Method for increasing rice planting yield in coastal mild salinized land by applying biochar

Abstract

The invention relates to the technical field of stress-resistant cultivation of rice, and particularly provides a method for increasing the planting yield of rice in a coastal mild salinized land by applying biochar. According to the method, rice straw biochar is applied to the coastal slightly-salted land, the rice straw biochar is uniformly applied at a time during soil preparation before rice transplanting in the first year, it is guaranteed that the biochar is fully and uniformly mixed with a soil layer of 0-20 cm, and the biochar is not applied any more in the second year. According to the method, the rice straw biochar is uniformly applied at one time during soil preparation before rice transplanting, the effect of continuously improving the coastal slightly-salted land for two years is achieved, the addition amount of the biochar can be effectively saved, the improvement cost is reduced, and the rice planting yield is increased.

Description

Technical Field

[0001] The invention relates to the technical field of rice stress-resistant cultivation, and specifically provides a method for applying biochar to increase rice planting yield in coastal lightly saline land. Background Art

[0002] More than 60% of the population in my country rely on rice as their staple food. Stabilizing the existing rice cultivation area and promoting the comprehensive development and utilization of saline land are of vital strategic importance to ensuring national food security. Saline land is an important reserve arable land resource in my country. Strengthening the comprehensive utilization of saline land is one of the important measures to keep the red line of arable land and ensure food security. In the context of the increasingly severe global food situation, how to comprehensively transform and utilize saline soil has become an important issue before us.

[0003] The application of biochar in agricultural production is particularly prominent. Its porous structure can absorb and store nutrients in the soil, reduce nutrient loss, and improve the soil's ability to retain water and fertilizer. At the same time, biochar can also improve soil aeration, promote the growth and reproduction of microorganisms, and is beneficial to the growth and development of crop roots. Biochar has the characteristics of improving soil structure, retaining water and fertilizer, and strong adsorption, which can affect the physical and chemical properties of saline soil and crop growth characteristics. In recent years, biochar has been increasingly used in saline soil remediation, and has played a good effect on reducing soil bulk density and the total amount of water-soluble salts. Studies have also shown that biochar has a positive effect on improving the salt tolerance of crops.

[0004] There are many types of biochar, and there are many types of soil in my country. The performance of biochar on different soils is also different. At present, there are few studies on the application of saline land improvement technology with biochar as the core to rice cultivation in coastal mild saline land, and most of them remain in the stage of indoor simulation, small plot field trials and potted trials. Compared with indoor simulation, small plot field trials and potted trials, the field exploration of biochar in coastal saline land has significant differences in soil environment, climatic conditions, crop growth and management measures. These differences make field exploration more challenging and complex, but they can also more truly reflect the application effect of biochar on coastal saline land. Summary of the invention

[0005] The present invention selects a biochar type that is simple to make and low in cost, in order to explore the effects of different biochar types and biochar application amounts on the growth, development and yield of rice in coastal saline land, and provides the best biochar type and application amount combination for rice yield performance in saline land, as well as the corresponding rice planting method. By applying biochar in the first year, the improvement effect of coastal mildly saline land for two consecutive years is achieved.

[0006] The present invention provides the following technical solutions: A method for applying biochar to increase rice planting yield in coastal lightly saline land, wherein rice straw biochar is applied to the coastal lightly saline land, the biochar is evenly applied once during land preparation before rice transplanting in the first year, and no biochar is applied in the second year, and the specific steps are as follows: The rice fields are prepared and ridged. 21 days before rice planting, rice straw biochar is applied to the shallow soil at one time during land preparation before rice transplanting, and the rice straw biochar is fully mixed with the soil layer using a rotary tiller to give full play to its improvement effect. The soil layer depth is 0-20 cm; The rice plant spacing is 20×20 cm; The rice is planted in small plots, each of which has an area of ​​18 m 2 ; Ten days after the rice turns green, shallow water irrigation is carried out with 0.3% w / v freshwater, and the salt concentration of each plot is measured every 1 day to ensure that the salt concentration of each plot does not change by more than 0.05%. Water is cut off 7 days before harvest; The pH value of the coastal lightly saline land is 7.24, the organic matter content is 25.09 g / kg, the alkaline nitrogen content is 213.38 mg / kg, the available phosphorus is 112.29 mg / kg, the available potassium is 256.64 mg / kg, and the conductivity is 2380 μS / cm; The rice straw biochar application rate is 60 t / hm 2 The rice variety is Shuangliangyou 138.

[0007] Furthermore, the rice is subjected to sowing and seedling raising treatment before planting.

[0008] Furthermore, the amount of fertilizer applied to the rice during the entire growth period is as follows: the total amount of pure nitrogen is 150 kg / hm 2 ; Total superphosphate dosage is 60 kg / hm 2 ; Total potassium oxide dosage is 100 kg / hm 2 .

[0009] Furthermore, the pH value of the rice straw biochar is 9.45, the total nitrogen is 8.2 g / kg, the total organic carbon is 602 g / kg, and the pore volume is 0.37 cm 2 / g, with a specific surface area of ​​681 m 2 / kg.

[0010] Beneficial effects of the present invention: The present invention applies rice straw biochar to the coastal mildly saline land before rice transplanting. The rice straw biochar is evenly applied once during land preparation before rice transplanting in the first year, achieving the improvement effect of the coastal mildly saline land for two consecutive years, which can effectively save the amount of biochar added, reduce the improvement cost, and increase the rice planting yield; there are many types of soil in my country, and the performance of biochar on different soils is also different. The present invention not only provides rice straw biochar for soil treatment of coastal mildly saline land, but also provides related rice planting methods and the optimal application amount of rice straw biochar to achieve the improvement of the coastal mildly saline land. At the same time, the present invention can not only explore the comprehensive utilization of biochar in saline land, but also take into account the ecological, economic and social benefits of saline land improvement. DETAILED DESCRIPTION

[0011] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0012] Example 1 Effects of different biochar types on rice yield Selection of test site: The test site is located in Leyi Village, Liguo Town, Ledong Li Autonomous County, Hainan Province, and the Ledong Experimental Demonstration Base of the National Salt-Alkali Tolerant Rice Technology Innovation Center (18°26′39″N, 108°53′32″E). The climate in this area belongs to tropical monsoon climate, and the soil type is dry red soil. The basic characteristics of the soil (0-20cm) before planting are as follows: pH value is 7.24, organic matter content is 25.09 g / kg, alkaline nitrogen content is 213.38 mg / kg, available phosphorus is 112.29 mg / kg, available potassium is 256.64 mg / kg, and conductivity is 2380 μS / cm. The test site is adjacent to the sea and is less than one kilometer away from the estuary. Due to the backflow of seawater during the high tide in the rainy season in Hainan over the years, there is enough coastal saline land for testing and salinization to varying degrees. The test is not in the rainy season and is less affected by severe climate such as sunlight, rain, and typhoons. The test facilities are complete and can meet the basic test conditions.

[0013] Variety selection: The variety selected is "Shuangliangyou 138", which has excellent comprehensive traits, medium tillering ability, large ears with many grains, dense grains, and high fruit setting rate; high yield, strong stress resistance, and stable fruit setting performance under high temperature and drought; moderately salt-tolerant, can be used and planted on abandoned land with high salinity and alkalinity, and is suitable for large-scale promotion and application.

[0014] Cultivation management during the whole growth period: Fertilizer application: The total amount of pure nitrogen is 150 kg / hm2, and the base fertilizer, tillering fertilizer, and panicle fertilizer are applied in a ratio of 1:1:1; the total amount of superphosphate and potassium oxide is 60 and 100 kg / hm2 respectively, which are applied once as base fertilizer. Field management, fertilization methods, and pest and disease control measures are the same as those of conventional rice field management in this area. The fertilizer, water, and pest and disease management of each variety during the growth period are the same. After the rice matures, it is manually selected 5m 2 Calculate production based on actual harvesting in the region and determine actual output.

[0015] Collection and analysis of experimental data: The original data collected in the field are recorded and archived for comparative analysis between treatments.

[0016] Experimental design: This experiment adopted a two-factor randomized block design; the two factors were biochar type and application amount. The biochar types included peanut straw biochar (T1), soybean straw biochar (T2), corn straw biochar (T3), wheat straw biochar (T4), and rice straw biochar (T5). The application amounts were S1 (30 t / hm 2 )、S2(60t / hm 2 ); no biochar application was used as the control (T0), with a total of 11 treatments, 3 replicates, and 33 plots. The plant spacing was 20×20 cm, and the plot area was 18 m 2 (6*3m). Biochar should be applied evenly at one time during land preparation before rice transplanting in the first year to ensure that the biochar is fully mixed with the 0-20cm soil layer. No biochar will be applied in the second year.

[0017] Biochar is made by carbonization under high temperature conditions of 500℃ in the absence of oxygen. The pH value of the peanut straw biochar is 8.5, the total nitrogen content is 14.0g / kg, the total organic carbon content is 670g / kg, the pore volume is 0.6cm² / g, and the specific surface area is 680m² / kg; the pH value of the soybean straw biochar is 8.3, the total nitrogen content is 6.0g / kg, the total organic carbon content is 610g / kg, the pore volume is 0.45cm² / g, and the specific surface area is 637m² / kg; the pH value of the wheat straw biochar is 8.2, the total nitrogen content is 6.9g / kg, the total organic carbon content is 627g / kg, the pore volume is 0.45cm² / g, and the specific surface area is 642m² / kg; the pH value of the rice straw biochar is 9.45, the total nitrogen is 8.2g / kg, the total organic carbon is 602g / kg, the pore volume is 0.37 cm2 / g, and the specific surface area is 681 m2 / kg.

[0018] Biochar application method: In February 2023, 21 days before rice planting, apply once during land preparation before rice transplanting. No biochar will be applied in the second year. Apply various types of biochar evenly on the shallow soil of the corresponding treatment according to the design, and then use a rotary tiller to fully mix the biochar with the surface soil (0-20cm). Ensure that the biochar is evenly distributed in the soil so that its improvement effect can be fully exerted.

[0019] Rice transplanting: The transplanting time is March 2023. When the seedlings grow to a certain number of leaves (usually 3-4 leaves) in March 2024, they will enter the transplanting stage. Two strong seedlings with the same growth momentum will be transplanted into each treatment. Pay attention to shallow transplanting and maintain the spacing between rows and plants (20 cm × 20 cm) to ensure that the seedlings are evenly distributed.

[0020] Ten days after the rice turned green, 0.3% w / v freshwater was used for shallow water irrigation, and the salt concentration of each plot was measured every 1 day to ensure that the salt concentration of each plot did not change by more than 0.05%. Water was cut off 7 days before harvest. The field management and fertilization methods, as well as pest and disease control measures were consistent for two years, which was the same as the conventional rice field management in this area.

[0021] The test results are as follows: (Harvest in July 2023 and July 2024, and rice yield statistics) (1) Appendix 1 shows the effects of different types of biochar and application rates on rice yield and composition factors (2023). As can be seen from Appendix 1, the rice yield of different types of biochar generally shows a trend of T5>T3>T4>T2>T1>T0, among which there is no significant difference between T5 and T3. T5 increases yield by 7.6%, 0.8%, 9.2%, 14.2%, and 22.0% compared with T4, T3, T2, T1, and T0 treatments, respectively. In terms of comprehensive application rate, the rice yield of T5 treatment at S2 application rate is the highest, which is 5.44 t / ha; even when rice straw biochar is used, and 60 t / hm 2 The rice yield under the highest application amount increased by 27.1% compared with the control.

[0022] (2) Appendix 2 shows the effects of different types of biochar and application rates on rice yield and yield components (in 2024). As can be seen from Appendix 2, the rice yield of different types of biochar generally shows a trend of T5>T3>T4>T2>T1>T0, among which there is no significant difference between T5 and T3. T5 increases yield by 14.8%, 7.1%, 1.4%, 11.2%, and 21.8% compared with T4, T3, T2, T1, and T0 treatments, respectively. In terms of comprehensive application rate, the rice yield of T5 treatment at S2 application rate is the highest, which is 5.28 t / ha; even when rice straw biochar is used, and 60 t / hm 2 The rice yield under the highest application amount increased by 29.4% compared with the control.

[0023] (3) Appendix 3 shows the interannual average of the effects of different types of biochar and application rates on rice yield and composition factors in two years. The average values ​​of the two years can be used to verify the results to ensure that the results are more accurate. The results show that the rice yield under different biochar application rates is T5>T3>T2>T4>T1>T0, and the rice yield under the S2 application rate under the T5 treatment is the highest, which is 5.36t / ha. Even if rice straw biochar is used, and 60 t / hm 2 The rice yield under the highest application amount increased by 28.2% compared with the control.

[0024] Appendix Description Appendix 1 Effects of different types of biochar and application rates on salt-tolerant rice yield and composition factors (2023)

[0025]

[0026] Note: Different capital letters in the same column indicate significant differences at the 0.05 level, and different lowercase letters in the same treatment indicate significant differences at the 0.05 level.

[0027] Appendix 2 Effects of different types of biochar application on salt-tolerant rice yield and composition factors (2024)

[0028] Note: Different capital letters in the same column indicate significant differences at the 0.05 level, and different lowercase letters in the same treatment indicate significant differences at the 0.05 level.

[0029] Appendix 3 Effects of different types of biochar and application rates on salt-tolerant rice yield and composition factors (annual average)

[0030]

[0031] Note: Different capital letters in the same column indicate significant differences at the 0.05 level, and different lowercase letters in the same treatment indicate significant differences at the 0.05 level.

[0032] Experimental conclusion: According to Tables 1-3, it can be concluded that applying rice straw biochar evenly at one time during land preparation before rice transplanting in the first year can achieve the best improvement effect on coastal lightly saline land for two consecutive years, effectively saving the amount of biochar added, reducing improvement costs, and increasing rice production.

[0033] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for increasing rice yield in coastal lightly saline land by applying biochar, It is characterized in that Rice straw biochar is applied to the coastal lightly saline land. The biochar is evenly applied once during land preparation before rice transplanting in the first year, and no biochar is applied in the second year. The specific steps are as follows: The rice fields are prepared and ridged. 21 days before rice planting, rice straw biochar is applied to the shallow soil at one time during land preparation before rice transplanting, and the rice straw biochar is fully mixed with the soil layer using a rotary tiller to give full play to its improvement effect. The soil layer depth is 0-20 cm; The rice plant spacing is 20×20 cm; The rice is planted in small plots, each of which has an area of ​​18 m 2 ; Ten days after the rice turns green, shallow water irrigation is carried out with 0.3% w / v freshwater, and the salt concentration of each plot is measured every 1 day to ensure that the salt concentration of each plot does not change by more than 0.05%. Water is cut off 7 days before harvest; The pH value of the coastal lightly saline land is 7.24, the organic matter content is 25.09 g / kg, the alkaline nitrogen content is 213.38 mg / kg, the available phosphorus is 112.29 mg / kg, the available potassium is 256.64 mg / kg, and the conductivity is 2380 μS / cm; The rice straw biochar application rate is 60 t / hm 2 ; The rice variety is Shuangliangyou 138.

2. The method according to claim 1, It is characterized in that The rice is subjected to sowing and seedling raising treatment before planting.

3. The method according to claim 1, It is characterized in that The amount of fertilizer applied to the rice during the entire growth period is as follows: the total amount of pure nitrogen is 150 kg / hm 2 ; Total superphosphate dosage is 60 kg / hm 2 ; Total potassium oxide dosage is 100 kg / hm 2 .

4. The method according to any one of claims 1 to 3, It is characterized in that The pH value of the rice straw biochar was 9.45, the total nitrogen was 8.2 g / kg, the total organic carbon was 602 g / kg, and the pore volume was 0.37 cm 2 / g, with a specific surface area of ​​681 m 2 / kg.

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