CN105144893B - A kind of soaked field phase for improveing soda alkaline land paddy field fills water discharge method - Google Patents

Abstract

The invention relates to an irrigation and drainage method for improving paddy fields in soda saline-alkali land during the soaking period, and relates to a method for improving paddy fields in soda saline-alkali land. The invention aims to solve the problems of poor saline-alkali removal effect and low rice yield in the paddy fields of soda saline-alkali land in the prior art. The method of the present invention: one, select the paddy field of soda saline-alkali land; two, level the land, add desulfurization gypsum according to the alkalization degree of the soil; three, carry out the first artificial irrigation soaking the field; four, carry out the first water rake stirring, and then stabilize for 24 Hours, then carry out the 1st horizontal drainage; 5. After the 1st horizontal drainage is completed, carry out the 2nd artificial irrigation soaking field; Stabilize for 24 hours, and then carry out the second horizontal drainage, that is, complete the irrigation and drainage of the improved soda saline-alkali paddy field soaking period. The improved soda saline-alkali paddy field of the invention has a thorough effect of draining the saline-alkali, and the rice yield is increased by 36%-63%. The invention is used for the improvement of paddy fields in soda saline-alkali land.

Description

A method of irrigation and drainage during the soaking period for improving paddy fields in soda saline-alkali land

technical field

The invention relates to a method for improving soda saline-alkali land.

Background technique

For the development of rice in saline-alkaline land, it is necessary to grasp the law of saline-alkali activity, and determine a reasonable irrigation technology under the conditions of supporting projects, which can ensure water supply for rice, leaching saline-alkali, and preventing secondary salinization. In the existing technology, when the irrigation system is formulated, only the water supply in each growth stage of rice is paid attention to, and a main process of irrigation, that is, water irrigation and drainage in the field soaking stage, is ignored. Water irrigation and drainage during the soaking period of saline-alkali soil is the main way to wash and discharge salt, which is of great significance to the improvement of saline-alkali land. The water irrigation and drainage in the soaking field period in the prior art is only a rough expression of the amount of irrigation and the number of irrigations, and there is no complete set of technical guidance for irrigation and drainage methods in the soaking field period, especially for improved saline-alkali soil paddy fields. The method is different from washing salt in ordinary soaking fields, and a complete set of technical guidance is urgently needed to guide the irrigation and drainage of paddy fields in soda saline-alkali land.

Contents of the invention

The invention aims to solve the problems of poor saline-alkali removal effect and low rice yield in soda-saline-alkali paddy fields in the prior art, and provides an irrigation and drainage method for improving soda-saline-alkali paddy fields during the soaking period.

The improved soda saline-alkali land paddy field soaking stage irrigation and drainage method of the present invention is realized according to the following steps:

One, select the soda saline-alkali paddy field with pH of 9.77-10.65; the EC of the soda saline-alkali paddy field is 0.68-2.94mS/cm;

2. To level the land, add 100% GR of desulfurized gypsum as a modifier according to the alkalinity of the soil;

The added amount of desulfurized gypsum is calculated according to the following formula:

100%GR＝1.25×CEC×(ESP _i –ESP _f )×10 ^-2

In the above formula:

100% GR is the amount of desulfurized gypsum added, and the unit is mol _c /kg, where the subscript c of mol _c is the charge number, and mol _c is the unit, which is equivalent to the equivalent concentration;

CEC is the soil cation exchange capacity, which is 200mmol _c /kg; ESP _i is the initial alkalinity of the soil;

ESP _f is the soil target alkalization degree, which is set to 5%;

The addition of 100% GR of desulfurized gypsum refers to the amount of desulfurized gypsum required to replace all the exchangeable Na ⁺ in the soil of 0-20 cm;

3. Carry out the first artificial irrigation soaking field, the water consumption of the first artificial irrigation soaking field is that the water surface reaches the height of 6-10cm above the soil surface; the first artificial irrigation soaking time is 24-48 Hour;

4. After the first artificial irrigation soaking the field, perform the first water rake stirring, then stabilize for 10-14 hours, and then perform the first horizontal drainage;

Five, after the first horizontal drainage is completed, carry out the second artificial irrigation soaking field; the water consumption of the second artificial irrigation soaking field is that the water surface reaches the height of 6-10cm above the soil surface; the second artificial irrigation Irrigation soaking time is 24-48 hours;

6. After the second artificial irrigation and soaking of the field, perform the second water rake to stir the slurry, then stabilize it for 4-8 hours, and then perform the second horizontal drainage, that is, complete the irrigation and drainage of the improved soda saline-alkali paddy field during the soaking period. Put water to settle the rice seedlings.

The method of the present invention has the following beneficial effects:

1. The present invention overcomes the prior art that only pays attention to the water supply in each growth stage of rice when the irrigation system is formulated, while ignoring the inherent thinking of irrigation and drainage in the soaking field stage, and the present invention establishes a complete set of technical guidance for the soaking field stage. The irrigation and drainage method is especially suitable for the irrigation and drainage method of the improved saline-alkali soil paddy field; the method of the present invention is drained after two times of stirring, so that more saline and alkali can be discharged, and the soil salinity in the root zone is guaranteed to be low. After the treatment, the pH of the saturated water in the saline-alkali ground water and the conductivity of the saline-alkali subsurface mud do not decrease with the prolongation of time, but remain stable, which shows that the method of the present invention has a thorough effect of removing salinity and alkali.

Two, the present invention is on the basis of experiment, the soaking field period irrigation and drainage method of discovery and summary, this method has solid theoretical basis; Compared with the paddy fields treated with pulp, the rice yield increased by 36%-63%.

Description of drawings

Fig. 1 is the time-varying graph of the pH of the saline-alkali field surface water of the first irrigation bubble field monitored in experiments 1 to 6;

Fig. 2 is a graph showing the change in pH of the surface water of the saline-alkali field for 24 hours after the first stirring of the slurry monitored in experiments 1 to 6;

Fig. 3 is a graph showing the change in pH of the field surface water in saline-alkali land for 24 hours after the second stirring of the slurry monitored in experiments 1 to 6;

Fig. 4 is a diagram showing the change of EC of the surface water of the saline-alkali field monitored in experiments 1 to 6 for the first irrigation;

Fig. 5 is a graph showing the change of EC of surface water in saline-alkali land for 24 hours after the first stirring in the field monitored in experiments 1 to 6;

Figure 6 is a graph showing the change of EC of surface water in different saline-alkali fields for 24 hours after the second stirring in experiments 1 to 6;

Fig. 7 is the time-varying graph of conductivity of saline-alkali subsurface mud (0-10 cm) monitored in experiments 1-6 for the first time;

Fig. 8 is a diagram showing the change in electrical conductivity of saline-alkali subsurface mud (0-10 cm) over time after the first stirring in the field for 24 hours, monitored in experiments 1 to 6;

Fig. 9 is a diagram showing the change in electrical conductivity of saline-alkali subsurface mud (0-10 cm) over time after the second stirring of slurry monitored in experiments 1-6 for 24 hours;

Fig. 10 is the time-varying diagram of the electrical conductivity of the saline-alkali subsurface mud (10-20cm) of the first irrigation bubble field monitored in experiments 1 to 6;

Fig. 11 is the time-varying graph of electrical conductivity of saline-alkali subsurface mud (10-20cm) after the first stirring of the slurry monitored in experiments 1 to 6 for 24 hours;

Fig. 12 is the time-varying diagram of the electrical conductivity of the saline-alkali subsurface mud (10-20cm) during the 24 hours after the second stirring in the field monitored in experiments 1 to 6;

Fig. 13 is the comparison chart of the rice output obtained by the saline-alkali paddy field and the contrast paddy field after adopting the irrigation and drainage method of the present invention;

In Figures 1 to 12: Indicates experiment 1; Indicates experiment 2; Indicates experiment 3; Indicates experiment 4; Indicates experiment 5; Denotes Experiment 6.

detailed description

The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any reasonable combination among the specific embodiments.

Specific implementation mode one: the method for irrigation and drainage during soaking period of the improved soda saline-alkali paddy field described in this implementation mode is realized according to the following steps:

One, select the soda saline-alkali paddy field with pH of 9.77-10.65; the EC of the soda saline-alkali paddy field is 0.68-2.94mS/cm;

2. To level the land, add 100% GR of desulfurized gypsum as a modifier according to the alkalinity of the soil; the amount of desulfurized gypsum added is calculated according to the following formula:

100%GR＝1.25×CEC×(ESP _i –ESP _f )×10 ^-2

In the above formula:

100% GR is the amount of desulfurized gypsum added, and the unit is mol _c /kg, where the subscript c of mol _c is the charge number, and mol _c is the unit, which is equivalent to the equivalent concentration;

CEC is the soil cation exchange capacity, which is 200mmol _c /kg; ESP _i is the initial alkalinity of the soil;

ESP _f is the soil target alkalization degree, which is set to 5%;

The addition of 100% GR of desulfurized gypsum refers to the amount of desulfurized gypsum required to replace all the exchangeable Na ⁺ in the soil of 0-20 cm;

3. Carry out the first artificial irrigation soaking field;

4. After the first artificial irrigation soaking the field, perform the first water rake stirring, then stabilize for 10-14 hours, and then perform the first horizontal drainage;

5. After the first horizontal drainage is completed, the second artificial irrigation is carried out to soak the field;

6. After the second artificial irrigation and soaking of the field, perform the second water rake to stir the slurry, then stabilize it for 4-8 hours, and then perform the second horizontal drainage, that is, complete the irrigation and drainage of the improved soda saline-alkali paddy field during the soaking period. Put water to settle the rice seedlings.

The method described in this embodiment has the following beneficial effects:

1. It overcomes the existing technology that only pays attention to the water supply in each growth period of rice when the irrigation system is formulated, while ignoring the inherent thinking of irrigation and drainage in the soaking field period, and the present invention establishes a complete set of technical guidance for irrigation and drainage in the soaking field period The method is especially suitable for the irrigation and drainage method of the improved saline-alkali soil paddy field; the method of the present invention can discharge more saline-alkali after twice stirring the slurry, so as to ensure that the soil salinity in the root zone is low, and after being treated by the method of the present invention , the pH of the saturated water in the saline-alkali ground water and the conductivity of the saline-alkali subsurface mud do not decrease with the prolongation of time, but remain stable, indicating that the method of the present invention has a thorough effect of removing saline-alkali.

Two, this embodiment is on the basis of experiments, the soaking field period irrigation and drainage method found and summarized, the method has a solid theoretical basis; the soda saline-alkali land paddy field improved through the method of the present invention and the soaking field period irrigation and drainage but not carried out Compared with the paddy field treated with stirring, the rice yield is increased by 36%-63%.

Specific embodiment two: the difference between this embodiment and specific embodiment one is: in the step 3, the water consumption for the first artificial irrigation soaking field is that the water surface reaches a height of 6-10 cm above the soil surface. Other steps and parameters are the same as in the first embodiment.

Specific embodiment three: the difference between this embodiment and specific embodiment two is: the water consumption for the first artificial irrigation soaking field in step three is that the water surface reaches the height of 8 cm above the soil surface. Other steps and parameters are the same as in the second embodiment.

Embodiment 4: This embodiment differs from Embodiments 1 to 3 in that: in step 3, the first artificial irrigation soaking time is 24-48 hours. Its steps and parameters are the same as those in Embodiments 1 to 3.

Embodiment 5: This embodiment is different from Embodiment 4 in that: the first artificial irrigation soaking time in step 3 is 24 hours. Its steps and parameters are the same as those in Embodiment 4.

Embodiment 6: The difference between this embodiment and Embodiments 1 to 5 is that in step 4, the first water rake is used to stir the slurry, and then it is stabilized for 10-14 hours. Its steps and parameters are the same as those in Embodiments 1 to 5.

Embodiment 7: The difference between this embodiment and Embodiment 6 is that in step 4, the slurry is stirred with a water rake for the first time, and then stabilized for 12 hours. Its steps and parameters are the same as those in Embodiment 6.

Embodiment eight: this embodiment is different from embodiment one to seven in that: the water consumption of the second artificial irrigation soaking field in step five is that the water surface reaches the height of 6-10cm above the soil surface. Its steps and parameters are the same as those in Embodiments 1 to 7.

Embodiment nine: this embodiment is different from embodiment eight in that: the water consumption of the second artificial irrigation soaking field in step five is that the water surface reaches the height of 8 cm above the soil surface. Its steps and parameters are the same as those in the eighth embodiment.

Embodiment 10: This embodiment differs from Embodiments 1 to 9 in that: the second artificial irrigation soaking time in step 5 is 24-48 hours. Its steps and parameters are the same as those in Embodiments 1 to 9.

Embodiment 11: This embodiment is different from Embodiments 1 to 10 in that: the second artificial irrigation soaking time in step 5 is 24 hours. Its steps and parameters are the same as those in Embodiments 1 to 10.

Embodiment 12: The difference between this embodiment and Embodiments 1 to 11 is that in step 6, the second time of water rake stirring is carried out, and then it is stabilized for 4-8 hours. Its steps and parameters are the same as those in Embodiments 1 to 11.

Specific embodiment thirteen: This embodiment is different from specific embodiments 1 to 12 in that: in step 6, the second time of water rake stirring is performed, and then it is stabilized for 6 hours. Its steps and parameters are the same as those in Embodiments 1 to 12.

For verifying that the present invention is beneficial effect, carry out following experiment:

The following experiment selects three kinds of paddy fields with different soils, namely mild saline-alkali soil, moderate saline-alkali soil and severe saline-alkali soil. The chemical properties of the three soils are shown in Table 1, and they are divided into 6 experimental groups, respectively: Experiment 1: Severe saline-alkali soil without stirring treatment; Experiment 2: Severe saline-alkali soil with stirring treatment; Experiment 3: Moderate saline-alkaline soil without stirring treatment; Experiment 4: Moderate saline-alkaline soil with stirring treatment; Experiment 5: Mild saline-alkaline soil without stirring Slurry treatment, experiment 6: mild saline-alkali soil stirring treatment; and respectively according to the following steps to achieve:

Experiment 1

One, select the soda saline-alkali paddy field with a pH of 10.65; the EC of the soda saline-alkali paddy field is 2.94mS/cm;

2. To level the land, add 100% GR of desulfurized gypsum as a modifier according to the alkalinity of the soil; the amount of desulfurized gypsum added is calculated according to the following formula:

100%GR＝1.25×CEC×(ESP _i –ESP _f )×10 ^-2

In the above formula:

100% GR is the amount of desulfurized gypsum added, and the unit is mol _c /kg, where the subscript c of mol _c is the charge number, and mol _c is the unit, which is equivalent to the equivalent concentration;

CEC is the soil cation exchange capacity, which is 200mmol _c /kg; ESP _i is the initial alkalinity of the soil;

ESP _f is the soil target alkalization degree, which is set to 5%;

The desulfurization gypsum added in the amount of 100% GR refers to the amount of gypsum required for all the exchangeable Na ⁺ to be replaced in the soil of 0-20 cm;

The desulfurized gypsum used in the experiment is an industrial by-product of Thermal Power Company, and the mass fraction of CaSO ₄ ·2H ₂ O in the desulfurized gypsum is 98.12%; the added amount of the desulfurized gypsum is calculated to be 25.0 g/kg;

3. Carry out the first artificial irrigation soaking field, the water consumption of the first artificial irrigation soaking field is that the water surface reaches a height of 8 cm above the soil surface; the first artificial irrigation soaking time is 24 hours;

4. After the first artificial irrigation soaked the field, perform the first horizontal drainage;

Five, after the 1st horizontal drainage is completed, carry out the 2nd artificial irrigation soaking field; the water consumption of the 2nd artificial irrigation soaking field is that the water surface reaches the height of 8cm above the soil surface; the 2nd artificial irrigation soaking Field time is 24 hours;

6. After the second artificial irrigation and soaking of the field, the second horizontal drainage is carried out, that is, the irrigation and drainage of the improved soda saline-alkali paddy field soaking period is completed, and the water can be released for sedimentation and transplanting.

Experiment 2:

One, select the soda saline-alkali paddy field with a pH of 10.65; the EC of the soda saline-alkali paddy field is 2.94mS/cm;

2. To level the land, add 100% GR of desulfurized gypsum as a modifier according to the alkalinity of the soil; the amount of desulfurized gypsum added is calculated according to the following formula:

100%GR＝1.25×CEC×(ESP _i –ESP _f )×10 ^-2

In the above formula:

100% GR is the amount of desulfurized gypsum added, and the unit is mol _c /kg, where the subscript c of mol _c is the charge number, and mol _c is the unit, which is equivalent to the equivalent concentration;

CEC is the soil cation exchange capacity, which is 200mmol _c /kg; ESP _i is the initial alkalinity of the soil;

ESP _f is the soil target alkalization degree, which is set to 5%;

The desulfurization gypsum added in the amount of 100% GR refers to the amount of gypsum required for all the exchangeable Na ⁺ to be replaced in the soil of 0-20 cm;

The desulfurized gypsum used in the experiment is an industrial by-product of Thermal Power Company, and the mass fraction of CaSO ₄ ·2H ₂ O in the desulfurized gypsum is 98.12%.

3. Carry out the first artificial irrigation soaking field, the water consumption of the first artificial irrigation soaking field is that the water surface reaches a height of 8 cm above the soil surface; the first artificial irrigation soaking time is 24 hours;

4. After the first artificial irrigation and soaking of the field, perform the first water rake stirring, then stabilize for 24 hours, and then perform the first horizontal drainage;

Five, after the 1st horizontal drainage is completed, carry out the 2nd artificial irrigation soaking field; the water consumption of the 2nd artificial irrigation soaking field is that the water surface reaches the height of 8cm above the soil surface; the 2nd artificial irrigation soaking Field time is 24 hours;

6. After the second artificial irrigation and soaking of the field, perform the second water rake to stir the slurry, then stabilize for 24 hours, and then perform the second horizontal drainage, that is, complete the irrigation and drainage of the improved soda saline-alkali paddy field soaking period, and then release the water and settle Transplanting.

Experiment 3:

One, the selection pH is the soda saline-alkali paddy field of 10.48; the EC of the soda saline-alkali paddy field is 0.99mS/cm;

2. To level the land, add 100% GR of desulfurized gypsum as a modifier according to the alkalinity of the soil; the amount of desulfurized gypsum added is calculated according to the following formula:

100%GR＝1.25×CEC×(ESP _i –ESP _f )×10 ^-2

In the above formula:

100% GR is the amount of desulfurized gypsum added, and the unit is mol _c /kg, where the subscript c of mol _c is the charge number, and mol _c is the unit, which is equivalent to the equivalent concentration;

CEC is the soil cation exchange capacity, which is 200mmol _c /kg; ESP _i is the initial alkalinity of the soil;

ESP _f is the soil target alkalization degree, which is set to 5%;

The desulfurization gypsum added in the amount of 100% GR refers to the amount of gypsum required for all the exchangeable Na ⁺ to be replaced in the soil of 0-20 cm;

The desulfurized gypsum used in the experiment is an industrial by-product of Thermal Power Company, and the mass fraction of CaSO ₄ ·2H ₂ O in the desulfurized gypsum is 98.12%; the added amount of the desulfurized gypsum is calculated to be 12.5g/kg;

3. Carry out the first artificial irrigation soaking field, the water consumption of the first artificial irrigation soaking field is that the water surface reaches a height of 8 cm above the soil surface; the first artificial irrigation soaking time is 24 hours;

4. After the first artificial irrigation soaked the field, perform the first horizontal drainage;

Five, after the 1st horizontal drainage is completed, carry out the 2nd artificial irrigation soaking field; the water consumption of the 2nd artificial irrigation soaking field is that the water surface reaches the height of 8cm above the soil surface; the 2nd artificial irrigation soaking Field time is 24 hours;

6. After the second artificial irrigation and soaking of the field, the second horizontal drainage is carried out, that is, the irrigation and drainage of the improved soda saline-alkali paddy field soaking period is completed, and the water can be released for sedimentation and transplanting.

Experiment 4:

One, select the soda saline-alkali paddy field with a pH of 10.18; the EC of the soda saline-alkali paddy field is 0.99mS/cm;

2. To level the land, add 100% GR of desulfurized gypsum as a modifier according to the alkalinity of the soil; the amount of desulfurized gypsum added is calculated according to the following formula:

100%GR＝1.25×CEC×(ESP _i –ESP _f )×10 ^-2

In the above formula:

100% GR is the amount of desulfurized gypsum added, and the unit is mol _c /kg, where the subscript c of mol _c is the charge number, and mol _c is the unit, which is equivalent to the equivalent concentration;

CEC is the soil cation exchange capacity, which is 200mmol _c /kg; ESP _i is the initial alkalinity of the soil;

ESP _f is the soil target alkalization degree, which is set to 5%;

The desulfurization gypsum added in the amount of 100% GR refers to the amount of gypsum required for all the exchangeable Na ⁺ to be replaced in the soil of 0-20 cm;

The desulfurized gypsum used in the experiment is an industrial by-product of Thermal Power Company, and the mass fraction of CaSO ₄ ·2H ₂ O in the desulfurized gypsum is 98.12%; the added amount of the desulfurized gypsum is calculated to be 12.5g/kg;

3. Carry out the first artificial irrigation soaking field, the water consumption of the first artificial irrigation soaking field is that the water surface reaches a height of 8 cm above the soil surface; the first artificial irrigation soaking time is 24 hours;

4. After the first artificial irrigation and soaking of the field, perform the first water rake stirring, then stabilize for 24 hours, and then perform the first horizontal drainage;

Five, after the 1st horizontal drainage is completed, carry out the 2nd artificial irrigation soaking field; the water consumption of the 2nd artificial irrigation soaking field is that the water surface reaches the height of 8cm above the soil surface; the 2nd artificial irrigation soaking Field time is 24 hours;

6. After the second artificial irrigation and soaking of the field, perform the second water rake to stir the slurry, then stabilize it for 4-8 hours, and then perform the second horizontal drainage, that is, complete the irrigation and drainage of the improved soda saline-alkali paddy field during the soaking period. Put water to settle the rice seedlings.

Experiment 5:

One, select the soda saline-alkali paddy field with a pH of 9.77; the EC of the soda saline-alkali paddy field is 0.68mS/cm;

2. To level the land, add 100% GR of desulfurized gypsum as a modifier according to the alkalinity of the soil; the amount of desulfurized gypsum added is calculated according to the following formula:

100%GR＝1.25×CEC×(ESP _i –ESP _f )×10 ^-2

In the above formula:

100% GR is the amount of desulfurized gypsum added, and the unit is mol _c /kg, where the subscript c of mol _c is the charge number, and mol _c is the unit, which is equivalent to the equivalent concentration;

CEC is the soil cation exchange capacity, which is 200mmol _c /kg; ESP _i is the initial alkalinity of the soil;

ESP _f is the soil target alkalization degree, which is set to 5%;

The desulfurization gypsum added in the amount of 100% GR refers to the amount of gypsum required for all the exchangeable Na ⁺ to be replaced in the soil of 0-20 cm;

The desulfurized gypsum used in the experiment is an industrial by-product of Thermal Power Company, and the mass fraction of CaSO ₄ ·2H ₂ O in the desulfurized gypsum is 98.12%; the added amount of the desulfurized gypsum is calculated to be 8.3g/kg;

3. Carry out the first artificial irrigation soaking field, the water consumption of the first artificial irrigation soaking field is that the water surface reaches a height of 8 cm above the soil surface; the first artificial irrigation soaking time is 24 hours;

4. After the first artificial irrigation soaked the field, perform the first horizontal drainage;

Five, after the 1st horizontal drainage is completed, carry out the 2nd artificial irrigation soaking field; the water consumption of the 2nd artificial irrigation soaking field is that the water surface reaches the height of 8cm above the soil surface; the 2nd artificial irrigation soaking Field time is 24 hours;

6. After the second artificial irrigation and soaking of the field, the second horizontal drainage is carried out, that is, the irrigation and drainage of the improved soda saline-alkali paddy field soaking period is completed, and the water can be released for sedimentation and transplanting.

Experiment 6:

One, select the soda saline-alkali paddy field with a pH of 9.77; the EC of the soda saline-alkali paddy field is 0.68mS/cm;

2. To level the land, add 100% GR of desulfurized gypsum as a modifier according to the alkalinity of the soil; the amount of desulfurized gypsum added is calculated according to the following formula:

100%GR＝1.25×CEC×(ESP _i –ESP _f )×10 ^-2

In the above formula:

100% GR is the amount of desulfurized gypsum added, and the unit is mol _c /kg, where the subscript c of mol _c is the charge number, and mol _c is the unit, which is equivalent to the equivalent concentration;

CEC is the soil cation exchange capacity, which is 200mmol _c /kg; ESP _i is the initial alkalinity of the soil;

ESP _f is the soil target alkalization degree, which is set to 5%;

The desulfurization gypsum added in the amount of 100% GR refers to the amount of gypsum required for all the exchangeable Na ⁺ to be replaced in the soil of 0-20 cm;

The desulfurized gypsum used in the experiment is an industrial by-product of Thermal Power Company, and the mass fraction of CaSO ₄ ·2H ₂ O in the desulfurized gypsum is 98.12%; the added amount of the desulfurized gypsum is calculated to be 8.3g/kg;

3. Carry out the first artificial irrigation soaking field, the water consumption of the first artificial irrigation soaking field is that the water surface reaches a height of 8 cm above the soil surface; the first artificial irrigation soaking time is 24 hours;

4. After the first artificial irrigation and soaking of the field, perform the first water rake stirring, then stabilize for 24 hours, and then perform the first horizontal drainage;

Five, after the 1st horizontal drainage is completed, carry out the 2nd artificial irrigation soaking field; the water consumption of the 2nd artificial irrigation soaking field is that the water surface reaches the height of 8cm above the soil surface; the 2nd artificial irrigation soaking Field time is 24 hours;

6. After the second artificial irrigation and soaking of the field, perform the second water rake to stir the slurry, then stabilize for 24 hours, and then perform the second horizontal drainage, that is, complete the irrigation and drainage of the improved soda saline-alkali paddy field soaking period, and then release the water and settle Transplanting.

The following monitoring was done during the experiment:

Figure 1 is the time-dependent diagram of the pH of the saline-alkali field surface water in the first irrigation soaked field monitored in Experiments 1 to 6, which was monitored every 2 hours after the first artificial irrigation soaked the field.

Figure 2 is a plot of the pH of the saline-alkali field surface water changing with time after soaking in the field for 24 hours after the first slurry stirring in experiments 1 to 6. In experiments 2, 4, and 6, the monitoring was performed every 2 hours after the first slurry stirring. Experiment 1 , 3, 5 monitoring start time is the same as experiment 2, 4, 6, monitoring once every 2h.

Figure 3 is a plot of the pH of the saline-alkali field surface water changing with time after soaking in the field for 24 hours after the second slurry stirring in experiments 1 to 6. In experiments 2, 4, and 6, the monitoring was performed every 2 hours after the second slurry stirring. Experiment 1 , 3, 5 monitoring start time is the same as experiment 2, 4, 6, monitoring once every 2h.

Figure 4 is the time-dependent chart of surface water EC of the saline-alkali field monitored in experiments 1 to 6 for the first irrigation, and monitored every 2 hours after the first artificial irrigation.

Figure 5 is the time-dependent diagram of EC of saline-alkali field surface water after soaking in the field for 24 hours after the first slurry stirring in experiments 1 to 6. In experiments 2, 4, and 6, monitoring was performed every 2 hours after the first slurry stirring. Experiment 1 , 3, 5 monitoring start time is the same as experiment 2, 4, 6, monitoring once every 2h.

Figure 6 is the time-dependent diagram of EC of saline-alkali field surface water after soaking in the field for 24 hours after the second slurry stirring in experiments 1 to 6. Experiments 2, 4, and 6 were monitored every 2 hours after the second slurry stirring. Experiment 1 , 3, 5 monitoring start time is the same as experiment 2, 4, 6, monitoring once every 2h.

Figure 7 is a time-dependent diagram of the electrical conductivity of the saline-alkali soil (0-10 cm) monitored in experiments 1-6 for the first irrigation, which was monitored every 2 hours after the first artificial irrigation.

Figure 8 is a time-dependent diagram of the electrical conductivity of the saline-alkali subsurface mud (0-10 cm) after soaking in the field for 24 hours after the first stirring in experiments 1 to 6, where experiments 2, 4, and 6 were carried out each time after the first stirring. It is monitored once every 2 hours, and the monitoring start time of Experiments 1, 3, and 5 is the same as that of Experiments 2, 4, and 6, and it is monitored every 2 hours.

Figure 9 is a graph showing the change in electrical conductivity of the saline-alkali subsurface mud (0-10 cm) over time after soaking in the field for 24 hours after the second stirring in experiments 1 to 6, where experiments 2, 4, and 6 were carried out each time after the second stirring. It is monitored once every 2 hours, and the monitoring start time of Experiments 1, 3, and 5 is the same as that of Experiments 2, 4, and 6, and it is monitored every 2 hours.

Figure 10 is a time-dependent diagram of the electrical conductivity of saline-alkali soil (10-20 cm) in the first irrigation soaked field monitored in Experiments 1 to 6, which was monitored every 2 hours after the first artificial irrigation of the soaked field.

Figure 11 is a graph showing the electrical conductivity of the saline-alkali subsurface mud (10-20cm) changing with time after soaking in the field for 24 hours after the first stirring in experiments 1 to 6, wherein experiments 2, 4, and 6 were carried out each time after the first stirring. It is monitored once every 2 hours, and the monitoring start time of Experiments 1, 3, and 5 is the same as that of Experiments 2, 4, and 6, and it is monitored every 2 hours.

Figure 12 is a graph of the conductivity of the saline-alkali subsurface mud (10-20cm) changing with time during the 24-hour soaking period after the second stirring in experiments 1 to 6, where experiments 2, 4, and 6 are the second stirring Then monitor once every 2h. The monitoring start time of Experiments 1, 3, and 5 is the same as that of Experiments 2, 4, and 6, and monitor once every 2h.

Fig. 13 is a comparison chart of rice yields between the paddy fields treated in Experiments 2, 4, and 6 and the paddy fields treated in Experiments 1, 3, and 5.

Table 1 Three kinds of soil chemical properties

deal with pH EC(mS/cm) Mild saline-alkali soil 9.77 0.68

Moderate saline-alkali soil 10.18 0.99 Severe saline-alkali soil 10.65 2.94

It can be seen from Figure 1-12 that the EC and pH of the field surface water increased after the implementation of the improved paddy field water rake agitation. After 4 hours, the EC and pH of the field surface water stabilized at a high value, but the EC of the sediment water decreased and remained stable, so the water After 4 hours of raking and stirring, the water is drained to facilitate the discharge of more saline. Soaking the field to wash the salt can flush out the soil salinity. Through experiments, the pH value of the field surface water and the conductivity of the sediment did not decrease with the extension of time, and remained stable after being drained after 2 times of slurry. In production practice, the irrigation and drainage system for saline-alkali paddy fields during the salt-washing period should be soaked in water for 24 hours, stirred twice, and drained 4 hours after the slurry is stirred, and then replenished with new irrigation water.

It can be seen from Figure 4-12 that the EC in the field water is high 10-14 hours after the first slurry stirring, and the EC in the soil bottom mud is low, so the best drainage is stable for 10-14 hours after the first slurry stirring. In the same way, it is best to drain the water for 4-8 hours after the second stirring.

As can be seen from Figure 13, the rice yield of the saline-alkali paddy field treated by the method of the present invention and the rice yield of the saline-alkali paddy field of the process of taking the inventive method but not doing 2 times of stirring have been significantly improved, reaching 47.3%, wherein a slight increase of 36% %, a moderate increase of 43.5%, and a severe increase of 62.4%.

Claims (7)

1. a method for irrigation and drainage of the soaking period of an improved soda saline-alkali paddy field, is characterized in that the method is realized in the following steps: 1. Choose a soda saline-alkali paddy field with a pH of 9.77-10.65; 2. To level the land, add 100% GR of desulfurized gypsum as a modifier according to the alkalinity of the soil; 3. Carry out the first artificial irrigation soaking field; The time for the first artificial irrigation soaking field is 24-48 hours; 4. After the first artificial irrigation soaking the field, perform the first water rake stirring, then stabilize for 10-14 hours, and then perform the first horizontal drainage; 5. After the first horizontal drainage is completed, the second artificial irrigation is carried out to soak the field; The second artificial irrigation soaking time is 24-48 hours; 6. After the second artificial irrigation and soaking of the field, perform the second water rake to stir the slurry, then stabilize it for 4-8 hours, and then perform the second horizontal drainage, that is, complete the irrigation and drainage of the improved soda saline-alkali paddy field during the soaking period. Put water to settle the rice seedlings. 2. A method for improving soaking field irrigation and drainage of soda saline-alkali paddy field according to claim 1, characterized in that the EC of soda saline-alkali paddy field in step 1 is 0.68-2.94mS/cm. 3. a kind of soaking field period irrigation and drainage method for improving soda saline-alkali paddy field according to claim 1, it is characterized in that the addition of desulfurization gypsum in step 2 is calculated by the following formula: 100%GR＝1.25×CEC×(ESP _i –ESP _f )×10 ^-2 In the above formula: 100% GR is the amount of desulfurized gypsum added; CEC is the soil cation exchange capacity; ESP _i is the initial alkalinity of soil; ESP _f is the soil target alkalinity, which is set to 5%. 4. a kind of method for irrigation and drainage of the soaking field stage of improving soda saline-alkali paddy field according to claim 1, it is characterized in that the water consumption of the 1st artificial irrigation soaking field described in step 3 is that the water surface reaches the height of 6-10cm above the soil surface . 5. The method for irrigation and drainage in soaking period of a kind of improved soda saline-alkali paddy field according to claim 1, it is characterized in that the first water rake stirring is carried out as described in step 4, and then it is stabilized for 12 hours. 6. a kind of method for irrigation and drainage of the soaking field stage of improving soda saline-alkali paddy field according to claim 1, it is characterized in that the water consumption of the 2nd artificial irrigation soaking field described in step 5 is that the water surface reaches the height of 6-10cm above the soil surface . 7. The method for irrigation and drainage of a paddy field in improved soda saline-alkali land according to claim 1, characterized in that in step 6, the rake is used to stir the slurry for the second time, and then stabilized for 6 hours.