 3: Mix 0.1g of the obtained calcium-modified biochar with 40mL of potassium dihydrogen phosphate solution with a concentration of 200mg P / L, and adsorb at 25℃ and a stirring speed of 200rpm for 24h to obtain phosphorus-loaded biochar.

[0053] Step 4: Mix 1.8 g of the obtained phosphorus-loaded biochar with 5 g of peat, shape the mixture, and air-dry it naturally for 48 hours to obtain organic fertilizer.

[0054] The peat was purchased from Ningbo Xiaorang Ecological Technology Co., Ltd.

[0055] Example 2

[0056] This invention provides a method for preparing an environmentally responsive intelligent controlled-release organic fertilizer, comprising the following steps:

[0057] Step 1: Crush soybean straw to 80 mesh, dry at 105℃ to obtain crushed material, add 1g of crushed material and 4g of calcium gluconate to 80mL of water, preload at 60℃ and stirring speed of 180rpm for 24h, dry at 105℃, grind to 80 mesh to obtain preloaded sample.

[0058] Step 2: Place the obtained preloaded sample in a tube furnace and heat it to 400℃ at a heating rate of 5℃ / min under a nitrogen atmosphere. Pyrolyze for 2 hours to obtain calcium-modified biochar.

[0059] Step 3: Mix 0.1g of the obtained calcium-modified biochar with 40mL of potassium dihydrogen phosphate solution with a concentration of 200mg P / L, and adsorb at 25℃ and a stirring speed of 200rpm for 24h to obtain phosphorus-loaded biochar.

[0060] Step 4: Mix 1.8 g of the obtained phosphorus-loaded biochar with 5 g of peat, shape the mixture, and air-dry it naturally for 48 hours to obtain organic fertilizer.

[0061] Example 3

[0062] This invention provides a method for preparing an environmentally responsive intelligent controlled-release organic fertilizer, comprising the following steps:

[0063] Step 1: Crush soybean straw to 80 mesh, dry at 105℃ to obtain crushed material, add 1g of crushed material and 5g of calcium gluconate to 80mL of water, preload at 60℃ and stirring speed of 180rpm for 24h, dry at 105℃, grind to 80 mesh to obtain preloaded sample.

[0064] Step 2: Place the obtained preloaded sample in a tube furnace and heat it to 400℃ at a heating rate of 5℃ / min under a nitrogen atmosphere. Pyrolyze for 2 hours to obtain calcium-modified biochar.

[0065] Step 3: Mix 0.1g of the obtained 1:4 calcium-modified biochar with 40mL of potassium dihydrogen phosphate solution with a concentration of 200mg P / L, and adsorb at 25℃ and a stirring speed of 200rpm for 24h to obtain phosphorus-loaded biochar.

[0066] Step 4: Mix 1.8g of phosphorus-loaded biochar with 5g of peat and air dry naturally for 48 hours to obtain organic fertilizer.

[0067] Experimental Example 1

[0068] This experiment investigated the effects of environmentally responsive intelligent controlled-release organic fertilizer on crop growth and soil improvement through pot experiments.

[0069] I. The specific grouping method for the potted plant experiment is as follows:

[0070] Using saline-alkali soil with a pH of 10.28 as the target for soil improvement, five groups of potting soil were prepared according to the following proportions:

[0071] (1) Example 1 Group CP-1: 1 wt% of the organic fertilizer prepared in Example 1 was added to saline-alkali soil;

[0072] (2) Example 2 Group CP-2: 1 wt% of the organic fertilizer prepared in Example 2 was added to saline-alkali soil;

[0073] (3) Example 3 Group CP-3: 1 wt% of the organic fertilizer prepared in Example 3 was added to saline-alkali soil;

[0074] (4) Control group CK: 1 wt% vermiculite was added to saline-alkali soil;

[0075] (5) Peat group CK-P: 0.75wt% naturally air-dried peat and 0.25wt% vermiculite were added to saline-alkali soil.

[0076] Soybeans were planted in pots, and the soil moisture content was kept at 70% of the maximum water holding capacity during the cultivation period.

[0077] II. Comparison of germination rate and plant growth

[0078] like Figure 1 As shown, the germination rate observed on the 3rd day after planting revealed that the germination rate of soybeans in saline-alkali soil was 30%; the germination rate after applying peat to saline-alkali soil was approximately 90%; and the average germination rate of soybeans after applying phosphorus-loaded biochar-peat compound organic fertilizer to saline-alkali soil was approximately 66.67%.

[0079] like Figure 2 As shown, the germination rate observed on the 7th day after planting was 44.4% for soybeans in saline-alkali soil; the germination rate was about 100% after applying peat to saline-alkali soil; and the average germination rate of soybeans was about 92.59% after applying phosphorus-loaded biochar-peat compound organic fertilizer to saline-alkali soil.

[0080] Peat, rich in humic acid, can rapidly lower the pH of saline-alkali soils and provide ample moisture, creating an immediate and suitable environment for seed germination. Therefore, it exhibits optimal germination rates on days 3 and 7. However, its drawbacks include rapid nutrient release, short-lasting effects, and the potential for soil compaction with long-term use. The organic fertilizer of this invention exhibits relatively mild effects during the germination stage, but continuously provides nutrients and improves soil structure during subsequent growth stages, resulting in higher yields and soil remediation efficiency.

[0081] like Figure 3 As shown, observations of plant growth on day 14 revealed that, compared to the control group and the CK-P peat group, the soybean population treated with the organic fertilizer of this invention performed better. The soybean populations in each pot showed more uniform growth, with smaller individual differences in plant height and stem thickness. The overall plant shape was more expansive, and the leaves were fuller. The soybean plant population exhibited greater uniformity, with more upright stems, and none of the weak plants and wilted leaves observed in the control group. Overall, the growth was more robust and uniform.

[0082] III. After sampling, determine the plant growth and nutrient content.

[0083] like Figure 4 As shown, with the application of the organic fertilizer of this invention, the total plant length (the sum of plant height and root length) exhibited a differentiated growth characteristic compared to the control group. Specifically, the plant height under the single peat treatment was not significantly different from the control, indicating that single peat has limited effect on improving the saline-alkali soil environment and cannot effectively relieve the inhibition of plant longitudinal growth caused by saline-alkali stress. However, the effects of different ratios of the organic fertilizer of this invention varied, with the treatment in Example 2 showing the most significant increase in plant height. The core mechanism lies in the fact that this ratio of organic fertilizer can effectively alleviate the inhibitory effect of alkali stress on plant cell elongation and differentiation, thereby significantly promoting the longitudinal growth of the plant, especially the underground parts.

[0084] like Figure 5 As shown, with the application of the organic fertilizer of this invention, the total fresh weight of the plants (the sum of the fresh weight of the aboveground parts and the roots) showed a trend of first decreasing and then increasing compared with the control group. Among them, the fresh weight of the plants under the single peat treatment did not change significantly compared with the saline-alkali soil treatment. This is because although peat can activate soil salt ions, it failed to effectively alleviate salt stress and instead inhibited plant growth. However, the fresh weight of the plants under different ratios of the organic fertilizer of this invention significantly increased, and the biomass of the treatment in Example 2 was the highest. This is attributed to the fact that the organic fertilizer loaded with biochar has both salt fixation ability and nutrient activation effect, which can synergistically optimize the soil physicochemical properties and create a suitable rhizosphere environment for plant growth. Its optimal ratio is more conducive to promoting the accumulation of dry matter and water in the plants.

[0085] like Figure 6As shown, with the application of the organic fertilizer of the present invention, the dry weight of plants in each treatment of the embodiments increased significantly compared with the control group, with the strongest improvement in the second embodiment group, indicating that the compound organic fertilizer of the present invention promotes the accumulation of plant dry matter. This is because the nutrient activation effect of the biochar load enhances the photosynthetic efficiency of the plants and promotes the synthesis and accumulation of organic matter.

[0086] like Figure 7 As shown, with the application of the organic fertilizer of this invention, the total potassium ion content of the plants (the sum of aboveground and underground parts) exhibited differentiated fluctuations compared to the control group. Specifically, the total potassium ion content of the plants under the single peat treatment was significantly lower than that of the control group, indicating that single peat not only failed to effectively enhance potassium accumulation in plants but may have also exacerbated the antagonistic effect of saline-alkali environment on potassium ion absorption, making it difficult to exert the role of potassium nutrient supply. Furthermore, the effects of different ratios of the organic fertilizer of this invention varied significantly, with the highest total potassium ion content in the treatment group of Example 2, followed by groups of Example 1 and Example 3. The core mechanism lies in the fact that the optimal ratio of the organic fertilizer of this invention (Example 2) can improve the soil rhizosphere environment, alleviate the inhibition of potassium ion transport by saline-alkali stress, promote the active absorption of potassium ions by roots and their transport to the aboveground parts, and simultaneously optimize the potassium distribution ratio within the plant, providing sufficient potassium support for the plant's stress-resistant growth and physiological metabolism.

[0087] like Figure 8 As shown, with the application of the organic fertilizer of this invention, the potassium ion migration index of the plants showed a trend of first increasing and then decreasing compared with the control group. Specifically, the potassium ion migration index under the single peat treatment was not significantly different from the control group, indicating that single peat had no significant effect on improving the efficiency of potassium ion transport from the underground parts to the aboveground parts. However, the potassium ion migration index was significantly increased under different ratios of the organic fertilizer of this invention. The migration index of the Example 2 group reached its peak, the Example 1 group was the same as the control group, and the Example 3 group showed a slight decrease. This indicates that the organic fertilizer of this invention can enhance the loading and unloading efficiency of potassium ions in the xylem by regulating the physiological processes related to potassium ion transport in the plant. The ratio in Example 2 more precisely matches the plant's potassium transport needs, significantly improving the migration efficiency of potassium to the aboveground parts, ensuring the potassium supply to the aboveground photosynthetic organs and growth sites, and thus strengthening the plant's osmotic regulation and photosynthetic capacity.

[0088] like Figure 9As shown, with the application of the organic fertilizer of this invention, the total sodium ion content of the plants (the sum of aboveground and underground parts) showed a significant decrease and tended to stabilize compared with the control group. While the sodium ion content of the plants under the single peat treatment was lower than that of the control group, the reduction effect was limited and it was difficult to effectively block the migration of sodium ions into the plant. However, different ratios of the organic fertilizer of this invention significantly reduced the accumulation of sodium ions in the plants. The sodium ion content of the plants treated in Example 2 was the lowest, followed by Example 1 and Example 3. The core mechanism lies in the fact that the biochar loaded on the organic fertilizer of this invention can fix rhizosphere sodium ions through physical adsorption and ion exchange, reducing the sodium ion concentration in the soil solution. Simultaneously, it regulates the ion transport process within the plant, reduces the absorption of sodium ions by the roots, and promotes the compartmentalized storage of sodium ions in vacuoles. The optimal ratio in Example 2 further enhances this regulatory process, effectively alleviating the ion toxicity of sodium ions to the plants.

[0089] like Figure 10 As shown, with the application of the organic fertilizer of this invention, the sodium ion migration index of the plants showed a significant increase followed by slight fluctuations compared to the control group. Specifically, the sodium ion migration index under the single peat treatment was not significantly different from the control group, indicating that single peat cannot effectively regulate the transtissue transport of sodium ions. However, different ratios of the organic fertilizer of this invention significantly increased the sodium ion migration index, with the migration indices of Example 1 and Example 3 reaching their peak values, while the indices of Example 2 were slightly lower. This indicates that the organic fertilizer of this invention can activate sodium ion transport pathways, transporting excess sodium ions from the aboveground parts to the underground parts and storing them separately, thus reducing the risk of sodium ion toxicity in the aboveground parts. The ratios of Example 1 and Example 3 are more efficient in retaining sodium ions underground, while Example 2 balances transport efficiency and mitigation of ion toxicity, thus improving the overall salt tolerance of the plants.

[0090] like Figure 11 As shown, with the application of the organic fertilizer of this invention, the sodium-potassium ratio (the sum of the ratios of sodium and potassium content in the aboveground and underground parts) of the plants showed a significant decrease and optimization compared to the control group. Specifically, the sodium-potassium ratio of the plants under the single peat treatment was significantly lower than that of the control group, but the reduction was limited. Different ratios of the organic fertilizer of this invention further reduced the sodium-potassium ratio, with the lowest ratio observed in the treatment group of Example 2, followed by groups 1 and 3. The sodium-potassium ratio of plants is a core indicator of salt tolerance; a lower ratio indicates a stronger antagonistic effect of potassium on sodium ions and a more stable ion balance. The organic fertilizer of this invention can synergistically enhance potassium absorption and reduce sodium ion accumulation, optimizing the sodium-potassium ion ratio within the plant. The optimal ratio in Example 2 more accurately balances the sodium-potassium ratio, alleviating ion imbalances caused by salt stress and ensuring the stability of plant cell membranes and the normal operation of physiological functions.

[0091] Table 1

[0092]

[0093] Table 1 shows the soybean root indicators for different treatment groups, as shown in Table 1 and Figure 12 As shown, compared with the control group, the application of peat alone significantly increased the average root diameter, but significantly lowered the root length, volume, and surface area compared to the control group, even showing an inhibitory effect. This indicates that the promoting effect of peat alone on roots is very limited, and may even restrict root expansion due to uneven nutrient supply. The treatment in Example 2 showed the best results: it achieved the highest values ​​among all treatments in the five core indicators of root length, volume, surface area, projected area, and root tip number, significantly outperforming both the control group and the peat-only group. This demonstrates that the organic fertilizer of this invention can significantly promote the growth and development of soybean roots, with effects far superior to peat-only treatment.

[0094] like Figure 13 As shown, with the application of the organic fertilizer of this invention, the soil potassium ion content exhibited a differentiated increase compared to the control group. Specifically, the soil potassium ion content under the single peat treatment was slightly higher than the control group, with a limited effect; while different ratios of the organic fertilizer of this invention significantly increased the soil potassium ion content. This indicates that the organic fertilizer of this invention can enhance soil potassium reserves and availability by activating fixed potassium in the soil and supplementing exogenous potassium. While single peat can only slightly activate soil potassium, the compound formula of the organic fertilizer of this invention can maintain soil potassium ion levels for a longer period, continuously providing potassium supply to plants and supporting their long-term growth and stress resistance.

[0095] like Figure 14 As shown, with the application of the organic fertilizer of this invention, the sodium ion content in the soil showed a significant decrease and stabilization compared to the control group. Specifically, the sodium ion content in the soil under the single peat treatment was significantly lower than that in the control group, but the reduction effect was significant but not as good as that of the organic fertilizer of this invention; while different ratios of the organic fertilizer of this invention could further reduce the sodium ion content in the soil. The core mechanism lies in the fact that the organic fertilizer of this invention, through the adsorption and fixation of sodium by biochar and the complexation of sodium by organic matter, reduces the concentration of soluble sodium ions in the soil, improves the rhizosphere environment of saline-alkali soil, reduces the damage of salt and alkali stress to plants from the source, and creates a low-sodium soil matrix for plant growth.

[0096] like Figure 15 As shown, with the application of the organic fertilizer of this invention, the soil sodium-potassium ratio compared to the control group showed a significant decrease and optimization. Specifically, the soil sodium-potassium ratio under the single peat treatment was significantly lower than that of the control group, indicating limited improvement; while different ratios of the organic fertilizer of this invention could significantly reduce the soil sodium-potassium ratio. The soil sodium-potassium ratio directly reflects the degree of soil salinization and nutrient availability; a lower ratio indicates higher potassium availability and weaker sodium ion toxicity. The organic fertilizer of this invention can simultaneously reduce sodium and increase potassium, optimizing the soil sodium-potassium ratio, significantly improving soil salinization, enhancing soil nutrient supply capacity, and laying a good foundation for plant root growth and nutrient absorption.

[0097] like Figure 16 As shown, with the application of the organic fertilizer of this invention, the available phosphorus content in the soil exhibited a significant stepwise increase compared to the control group. Specifically, the available phosphorus content in the soil under the single peat treatment showed no significant difference from the control group, indicating that single peat cannot effectively improve the soil's available phosphorus supply capacity. However, different ratios of the organic fertilizer of this invention significantly increased the available phosphorus content in the soil, with the peak value reached in group 3, followed by group 1, and slightly lower in group 2. Phosphorus is a core element for plant energy metabolism and root development. The organic fertilizer of this invention can activate fixed phosphorus in the soil through phosphorus-solubilizing microorganisms and supplement exogenous available phosphorus, thereby improving the availability of phosphorus in the soil. The ratio in Example 3 further enhances the phosphorus activation and replenishment effect, providing sufficient phosphorus for plant growth and promoting root elongation and photosynthetic efficiency.

[0098] like Figure 17 As shown, with the application of the organic fertilizer of this invention, the soil available potassium content exhibited a significant stepwise increase compared to the control group. Specifically, the soil available potassium content under the single peat treatment was slightly higher than the control group, with a limited effect; however, all different ratios of the organic fertilizer of this invention significantly increased the soil available potassium content, with the first example group reaching the peak, followed by the second example group. Soil available potassium is a form of potassium that plants can directly absorb and utilize. The organic fertilizer of this invention can enhance the soil's potassium supply capacity by activating mineral potassium, releasing organic potassium, and reducing potassium fixation. The ratio in Example 1 showed the most significant advantage in increasing soil available potassium, providing a stable and efficient potassium source for plant growth.

[0099] like Figure 18 As shown, with the application of the organic fertilizer of this invention, the total phosphorus content in the soil exhibited a significant stepwise increase compared to the control group. Specifically, the total phosphorus content in the CK-P group was slightly lower than that in the CK group; however, all different ratios of the organic fertilizer of this invention significantly increased the total phosphorus content in the soil, with the 2nd example group reaching the peak, followed by the 3rd example group, and the 1st example group slightly lower. Total phosphorus in the soil is a core indicator of the soil phosphorus pool. The organic fertilizer of this invention can enhance the soil's phosphorus supply capacity by activating inorganic phosphorus, mineralizing organic phosphorus, and reducing phosphorus fixation. The ratio in Example 2 showed the most significant advantage in increasing total phosphorus in the soil, providing sufficient phosphorus reserves for plant growth.

[0100] like Figure 19As shown, with the application of the organic fertilizer of this invention, the total potassium content of the soil exhibited a significant gradient increase compared to the control group. Specifically, there was no significant difference in total potassium content between the CK and CK-P groups, indicating that the phosphorus deficiency treatment did not alter the soil's basic potassium pool. However, different ratios of the organic fertilizer of this invention significantly increased the total potassium content of the soil, with the 3rd group reaching the peak, followed by the 2nd group, and the 1st group slightly lower. Total potassium in the soil reflects the total potassium reserves. The organic fertilizer of this invention can enhance the soil potassium pool by promoting the release of mineral potassium, replenishing organic potassium, and reducing the risk of potassium leaching. The ratio in Example 3 showed the best performance in increasing total potassium in the soil, ensuring a continuous supply of potassium to the soil.

[0101] like Figure 20 As shown, with the application of the organic fertilizer of this invention, the total potassium content in the aboveground and underground parts of the plant exhibits differentiated distribution characteristics. Specifically, the total potassium content in the aboveground parts is highest in Group 1, followed by the CK and CK-P groups, with slightly lower content in Groups 2 and 3. In the underground parts, the total potassium content is highest in the CK-P group, followed by Group 2, with relatively lower content in the CK, 1, and 3 groups. Total potassium content in the plant is a key indicator for measuring potassium absorption and distribution. The organic fertilizer of this invention can optimize the distribution ratio of potassium between the aboveground and underground parts by regulating the plant's potassium transport pathways. The formulation in Example 1 is more biased towards promoting potassium accumulation in the aboveground parts, which is more conducive to plant photosynthesis and biomass formation.

[0102] like Figure 21 As shown, with the application of the organic fertilizer of this invention, the total phosphorus content in the aboveground parts of the plants gradually decreased, while the total phosphorus content in the underground parts remained relatively stable. Specifically, the total phosphorus content in the aboveground parts was highest in the CK group, decreasing sequentially with the treatment gradient (CK-P to Examples 1, 2, and 3), with the lowest content in Example 3. The total phosphorus content in the underground parts was higher in Example 2, and slightly lower in Examples 1 and 3. The distribution of total phosphorus in the plants reflects the phosphorus utilization strategy. The organic fertilizer of this invention can enhance soil phosphorus fixation and regulate plant phosphorus redistribution, maintaining the stability of the underground phosphorus pool while moderately reducing phosphorus accumulation in the aboveground parts, thus promoting plant stress resistance and efficient nutrient utilization.

Claims

1. A method for preparing an environmentally responsive intelligent controlled-release organic fertilizer, characterized in that, Includes the following steps: Step 1: After crushing and drying agricultural and forestry waste, the crushed material is placed in a calcium source compound solution, stirred to complete the pre-loading, dried and ground to obtain a pre-loaded sample. Step 2: Pyrolyze the obtained pre-loaded sample under an inert atmosphere to obtain calcium-modified biochar; Step 3: Mix the obtained calcium-modified biochar with a phosphorus-containing solution for adsorption to obtain phosphorus-loaded biochar; Step 4: Mix the obtained phosphorus-loaded biochar with peat and air dry to obtain organic fertilizer.

2. The method for preparing an environmentally responsive intelligent controlled-release organic fertilizer according to claim 1, characterized in that, The agricultural and forestry waste mentioned in step one is straw waste, shell waste, wood waste, or agricultural product processing residue waste; the particle size of the crushed material is 80 mesh.

3. The method for preparing an environmentally responsive intelligent controlled-release organic fertilizer according to claim 1 or 2, characterized in that, The calcium source compound solution in step one is a calcium gluconate solution, and the mass ratio of the pulverized material to calcium gluconate is 1:2~5; the pre-loading temperature is 40~60℃, the pre-loading stirring speed is 180rpm, and the pre-loading time is 12~24h.

4. The method for preparing an environmentally responsive intelligent controlled-release organic fertilizer according to claim 3, characterized in that, The drying temperature in step one is 105℃, and the particle size of the preloaded sample obtained by grinding is 80 mesh.

5. The method for preparing an environmentally responsive intelligent controlled-release organic fertilizer according to claim 4, characterized in that, The inert atmosphere in step two is nitrogen atmosphere, the heating rate of the pyrolysis is 5℃ / min, the pyrolysis temperature is 200~400℃, and the pyrolysis time is 1~2h.

6. The method for preparing an environmentally responsive intelligent controlled-release organic fertilizer according to claim 5, characterized in that, The phosphorus-containing solution mentioned in step three is a potassium dihydrogen phosphate solution with a concentration of 100~200 mg P / L, and the mass-volume ratio of the calcium-modified biochar to the phosphorus-containing solution is 0.1g:30mL~0.1g:50mL.

7. The method for preparing an environmentally responsive intelligent controlled-release organic fertilizer according to claim 6, characterized in that, The adsorption temperature in step three is 25℃, the stirring speed during adsorption is 200 rpm, and the adsorption time is 24 hours.

8. The method for preparing an environmentally responsive intelligent controlled-release organic fertilizer according to claim 7, characterized in that, The mass ratio of phosphorus-loaded biochar to peat in step four is 1.8:

5.

9. The method for preparing an environmentally responsive intelligent controlled-release organic fertilizer according to claim 8, characterized in that, The air-drying temperature in step four is controlled at 20-25℃, and the air-drying time is 48 hours.

10. An environmentally responsive intelligent controlled-release organic fertilizer prepared by any one of the preparation methods described in claims 1-9.

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