Method for improving soda saline-alkali soil

Abstract

The invention provides an improvement method of soda saline-alkali soil, and belongs to the technical field of soil improvement. The method comprises the following steps: crushing corn straws, spreading the crushed corn straws on the surface of soda saline-alkali soil according to the addition amount of 15-20 tons / hectare, ploughing, harrowing, ridging, sowing jute seeds, fertilizing, and burying a drip irrigation belt in the middle of a ridge at a position 3-5 cm away from the earth surface. According to the method, the straw returning technology is matched with jute planting, the soil salinity and alkalinity of the soda saline-alkali soil are remarkably reduced, the soil fertility is improved, the soil environment is improved, and the yield and quality of jute are remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of soil improvement, and in particular relates to a method for improving soda saline-alkali soil. Background Art

[0002] The main components of soda saline-alkali land are sodium carbonate and sodium bicarbonate, namely soda and baking soda. These salt substances accumulate in the soil, leading to increased soil pH, damaged soil structure, reduced permeability, and decreased nutrient effectiveness, which seriously affects the growth and development of crops.

[0003] Jute (Corchorus capsularis L.) is an annual herbaceous plant of the genus Jute in the Tiliaceae family. The root system of jute can absorb salt from the soil and fix the salt in the plant body during its growth process, thereby reducing the salt content of the soil. At the same time, jute has a taproot system with a well-developed root system. The main root can penetrate the soil vertically to a depth of more than 1 meter. The fibrous roots are mainly distributed in the 0-20cm soil layer, which plays an important role in improving the physical properties of the soil.

[0004] Chinese patent CN 101305673A discloses a method for planting jute in saline-alkali land, including land preparation, sowing and harvesting. The land preparation includes building a drainage system; draining the accumulated water in the saline-alkali land to the river system; the drainage system includes drainage ditches arranged along the length of the land; and planting jute on the plots formed between adjacent drainage ditches. Improving the economic benefits of planting jute in saline-alkali land also further reduces the salinity of the saline-alkali land in the hemp field. The drainage system needs to be regularly maintained and maintained during use to ensure its normal operation. However, due to the complex and changeable environment of saline-alkali land, maintenance is difficult and requires more manpower and material resources. If the drainage system lacks an effective management and supervision mechanism, problems such as facility damage and blockage may occur, affecting the drainage effect and even causing greater environmental problems.

[0005] Chinese patent CN109874438A discloses a method for improving saline-alkali land, which includes deep plowing the saline-alkali land and laying a layer of mushroom residue; filling the soil back to make ridges, applying 1500-3000kg / mu of decomposed organic fertilizer in the ridges, and covering with film; planting kenaf on the ridges, with 2-3 rows per ridge, a sowing amount of 2-2.5kg / mu, a sowing depth of 3-5cm, and a spacing of 4-6cm. In addition, culture materials are laid in the ridges to plant mushrooms to form intercropping. It can effectively reduce the salinity and alkalinity of the soil and improve the growth and quality of kenaf. Although the film covering technology can reduce the evaporation of water in the soil surface, thereby reducing the accumulation of salt in the soil surface, this effect is temporary. With the changes of time and environment, especially when the water in the soil is absorbed or evaporated by crops, the salt in the deep soil may rise to the surface with capillary water, resulting in the phenomenon of "returning salt". The phenomenon of returning salt will lead to an increase in soil salinity and alkalinity, affecting the normal growth and development of crops, and may even cause crop death. After film covering, the gas exchange between the soil and the atmosphere is restricted, resulting in reduced soil permeability. Reduced soil permeability will affect the respiration of crop roots, which in turn affects the growth rate and yield of crops. At the same time, soil with poor permeability is more likely to breed harmful microorganisms, increasing the risk of crop diseases. After film covering, the soil temperature is more directly and significantly affected by the outside temperature. In sunny weather, the temperature inside the film may rise rapidly; while in rainy weather or at night, the temperature inside the film may drop rapidly. The drastic fluctuations in soil temperature will have an adverse effect on the growth of crops, such as causing heat damage or frost damage to crops. After film covering, since the soil surface is covered, it is difficult to directly contact the soil and crop roots during fertilization and topdressing, which increases the difficulty of fertilization. The difficulty of fertilization and topdressing may lead to insufficient nutrient supply for crops, affecting the normal growth and development of crops. In addition, improper fertilization may also cause problems such as nutrient loss or soil pollution. Film covering technology requires a lot of material and labor costs. For farmers with relatively poor economic conditions, higher cost inputs may increase their economic burden and affect their planting enthusiasm and income. It is difficult for mulch to be completely degraded after use. If not handled properly, it may remain in the soil, causing long-term pollution to the soil structure and ecological environment. Film covering technology may change the soil microecological environment, affect the diversity and activity of soil organisms, and further affect the balance and stability of the entire ecosystem. Existing improvement methods are often costly and slow in effect.

[0006] Therefore, there is an urgent need to provide a new method to improve soda saline-alkali land soil, significantly reduce the salinity of soda saline-alkali land soil, and promote sustainable agricultural development. Summary of the invention

[0007] In view of this, the object of the present invention is to provide a method for improving soda saline-alkali soil to solve the problems of high cost and slow effect of existing saline-alkali soil improvement methods.

[0008] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0009] The present invention provides a method for improving soda saline-alkali soil, comprising the following steps:

[0010] After the corn stalks are crushed, they are spread evenly on the surface of the soda saline-alkali soil at a rate of 15 to 20 tons per hectare. The soil is plowed and leveled to form ridges. Then jute seeds are sown, fertilizers are applied, and drip irrigation tapes are buried in the middle of the ridges 3 to 5 cm above the ground surface.

[0011] Preferably, the corn stalks are crushed to 3 to 6 cm.

[0012] Preferably, the paving thickness is 2 to 3 cm.

[0013] Preferably, the tillage depth is 25 to 35 cm.

[0014] Preferably, the ridge distance is 90 to 110 cm, the ridge height is 25 to 30 cm, and the ridge width is 65 to 75 cm.

[0015] Preferably, the sowing depth is 1 to 3 cm, the sowing row spacing is 40 to 70 cm, and the sowing amount is 20 to 25 kg / hectare.

[0016] Preferably, the amount of fertilizer applied is 1400-1600 kg / hectare.

[0017] Preferably, the sowing time is from mid-to-late April to early May.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention uses the straw return technology in combination with jute planting to significantly reduce the salinity of soda saline-alkali land soil, increase soil fertility, improve the soil environment, and significantly improve the yield and quality of jute.

[0020] The salt content of the soda saline-alkali soil is mainly sodium carbonate and sodium bicarbonate, with high salt content and high alkalinity. The present invention can gradually reduce the salt and alkalinity in the soda saline-alkali soil through physical leaching and salt inhibition and its decomposition through deep plowing with an appropriate amount of corn stalks, thereby creating a more favorable soil environment for the growth of jute. After the corn stalks are decomposed in the soda saline-alkali soil, the organic matter content of the soil will be increased, the soil structure will be improved, and the water and fertilizer retention capacity of the soil will be improved. At the same time, jute is a taproot plant, and the lateral roots are mainly distributed in the cultivated layer of soil, and the main roots can be distributed in the soil layer above 1 meter. The extension of the developed main roots and lateral roots in the soil can increase the soil porosity, improve the physical structure of the soil, reduce the degree of salinity, and increase the organic matter in the deep soil.

[0021] The present invention can accurately control the amount of irrigation water through the drip irrigation belt, directly transport water to the roots of jute, reduce water evaporation on the surface and leakage into the deep soil, thereby greatly improving irrigation efficiency. Drip irrigation technology can also reduce the scouring of the soil surface by irrigation water, prevent saline-alkali substances from rising to the surface with water, and further reduce the harm of salinity to jute growth.

[0022] The present invention provides necessary nutrients for the growth of jute through the nutrients released by corn stalks during the decomposition process. At the same time, the drip irrigation belt can also be combined with a fertilization system to transport fertilizers to the roots of jute along with water, thereby realizing integrated water and fertilizer management and promoting the growth and development of jute. Returning straw to the field and laying drip irrigation belts can improve the growth environment of the jute root system, making the root system more developed, which is conducive to jute absorbing water and nutrients in the soil, and improving jute's stress resistance and yield; it helps to reduce the use of chemical fertilizers and pesticides, and reduce the risk of agricultural non-point source pollution; it promotes the improvement and management of saline-alkali land, and lays the foundation for the sustainable development of agricultural production. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a diagram of the jute growth process (upper left: jute seedlings emerging from planting; upper right: jute's growing season; lower left: jute's root system; lower right: jute stem bark). DETAILED DESCRIPTION

[0024] The present invention provides a method for improving soda saline-alkali soil, comprising the following steps:

[0025] After the corn stalks are crushed, they are spread evenly on the surface of the soda saline-alkali soil at a rate of 15 to 20 tons per hectare. The soil is plowed and leveled to form ridges. Then jute seeds are sown, fertilizers are applied, and drip irrigation tapes are buried in the middle of the ridges 3 to 5 cm above the ground surface.

[0026] In the present invention, the corn stalks are crushed to 3-6 cm, and further crushed to 4-5 cm; the addition amount is preferably 16-18 tons / hectare; the tillage depth is preferably 25-35 cm, and more preferably 28-32 cm; the ridge distance is preferably 90-110 cm, and more preferably 95-105 cm; the ridge height is preferably 25-30 cm, and more preferably 26-28 cm; the ridge width is preferably 65-75 cm, and more preferably 70 cm; the sowing time is preferably from mid-to-late April to May Early April, more preferably late April; the sowing method is preferably row sowing; the sowing depth is preferably 1-3 cm, more preferably 2 cm; the sowing row spacing is preferably 40-70 cm, more preferably 45-55 cm; the sowing amount is preferably 20-25 kg / hectare, more preferably 22-24 kg / hectare; the fertilizer application amount is preferably 1400-1600 kg / hectare, more preferably 1450-1550 kg / hectare; the distance between the drip irrigation belt and the ground surface is more preferably 4 cm.

[0027] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0028] Example 1

[0029] 18 tons / hectare of corn stalks crushed to 4 cm were spread on the surface of the heavily saline-alkali land with a thickness of 2 cm. The crushed corn stalks spread on the heavily saline-alkali land were turned deeply to a 30 cm soil layer, and the surface was leveled with a tiller twice. Then a wide ridge platform was made with a ridging machine, with a ridge spacing of 100 cm, a ridge platform height of 23 cm, and a ridge width of 70 cm. Salt-alkali-tolerant, high-yield and high-quality jute seeds were selected, and a sowing-fertilization-laying machine was used for sowing, fertilization, and laying of drip irrigation tapes. Two rows of jute were sown on the wide ridges, with a sowing depth of 2.5 cm, a sowing row spacing of 50 cm, and a sowing amount of 22.5 kg / hectare; 1500 kg / hectare of compound fertilizer (18-18-18) was applied; the drip irrigation tape was laid in the middle of the wide ridge, 4 cm from the surface. For field management, water was supplemented through drip irrigation according to actual precipitation conditions, and pest and disease management was carried out routinely.

[0030] Example 2

[0031] 15 tons / hectare of corn stalks crushed to 3 cm were spread on the surface of the heavily saline-alkali land with a thickness of 1 cm. The crushed corn stalks spread on the heavily saline-alkali land were turned deeply to a 25 cm soil layer, and the surface was leveled with a tiller twice. Then a ridger was used to make a wide ridge platform with a ridge spacing of 90 cm, a ridge platform height of 20 cm, and a ridge width of 65 cm. Salt-alkali-tolerant, high-yield and high-quality jute seeds were selected, and a sowing-fertilization-laying machine was used for sowing, fertilization, and laying of drip irrigation tapes. Two rows of jute were sown on the wide ridges with a sowing depth of 2 cm, a sowing row spacing of 40 cm, and a sowing amount of 20 kg / hectare; 1400 kg / hectare of compound fertilizer (18-18-18) was applied; the drip irrigation tape was laid in the middle of the wide ridge, 3 cm from the surface. For field management, water was supplemented through drip irrigation according to actual precipitation conditions, and pest and disease management was carried out routinely.

[0032] Example 3

[0033] 20 tons / hectare of corn stalks crushed to 5 cm were spread on the surface of the heavily saline-alkali land with a thickness of 3 cm. The crushed corn stalks spread on the heavily saline-alkali land were turned deeply to a 35 cm soil layer, and the surface was leveled with a tiller twice. Then a ridger was used to make a wide ridge platform with a ridge spacing of 110 cm, a ridge platform height of 25 cm, and a ridge width of 75 cm. Salt-alkali-tolerant, high-yield and high-quality jute seeds were selected, and a sowing-fertilization-laying machine was used for sowing, fertilization, and laying of drip irrigation tapes. Two rows of jute were sown on the wide ridges with a sowing depth of 3 cm, a sowing row spacing of 60 cm, and a sowing amount of 25 kg / hectare; 1,600 kg / hectare of compound fertilizer (18-18-18) was applied; the drip irrigation tape was laid in the middle of the wide ridge, 5 cm from the surface. For field management, water was supplemented through drip irrigation according to actual precipitation conditions, and pest and disease management was carried out routinely.

[0034] Experimental Example 1

[0035] On April 25, 2023, an experiment on planting jute to improve severe soda saline-alkali land was arranged in Guanshanzi Town, Changling County, Songyuan City, Jilin Province. The soil with a depth of 0 to 20 cm in severe saline-alkali land was selected to measure the pH of 10.05 and the EC of 1325 μS / cm. The experiment set up two treatments, namely planting jute and control (no planting), each treatment was repeated 3 times, with a total of 6 plots, each plot area of ​​200 square meters. Improvement was carried out according to the method of Example 1.

[0036] 1. Soil samples were collected from different depths of soil at different growth stages of jute to determine soil organic carbon (SOC), pH, and EC. SOC was determined using potassium dichromate oxidation method; pH and EC were determined using a pH meter.

[0037] At the same time, due to the patchiness of heavily saline-alkali land, soil samples were also collected from 30% of the area where jute was not grown in the jute planting area.

[0038] Experimental results: As shown in Table 1.

[0039] Table 1 Changes in soil organic matter and salinity degree after jute planting in severely saline-alkali soil

[0040]

[0041] It can be seen from Table 1 that the SOC, pH, and EC of each treatment showed the same change trend at different growth stages. Compared with the control (CK), the EC of different soil layers in the jute-planting area and the area without jute in the jute field decreased significantly, and the SOC increased significantly, indicating that planting jute can significantly reduce the soil salt content and alleviate the inhibitory effect on plants. Compared with CK, after jute harvest (soil samples on November 4th), the EC of the soil layers of 0-10 cm, 10-20 cm, 20-30 cm, and 30-40 cm decreased by 75.17%, 63.34%, 46.50%, and 47.69% respectively, and the SOC content increased by 18.68%, 81.25%, 86.82%, and 86.36% respectively. This further indicates that planting jute is beneficial to salt reduction and organic matter formation. At the same time, the distribution of jute roots in the deep soil further promotes the improvement of deep organic matter. For the soil without jute in the jute field, compared with CK, the EC of the soil layers of 0-10 cm, 10-20 cm, 20-30 cm, and 30-40 cm decreased by 31.45%, 29.67%, 17.25%, and 26.26% respectively (soil samples on November 4th), indicating that planting jute slows down the surface evaporation through the shading of the tall plants in the saline-alkali spot area, thus being beneficial to alleviating the salinity degree of the saline-alkali spot. After jute harvest, the soil pH of different soil layers showed that the pH of the jute-planting area < the area without jute in the jute field < CK, which also indicates that planting jute can reduce the soil pH, reduce the alkalization degree, and alleviate the inhibition of alkalinity on plants.

[0042] 2. Statistically analyze the biomass and agronomic indicators of jute at the mature stage. Randomly select 5 sampling points in the plot where jute is planted. Randomly select 1 linear meter of jute at each sampling point, count the number of jute plants, and then use the excavation method to dig out the jute plants with roots. Randomly select 10 jute plants at each sampling point to measure the plant height, and use a vernier caliper to measure the stem diameter and bark thickness. Separate the above-ground part and roots of the jute, shake off the soil on the roots, and then weigh them. Calculate the above-ground biomass and root biomass of jute per hectare according to the number of plants and the planting row spacing.

[0043] Experimental results: As shown in Table 2 and Table 3.

[0044] Table 2 Biomass of jute planted in severely saline-alkali soil

[0045]

[0046] Table 3 Agronomic indicators of jute planted in severely saline-alkali soil

[0047]

[0048]

[0049] As shown in Tables 2 and 3, in the soda severe saline-alkali land (pH 10.05, EC 1325μS / cm), jute can grow normally and bloom and mature after laying crushed straw and deep plowing, and the aboveground biomass reaches 42.31±1.71t / hm 2 , the root biomass reached 8.77±0.24t / hm 2 The plant height is 226.86±18.91cm, the stem thickness is 16.36±1.58mm, and the bark thickness is 1.33±0.22mm.

[0050] From the above embodiments and experimental examples, it can be seen that the improved method of the present invention is to plant jute on soda severe saline-alkali land. On the one hand, planting jute can effectively reduce soil salinity barriers, and continuous planting can achieve the planting of conventional crops. On the other hand, jute has high biological quality and considerable economic value. It can not only be used as hemp industrial products, but also high-lignin jute is a good biomass fuel. For this reason, planting jute on soda severe saline-alkali land is an effective measure to improve saline-alkali land and utilize saline-alkali land.

[0051] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for improving soda saline-alkali soil, characterized in that: The following steps are involved: After the corn stalks are crushed, they are spread evenly on the surface of the soda saline-alkali soil at a rate of 15 to 20 tons per hectare. The land is plowed, harrowed, and ridged. Then jute seeds are sown, fertilizers are applied, and the drip irrigation tape is buried in the middle of the ridge 3 to 5 cm from the ground surface.

2. The improved method according to claim 1, characterized in that: The corn stalks are crushed to 3-6 cm.

3. The improved method according to claim 1, characterized in that: The thickness of the paving is 2 to 3 cm.

4. The improved method according to claim 1, characterized in that: The tillage depth is 25 to 35 cm.

5. The improved method according to claim 1, characterized in that: The ridge distance is 90-110 cm, the ridge height is 25-30 cm, and the ridge width is 65-75 cm.

6. The improved method according to claim 1, characterized in that: The sowing depth is 1-3 cm, the sowing row spacing is 40-70 cm, and the sowing amount is 20-25 kg / hectare.

7. The improved method according to claim 1, characterized in that: The amount of fertilizer applied is 1400-1600 kg / hectare.

8. The improved method according to claim 1, characterized in that: The sowing time is from mid-to-late April to early May.

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