Saline-alkali soil improver for improving saline-alkali soil and reducing nitrogen loss and use method thereof

Abstract

The invention discloses a saline-alkali soil modifier for improving saline-alkali soil and reducing nitrogen loss and a use method thereof. The modifier comprises livestock manure, wheat straw, micron-sized charcoal, biochemical fulvic acid, amino acid, 20% gamma polyglutamic acid and nano attapulgite. In the using process, the soil conditioner is applied to saline-alkali soil to be treated, then the soil area where the saline-alkali soil conditioner is applied is turned over, and then sowing and irrigation are conducted. The components of the modifier have a synergistic effect, the saline-alkali soil is effectively improved, the nitrogen loss is reduced, and the modifier is convenient to use and suitable for large-area popularization and application.

Description

Technical Field

[0001] This invention relates to the field of soil improvement technology, and more specifically to a saline-alkali soil conditioner and its application method for improving saline-alkali soil and reducing nitrogen loss. Background Technology

[0002] Saline-alkali land, as an important reserve of arable land globally, plays a vital role in ensuring food security and alleviating land resource shortages through its improvement and utilization. However, due to its high salt content, high pH value, and poor physical structure, saline-alkali soil severely restricts crop growth. High salinity makes it difficult for crop roots to absorb water, leading to physiological drought; high pH value reduces the solubility of available nutrients in the soil, especially affecting the absorption of trace elements such as phosphorus, iron, and zinc, while also inhibiting soil microbial activity and disrupting the material cycle of the soil ecosystem. Currently, saline-alkali land improvement technologies mainly include physical, chemical, biological, and agronomical methods. Among these, chemical improvement is one of the most widely used technologies due to its simplicity and rapid effectiveness. However, existing chemical amendments have significant limitations. Traditional gypsum-based amendments, while able to reduce soil alkalinity by replacing sodium ions on the surface of soil colloids with calcium ions, have limited ability to regulate soil pH, and secondary salinization rebound is common after improvement. Organic acid-based amendments, although able to quickly lower soil pH, have a short-term effect, require frequent application, and may lead to excessive soil acidification. Industrial waste-based amendments may pose ecological risks due to heavy metal residues. At the same time, saline-alkali land improvement generally faces the problem of severe nitrogen loss. To increase crop yields, nitrogen fertilizer is often applied in saline-alkali land cultivation. However, the high pH value of saline-alkali soil accelerates the volatilization of nitrogen fertilizer (especially ammonium nitrogen). When the soil pH value exceeds 7.5, ammonium nitrogen is easily converted into ammonia gas and released, leading to a surge in nitrogen loss. In addition, the poor permeability of saline-alkali land can cause waterlogging, intensifying denitrification and causing nitrate nitrogen to be converted into nitrogen gas or nitrous oxide and lost. This not only reduces nitrogen fertilizer utilization but also causes environmental pollution. Most existing soil amendments focus only on improving the salinity and alkalinity of the soil and lack targeted design for nitrogen retention, leading to a vicious cycle of amendment → fertilization → nitrogen loss → re-fertilization, which increases agricultural production costs and wastes nutrient resources. On the other hand, some technological attempts that combine soil improvement and fertilizer retention also have shortcomings. For example, while returning straw to the field can improve soil structure and provide some organic matter, straw decomposes slowly in saline-alkali environments, making it difficult to achieve improvement effects in the short term. Although clay minerals such as bentonite can adsorb nitrogen, they further exacerbate the heavy, clayey structure of saline-alkali soils and reduce permeability. While traditional slow-release nitrogen fertilizers can reduce nitrogen release, they cannot solve the problem of nitrogen transformation and loss caused by saline-alkali soils themselves. Therefore, developing a multifunctional soil conditioner that can both efficiently improve the physicochemical properties of saline-alkali soils and reduce losses by regulating the nitrogen transformation process has become the key to overcoming existing technological bottlenecks. Summary of the Invention

[0003] In view of this, the present invention provides a saline-alkali soil conditioner for improving saline-alkali soil and reducing nitrogen loss, and a corresponding method of application. To achieve the above objectives, the present invention adopts the following technical solution: First, this invention provides a saline-alkali soil conditioner for improving saline-alkali soil and reducing nitrogen loss, comprising, by weight: 30-45 parts of poultry and livestock manure compost, 20-30 parts of micron-sized biochar, 10-15 parts of biochemical fulvic acid, 3-5 parts of amino acids, 1-2 parts of 20% pure γ-polyglutamic acid, and 1-2 parts of nano-attapulgite.

[0004] Preferably, the poultry and livestock manure compost is prepared using the following method: The wheat straw is crushed into 1-2cm pieces, and then poultry and livestock manure and wheat straw are mixed in a certain fresh weight ratio and aerobic fermentation is carried out. The initial moisture content of the compost is 60%, the composting temperature is 55-65℃, the composting cycle is 28 days, the final moisture content is ≤15%, the pH is 6.5-7.5, and then it is processed into 1-3mm solid granules.

[0005] Furthermore, the weight ratio of wheat straw to poultry and livestock manure is (20~30):(30~45).

[0006] Preferably, the micron-sized biochar is wheat straw biochar, prepared using the following method: After crushing wheat straw to 1-2 cm, it is carbonized at 450℃ for 15 days. The resulting solid product has a carbon content ≥50%, an ash content ≤20%, and a pH of 7-9. It is then ground in a ball mill and passed through a micron sieve.

[0007] Preferably, the biochemical fulvic acid is a powdered, water-soluble biohumic acid with a BFA ≥ 95%, total nitrogen content 2%, dry basis content ≥ 75 wt.%, and pH 5-7. The water-soluble biohumic acid is extracted from plant sources using biotechnology and then purified. It has a small molecular weight, many active groups, good buffering capacity, and good chelating ability for trace elements. No special limitations are made in this invention, and commercially available products that meet the requirements are acceptable.

[0008] Preferably, the amino acid is glutamic acid and / or lysine. Amino acids are a type of complex amino acid mixture produced by enzymatic hydrolysis of agricultural waste such as soybean meal and corn protein. The amino acid mixture containing glutamic acid and lysine is produced by fermentation with Corynebacterium glutamicum. Plants can directly absorb small molecule amino acids, saving the energy consumption of synthesis. The effect is particularly significant under adverse conditions such as saline-alkali soil. At the same time, it can combine with trace elements in the soil to form chelates, improving the efficiency of nutrient absorption and utilization.

[0009] γ-polyglutamic acid is a high-molecular-weight biopolymer produced by microbial fermentation, formed by the polymerization of glutamic acid monomers through γ-carboxyl groups. Its raw materials are simple, the product has high purity, and it has high water absorption and retention capacity and biodegradability. It can help alleviate water retention and drought resistance in arid and semi-arid areas, reduce the loss of nutrients such as nitrogen, phosphorus and potassium through adsorption, stimulate the root system to secrete organic acids, activate insoluble phosphorus in the soil, and improve soil aggregate structure to alleviate soil salinity.

[0010] Nano-attapulgite is a hydrous magnesium aluminum silicate with a unique chain-like layered structure, multiple internal channels, and a surface rich in silanol and aluminum hydroxyl groups. Attapulgite is broken down to the nanoscale through mechanical grinding and ultrasonic dispersion. Nano-attapulgite can be used in arid and semi-arid areas for water retention and moisture conservation, improving soil aeration and root development. It can also be loaded with nitrogen, phosphorus, potassium, or trace elements. The nanopores control nutrient release, reduce nutrient leaching, and improve fertilizer utilization efficiency.

[0011] This invention also provides a method for improving saline-alkali soil using the aforementioned soil conditioner that improves saline-alkali soil and reduces nitrogen loss, comprising the following steps: Apply soil conditioner to the saline-alkali soil to be treated, at a rate of 1% of the soil weight within a depth of 10cm, and then till the soil to a depth of 0-20cm.

[0012] The present invention also provides a method for planting crops on saline-alkali land treated by the method, comprising the following steps: Sow seeds in the treated land and then irrigate.

[0013] Furthermore, the crop is rice, corn, or sunflower.

[0014] Furthermore, for the planting and irrigation of corn and sunflowers, an integrated seeding and drip irrigation tape laying machine is used to simultaneously sow seeds and lay drip irrigation tape. Then, a mulching machine is used to cover the drip irrigation tape and crop rows with mulch. Corn and sunflowers are planted using a wide-narrow row planting method, with wide rows 70-80cm wide and narrow rows 40-50cm wide. The drip irrigation tape is laid between the two narrow rows of crops, with a mulch distance of 85-95cm and a crop spacing of 50-55cm. For rice planting, flood irrigation is used, with a water depth of 30-35cm. Rice is sown 3 days after flood irrigation.

[0015] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a saline-alkali soil conditioner and its application method for improving saline-alkali soil and reducing nitrogen loss, which has the following beneficial effects: The saline-alkali soil conditioner of the present invention can effectively improve the pH and electrical conductivity of saline-alkali land, has a good effect on salt removal and alkali reduction, and can also effectively increase the content of mineral nitrogen and soil aggregates in the topsoil, reduce nitrogen volatilization, and effectively increase crop yield. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0017] Figure 1 This is a diagram showing the effect of soil amendments on soil pH. Figure 2 This is a graph showing the effect of soil amendments on soil EC values. Figure 3 This is a graph showing the effect of soil amendments on soil mineral nitrogen content. Figure 4 This is a diagram showing the effect of soil amendments on surface biomass. Figure 5 This is a graph showing the effect of soil amendments on the content of soil aggregates. Figure 6 This is a graph showing the effect of the modifier on the cumulative nitrogen volatilization. Detailed Implementation

[0018] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] In the following embodiments, livestock manure compost is prepared using the following method: The wheat straw is crushed into 1-2cm pieces. Then, poultry and livestock manure and wheat straw are mixed in a fresh weight ratio of 25:40 and fermented aerobically. The initial moisture content of the compost is 60%, the composting temperature is 55-65℃, the composting cycle is 28 days, the final moisture content is ≤15%, and the pH is 6.5-7.5. Then, it is mechanically processed into 1-3mm solid granules.

[0020] Micron-sized biochar, made from wheat straw biochar, was prepared using the following method: After crushing wheat straw to 1-2 cm, it is carbonized at 450℃ for 15 days. The resulting solid product has a carbon content ≥50%, an ash content ≤20%, and a pH of 7-9. It is then ground in a ball mill and passed through a micron sieve.

[0021] Biochemical fulvic acids are powdered, water-soluble biological humic acids. Commercially available samples that meet the requirements are used, with BFA ≥ 95%, total nitrogen content 2%, dry basis content ≥ 75 wt.%, and pH 5~7.

[0022] Example 1 The saline-alkali soil conditioner for improving saline-alkali soil and reducing nitrogen loss comprises, by weight, 40 parts of poultry and livestock manure compost, 25 parts of micron-sized biochar, 13 parts of biochemical fulvic acid, 4 parts of amino acids, 2 parts of 20% pure γ-polyglutamic acid, and 2 parts of nano-attapulgite.

[0023] Example 2 The formulation in this embodiment focuses on rapidly reducing alkali and providing quick-acting nutrients. The soil conditioner provided in this embodiment focuses on using a high proportion of acidic substances and readily available nitrogen sources to rapidly reduce soil pH and provide sufficient nitrogen for the early stages of crop growth. It comprises, by weight: 30 portions of poultry and livestock manure compost (lower content reduces the alkaline substances released during the slow decomposition of organic matter). 20 parts of micron-sized biochar (low content to ensure basic pore structure) 15 portions of biochemical fulvic acid (high content, utilizing its acidic groups and chelating ability to rapidly lower pH and activate trace elements) Five portions of amino acids (high content, providing organic nitrogen that plants can directly absorb, saving metabolic energy). 1.5 parts of 20% pure γ-polyglutamic acid One part of nano-attapulgite.

[0024] Example 3 The formulation in this embodiment focuses on long-term improvement of soil structure and water and fertilizer retention. The soil conditioner provided in this embodiment focuses on sustainably improving soil aggregate structure and water retention capacity by increasing organic matter and porous materials, and utilizes nanomaterials to achieve slow nutrient release. It comprises, by weight: 45 parts of poultry and livestock manure compost (high content, providing a large amount of organic matter to promote the formation of aggregate structure) 30 portions of micron-sized biochar (high content to maximize soil porosity, adsorption sites, and carbon sequestration) 10 portions of biochemical fulvic acid 3 portions of amino acids 1 part of 20% pure γ-polyglutamic acid Two portions of nano-attapulgite (higher content, to enhance the adsorption and slow release of nutrients).

[0025] Example 4 The formulation in this embodiment focuses on a balanced ratio. The soil conditioner provided in this embodiment uses intermediate values ​​for each component to achieve a balance of multiple functions such as soil improvement, nitrogen supply, and nitrogen retention, making it suitable for most moderately saline-alkali lands. It comprises, by weight: 37 portions of poultry and livestock manure compost 25 portions of micron-sized biochar 12 portions of biochemical fulvic acid 4 portions of amino acids 1.5 parts of 20% pure γ-polyglutamic acid 1.5 parts of nano-attapulgite.

[0026] Experimental Example 1 This experiment was conducted in Xinjian Village, Wuyuan County, Bayannur City, Inner Mongolia Autonomous Region, and Qianjin Farm, Pingluo County, Shizuishan City, Ningxia Hui Autonomous Region, with sunflowers (dry field) and rice (paddy field) planted respectively.

[0027] Xinjian Village, Wuyuan County, Bayannur City, Inner Mongolia Autonomous Region, is located in the southern part of Bayannur City, in the heart of the Hetao Plain. The county is bordered by the Yellow River to the south, the Yinshan Mountains to the north, Baotou to the east, and Linhe to the west. Wuyuan County has a mid-latitude continental climate, characterized by abundant sunshine, large temperature differences, and strong evaporation. The average annual total radiation is 153.44 kcal / cm², with 3263 hours of sunshine annually. The average temperature is 6.1℃, with an accumulated temperature of 3362.5℃. The frost-free period is relatively short, ranging from 117 to 136 days, and the annual rainfall is approximately 170 mm. Spring is dry and windy with rapid warming; summer is hot with concentrated rainfall; autumn is short with large diurnal temperature differences and rapid cooling; winter is dry and cold with little precipitation. The soil in this area is mainly saline, with poor fertility.

[0028] Pingluo County, Ningxia Hui Autonomous Region, is located in the northern part of the Ningxia Plain, under the jurisdiction of Shizuishan City. It borders the Yellow River to the east, adjacent to Wuhai City, Etuoke Banner, and Etuoke Banner of Inner Mongolia, and is bordered by the Helan Mountains and Alxa League to the west. It belongs to the mid-temperate arid climate zone and is a typical continental climate. The climate is arid with little rainfall, strong winds and abundant sand, high evaporation, and large temperature differences. The annual average temperature is 9.1℃, the annual precipitation is approximately 189.9 mm, and the annual evaporation is approximately 2249.5 mm.

[0029] The sunflower variety selected for the experiment was "San Duan 10". Sowing was conducted in late April / early May, with harvesting in late August / early September. The experimental design included three treatments: the improver prepared in Example 1 of this invention (FAOF), conventional organic fertilizer improver (OF), and local conventional planting pattern (CK). Each treatment had three replicates, and the plot area was 10m × 10m. Drip irrigation was used for irrigation, with integrated water and fertilizer management. The rice variety selected for the experiment was Ningjing 63. Sowing was conducted in late April, with harvesting in late September. The experimental design included three treatments: the improver prepared in Example 1 of this invention (FAOF), conventional organic fertilizer improver (OF), and local conventional planting pattern (CK). Each treatment had three replicates, and the plot area was 10m × 10m.

[0030] Before sowing sunflowers, various soil amendments are manually and evenly applied to the surface of saline-alkali soil at a depth of 10cm, and then the amendments are mixed into the soil thoroughly and evenly using a rotary tiller to a depth of 15cm. Sowing and drip irrigation tape laying are carried out simultaneously using a sowing and drip irrigation tape integrated machine. Subsequently, mulch film is laid using a mulch film laying machine. During the sunflower growth management period, the management methods are carried out according to the local farmers' management methods.

[0031] Before planting rice, various improvement materials are manually and evenly applied to the surface of saline-alkali soil at a depth of 10cm, and then the materials are thoroughly and evenly mixed into the soil using a rotary tiller. The tillage depth is 15cm. Irrigation is done by flood irrigation with a water depth of 35cm. Rice is sown 3 days after flood irrigation.

[0032] Relevant test results are as follows Figure 1-6 As shown. From Figures 1 to 6It can be seen that during the sunflower and rice harvest periods, the pH and EC of the topsoil treated with the soil conditioner from Example 1 were lower than those treated with conventional organic fertilizer and the local conventional planting model. The treatment showed the most ideal and significant reduction in pH and electrical conductivity of the saline-alkali land, indicating that this technology has a significant effect on desalination and alkali reduction. During the sunflower and rice harvest periods in Example 1, the mineral nitrogen in the topsoil was higher to varying degrees than that treated with conventional organic fertilizer and the local conventional planting model. The treatment showed the most significant increase in mineral nitrogen in the saline-alkali land, indicating that this technology has a certain degree of nitrogen supply capacity. During the sunflower and rice harvest periods, the yields of sunflower and rice were higher to varying degrees than those treated with conventional organic fertilizer. Compared with the local conventional planting model, the yield increase of saline-alkali land after treatment was the most significant, indicating that this technology has a certain yield-increasing effect. During the sunflower and rice harvesting periods in the examples, the content of soil aggregates >2mm in the topsoil was higher than that of conventional organic fertilizer improvement and the local conventional planting model. The level of large aggregates in saline-alkali land after treatment was the most significant, indicating that this technology has a certain ability to promote aggregation. During the sunflower and rice planting periods, the cumulative ammonia volatilization in the soil was lower to varying degrees than that of conventional organic fertilizer improvement and the local conventional planting model. The cumulative ammonia volatilization reduction effect of saline-alkali land after treatment was the most significant, indicating that this technology has a certain nitrogen loss reduction and nitrogen retention capacity.

[0033] Experiment Example 2 Effect verification: Through indoor soil culture experiments and field trials, the amendments prepared in Examples 2-4 above, under the same application conditions, similar to Example 1, can significantly reduce soil pH and EC values, increase the number of soil aggregates and mineral nitrogen content, effectively inhibit nitrogen volatilization, and promote the growth and yield of crops such as rice, corn, or sunflower. This shows that the beneficial effects of the present invention can be achieved by adjusting the proportions within the range described in the present invention.

[0034] The various embodiments described in this specification are presented in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A soil conditioner for improving saline-alkali soil and reducing nitrogen loss, characterized in that, By weight, it includes: 30-45 parts of poultry and livestock manure compost, 20-30 parts of micron-sized biochar, 10-15 parts of biochemical fulvic acid, 3-5 parts of amino acids, 1-2 parts of 20% pure γ-polyglutamic acid, and 1-2 parts of nano-attapulgite.

2. The saline-alkali soil conditioner for improving saline-alkali soil and reducing nitrogen loss according to claim 1, characterized in that, The poultry and livestock manure compost is prepared using the following method: The wheat straw is crushed into 1-2cm pieces, and then poultry and livestock manure and wheat straw are mixed in a certain fresh weight ratio and aerobic fermentation is carried out. The initial moisture content of the compost is 60%, the composting temperature is 55-65℃, the composting cycle is 28 days, the final moisture content is ≤15%, the pH is 6.5-7.5, and then it is processed into 1-3mm solid granules.

3. The saline-alkali soil conditioner for improving saline-alkali soil and reducing nitrogen loss according to claim 2, characterized in that, The weight ratio of wheat straw to poultry and livestock manure is (20~30):(30~45).

4. The saline-alkali soil conditioner for improving saline-alkali soil and reducing nitrogen loss according to claim 1, characterized in that, The micron-sized biochar is wheat straw biochar, prepared using the following method: After crushing wheat straw to 1-2 cm, it is carbonized at 450℃ for 15 days. The resulting solid product has a carbon content ≥50%, an ash content ≤20%, and a pH of 7-9. It is then ground in a ball mill and passed through a micron sieve.

5. A saline-alkali soil conditioner for improving saline-alkali soil and reducing nitrogen loss according to claim 1, characterized in that, The biochemical fulvic acid is a powdered, water-soluble biological humic acid with a BFA ≥ 95%, total nitrogen content 2%, dry basis content ≥ 75 wt.%, and pH 5~7.

6. A saline-alkali soil conditioner for improving saline-alkali soil and reducing nitrogen loss according to claim 1, characterized in that, The amino acid is glutamic acid and / or lysine.

7. A method for improving saline-alkali soil using the saline-alkali soil conditioner according to any one of claims 1-6, characterized in that, Includes the following steps: Apply soil conditioner to the saline-alkali soil to be treated, at a rate of 1% of the soil weight within a depth of 10cm, and then till the soil to a depth of 0-20cm.

8. A method for planting crops on saline-alkali land treated according to claim 7, characterized in that, Includes the following steps: Sow seeds in the treated land and then irrigate.

9. The method according to claim 8, characterized in that, The crop is rice, corn, or sunflower.

10. The method according to claim 9, characterized in that, For the planting and irrigation of corn and sunflowers, a combined sowing and drip irrigation tape laying machine is used to simultaneously sow seeds and lay drip irrigation tape. Then, a mulching machine is used to cover the drip irrigation tape and crop rows with mulch. Corn and sunflowers are planted using a wide-narrow row planting method, with wide rows 70-80cm wide and narrow rows 40-50cm wide. The drip irrigation tape is laid between the two narrow rows of crops, with a mulch distance of 85-95cm and a crop spacing of 50-55cm. For rice planting, flood irrigation is used, with a water depth of 30-35cm. Rice is sown 3 days after flood irrigation.

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