A method to alleviate hydrogen sulfide poisoning in cold-soaked muddy fields

Abstract

This invention discloses a method for alleviating hydrogen sulfide poisoning in cold-waterlogged muddy paddy fields. The method includes: during the rice's greening stage, mixing urea, ammonium sulfate, and ammonium nitrate in a pre-set first ratio and then spreading the mixture into the paddy field's water layer; during the rice's tillering stage, mixing urea, ammonium sulfate, and ammonium nitrate in a pre-set second ratio and then spreading the mixture into the paddy field's water layer, wherein the amount of ammonium nitrate used in the second ratio is greater than the amount used in the first ratio. Applying this invention can improve the condition of cold-waterlogged muddy paddy fields.

Description

Technical Field

[0001] This invention relates to the field of soil improvement technology, and in particular to a method for alleviating hydrogen sulfide poisoning in cold-soaked muddy fields. Background Technology

[0002] Rice is the most important food crop, and the stability and development of food production play a crucial role in ensuring the stability of the world's population. Among rice paddies, cold-waterlogged and muddy paddies account for a large proportion. Because these paddies are widely distributed in the lower parts of reservoirs and ponds, and in low-lying areas of plains and lakes, they are characterized by deep mud, rotten soil, and cold water. This leads to imbalances in water, fertilizer, air, and heat, poor soil structure or no structure at all, highly dispersed soil particles, poor permeability, and the dominance of anaerobic microorganisms in the soil. Nutrient decomposition is slow, and reducing substances accumulate in large quantities, which has become one of the factors hindering high rice yields. Especially in saline-alkali areas, sulfates readily undergo desulfurization, being reduced to hydrogen sulfide. Simultaneously, traditional fertilization practices by farmers often involve applying ammonium sulfate as topdressing nitrogen fertilizer, leading to a rapid accumulation of large amounts of sulfate ions and subsequent desulfurization. During the early tillering and greening stages after transplanting, the desulfurization process is weaker due to cool water and mud, resulting in a relatively low rate and concentration of hydrogen sulfide production and minimal impact on rice growth. However, as temperatures gradually rise later, desulfurization intensifies, leading to rapid hydrogen sulfide production. Since cold, waterlogged, and muddy fields have extremely poor soil permeability, toxic gases cannot be quickly expelled, making them highly susceptible to hydrogen sulfide poisoning, which harms rice growth, and in severe cases, causes black root growth and seedling death. Studies have shown that hydrogen sulfide poisoning in cold, waterlogged, and muddy fields reduces rice yield by 10% to 30% below normal levels, making it one of the types of paddy fields hindering high rice yields. Therefore, improving cold, waterlogged, and muddy fields is an urgent technical problem that needs to be solved. Summary of the Invention

[0003] In view of this, the main objective of this invention is to propose a method to alleviate hydrogen sulfide poisoning in cold-waterlogged muddy fields and improve the improvement efficiency of such fields.

[0004] To achieve the above objectives, the present invention provides a method for alleviating hydrogen sulfide poisoning in cold-soaked muddy fields, comprising:

[0005] During the rice's greening stage, urea, ammonium sulfate, and ammonium nitrate are mixed in a pre-set first ratio and then scattered into the paddy field water layer.

[0006] During the tillering stage of rice, urea, ammonium sulfate, and ammonium nitrate are mixed in a pre-set second ratio and then scattered into the paddy field water layer. The amount of ammonium nitrate in the second ratio is greater than the amount of ammonium nitrate in the first ratio.

[0007] Optionally, the ammonium nitrate salt is calcium ammonium nitrate.

[0008] Optionally, the first ratio is: 50 kg / ha of urea, 36.5 kg / ha of ammonium sulfate, and 27 kg / ha of calcium ammonium nitrate.

[0009] Optionally, the greening period is from June 3 to June 8.

[0010] Optionally, the second ratio is: 30 kg / ha of urea, 31.5 kg / ha of ammonium sulfate, and 48 kg / ha of calcium ammonium nitrate.

[0011] Optionally, the tillering period is between June 10th and June 15th.

[0012] As can be seen from the above technical solution, the method for alleviating hydrogen sulfide poisoning in cold-waterlogged muddy fields according to the embodiments of the present invention involves mixing urea, ammonium sulfate, and ammonium nitrate in a pre-set first ratio during the rice's greening stage and then spreading the mixture into the paddy field's water layer; during the rice's tillering stage, mixing urea, ammonium sulfate, and ammonium nitrate in a pre-set second ratio and then spreading the mixture into the paddy field's water layer, wherein the amount of ammonium nitrate in the second ratio is greater than the amount of ammonium nitrate in the first ratio. This utilizes the preferential occurrence of nitrate denitrification in ammonium nitrate to inhibit desulfurization, thereby reducing hydrogen sulfide production and improving the cold-waterlogged muddy fields. Simultaneously, the cationic calcium contained in ammonium nitrate adsorbs negatively charged soil colloids in the cold-waterlogged muddy fields, promoting the formation of soil aggregates and thus improving soil structure. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the method for alleviating hydrogen sulfide poisoning in cold-soaked muddy fields provided in an embodiment of the present invention. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0015] Cold-waterlogged, muddy paddy fields account for a large proportion of rice paddies. The soil particles are highly dispersed and have poor permeability. Anaerobic microorganisms dominate in the soil, while aerobic microorganisms are weak, resulting in slow decomposition of organic matter. This leads to slow nutrient decomposition and a high accumulation of reducing substances. Especially in saline-alkali areas with sulfate, sulfates undergo desulfurization and are reduced to hydrogen sulfide, affecting rice growth. At the same time, since nitrate nitrogen cannot be directly absorbed and utilized by rice roots, it needs to be converted into ammonium nitrogen through nitrate reduction before it can be absorbed by crops. Fertilization is slow to take effect. Therefore, farmers often use ammonium sulfate, which has a fast effect, for topdressing nitrogen fertilizer, further enhancing the desulfurization process.

[0016] In this embodiment, ammonium nitrates, such as calcium ammonium nitrate or potassium ammonium nitrate, are considered to be used. These contain both nitrate and ammonium nitrogen, offering the advantages of rapid nitrogen replenishment and the ability of cationic nutrients to improve the structure of acidic soils. Simultaneously, the water-soluble cationic nutrients provided, such as calcium and potassium, can enhance plant resistance to diseases, promote the activity of beneficial microorganisms in the soil, and preferentially promote nitrate denitrification. Nitrate denitrification is used to inhibit desulfurization, that is, the antagonistic effect between microorganisms is used to suppress the number and activity of sulfate-reducing bacteria. Nitrate can stimulate the growth of denitrifying bacteria that compete with sulfate-reducing bacteria for carbon sources (organic acids), inhibiting the growth of sulfate-reducing bacteria and desulfurization. Under the same carbon source conditions, the denitrification rate of microorganisms is more than twice that of sulfate reduction. The redox potential can characterize the system reaction state. When the redox potential is between -50mV and -150mV, denitrification mainly occurs; when the redox potential is between -300mV and -400mV, sulfate reduction mainly occurs. Under the same conditions, microorganisms are more capable of denitrification than sulfate reduction, thus nitrate reduction has a greater advantage. This reduces the production of H2S from desulfurization, thereby reducing hydrogen sulfide production and improving cold-soaked muddy fields.

[0017] Figure 1 This is a schematic diagram of the method for alleviating hydrogen sulfide poisoning in cold-soaked muddy fields provided by an embodiment of the present invention, as shown below. Figure 1 As shown, the method includes:

[0018] Step 101: During the rice's greening stage, mix urea, ammonium sulfate, and ammonium nitrate in a pre-set first ratio and then spread them into the paddy field water layer.

[0019] In this embodiment, considering that denitrification preferentially occurs in the presence of ammonium nitrate, leading to a weakening of desulfurization, the production of hydrogen sulfide can be effectively reduced. Furthermore, due to the poor soil structure of cold-waterlogged mudflats, and the fact that both nitrate nitrogen in ammonium nitrate carries a negative charge and soil colloids also carry a negative charge, nitrate nitrogen is not easily adsorbed and fixed by the soil, resulting in leaching loss. In this embodiment, cations, such as calcium and potassium, are introduced into the ammonium nitrate to promote the formation of soil aggregates.

[0020] In this embodiment, as an optional embodiment, the ammonium nitrate salt is calcium ammonium nitrate. Using calcium ammonium nitrate fertilizer serves two purposes: firstly, the cationic calcium in the fertilizer adsorbs negatively charged soil colloids in cold-soaked muddy fields, promoting the formation of soil aggregates and thus improving soil structure; secondly, the nitrate ions in the fertilizer preferentially undergo denitrification under the same environmental conditions compared to sulfate ions, thereby weakening desulfurization and reducing hydrogen sulfide production, thus improving the rice growing environment and increasing yield; and thirdly, through the denitrification (reduction) of nitrate ions, nitrate nitrogen can be converted into ammonium nitrogen, providing nutrients for crops.

[0021] In this embodiment, calcium ammonium nitrate is used because it contains both nitrate nitrogen and ammonium nitrogen. It contains 14% nitrate nitrogen and 1% ammonium nitrogen. Nitrate nitrogen has a weaker adsorption and fixation capacity with soil colloids, while ammonium nitrogen has a stronger adsorption and fixation capacity with soil colloids. Since the conversion of nitrate nitrogen to ammonium nitrogen takes a long time, calcium ammonium nitrate is used to partially replace ammonium sulfate when fertilizing.

[0022] In this embodiment, a mixed fertilization method of ammonium calcium nitrate and ammonium sulfate is adopted. Since the ammonium calcium nitrate has a nitrogen content of 15% (14% nitrate nitrogen + 1% ammonium nitrogen) and the ammonium sulfate has a nitrogen content of 21%, the low nitrogen content of ammonium calcium nitrate necessitates the conversion of nitrate nitrogen to ammonium nitrogen for crop absorption and utilization. Therefore, this mixed application method has two advantages: firstly, after initial fertilization, ammonium sulfate can provide ammonium nitrogen to meet the crop's growth needs, reducing the total amount of fertilizer applied. Secondly, nitrate ions are prone to denitrification, thereby reducing the desulfurization of sulfate ions. Thus, the introduction of ammonium nitrate can, to a certain extent, inhibit sulfate desulfurization and reduce the production of hydrogen sulfide gas in paddy fields. On the other hand, whether soil colloids aggregate or disperse mainly depends on their electrochemical potential. Normally, soil colloids carry a negative charge, especially those from cold-waterlogged, muddy fields. Due to the negative electrochemical potential between soil colloids, they repel each other. The higher the negative electrochemical potential, the stronger the repulsion, and the more stable the sol. However, when this negative electrochemical potential decreases to the point where the intermolecular attraction between soil colloids exceeds the electrostatic repulsion, the soil colloids will aggregate to form a gel. Therefore, utilizing the cationic calcium in the calcium ammonium nitrate solution to adsorb onto the negatively charged soil colloids, promoting the formation of soil aggregates through bonding, thereby reducing the negative electrochemical potential and promoting rapid aggregation of soil colloids, thus improving soil aggregate structure.

[0023] In this embodiment, when soil colloids are in a gel state, it is conducive to the formation of water-stable aggregates and improves soil structure. Therefore, applying calcium ammonium nitrate to cold-waterlogged muddy fields can promote colloid aggregation, which is beneficial to the formation of water-stable aggregates and has a good effect on improving soil structure and aeration. Furthermore, it inhibits the generation of hydrogen sulfide gas, thereby mitigating hydrogen sulfide poisoning caused by desulfurization in cold-waterlogged muddy fields.

[0024] In this embodiment, as an optional embodiment, the first ratio is: 50 kg / ha of urea, 36.5 kg / ha of ammonium sulfate, and 27 kg / ha of calcium ammonium nitrate.

[0025] In this embodiment, as an optional implementation, the greening period is from June 3rd to June 8th. Urea (50 kg / ha), ammonium sulfate (36.5 kg / ha), and calcium ammonium nitrate (27 kg / ha) are mixed and then spread onto the paddy field's water layer. This utilizes the preferential occurrence of nitrate denitrification, thereby inhibiting desulfurization and reducing hydrogen sulfide production.

[0026] In this embodiment, the fertilizer applied during the greening period is greening fertilizer. During this period, although hydrogen sulfide is produced due to the cool weather, the amount produced is very low. Therefore, when applying nitrogen fertilizer at this stage, a small amount of ammonium calcium nitrate is used instead of ammonium sulfate, which can meet the nitrogen fertilizer requirements of rice during the greening period and reduce the amount of hydrogen sulfide produced at this stage.

[0027] Step 102: During the tillering stage of rice, urea, ammonium sulfate and ammonium nitrate are mixed in a pre-set second ratio and then scattered into the paddy field water layer. The amount of ammonium nitrate in the second ratio is greater than the amount of ammonium nitrate in the first ratio.

[0028] In this embodiment, as an optional embodiment, the second ratio is: 30 kg / ha of urea, 31.5 kg / ha of ammonium sulfate, and 48 kg / ha of calcium ammonium nitrate.

[0029] In this embodiment, as an optional embodiment, the tillering period is from June 10th to June 15th. Urea 30kg / ha, ammonium sulfate 31.5kg / ha, and calcium ammonium nitrate 48kg / ha are mixed and then spread in the paddy field water layer.

[0030] In this embodiment, tillering fertilizer is applied in mid-June. During this stage, the weather gradually warms up, and rice begins to tiller rapidly, leading to a rapid increase in hydrogen sulfide production. Therefore, the dosage of ammonium calcium nitrate is increased. The reaction time is about one week, and the effect can last for half a month, effectively preventing hydrogen sulfide poisoning in crops and ensuring normal crop growth during this period. In July and August after the tillering stage, with the reduction or elimination of the application of nitrogen fertilizers such as ammonium sulfate, there is no need to apply ammonium nitrate.

[0031] In this embodiment, as an optional embodiment, urea, ammonium sulfate, and calcium ammonium nitrate are directly scattered into the paddy field water layer during the greening stage and tillering stage, respectively.

[0032] In this embodiment, the comparison data before and after use is shown in Table 1.

[0033] Table 1

[0034]

[0035] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for alleviating hydrogen sulfide poisoning in cold-soaked, muddy fields, characterized in that, The method includes: During the rice's greening stage, urea, ammonium sulfate, and ammonium nitrate are mixed in a pre-set first ratio and then scattered into the paddy field water layer. During the tillering stage of rice, urea, ammonium sulfate, and ammonium nitrate are mixed in a pre-set second ratio and then spread into the paddy field water layer. The amount of ammonium nitrate in the second ratio is greater than that in the first ratio. Under the same environmental conditions, nitrate ions in ammonium nitrate preferentially undergo denitrification compared to sulfate ions, inhibiting desulfurization. Furthermore, through the denitrification of nitrate ions, nitrate nitrogen is converted into ammonium nitrogen, thereby providing nutrients for the crop.

2. The method as described in claim 1, characterized in that, The ammonium nitrate salt is calcium ammonium nitrate.

3. The method as described in claim 2, characterized in that, The first ratio is: 50 kg / ha of urea, 36.5 kg / ha of ammonium sulfate, and 27 kg / ha of calcium ammonium nitrate.

4. The method as described in claim 1, characterized in that, The period for the return to green is from June 3rd to June 8th.

5. The method as described in claim 2, characterized in that, The second ratio is: 30 kg / ha of urea, 31.5 kg / ha of ammonium sulfate, and 48 kg / ha of calcium ammonium nitrate.

6. The method according to any one of claims 1 to 5, characterized in that, The tillering period is from June 10th to June 15th.

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