Method for improving fertility of newly reclaimed red and yellow soil cultivated land

Abstract

The invention relates to the technical field of soil improvement, and discloses a method for improving fertility of newly-reclaimed red and yellow soil cultivated land, which comprises the following steps: (1) after the height of the newly-reclaimed red and yellow soil cultivated land is leveled, applying urea formaldehyde fertilizer and humic acid fertilizer; (2) applying a decomposed cow dung or sheep manure organic fertilizer; (3) applying a soil conditioner, wherein the soil conditioner comprises hydroxyl calcium phosphate and silica sol modified enteromorpha-based biochar, diatomite and a calcium magnesium phosphate fertilizer; (4) applying liquid fertilizer; the step (1) to the step (4) need to be turned and pressed into the soil for a plurality of times, so that the fertilizer is uniformly mixed with the soil of the plough layer. According to the method, different fertilizers are applied to synergistically improve the acid environment of the red and yellow soil, the content of mineral nutrients such as organic matters and total nitrogen in the surface soil of the newly-cultivated land is increased, the effects of rapidly improving the physicochemical property of the soil and increasing the microbial activity are achieved, and then the newly-cultivated red and yellow soil is fertilized and improved.

Description

Technical Field

[0001] The invention relates to the technical field of soil improvement, and in particular to a method for improving the fertility of newly reclaimed red-yellow soil farmland. Background Art

[0002] Red soil is a common type of soil developed in subtropical and tropical regions, mainly distributed in most areas south of the Yangtze River and the mountains around the Sichuan Basin. In these areas, the climate is usually warm, the rainfall is abundant, and the organic matter source is rich, but it decomposes quickly and loses a lot, so there is less humus in the soil, the soil is sticky, and due to the strong leaching effect, there is less accumulation of potassium, sodium, calcium, and magnesium, but it contains more iron and aluminum, and the soil is uniformly red. According to the differences in its formation process, soil composition and properties, it can be further subdivided into the following subcategories: red-yellow soil, red pure soil, red-yellow gauze soil and red mountain soil.

[0003] Among them, red-yellow soil is a type of soil that transitions from red soil to yellow soil, and its soil color varies between red and reddish yellow. The soil formation process of red-yellow soil is still dominated by desiliconization and aluminization. Silicon and base are leached, clay particles and secondary clay minerals are continuously formed, and iron and aluminum oxides are obviously accumulated. In addition, due to the relatively warm, cool and humid climate conditions in the mountains, the humidity of the soil and air increases, showing an additional yellowing process, that is, due to the increase in the crystal water of iron oxide in the soil, the soil gradually turns orange-yellow. However, due to its weak degree of desiliconization and aluminization, it shows the characteristics of transition from red soil to yellow soil.

[0004] The invention patent with publication number 115176552A discloses a method for improving the soil quality of red soil and yellow soil, comprising the following steps: (1) land leveling; (2) laying out lines at a row spacing of 40-60 cm and digging planting furrows; (3) sowing sesbania and covering the soil; (4) laying out lines 10-15 days after sesbania emerges, digging furrows between two adjacent rows of sesbania, and planting peanuts; (5) cutting the aboveground part of peanuts at the ground level before the peanuts are podded and mature; (6) before the flowering period of sesbania, harvesting the aboveground part of sesbania at the ground level, crushing, and obtaining sesbania crushed segments; (7) digging along the sesbania planting rows, and burying the sesbania crushed segments in the soil. This method can improve the permeability and gas phase space ratio of the topsoil planting layer of red soil and yellow soil, but the effect on improving soil fertility is not significant, and it takes a long time and consumes a lot of manpower, and cannot achieve the purpose of efficient utilization in the same year of reclamation. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a method for improving the fertility of newly reclaimed red-yellow soil farmland. By applying various organic materials with different characteristics such as humic acid, cow dung, urea-formaldehyde fertilizer and soil conditioners, the soil nutrient pools such as carbon source and nitrogen source are rationally optimized and improved, the soil carbon-nitrogen ratio is adjusted, and the acidic environment of the red-yellow soil is synergistically improved, so as to achieve the effect of quickly improving soil physicochemical properties and increasing microbial activity, thereby fertilizing and improving the newly reclaimed red-yellow soil.

[0006] The purpose of the present invention is achieved through the following technical solutions: The present invention provides a method for improving the fertility of newly reclaimed red-yellow soil farmland, comprising the following steps: (1) After the newly reclaimed red-yellow soil land is leveled, urea-formaldehyde fertilizer and humic acid fertilizer are applied; (2) Applying decomposed cow dung or sheep dung organic fertilizer; (3) applying soil conditioners, including calcium hydroxyphosphate and silica sol-modified Enteromorpha-based biochar, diatomaceous earth, and calcium magnesium phosphate fertilizer; (4) Apply liquid fertilizer; Steps (1) to (4) need to be turned over and pressed into the soil several times to ensure that the fertilizer and the cultivated layer soil are evenly mixed.

[0007] Humic acid in humic acid fertilizer is a macromolecular polymer with high stable organic matter content and slow decomposition and mineralization rate, which can quickly and efficiently increase the organic matter in low-fertility soil. Urea formaldehyde in urea formaldehyde fertilizer is a polymer connected to carbon with a low salt index, which can provide slow-release nitrogen nutrients. Its reliable and safe slow-release nitrogen can be consumed by microorganisms as nutrition and energy and gradually released. After applying it to the soil, it can quickly melt into colloids and be tightly adsorbed and fused by the soil, thereby ensuring that nutrients are not lost for a long time and less is lost to the environment.

[0008] Cow dung or sheep dung organic fertilizer is the decomposed livestock and poultry manure of herbivorous animals. It has a relatively high carbon content and decomposes slowly. It can effectively increase the organic matter in red-yellow soil, while providing a complete range of effective crop nutrients and carbon sources for beneficial soil microorganisms. The combined use of humic acid, urea-formaldehyde fertilizer, and cow dung or sheep dung organic fertilizers coordinates the slow mineralization of balanced carbon and nitrogen nutrients, provides excellent carbon and nitrogen sources required for soil microbial reproduction, creates an optimized soil carbon-nitrogen ratio, accelerates the growth and reproduction of beneficial microorganisms in red-yellow soil, and promotes rapid improvement of soil fertility.

[0009] The application of silicon, calcium and magnesium-containing soil conditioners can improve soil acidity and alkalinity, optimize and improve the soil pH environment to make it suitable for crop growth needs, and provide mineral nutrients such as silicon, calcium and magnesium to accelerate the formation and development of soil aggregate structure in newly reclaimed farmland. Organic liquid fertilizers inoculated with local mature high-fertility farmland flora can quickly improve the fertilizer efficiency of newly reclaimed soil, promote the rapid proliferation and growth of soil microorganisms, and quickly create and build beneficial microbial flora in the soil.

[0010] Therefore, the present invention reasonably optimizes and improves the soil carbon source, nitrogen source and other nutrient pools, adjusts the soil carbon-nitrogen ratio, and synergistically improves the acidic environment of the red-yellow soil by applying various organic materials with different characteristics such as humic acid, cow dung, urea-formaldehyde fertilizer and soil conditioners, increases the content of mineral nutrients such as organic matter and total nitrogen in the cultivated layer of newly reclaimed cultivated land, achieves the effect of quickly improving soil physicochemistry and increasing microbial activity, and then fertilizes and improves the newly reclaimed red-yellow soil, promotes the healthy and normal growth of crops, and ensures food security.

[0011] Preferably, the preparation method of the soil conditioner comprises the following steps: dispersing calcium hydroxyphosphate into an aqueous solution containing polyethylene glycol distearate to obtain a mixed solution I; dropping the mixed solution I into the silica sol while stirring to obtain a mixed solution II; immersing the Enteromorpha-based biochar in the mixed solution II and letting it stand, taking it out, first reacting it anaerobically at 300-400°C for 1-3h, and then reacting it anaerobically at 500-600°C for 30-50min; mixing the obtained reaction product with diatomaceous earth and calcium magnesium phosphate fertilizer and stirring to obtain a soil conditioner.

[0012] There is a serious phenomenon of desiliconization and aluminum enrichment in red-yellow soil. The soil conditioner in the present invention can supplement cations such as calcium and magnesium, reduce the exchangeable Al content of the soil, and reduce the exchangeable Al content of the soil. 3+ Compared with other biochars, Enteromorpha-based biochar has more -OH, -COOH and -NH2 functional groups on its surface, and Enteromorpha has high N and P content. Adding it to the soil can more effectively increase the content of soil organic matter and nutrients.

[0013] In addition, the Enteromorpha-based biochar is modified by silica sol and hydroxy calcium phosphate. The added polyethylene glycol distearate can improve the dispersibility and compatibility of hydroxy calcium phosphate and silica sol, and it has a thickening effect, which is beneficial to the loading of the mixed liquid on the surface of Enteromorpha-based biochar, so that the silica sol and hydroxy calcium phosphate can be evenly distributed on the surface of the biochar. Then, through high-temperature reaction, the silica sol will first gel and dehydrate at high temperature and agglomerate particles, so that the Si-OH bond becomes a Si-O bond, resulting in a densification effect, and the generated amorphous silica can be slowly released to better provide silicon elements for the soil. However, after losing a large amount of water, the volume and strength of the silica sol will be greatly affected. Through the thickening effect of polyethylene glycol distearate, the surface of the biochar can be loaded with more silica particles and hydroxy calcium phosphate particles, reducing the impact of water loss. Then, by controlling the condition parameters of the high-temperature reaction, the modified Enteromorpha-based biochar has higher binding and stability, and can slowly release silicon and calcium elements.

[0014] Therefore, the soil conditioner prepared by the present invention can effectively supplement the calcium, magnesium and silicon nutrient elements required for plant growth. The diatomaceous earth and calcium magnesium phosphate fertilizer can quickly increase the soil pH and timely improve the soil acidity. In addition, the addition of modified Enteromorpha-based biochar has a better fertilizer and water retention effect, and can significantly reduce the exchangeable Al content of the soil. 3+ activity, promoting soil exchangeable Al 3+ It is converted into hydroxyaluminum ions or hydroxide precipitation to alleviate aluminum toxicity. In addition, silicon can improve the absorption of nutrients by crops. Modified Enteromorpha-based biochar can maintain the slow release of silicon and calcium elements, avoid soil compaction and "re-acidification" after long-term use, reduce loss to the environment, and maintain soil fertility.

[0015] Preferably, the amount of calcium hydroxyphosphate added is 5-10% of the mass of the aqueous solution containing polyethylene glycol distearate; the mass concentration of the aqueous solution containing polyethylene glycol distearate is 1-2%.

[0016] Preferably, the polyethylene glycol distearate is polyethylene glycol 6000 distearate (PEG6000DS).

[0017] Preferably, the mixing mass ratio of the mixed solution I to the silica sol is 1:4-5; the mass concentration of the silica sol is 20-30%, calculated as the content of silicon dioxide.

[0018] Preferably, the heating rate is 1-5°C / min; the mass ratio of the reaction product to diatomaceous earth and calcium magnesium phosphate is 3-4:1-2:1-2.

[0019] Preferably, the dosage of the soil conditioner is 50-100 kg / mu, and the main indicators are organic matter ≥ 50% and total nutrients ≥ 4%.

[0020] Preferably, the dosage of the humic acid fertilizer is 2000-6000 kg / mu; the dosage of the urea-formaldehyde fertilizer is 120-200 kg / mu.

[0021] The application amount of humic acid fertilizer and urea-formaldehyde fertilizer is selected according to the soil fertility level of the newly reclaimed cultivated land.

[0022] Preferably, the method for preparing the urea-formaldehyde fertilizer comprises the following steps: mixing urea and formaldehyde at a molar ratio of 1.2-1.4:1, and polymerizing them under alkaline conditions of pH 8.5-9.0.

[0023] The alkaline condition is to use KOH to adjust the pH. By adding KOH and the alkaline environment synthesis process, the product becomes weakly alkaline, which helps to improve the pH of the red-yellow soil and increase the nutrient content.

[0024] Preferably, the amount of the cow dung or sheep dung organic fertilizer is 1.5-3.0 tons / mu.

[0025] Preferably, the liquid fertilizer is a biological fertilizer containing active microbial agents, which are inoculated with soil flora of high-fertility farmland cultivated for a long time nearby; the dosage of the liquid fertilizer is 10-30 kg / mu.

[0026] Preferably, the soil conditioner is applied 3-8 days after the cow dung or sheep dung organic fertilizer is applied and mixed with the soil.

[0027] Preferably, liquid fertilizer is applied 3-8 days after the soil conditioner is applied and mixed with the soil.

[0028] Preferably, the tillage depth of the soil is controlled to 15-25 cm, and the number of tillages in each step is 3 to 5 times.

[0029] Compared with the prior art, the present invention has the following beneficial effects: (1) By applying various organic materials with different characteristics and soil conditioners such as humic acid, cow dung, and urea-formaldehyde fertilizers, we can rationally optimize and improve the soil nutrient pool such as carbon source and nitrogen source, adjust the soil carbon-nitrogen ratio, and synergistically improve the acidic environment of red-yellow soil. We can increase the content of mineral nutrients such as organic matter and total nitrogen in the topsoil of newly reclaimed cultivated land, so as to quickly improve the physical and chemical properties of the soil and increase the activity of microorganisms, thereby fertilizing and improving the newly reclaimed red-yellow soil, promoting the healthy and normal growth of crops, and ensuring food security.

[0030] (2) Soil conditioners can effectively supplement the calcium, magnesium, and silicon nutrients required for plant growth. Diatomaceous earth and calcium magnesium phosphate fertilizer can quickly increase soil pH and improve soil acidity in a timely manner. In addition, the addition of modified Enteromorpha-based biochar can better retain fertilizer and water, and can significantly reduce soil exchangeable Al 3+ activity, so as to alleviate aluminum poisoning. DETAILED DESCRIPTION

[0031] The technical solution of the present invention is described below with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0032] Newly reclaimed low-fertility red-yellow soil farmland was selected in the southern hilly area of ​​Jinhua, Zhejiang Province. Representative soil samples from the 0-20 cm tillage layer were collected to analyze the basic physical and chemical properties of the soil and determine the input amount of fertilization materials.

[0033] The preparation of urea-formaldehyde fertilizer includes the following steps: mixing urea and formaldehyde (37% formaldehyde aqueous solution by mass concentration) at a feeding molar ratio of 1.2-1.4:1, polymerizing under alkaline conditions, adding KOH to adjust the pH to 8.5-9.0, controlling the reaction temperature to 55-75°C, and the reaction time to 75-100 minutes.

[0034] Humic acid fertilizer comes from Zhejiang Fengyu Ecological Technology Co., Ltd.

[0035] The decomposed cow dung or sheep dung organic fertilizer comes from Longyou County Wangnong Organic Fertilizer Co., Ltd.

[0036] Liquid fertilizer comes from Zhejiang Fengyu Ecological Technology Co., Ltd.

[0037] Calcium magnesium phosphate fertilizer comes from Yunnan Gaoyuan Fertilizer Co., Ltd.

[0038] Example 1 (1) The test field was first irrigated with 2-5 cm of water, and the topsoil was leveled mechanically so that the topsoil height difference around the cultivated land did not exceed 5 cm. After the land was leveled, urea-formaldehyde fertilizer and humic acid fertilizer were evenly spread at a rate of 160 kg / mu and 2,800 kg / mu, respectively. The soil was mechanically plowed into the soil at a plowing depth of 20 cm and the number of plowings was 3-5 times to fully mix the fertilizer with the cultivated layer of soil.

[0039] (2) Apply decomposed cow dung or sheep dung organic fertilizer at a rate of 2.0 tons / mu, till the soil mechanically to a tillage depth of 20 cm, and 3 to 5 times to mix the fertilizer and the cultivated layer of soil thoroughly.

[0040] (3) Five days after the soil is fully mixed, apply soil conditioner at a dosage of 75 kg / mu and till the soil mechanically to a depth of 20 cm and 3 to 5 times to fully mix the soil conditioner with the cultivated layer of soil.

[0041] The preparation of the soil conditioner includes the following steps: dispersing calcium hydroxyphosphate into an aqueous solution containing polyethylene glycol 6000 distearate with a mass concentration of 2%, wherein the amount of calcium hydroxyphosphate added is 8% of the mass of the aqueous solution containing polyethylene glycol 6000 distearate, to obtain a mixed solution I; dropping the mixed solution I into a silica sol with a mass concentration of 20% (calculated by the content of silicon dioxide), wherein the mixed solution I and the silica sol have a mixing mass ratio of 1:4, and stirring at the same time to obtain a mixed solution II; immersing Enteromorpha-based biochar in the mixed solution II and allowing it to stand, after taking it out, first reacting it anaerobically at 300°C for 2h, and then reacting it anaerobically at 550°C for 30min; mixing the obtained reaction product with diatomaceous earth and calcium magnesium phosphate at a mass ratio of 4:1:1 and stirring to obtain a soil conditioner.

[0042] (4) Five days after the soil is fully mixed, apply liquid fertilizer at a rate of 30 kg / mu, plow the soil mechanically to a depth of 20 cm, and plow 3 to 5 times to fully mix the fertilizer with the cultivated layer of soil.

[0043] Example 2 (1) The field was first irrigated with 2-5 cm of water, and the topsoil was leveled mechanically so that the height difference of the topsoil around the cultivated land did not exceed 5 cm. After the land was leveled, urea-formaldehyde fertilizer and humic acid fertilizer were evenly spread at a rate of 140 kg / mu and 3,400 kg / mu respectively, and the soil was mechanically plowed into the soil at a plowing depth of 20 cm and 3-5 times to fully mix the fertilizer with the cultivated layer of soil.

[0044] (2) Apply decomposed cow dung or sheep dung organic fertilizer at a rate of 2.0 tons / mu, till the soil mechanically to a tillage depth of 20 cm, and 3 to 5 times to mix the fertilizer and the cultivated layer of soil thoroughly.

[0045] (3) Five days after the soil is fully mixed, apply soil conditioner at a rate of 85 kg / mu and till the soil mechanically to a depth of 20 cm and 3 to 5 times to fully mix the soil conditioner with the cultivated layer of soil.

[0046] The preparation of the soil conditioner includes the following steps: dispersing calcium hydroxyphosphate into an aqueous solution containing polyethylene glycol 6000 distearate with a mass concentration of 2%, wherein the amount of calcium hydroxyphosphate added is 8% of the mass of the aqueous solution containing polyethylene glycol 6000 distearate, to obtain a mixed solution I; dropping the mixed solution I into a silica sol with a mass concentration of 20% (calculated by the content of silicon dioxide), wherein the mixed solution I and the silica sol have a mixing mass ratio of 1:4, and stirring at the same time to obtain a mixed solution II; immersing Enteromorpha-based biochar in the mixed solution II and allowing it to stand, after taking it out, first reacting it anaerobically at 300°C for 2h, and then reacting it anaerobically at 550°C for 30min; mixing the obtained reaction product with diatomaceous earth and calcium magnesium phosphate at a mass ratio of 4:1:1 and stirring to obtain a soil conditioner.

[0047] (4) Five days after the soil is fully mixed, apply liquid fertilizer at a rate of 20 kg / mu, plow the soil mechanically to a depth of 20 cm, and plow 3 to 5 times to fully mix the fertilizer with the cultivated layer of soil.

[0048] Example 3 (1) The test field was first irrigated with 2-5 cm of water, and the topsoil was leveled mechanically so that the topsoil height difference around the cultivated land did not exceed 5 cm. After the land was leveled, urea-formaldehyde fertilizer and humic acid fertilizer were evenly spread at a rate of 160 kg / mu and 2,800 kg / mu, respectively. The soil was mechanically plowed into the soil at a plowing depth of 20 cm and the number of plowings was 3-5 times to fully mix the fertilizer with the cultivated layer of soil.

[0049] (2) Apply decomposed cow dung or sheep dung organic fertilizer at a rate of 2.0 tons / mu, till the soil mechanically to a tillage depth of 20 cm, and 3 to 5 times to mix the fertilizer and the cultivated layer of soil thoroughly.

[0050] (3) Five days after the soil is fully mixed, apply soil conditioner at a dosage of 75 kg / mu and till the soil mechanically to a depth of 20 cm and 3 to 5 times to fully mix the soil conditioner with the cultivated layer of soil.

[0051] The preparation of the soil conditioner includes the following steps: dispersing calcium hydroxyphosphate into an aqueous solution containing polyethylene glycol distearate with a mass concentration of 2%, wherein the amount of calcium hydroxyphosphate added is 5% of the mass of the aqueous solution containing polyethylene glycol distearate, to obtain a mixed solution I; dropping the mixed solution I into a silica sol with a mass concentration of 25% (calculated by the content of silicon dioxide), wherein the mixed solution I and the silica sol have a mixing mass ratio of 1:5, and stirring at the same time to obtain a mixed solution II; immersing Enteromorpha-based biochar in the mixed solution II and allowing it to stand, after being taken out, first reacting it anaerobically at 400°C for 2h, and then reacting it anaerobically at 550°C for 40min; mixing the obtained reaction product with diatomaceous earth and calcium magnesium phosphate at a mass ratio of 3:1.5:1.5 and stirring to obtain a soil conditioner.

[0052] (4) Five days after the soil is fully mixed, apply liquid fertilizer at a rate of 30 kg / mu, plow the soil mechanically to a depth of 20 cm, and plow 3 to 5 times to fully mix the fertilizer with the cultivated layer of soil.

[0053] Example 4 (1) The test field was first irrigated with 2-5 cm of water, and the topsoil was leveled mechanically so that the topsoil height difference around the cultivated land did not exceed 5 cm. After the land was leveled, urea-formaldehyde fertilizer and humic acid fertilizer were evenly spread at a rate of 160 kg / mu and 2,800 kg / mu, respectively. The soil was mechanically plowed into the soil at a plowing depth of 20 cm and the number of plowings was 3-5 times to fully mix the fertilizer with the cultivated layer of soil.

[0054] (2) Apply decomposed cow dung or sheep dung organic fertilizer at a rate of 2.0 tons / mu, till the soil mechanically to a tillage depth of 20 cm, and 3 to 5 times to mix the fertilizer and the cultivated layer of soil thoroughly.

[0055] (3) Five days after the soil is fully mixed, apply soil conditioner at a dosage of 75 kg / mu and till the soil mechanically to a depth of 20 cm and 3 to 5 times to fully mix the soil conditioner with the cultivated layer of soil.

[0056] The preparation of the soil conditioner includes the following steps: dispersing calcium hydroxyphosphate into an aqueous solution containing polyethylene glycol distearate at a mass concentration of 1%, wherein the amount of calcium hydroxyphosphate added is 10% of the mass of the aqueous solution containing polyethylene glycol distearate, to obtain a mixed solution I; dropping the mixed solution I into a silica sol (calculated by the content of silicon dioxide) at a mass concentration of 20%, wherein the mixed solution I and the silica sol have a mixing mass ratio of 1:5, and stirring at the same time to obtain a mixed solution II; immersing Enteromorpha-based biochar in the mixed solution II and allowing it to stand, after being taken out, first reacting it at 400°C for 2h in an anaerobically manner, and then reacting it at 500°C for 50min in an anaerobically manner; the obtained reaction product is mixed and stirred with diatomaceous earth and calcium magnesium phosphate at a mass ratio of 4:1:1 to obtain a soil conditioner.

[0057] (4) Five days after the soil is fully mixed, apply liquid fertilizer at a rate of 30 kg / mu, plow the soil mechanically to a depth of 20 cm, and plow 3 to 5 times to fully mix the fertilizer with the cultivated layer of soil.

[0058] Comparative Example 1 The difference from Example 1 is that during the preparation of the soil conditioner, no modified biochar is added.

[0059] (1) The test field was first irrigated with 2-5 cm of water, and the topsoil was leveled mechanically so that the topsoil height difference around the cultivated land did not exceed 5 cm. After the land was leveled, urea-formaldehyde fertilizer and humic acid fertilizer were evenly spread at a rate of 160 kg / mu and 2,800 kg / mu, respectively. The soil was mechanically plowed into the soil at a plowing depth of 20 cm and the number of plowings was 3-5 times to fully mix the fertilizer with the cultivated layer of soil.

[0060] (2) Apply decomposed cow dung or sheep dung organic fertilizer at a rate of 2.0 tons / mu, till the soil mechanically to a tillage depth of 20 cm, and 3 to 5 times to mix the fertilizer and the cultivated layer of soil thoroughly.

[0061] (3) Five days after the soil is fully mixed, apply soil conditioner at a dosage of 75 kg / mu and till the soil mechanically to a depth of 20 cm and 3 to 5 times to fully mix the soil conditioner with the cultivated layer of soil.

[0062] The preparation of the soil conditioner comprises the following steps: diatomaceous earth and calcium magnesium phosphate fertilizer are mixed and stirred in a mass ratio of 1:1 to obtain the soil conditioner.

[0063] (4) Five days after the soil is fully mixed, apply liquid fertilizer at a rate of 30 kg / mu, plow the soil mechanically to a depth of 20 cm, and plow 3 to 5 times to fully mix the fertilizer with the cultivated layer of soil.

[0064] Comparative Example 2 The difference from Example 1 is that during the preparation of the soil conditioner, the biochar was not modified.

[0065] (1) The test field was first irrigated with 2-5 cm of water, and the topsoil was leveled mechanically so that the topsoil height difference around the cultivated land did not exceed 5 cm. After the land was leveled, urea-formaldehyde fertilizer and humic acid fertilizer were evenly spread at a rate of 160 kg / mu and 2,800 kg / mu, respectively. The soil was mechanically plowed into the soil at a plowing depth of 20 cm and the number of plowings was 3-5 times to fully mix the fertilizer with the cultivated layer of soil.

[0066] (2) Apply decomposed cow dung or sheep dung organic fertilizer at a rate of 2.0 tons / mu, till the soil mechanically to a tillage depth of 20 cm, and 3 to 5 times to mix the fertilizer and the cultivated layer of soil thoroughly.

[0067] (3) Five days after the soil is fully mixed, apply soil conditioner at a dosage of 75 kg / mu and till the soil mechanically to a depth of 20 cm and 3 to 5 times to fully mix the soil conditioner with the cultivated layer of soil.

[0068] The preparation of the soil conditioner comprises the following steps: mixing enteromorpha-based biochar, diatomaceous earth and calcium magnesium phosphate fertilizer in a mass ratio of 4:1:1 to obtain the soil conditioner.

[0069] (4) Five days after the soil is fully mixed, apply liquid fertilizer at a rate of 30 kg / mu, plow the soil mechanically to a depth of 20 cm, and plow 3 to 5 times to fully mix the fertilizer with the cultivated layer of soil.

[0070] Comparative Example 3 The difference from Example 1 is that polyethylene glycol distearate is not added during the preparation of the soil conditioner.

[0071] (1) The test field was first irrigated with 2-5 cm of water, and the topsoil was leveled mechanically so that the topsoil height difference around the cultivated land did not exceed 5 cm. After the land was leveled, urea-formaldehyde fertilizer and humic acid fertilizer were evenly spread at a rate of 160 kg / mu and 2,800 kg / mu, respectively. The soil was mechanically plowed into the soil at a plowing depth of 20 cm and the number of plowings was 3-5 times to fully mix the fertilizer with the cultivated layer of soil.

[0072] (2) Apply decomposed cow dung or sheep dung organic fertilizer at a rate of 2.0 tons / mu, till the soil mechanically to a tillage depth of 20 cm, and 3 to 5 times to mix the fertilizer and the cultivated layer of soil thoroughly.

[0073] (3) Five days after the soil is fully mixed, apply soil conditioner at a dosage of 75 kg / mu and till the soil mechanically to a depth of 20 cm and 3 to 5 times to fully mix the soil conditioner with the cultivated layer of soil.

[0074] The preparation of the soil conditioner includes the following steps: dispersing calcium hydroxyphosphate into an aqueous solution, wherein the amount of calcium hydroxyphosphate added is 8% by mass of the aqueous solution, to obtain a mixed solution I; dropping the mixed solution I into a silica sol (calculated by the content of silicon dioxide) with a mass concentration of 20%, wherein the mixed solution I and the silica sol have a mixing mass ratio of 1:4, and stirring at the same time to obtain a mixed solution II; immersing Enteromorpha-based biochar in the mixed solution II and allowing it to stand, and after taking it out, first reacting it anaerobically at 300°C for 2h, and then reacting it anaerobically at 550°C for 30min; the obtained reaction product is mixed and stirred with diatomaceous earth and calcium magnesium phosphate at a mass ratio of 4:1:1 to obtain a soil conditioner.

[0075] (4) Five days after the soil is fully mixed, apply liquid fertilizer at a rate of 30 kg / mu, plow the soil mechanically to a depth of 20 cm, and plow 3 to 5 times to fully mix the fertilizer with the cultivated layer of soil.

[0076] Comparative Example 4 The difference from Example 1 is that in the preparation process of the soil conditioner, the mixing mass ratio of the mixed solution I and the silica sol is 1:2.

[0077] (1) The test field was first irrigated with 2-5 cm of water, and the topsoil was leveled mechanically so that the topsoil height difference around the cultivated land did not exceed 5 cm. After the land was leveled, urea-formaldehyde fertilizer and humic acid fertilizer were evenly spread at a rate of 160 kg / mu and 2,800 kg / mu, respectively. The soil was mechanically plowed into the soil at a plowing depth of 20 cm and the number of plowings was 3-5 times to fully mix the fertilizer with the cultivated layer of soil.

[0078] (2) Apply decomposed cow dung or sheep dung organic fertilizer at a rate of 2.0 tons / mu, till the soil mechanically to a tillage depth of 20 cm, and 3 to 5 times to mix the fertilizer and the cultivated layer of soil thoroughly.

[0079] (3) Five days after the soil is fully mixed, apply soil conditioner at a dosage of 75 kg / mu and till the soil mechanically to a depth of 20 cm and 3 to 5 times to fully mix the soil conditioner with the cultivated layer of soil.

[0080] The preparation of the soil conditioner includes the following steps: dispersing calcium hydroxyphosphate into an aqueous solution containing polyethylene glycol 6000 distearate with a mass concentration of 2%, wherein the amount of calcium hydroxyphosphate added is 8% of the mass of the aqueous solution containing polyethylene glycol 6000 distearate, to obtain a mixed solution I; dropping the mixed solution I into a silica sol with a mass concentration of 20% (calculated by the content of silicon dioxide), wherein the mixed solution I and the silica sol have a mixing mass ratio of 1:2, and stirring at the same time to obtain a mixed solution II; immersing Enteromorpha-based biochar in the mixed solution II and allowing it to stand, after taking it out, first reacting it anaerobically at 300°C for 2h, and then reacting it anaerobically at 550°C for 30min; mixing the obtained reaction product with diatomaceous earth and calcium magnesium phosphate fertilizer at a mass ratio of 4:1:1 and stirring to obtain a soil conditioner.

[0081] (4) Five days after the soil is fully mixed, apply liquid fertilizer at a rate of 30 kg / mu, plow the soil mechanically to a depth of 20 cm, and plow 3 to 5 times to fully mix the fertilizer with the cultivated layer of soil.

[0082] After the operation was carried out according to the methods in Examples 1-4 and Comparative Examples 1-3, a test area was set up to plant rice. The rice was planted using direct seeding technology, and the variety was Zheyou 18. Routine management of rice nutrients and water and prevention of pests and diseases were carried out according to local customs. After the rice was harvested, soil organic matter content, pH, soil exchangeable Al 3+ Analysis and yield determination.

[0083] The blank group was the initial soil basic physical and chemical properties of the newly reclaimed low-fertility red-yellow soil farmland in the southern hilly area of ​​Jinhua, Zhejiang Province. The organic matter content was 8.76 g / kg, the pH was 5.22, and the soil exchangeable Al 3+ It is 2.85cmol / kg.

[0084] Table 1 As shown in Table 1, the method of the present invention can rapidly improve the soil fertility of newly reclaimed red-yellow soil farmland, increase soil pH, and timely improve soil acidity, and the rice yield in the same year can reach a high level. Among them, the diatomaceous earth and calcium magnesium phosphate fertilizer in the soil conditioner can rapidly increase soil pH and timely improve soil acidity. The addition of modified Enteromorpha-based biochar can achieve better fertilizer and water retention effects, and can effectively reduce the exchangeable Al content of the soil. 3+ The addition of modified Enteromorpha-based biochar can slow-release calcium and silicon elements, which can prevent soil compaction and "re-acidification" after long-term use, and maintain a high level of soil fertility, thus increasing rice yields.

[0085] Since no modified Enteromorpha-based biochar was added to Comparative Examples 1 and 2, the exchangeable Al in the soil 3+ Still at a high level, and the organic matter content in the soil will also be affected, resulting in a decrease in rice yield. Comparative Examples 3 and 4 show that the parameter adjustment during the preparation of modified Enteromorpha-based biochar will also affect the synergistic effect of each component, thereby affecting soil fertility and rice yield.

[0086] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the specification of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for improving the fertility of newly reclaimed red-yellow soil farmland, characterized in that: The steps include: (1) After the newly reclaimed red-yellow soil land is leveled, urea-formaldehyde fertilizer and humic acid fertilizer are applied; (2) Applying decomposed cow dung or sheep dung as organic fertilizer; (3) applying soil conditioners, including calcium hydroxyphosphate and silica sol-modified Enteromorpha-based biochar, diatomaceous earth, and calcium magnesium phosphate fertilizer; (4) Apply liquid fertilizer; Steps (1) to (4) need to be turned over and pressed into the soil several times to ensure that the fertilizer and the cultivated layer soil are evenly mixed.

2. The method for improving the fertility of newly reclaimed red-yellow soil farmland according to claim 1, characterized in that: The preparation method of the soil conditioner comprises the following steps: dispersing calcium hydroxyphosphate into an aqueous solution containing polyethylene glycol distearate to obtain a mixed solution I; dropping the mixed solution I into silica sol while stirring to obtain a mixed solution II; immersing enteromorpha-based biochar in the mixed solution II and allowing it to stand, taking it out, first reacting it anaerobically at 300-400°C for 1-3h, and then reacting it anaerobically at 500-600°C for 30-50min; mixing the obtained reaction product with diatomaceous earth and calcium magnesium phosphate fertilizer and stirring to obtain the soil conditioner.

3. The method for improving the fertility of newly reclaimed red-yellow soil farmland according to claim 2, characterized in that: The amount of calcium hydroxyphosphate added is 5-10% of the mass of the aqueous solution containing polyethylene glycol distearate; the mass concentration of the aqueous solution containing polyethylene glycol distearate is 1-2%.

4. The method for improving the fertility of newly reclaimed red-yellow soil farmland according to claim 2, characterized in that: The mixing mass ratio of the mixed solution I to the silica sol is 1:4-5; the mass concentration of the silica sol is 20-30%, calculated based on the content of silicon dioxide; the mass ratio of the reaction product to diatomaceous earth and calcium magnesium phosphate is 3-4:1-2:1-2.

5. The method for improving the fertility of newly reclaimed red-yellow soil farmland according to any one of claims 1 to 4, characterized in that: The dosage of the soil conditioner is 50-100 kg / mu.

6. The method for improving the fertility of newly reclaimed red-yellow soil farmland according to claim 1, characterized in that: The dosage of the humic acid fertilizer is 2000-6000 kg / mu; the dosage of the urea-formaldehyde fertilizer is 120-200 kg / mu.

7. The method for improving the fertility of newly reclaimed red-yellow soil farmland according to claim 1 or 6, characterized in that: The preparation method of the urea-formaldehyde fertilizer comprises the following steps: mixing urea and formaldehyde at a feeding molar ratio of 1.2-1.4:1, and polymerizing them under alkaline conditions of pH 8.5-9.

0.

8. The method for improving the fertility of newly reclaimed red-yellow soil farmland according to claim 1, characterized in that: The amount of the cow dung or sheep dung organic fertilizer used is 1.5-3.0 tons / mu.

9. The method for improving the fertility of newly reclaimed red-yellow soil farmland according to claim 1 or 8, characterized in that: The liquid fertilizer is a biological fertilizer containing active microbial agents; the dosage of the liquid fertilizer is 10-30 kg / mu.

10. The method for improving the fertility of newly reclaimed red-yellow soil farmland according to claim 1, characterized in that: The tillage depth of the soil is adjusted to 15-25 cm, and the number of tillages in each step is 3-5 times.

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