Soil-improving, fertilizing and high-yield composition for soda saline-alkali soil

Abstract

The invention belongs to the technical field of saline-alkali land treatment and utilization, and particularly relates to a soil-improving, fertilizing and high-yield composition for saline-alkali land, in particular to a soil-improving, fertilizing and high-yield composition for soda saline-alkali land. The invention aims to solve the problems of salt return and salt increase in the alkali-reducing, salt-eliminating and yield-increasing treatment process of moderate-severe newly-reclaimed soda saline-alkali soil. The soil-improving, fertilizing and yield-increasing composition for soda saline-alkali soil is prepared from the following components in percentage by mass: 10 to 60 percent of phosphogypsum, 10 to 60 percent of organic fertilizer, 0 to 15 percent of humic acid, 0 to 2 percent of bacterial manure and the balance of water-retaining agent. The composition disclosed by the invention can be used for effectively reducing the pH and ESP of soil and improving the organic matter and rice yield of the soil.

Description

Technical Field

[0001] The invention belongs to the technical field of saline-alkali land management and utilization, and particularly relates to a saline-alkali land soil improvement, fertilization and high-yield composition. Background Art

[0002] It is of great significance to carry out comprehensive utilization of saline-alkali land. Soda saline-alkali land is one of the types of saline-alkali land in my country. Its main salts are NaHCO3 and Na2CO3. It has strong alkalinity, mixed saline-alkali stress, poor permeability, low basic soil fertility, lack of organic matter, difficult cultivation, and slow effect. It has become a major scientific and technological problem that seriously restricts the improvement of soil fertility of newly reclaimed paddy fields in soda saline-alkali land and the increase of rice yield. However, under such conditions, saline-alkali stress often seriously restricts the improvement of saline-alkali land fertility and the growth, development and yield of rice.

[0003] How to quickly regulate the improvement of soil fertility and increase yield in soda saline-alkali land is an important goal of the development of newly-cultivated saline-alkali paddy fields. Although there are many studies on the improvement of saline-alkali soil using single improvers such as gypsum, and certain improvement effects and theoretical basis have been achieved, the improvement effect achieved by single improvers is limited. For the soda saline-alkali soil in western Jilin Province with high salinity and poor physical and chemical properties, screening and applying composite improvers is one of the future trends in the improvement of soda saline-alkali soil. The main role of gypsum improvers in the process of improving soda saline-alkali soil is to reduce soil alkalinity, thereby promoting crop growth by reducing alkalinity. Its role in reducing soil salinity and improving nutrients is only an indirect effect after alkalinity reduction. The simple application of gypsum and increasing its dosage will increase the risk of increased salt content and aggravated soil salinization. In addition, water washing during soil improvement will lead to the loss of dissolved organic matter while desalting. It is difficult to simultaneously take into account the goals of rapid reduction of saline-alkali barriers and rapid improvement of soil fertility and yield. It must be combined with subsequent soil fertilization to truly achieve the successful management of soda saline-alkali soil.

[0004] Organic materials such as cow dung mainly reduce salinity by reducing soil bulk density. The soil improvement effect is difficult to show in the short term, so it is suitable for long-term improvement and fertilization. In addition, organic materials are low in price and too much application can easily cause the dispersion of aggregates, reduce stability, and thus affect salinity leaching. Therefore, the composite method with phosphogypsum and organic fertilizer as the core is one of the current technical means to quickly reduce obstacles and improve soil fertility in soda saline-alkali paddy fields. Liang Zhengwei et al. (2023) proposed that organic fertilization should increase the application of organic fertilizer according to the nutrient status of salinized soil based on the technical requirements of soil improvement and fertilization of newly reclaimed paddy fields in soda saline-alkali land. Organic fertilizer should meet the requirements of NY / T 525, and decomposed and harmless farmyard manure can also be applied. It is recommended to apply 30-45 tons / hectare per year for 3 consecutive years. However, in practice, when gypsum and other improvers are put in, a large amount of organic fertilizer is required in a short period of time. The compound improvement of saline-alkali land is prone to the problem of increased salt content, which affects the goal of reducing alkali, draining salt, fertilizing and high yield. Summary of the invention

[0005] The purpose of the present invention is to solve the technical problems of salt return and salt increase in the process of reducing alkali, draining salt and increasing production in newly reclaimed medium-to-severe soda saline-alkali land, and to provide a soda saline-alkali land soil improvement, fertilization and high-yield composition.

[0006] The composition for improving soil and fertilizing soda saline-alkali land to increase yield consists of 10-60% of phosphogypsum, 10-60% of organic fertilizer, 0-15% of humic acid, 0-2% of microbial fertilizer and the remainder of water retaining agent according to mass fraction.

[0007] The water retaining agent is polyacrylamide.

[0008] The humic acid is regenerated humic acid.

[0009] The microbial fertilizer is nitrogen-fixing bacteria, phosphate-dissolving bacteria, potassium-dissolving bacteria, potassium humate, seaweed or amino acid.

[0010] Application method of the soda saline-alkali land soil improvement and fertilization high-yield composition: before the field soaking period, mix it with the surface soil by rotary tillage, harrow the land and stir it during the field soaking period, irrigate and drain 2-3 times to discharge the replaced salt, thereby improving the soil to be suitable for the growth of rice plants. Application rate of phosphogypsum 20-60t / hm 2 , organic fertilizer application rate 20-60t / hm 2 , humic acid application rate 0-10t / hm 2 , application amount of microbial fertilizer 0-2t / hm 2 .

[0011] Phosphogypsum is a solid waste residue produced when phosphate rock is treated with sulfuric acid in phosphoric acid production. Its main component is calcium sulfate, including a small amount of incompletely decomposed phosphate rock, residual phosphoric acid, acid insoluble matter, iron-aluminum compounds, organic matter, etc. Calcium ions in phosphogypsum can replace sodium ions in soda saline-alkali soil to form sodium sulfate, and then irrigation and drainage can remove the sodium sulfate with higher solubility to achieve the effect of reducing alkali. The pH of phosphogypsum is generally between 1.5-4.5, which is highly acidic. It can improve the high pH of soda saline-alkali land. At the same time, the acid components such as phosphoric acid in phosphogypsum can promote the flocculation of soda saline-alkali soil aggregates and promote the combination of aggregates with calcium carbonate and other soil minerals dissolved in the soil. Released calcium, iron and aluminum, thereby improving the efficiency of desalination and alkali reduction. At the same time, phosphogypsum contains nutrients required for rice growth, such as phosphorus, calcium, magnesium, iron, silicon, and sulfur. However, phosphogypsum has limited effect on quickly increasing soil organic matter in a short period of time. Based on this, decomposed organic fertilizers are used in combination with phosphogypsum for soil improvement and fertilization. Applying organic fertilizer to soda saline-alkali soil can effectively reduce soil salinity and increase soil organic carbon content. Applying organic fertilizer to soil with low fertility can help form organic-inorganic complexes and improve soil structure, thereby effectively improving soil fertility.

[0012] Humic acid is widely used in saline-alkali soil improvement due to its abundant reserves, strong price competitiveness and non-polluting properties. The application of humic acid and its derivatives has become an important means of improving soil. The application of humic acid can effectively improve soil structure, increase the effectiveness of soil organic matter and nutrients, and promote the dissolution of gypsum. Therefore, the combination of humic acid and phosphogypsum has the technical potential to simultaneously reduce alkali, desalinate and improve fertility.

[0013] Microbial fertilizer provides a large number of beneficial microorganisms to the soil, which can fix nitrogen, dissolve phosphorus and potassium, and release nutrients for crops to absorb. At the same time, the beneficial bacteria in microbial fertilizer combined with organic fertilizer can not only improve the permeability of saline-alkali land, but also the large amount of humus produced by decomposing manure can have a positive impact on soil structure and rice growth, realizing a beneficial combination of different governance measures.

[0014] As a water retaining agent, polyacrylamide (PAM) is also a soil structure improver. It can increase soil water content, soil porosity and cation exchange capacity, reduce soil bulk density, and increase crop yield and water utilization rate, promoting crop growth. In addition, the application of PAM in the soil can significantly increase the content of organic matter, available phosphorus, alkaline nitrogen and available potassium in the soil. The application of water retaining agents in soda saline-alkali land, combined with phosphogypsum, has the potential to convert soda salt into neutral salt and provide a good soil structure for the rapid leaching of salt.

[0015] The present invention mainly solves the risks of salt return and salt increase that are prone to occur in the process of reducing alkali, fertilizing and increasing yields in newly reclaimed soda saline-alkali paddy fields, makes up for the technical shortcomings in the process of soil improvement, fertilization and increasing yields in saline-alkali land with gypsum organic fertilizer soil improvement and fertilization technology as the core, and quickly achieves the technical indicators of reducing soil pH, ESP and EC and increasing organic matter and rice yield, effectively providing scientific and technological support for solving the major industrial technical problems of rapid and synchronous alkali reduction, desalination, fertilization and high yields in soda saline-alkali paddy fields.

[0016] Beneficial effects of the present invention:

[0017] (1) The composite formula for reducing alkali, improving fertilizer and increasing yield in severe saline-alkali land of the present invention uses environmentally friendly raw materials, is safe to humans, animals and the environment, and is safe to use, environmentally friendly, simple to operate, low in cost, and not prone to causing pesticide damage.

[0018] (2) The application of the composition of the present invention can effectively reduce soil pH and ESP, and increase soil organic matter and rice yield.

[0019] (3) The composition of the present invention can effectively reduce soil EC, thus overcoming the harmful problem of increased soil EC often caused by the combined application of gypsum and gypsum-organic fertilizer.

[0020] (4) Main performance indicators:

[0021] Under severe saline-alkali soil potting conditions (pH 10.20, EC 2.36 mS / cm), compared with the unamended control, the pH of the composite formula of phosphogypsum, organic fertilizer, and humic acid decreased by 14.24%, ESP by 15.83%, EC by 16.82%, and organic matter increased by 49.44%;

[0022] Compared with the composite improvement of phosphogypsum and organic fertilizer, the composite formula of phosphogypsum, organic fertilizer and humic acid increased pH by 1.32%, decreased EC by 29.43%, decreased ESP by 0.90%, and increased organic matter by 19.14%;

[0023] After the composite formula of phosphogypsum, organic fertilizer and microbial fertilizer was applied, the pH decreased by 14.24%, ESP decreased by 16.85%, EC decreased by 19.55%, and organic matter increased by 38.14% compared with the unmodified control.

[0024] After the combined application of phosphogypsum, organic fertilizer and microbial fertilizer, the pH increased by 1.32%, EC decreased by 31.75%, ESP decreased by 2.09%, and organic matter increased by 10.14%. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a pH comparison chart of different combinations of conditioning agents for reducing alkali and salt removal and fertilizing in severe saline-alkali land in Experiment 1;

[0026] Figure 2 This is a comparison chart of EC of different combinations of conditioning agents for reducing alkali and removing salt and fertilizing in severe saline-alkali land in Experiment 1;

[0027] Figure 3 This is a comparison chart of different combinations of conditioning agents for reducing alkali and removing salt and improving fertility ESP in severe saline-alkali land in Experiment 1;

[0028] Figure 4 This is a comparison chart of different combinations of conditioning agents for reducing alkali, draining salt and increasing fertility and organic matter in severe saline-alkali land in Experiment 1;

[0029] Figure 5 This is a pH comparison chart of typical conditioning agent formulas for reducing alkali and removing salt for fertilization in Qian'an's severely saline-alkali land in Experiment 2;

[0030] Figure 6 This is the EC comparison chart of typical conditioning agent formula for reducing alkali and removing salt and fertilizing in Qian'an heavy saline-alkali land in Experiment 2;

[0031] Figure 7 This is a comparison chart of organic matter in typical conditioning agent formulas for reducing alkali and removing salt and fertilizing in the heavily saline-alkali land of Qian'an in Experiment 2;

[0032] Figure 8 This is a comparison chart of the yield of typical conditioning agent formulas for reducing alkali and draining salt and fertilizing the severely saline-alkali land in Qian'an in Experiment 2;

[0033] Fig. 9 This is the pH comparison chart of typical conditioning agent formula for reducing alkali and draining salt and fertilizing in Zhaoyuan heavy saline-alkali land in Experiment 3;

[0034] Fig.10 This is the EC comparison chart of typical conditioning agent formula for reducing alkali and draining salt and fertilizing in Zhaoyuan heavy saline-alkali land in Experiment 3;

[0035] Fig.11 This is a comparison chart of typical conditioning agent formula ESP for reducing alkali and draining salt and fertilizing in Zhaoyuan heavy saline-alkali land in Experiment 3;

[0036] Fig.12 This is a comparison chart of organic matter in typical conditioning agent formulas for reducing alkali and draining salt and fertilizing the severely saline-alkali land in Zhaoyuan in Experiment 3. DETAILED DESCRIPTION

[0037] The technical solution of the present invention is not limited to the specific implementation modes listed below, but also includes any combination of the specific implementation modes.

[0038] Specific implementation method 1: In this implementation method, the composition for improving soil and fertilizing soda saline-alkali land and increasing yield is composed of 10-60% phosphogypsum, 10-60% organic fertilizer, 0-15% humic acid, 0-2% microbial fertilizer and the remainder water retaining agent according to mass fraction.

[0039] Specific implementation method 2: This implementation method is different from the specific implementation method 1 in that the water retaining agent is polyacrylamide. The rest is the same as the specific implementation method 1.

[0040] Specific implementation method 3: This implementation method is different from specific implementation method 1 or 2 in that the humic acid is regenerated humic acid. The rest is the same as specific implementation method 1 or 2.

[0041] Specific embodiment 4: This embodiment is different from specific embodiments 1 to 3 in that the microbial fertilizer is nitrogen-fixing bacteria, phosphate-dissolving bacteria, potassium-dissolving bacteria, potassium humate, seaweed or amino acid, etc. The rest is the same as specific embodiments 1 to 3.

[0042] The following experiments were used to verify the effect of the present invention:

[0043] Experiment 1: Potted experiment of different alkali-reducing, salt-draining and fertilizing conditioners in severe saline-alkali land

[0044] Location: Jilin Da'an Farmland Ecosystem National Field Scientific Observation and Research Station, Honggangzi Township, Da'an City. The selected soil (pH 10.2, EC 2.61mS / cm) was soda saline soil.

[0045] The experiment was a potted experiment with seven treatments, including unmodified control (CK), phosphogypsum (application rate: 10-80t / hm 2)(T1), phosphogypsum (application amount: 10-80t / hm 2 )(T2), phosphogypsum (application amount: 10-80t / hm 2 )(T3), phosphogypsum (application amount: 10-80t / hm 2 )+organic fertilizer (application amount: 10-80t / hm 2 )(T4), phosphogypsum (application amount: 10-80t / hm 2 )+organic fertilizer (application amount: 10-80t / hm 2 )+humic acid (application amount: 0-10t / hm 2 )(T5), phosphogypsum (application amount: 10-80t / hm 2 )+organic fertilizer (application amount: 10-80t / hm 2 )+microbial fertilizer (application amount: 0-2t / hm 2 )+water retaining agent (application amount: 0-6t / hm 2 )(T6).

[0046] The experiment was repeated three times. Each treatment was applied to the selected saline-alkali soil according to the application amount and mixed evenly. When soaking the field, the well water was used for irrigation. After the field was stirred, the water was drained out. The irrigation and drainage were repeated three times. When the drainage EC < 2mS / cm and pH < 9.0, the water was irrigated and rice was transplanted.

[0047] The rice variety was Dongdao 122. Rice seedlings were transplanted on June 4, and the field surface water was drained and irrigated again when EC>2mS / cm or pH>9.0. Other management was the same as conventional rice planting management.

[0048] Compared with the unimproved control, under T1 treatment, organic matter increased by 4.52%, pH decreased by 10.16%, EC decreased by 10.61%, and ESP increased by 3.31%; compared with the unimproved control, under T2 treatment, organic matter increased by 5.93%, pH decreased by 14.03%, EC increased by 17.88%, and ESP decreased by 12.87%; under T3 treatment, organic matter decreased by 0.85%, pH decreased by 16.24%, EC increased by 31.06%, and ESP decreased by 18.52%; under T4 treatment, organic matter increased by 25.42%, pH decreased by 15.36%, EC increased by 47.27%, and ESP decreased by 24.32%; under T5 treatment, organic matter increased by 49.44%, pH decreased by 14.24%, EC decreased by 16.82%, and ESP decreased by 15.07%; under T6 treatment, organic matter increased by 38.14%, pH decreased by 14.48%, EC decreased by 19.55%, and ESP decreased by 15.83%. In general, compared with the unmodified control, the typical phosphogypsum modification treatment, and the phosphogypsum and organic fertilizer compound modification treatment, T5 and T6 had better effects. It was confirmed that under the conditions of severe soda saline-alkali land, the technical combinations of phosphogypsum + organic fertilizer + humic acid, phosphogypsum + organic fertilizer + microbial fertilizer + water retaining agent all showed the technical effects of reducing alkali, desalting, fertilizing and increasing production.

[0049] Experiment 2: Qian'an field experiment on typical conditioning agent formula for reducing alkali and salt removal and fertilizing in severe saline-alkali land

[0050] The experiment was conducted in Wangzi Village, Shuizi Town, Qian'an County, Songyuan City (pH = 10.01; EC = 1415μS / cm). Six treatments were set up in the field experiment, including unimproved control (CK), phosphogypsum (application rate: 10-80t / hm 2 )(T1), phosphogypsum (application amount: 10-80t / hm 2 )+organic fertilizer (application amount: 10-80t / hm 2 )(T2), phosphogypsum (application amount: 10-80t / hm 2 )+organic fertilizer (application amount: 10-80t / hm 2 )+humic acid (application amount: 0-10t / hm 2 )(T3), phosphogypsum (application amount: 10-80t / hm 2 )+organic fertilizer (application amount: 10-80t / hm 2 )+microbial fertilizer (application amount: 0-6t / hm 2 )+water retaining agent (application amount: 0-6t / hm 2 )(T4), phosphogypsum (application amount: 10-80t / hm 2 )+organic fertilizer (application amount: 10-80t / hm 2)+microbial fertilizer (application amount: 0-6t / hm 2 )+water retaining agent (application amount: 0-6t / hm 2 )(T5). The experiment was repeated three times. Each treatment was applied to the selected saline-alkali soil according to the application amount, mixed evenly, soaked and harrowed, and then irrigated and flushed before transplanting. The rice variety was Songliao No. 5. Rice was transplanted on June 4, and when the field surface water EC>2mS / cm or pH>9.0, it was drained and irrigated again. Other management was the same as conventional rice planting management.

[0051] Compared with the unmodified control, the pH of T1 treatment decreased by 14.16%, EC decreased by 23.46%, and organic matter increased by 33.41%; the pH of T2 treatment decreased by 15.89%, EC decreased by 29.98%, and organic matter increased by 93.13%; the pH of T3 treatment decreased by 21.10%, EC decreased by 34.60%, and organic matter increased by 110.68%; the pH of T4 treatment decreased by 19.37%, EC decreased by 29.94%, and organic matter increased by 136.03%; the pH of T5 treatment decreased by 22.20%, EC decreased by 31.62%, and organic matter increased by 123.94%. For yield, compared with the control, the other treatments were significantly improved; compared with the phosphogypsum and phosphogypsum + organic fertilizer compound treatment, the yield of the phosphogypsum + organic fertilizer + humic acid compound formula treatment and the phosphogypsum + organic fertilizer + microbial fertilizer + water retaining agent treatment was significantly improved.

[0052] Under the severe saline-alkali conditions in Qian'an (pH=10.01; EC=1415μS / cm), the pH, EC, and ESP of the composite formulas of phosphogypsum, organic fertilizer, humic acid and other components, as well as the composite formulas of phosphogypsum, organic fertilizer, and microbial agents were applied in the first year compared with the control. The soil organic matter was significantly improved, and the rice yields reached 557.49 kg / mu and 565.9 kg / mu, which were 19.9 times and 20.2 times higher than the control of 26.7 kg / mu.

[0053] In general, under the conditions of severe saline-alkali land, compared with the unamended control, different combinations of phosphogypsum, organic fertilizer, humic acid, and microbial fertilizer significantly improved soil salinity, nutrients, and yield, indicating that the combined effect of phosphogypsum, organic fertilizer, humic acid, microbial fertilizer, etc. is better than the simple application of different doses of phosphogypsum and the combination of phosphogypsum and organic fertilizer.

[0054] Experiment 3: Field experiment of typical conditioning agent formula for reducing alkali and salt removal and fertilizing in heavy saline-alkali land in Zhaoyuan

[0055] The experiment was conducted in Xinzhao, Zhaoyuan County, Daqing City (pH = 10.0; EC = 600μS / cm), which is located in the western part of the Songnen Plain and has a temperate continental monsoon climate. Three treatments were set up in the field experiment:

[0056] Treatment 1: Phosphogypsum (application rate: 10-80t / hm 2 )+organic fertilizer (application amount: 10-80t / hm 2 )+microbial fertilizer (application amount: 0-6t / hm 2 )(Supporting variety Tongze 861);

[0057] Treatment 2: Phosphogypsum (application rate: 10-80t / hm 2 )+organic fertilizer (application amount: 10-80t / hm 2 )+microbial fertilizer (application amount: 0-6t / hm 2 )(Complementary variety Dongdao 122);

[0058] Treatment 3: Phosphogypsum (application rate: 10-80t / hm 2 )+organic fertilizer (application amount: 10-80t / hm 2 )+ side deep fertilization (matching variety Dongdao 122).

[0059] The control was unamended. Three replicates were set for each treatment, and each replicate was a 0.5-hectare field. The amendment was applied in May, and the field was mechanically harrowed after soaking. Rice seedlings were planted on June 17. The rice was harvested in the field, and experts were organized to measure the rice yield. Soil pH, EC, and organic matter were measured after harvest.

[0060] The rice yield of the control field in the severe saline-alkali land (soil pH 10.00, EC 0.60mS / cm) in the first year of rice planting was only 3.02 kg / mu. Four treatments were set up in the field, including unimproved control (CK), phosphogypsum + organic fertilizer + microbial fertilizer + Tongze 816 (MGB1), phosphogypsum + organic fertilizer + microbial fertilizer + Dongdao 122 (MGB2), and phosphogypsum + organic fertilizer + Dongdao 122 + side deep fertilization (MGB3).

[0061] In that year, the soil improvement and fertilization technology with phosphogypsum + organic fertilizer + microbial fertilizer as the core was adopted, matched with Dongdao 122 and related cultivation measures, and the rice yield was 426.60 kg / mu, while the rice yield was 412.34 kg / mu with Tongze 861 and related cultivation technology. The yield of phosphogypsum + organic fertilizer treatment, Dongdao 122 and side deep fertilization treatment was 456.16 kg / mu. From the soil characteristics, the pH of the MGB1 treatment decreased by 16.65%, EC by 61.63%, ESP by 43.85%, and organic matter increased by 113.20%; the pH of the MGB2 treatment decreased by 9.21%, EC by 38.12%, ESP by 20.19%, and organic matter increased by 102.14%; the pH of the MGB3 treatment decreased by 12.10%, EC by 36.48%, ESP by 45.23%, and organic matter increased by 131.79%, with significant results.

[0062] Under the severe saline-alkali conditions in Zhaoyuan (pH=10.0; EC=600μS / cm), a composite formula of components such as phosphogypsum, organic fertilizer, and microbial bacteria was applied in the first year, and the Tongze 861 and Dongdao 122 varieties were matched. Compared with the unimproved control, the pH, EC, and ESP were significantly reduced, and the soil organic matter was significantly increased. The rice yields reached 412.34 kg / mu and 426.6 kg / mu, respectively, which were 135.5 times and 140.3 times higher than the control.

[0063] In general, under severe saline-alkali conditions, compared with the unamended control, different combinations of phosphogypsum, organic fertilizer, and microbial fertilizer significantly improved soil salinity, nutrients, and yield, indicating that the combination of phosphogypsum, organic fertilizer, and microbial fertilizer has a better effect.

Claims

1. A composition for improving soil quality and fertilizing soda saline-alkali land and increasing yield, characterized in that The soda saline-alkali land soil improvement and fertilization high-yield composition consists of 10-60% of phosphogypsum, 10-60% of organic fertilizer, 0-15% of humic acid, 0-2% of microbial fertilizer and the remainder of water retaining agent according to mass fraction.

2. The composition for improving soil quality and fertilizing soda saline-alkali land according to claim 1, characterized in that The water retaining agent is polyacrylamide.

3. The composition for improving soil and fertilizing soda saline-alkali land according to claim 1, characterized in that The humic acid is regenerated humic acid derived from lignite.

4. The composition for improving soil and fertilizing soda saline-alkali land according to claim 1, characterized in that The microbial fertilizer is nitrogen-fixing bacteria, phosphate-dissolving bacteria, potassium-dissolving bacteria, potassium humate, seaweed or amino acid.

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