Method for suppressing saline-alkali soil in autumn and winter and plowing in early spring, improving soil moisture and controlling salt

Abstract

The invention relates to the technical field of soil improvement, in particular to a method for suppressing saline-alkali soil in autumn and winter and ploughing in early spring, improving soil moisture and controlling salt in saline-alkali soil, which utilizes the fact that a large amount of moisture migrates from deep soil or underground water to the surface layer in the winter soil freezing process of a water-deficient saline-alkali area and the moisture content of the surface layer soil is obviously increased after the soil freezing layer is ablated in spring. According to the dynamic law of soil water and salt in the soil freezing and thawing process, a compacting machine is used for compacting the land before soil freezing in winter in the current year, the compactness of the soil is improved, the soil pore proportion of rising water is increased, the soil freezing process in winter is used for promoting the migration of deep soil moisture to the surface layer, and in the early spring of the next year and in the soil freezing layer ablation and slurry returning period, the soil moisture content is increased. A large-scale ploughing machine is adopted to conduct deep ploughing on the land, the conditions of high moisture and low salinity of a plough layer are kept, and normal seedling emergence and growth of spring crops are guaranteed in combination with micro-ditch sowing of spring sowing crops such as sorghum, oil sunflowers and oats.

Description

Technical Field

[0001] The invention relates to the technical field of soil improvement, and in particular to a method for suppressing saline-alkali land in autumn and winter and plowing in early spring to increase soil moisture and control salt. Background Art

[0002] The Bohai Rim is one of the main distribution areas of coastal saline-alkali land in my country. The groundwater level in the region is shallow and highly mineralized, the soil is heavily saline and alkaline and changes frequently, the tillage layer is shallow and the salt control ability is weak, which seriously restricts the growth of crops. In the fields, salt spots are obvious in the spring, and the soil salt distribution is extremely uneven, resulting in low land productivity.

[0003] The core goal of saline-alkali land improvement is to reduce soil salinity and improve soil quality, which not only reduces the salt stress on plants, but also meets their needs for water and nutrients. However, the regional climate and hydrogeological conditions in the Bohai Rim make the soil salinity problem stubborn and recurring, and the shallow tillage layer further restricts agricultural production. The soil water and salt in the region show obvious seasonal changes: in summer, rainfall is heavy and concentrated, which has a significant leaching effect on soil salt, which is the salt leaching period; while in spring, autumn and winter, evaporation is large and rainfall is small, and the soil is in a salt return period, especially in spring. As the salt-sensitive and critical period for crop growth, excessive soil salinity seriously affects crop growth and leads to low yields.

[0004] At present, the key to the improvement and utilization of saline-alkali land lies in sufficient fresh water resources. Through fresh water dissolution and leaching, soil salt is discharged from farmland or deep soil, reducing the damage of salt to crops. On this basis, soil fertility and crop yield are improved through soil fertilization. However, the Bohai Rim region faces the problem of lack of fresh water resources. In addition to rainfall, there is almost no fresh water source available for irrigation, and the agricultural planting model mainly relies on rain-fed dry farming. Although the annual rainfall in the region reaches 520-600mm, more than 70% is concentrated in the summer (June-September), and the rainfall in spring is less than 100mm, while the evaporation is nearly 1000mm. This high evaporation-fall ratio causes the rapid surface accumulation of soil salt in spring, which seriously affects the emergence and growth of crops, thereby restricting the increase in production capacity.

[0005] Under such severe constraints on water and soil resources, it is particularly important to coordinate regional water, soil and atmospheric resources and develop fertile arable land in saline-alkali land. The water-deficient saline-alkali area of ​​Bohai belongs to a typical continental monsoon climate zone. Precipitation is the main source of fresh water in the region, but the distribution is extremely uneven throughout the year and the inter-annual fluctuations are also large. The local planting pattern mainly relies on rain-fed crops. In a wet year, winter wheat and summer corn are mainly planted for two crops a year. In a dry year, spring corn, sweet sorghum, oil sunflower and other crops are sown according to precipitation conditions. Therefore, local agricultural production is highly dependent on precipitation, and crop yields and farmers' income fluctuate greatly from year to year, which is also the main reason why agricultural production is difficult to increase steadily.

[0006] In addition to the impact of precipitation patterns, the cultivation of the soil arable layer is also a key measure to alleviate the impact of precipitation patterns on agricultural production. However, field cultivation currently does not fully consider the dynamic laws of soil water and salt, and supporting measures such as tillage time and tillage depth are insufficient, resulting in weak salt control and moisture conservation capabilities of the arable layer in the region, affecting crop yields. Therefore, it is urgent to take appropriate farming and fertilization measures according to local climatic conditions and soil water and salt migration laws, improve the salt control capacity of cultivated land, and achieve optimal regulation of water and salt in the arable layer of saline-alkali land and increase production capacity. Summary of the invention

[0007] The purpose of the present invention is to provide a method for suppressing saline-alkali land in autumn and winter and plowing in early spring to increase soil moisture and control salt. The method utilizes winter suppression to compact the soil to reduce the proportion of large pores, utilizes the winter soil freezing and thawing process to promote the migration of deep moisture to the surface, and during the early spring soil return period, deep plowing and deep turning measures are used to maintain low salt and high water conditions, improve the emergence and growth of subsequent spring-sown crops, and achieve a coordinated improvement in the quality of the plow layer and production capacity of saline-alkali land.

[0008] The objective of the present invention is achieved through the following technical solutions:

[0009] The invention provides a method for suppressing saline-alkali land in autumn and winter and tilling it in early spring to increase soil moisture and control salt. The method comprises the steps of deep soil suppression in autumn and winter, deep tillage for melting of frozen layer in early spring of next year, shallow rotary tillage and fertilization in spring, micro-ditch sowing of crops and water and fertilizer management during crop growth period.

[0010] Furthermore, it also includes the step of conducting field land preparation before deep soil compaction in autumn and winter.

[0011] Furthermore, the field land preparation is to level the land and establish fields and ridges.

[0012] Furthermore, the deep soil compaction in autumn and winter is to use a compactor to repeatedly compact the land to ensure that the soil bulk density is higher than 1.5g / cm 3 above.

[0013] Furthermore, the deep plowing after the thawing of the frozen layer in early spring of the following year is deep plowing of the land after the soil frozen layer melts in the spring of the following year, and the plowing depth is more than 20 cm.

[0014] Furthermore, the shallow rotary tillage and fertilization in spring is to use a rotary tiller to shallowly till the soil, the tillage depth is 15 cm, and 3 cubic meters of cow dung per mu, 20 kg of diamine per mu, and 20 kg of superphosphate per mu are applied before rotary tillage.

[0015] Furthermore, the crop micro-ditch sowing is performed by using a micro-ditch seeder to sow the crops in micro-ditches, and the depth of the micro-ditch is 5-8 cm.

[0016] Furthermore, the crop is oil sunflower or sorghum.

[0017] Furthermore, the sorghum sowing rate is 1.5-2.5 kg / mu, and the oil sunflower sowing rate is 0.5-0.8 kg / mu; the sorghum plant spacing is 20 cm, the row spacing is 25 cm, and the oil sunflower plant spacing is 25 cm, and the row spacing is 40 cm.

[0018] Furthermore, the water and fertilizer management during the crop growth period is to spray 1.5 kg / mu of potassium dihydrogen phosphate at the seedling stage and to spread 15 kg / mu of urea during the concentrated rainfall season.

[0019] The present invention makes full use of the fact that during the winter soil freezing process in water-deficient saline-alkali areas, a large amount of water migrates from deep soil or groundwater to the surface layer. After the frozen layer of soil melts in spring, the moisture content of the surface soil significantly increases. This soil water-salt dynamic law during the soil freezing-thawing process is used to compact the land with a roller before the soil freezes in winter of the same year to improve the compactness of the soil and increase the soil pore ratio of rising water. The winter soil freezing process is used to promote the migration of deep soil moisture to the surface layer. In the early spring of the following year, when the frozen layer of soil melts and returns to pulp, a large-scale tilling machine is used to deep plow the land to maintain higher moisture and lower salt conditions in the plow layer. Combined with the micro-ditch sowing of spring-sown crops such as sorghum, oil sunflower, and oats, the normal emergence and growth of spring crops are guaranteed.

[0020] The beneficial effects of the present invention are:

[0021] (1) It increases the soil moisture in spring, ensuring the stable yield of spring-sown crops such as sorghum and sunflower. It improves soil compaction through soil compaction in autumn and winter, reduces water evaporation, and promotes the moisture content of the surface soil during the winter soil freezing period, thereby increasing the emergence rate and yield of crops in the next year. (2) It reduces the salinity of the cultivated soil, improves the soil structure, and makes full use of the dynamic process of soil water and salt during the soil freeze-thaw period. Through early spring compaction, it blocks the migration of salt from the lower soil and groundwater to the surface, maintains moisture, reduces salinity, and improves soil structure. (3) It is simple to operate, pollution-free, low-cost, and suitable for large-scale mechanized operation: the present invention does not require the additional development and purchase of new agricultural machinery, and can be achieved through mechanical compaction, plowing, rotary tillage, and micro-ditch sowing, etc., with significant economic and ecological benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 This is a comparison chart of the growth of sorghum in the field implemented in a heavy saline-alkali area according to Example 1 of the present invention. DETAILED DESCRIPTION

[0024] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0025] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0026] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0027] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0028] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0029] The method for soil moisture improvement and salt control in saline-alkali land of the present invention comprises the following steps:

[0030] (1) Field preparation: In autumn (October), the land was leveled. According to the strip field model established in the coastal area, a field with a length of 250 m and a width of 40 m was established. A ridging machine was used to build ridges with a width of 0.4 m and a height of 0.3 m around the field. A laser land leveler was used to level the land.

[0031] (2) Deep soil compaction in autumn and winter: After land preparation is completed, from the end of October to the beginning of December, a high-horsepower tractor with a compactor is used to repeatedly compact the land to ensure that the soil bulk density is higher than 1.5g / cm 3The above reduces the proportion of large pores to reduce water loss, increases the proportion of small and medium pores, and promotes the upward movement of water during the freezing period.

[0032] (3) Deep plowing in early spring to control salt and conserve moisture: In the spring of the following year, after the soil permafrost melts (around mid-to-late February), use a high-horsepower tractor with a reversible plow to deep plow the land to a depth of more than 20 cm to maintain high soil moisture conditions and low salinity conditions.

[0033] (4) Shallow tillage and fertilization in spring: During the spring crop sowing period (around mid-to-late April), use a rotary tiller to shallowly till the soil to a depth of 15 cm. Before tilling, apply 3 cubic meters of cow dung per mu, 20 kg of diamine per mu, and 20 kg of superphosphate per mu.

[0034] (5) Micro-ditch sowing of crops: After rotary tillage and fertilization, a micro-ditch seeder is used to sow crops (such as oil sunflower or sorghum) in micro-ditches. The sowing rate of sorghum is 1.5-2.5 kg / mu, and the sowing rate of oil sunflower is 0.5-0.8 kg / mu. The depth of the micro-ditch is 5-8 cm, the spacing between sorghum plants is 20 cm, the row spacing is 25 cm, and the spacing between oil sunflower plants is 25 cm, and the row spacing is 40 cm. The sowing rate and row spacing of the above crops are achieved by adjusting the row spacing of the micro-ditch seeder.

[0035] (6) Crop water and fertilizer management: After the crops emerge, during the seedling stage (approximately early to mid-June), drones are used to spray "potassium dihydrogen phosphate" at 1.5 kg / mu for foliar fertilization. During the concentrated rainfall season (August to September), drones are used to spread urea at 15 kg / mu according to the rainfall.

[0036] The present invention will be described in detail below using the saline-alkali land autumn and winter suppression and early spring tillage and salt control technology for soil moisture improvement at the coastal saline-alkali land efficient utilization base as an example.

[0037] Example 1

[0038] The geographical environment of the saline-alkali land involved in this embodiment is located in Haixing County, Hebei Province, with a warm temperate continental monsoon climate, an annual average temperature of 12.1°C, an average temperature of -4.6°C in January, an extreme minimum temperature of -19.9°C, and a frost-free period of 217 days. The annual sunshine hours are 2718.8 hours, and the annual average precipitation is 582 mm, mainly concentrated in August to September, accounting for 75% of the annual precipitation. This area is a coastal plain with low-lying and flat terrain, 1.3-3.6 meters above sea level. The soil type is mainly coastal saline soil, and the ion composition is mainly NaCl. The average soil salt content is more than 0.8%. The salt content is 0.4% during the summer salting period, and it reaches 1.2% during the peak period of spring salt return. The salinity level is typical of coastal heavy saline-alkali land. There are also extreme low temperatures in winter. The deepest frozen layer depth reaches 50cm and the shallowest reaches 28cm. The average mass water content of the frozen layer soil is about 28.97%, and the average soil salt content is about 3.21g / kg. In addition, the groundwater level of this saline-alkali land is shallow, averaging about 1 meter, and the mineralization is high, with a salt content of 7-20g·L -1 .

[0039] This example selected typical saline-alkali land since 2021, and conducted research on deep suppression in autumn and winter and deep tillage and salt control in early spring. The selected land was arranged in the early strip field mode, and the surrounding drainage ditches, land leveling and field ridge construction were repaired. In the autumn, the land leveling preparation work was carried out. The specific steps are as follows:

[0040] (1) From September 28 to 30, the land was leveled using a laser land leveler and ridges were built with a height of 30 cm and a width of 40 cm.

[0041] (2) From October 15 to 18, the land was repeatedly compacted using a high-horsepower tractor mounted with a compactor;

[0042] (3) From February 18 to 20, the land was deep plowed using a high-horsepower tractor and a three-furrow plow to a depth of 20 cm;

[0043] (4) From April 20 to April 25, the plots were shallowly tilled with a rotary tiller to a depth of 15 cm. Fertilizer and organic fertilizer were spread during the tillage. Sorghum and oil sunflower were sown using a local micro-ditch seeder. During sowing, the seeds were mixed with pesticides to prevent and control underground pests such as mole crickets and white grubs in a timely manner. Herbicides were sprayed during the seedling stage to prevent and control weeds in a timely manner. Leaf-feeding pests such as aphids and armyworms were prevented during the plant growth period.

[0044] (5) From June 10 to June 15, foliar fertilizer spraying was carried out using drones.

[0045] Experimental results:

[0046] According to the above method, the comparison chart of sorghum growth in the field is as follows: Figure 1 The specific experimental data are shown in Table 1.

[0047] Table 1 Soil data and crop data during the application of the method of the present invention

[0048]

[0049] Note: Soil data testing is done in mid-to-late April, before planting sorghum or oil sunflower

[0050] As can be seen from Table 1, from March to May in 2021 to 2022, the soil salinity in the 20cm tillage layer was controlled at 0.36-0.39%, the soil moisture content was not less than 22%, the sorghum emergence rate reached more than 75%, and the soil salinity in the tillage layer was controlled below 0.4% during the entire sorghum growing period. The sorghum grain yield reached 395kg / mu, and the sunflower grain yield reached 120kg / mu. In the dry year of the coastal saline-alkali area, compared with the traditional winter wheat-summer corn double-cropping planting mode, the net income per mu increased by 1.2 times. Through years of cultivation, the soil organic matter increased by 12%, and the soil bulk density decreased by 30%, achieving a coordinated improvement in the quality and production capacity of saline-alkali farmland in the coastal area. Through three years of coastal saline-alkali land experiments and demonstrations, the average soil salt content in the spring sorghum sowing period showed a gradual downward trend, from the initial 0.56% to 0.36% three years later, the soil moisture content increased by more than 25%, soil salinization was rapidly alleviated, the area of ​​field saline-alkali patches decreased from the initial 45% to less than 6%, and the soil structure of the plough layer was significantly improved, and the soil porosity and organic matter were significantly improved, respectively by more than 12% and 9%. The present invention has significant economic, social and ecological benefits and has broad application prospects.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be covered by the scope of the claims of the present invention.

Claims

1. A method for suppressing saline-alkali land in autumn and winter and tilling in early spring to increase soil moisture and control salt, characterized in that: The method comprises the steps of deep soil compaction in autumn and winter, deep tillage to melt the frozen layer in early spring of the next year, shallow rotary tillage and fertilization in spring, micro-ditch sowing of crops and water and fertilizer management during the crop growth period.

2. The method according to claim 1, characterized in that It also includes steps for field land preparation before deep soil compaction in the fall and winter.

3. The method according to claim 2, characterized in that The field land preparation is to level the land and establish fields and ridges.

4. The method according to claim 1, characterized in that The deep soil compaction in autumn and winter is to use a compactor to repeatedly compact the land to ensure that the soil bulk density is higher than 1.5g / cm 3 above.

5. The method according to claim 1, characterized in that The deep plowing after the thawing of the frozen layer in the early spring of the following year refers to deep plowing of the land after the soil frozen layer melts in the spring of the following year, with the plowing depth being more than 20 cm.

6. The method according to claim 1, characterized in that The shallow rotary tillage and fertilization in spring is to use a rotary tiller to shallowly till the soil, the tillage depth is 15 cm, and before the rotary tillage, 3 cubic meters of cow dung per mu, 20 kg of diamine per mu, and 20 kg of superphosphate per mu are applied.

7. The method according to claim 1, characterized in that The micro-ditch sowing of crops is to use a micro-ditch seeder to perform micro-ditch sowing on crops, and the depth of the micro-ditch is 5-8 cm.

8. The method according to claim 7, characterized in that The crops include oil sunflower or sorghum.

9. The method according to claim 8, characterized in that The sowing rate of sorghum is 1.5-2.5 kg / mu, and the sowing rate of oil sunflower is 0.5-0.8 kg / mu; the plant spacing of sorghum is 20 cm, and the row spacing is 25 cm, and the plant spacing of oil sunflower is 25 cm, and the row spacing is 40 cm.

10. The method according to claim 1, characterized in that The water and fertilizer management during the crop growth period is to spray 1.5 kg / mu of potassium dihydrogen phosphate at the seedling stage and to spread 15 kg / mu of urea during the concentrated rainfall season.

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