A method for salinity control and moisture conservation in autumn and winter by compacting and in early spring by ploughing

Abstract

The application belongs to the technical field of soil improvement, and particularly relates to a method for autumn and winter pressing and early spring plowing to increase soil moisture and control salt in saline-alkali land. In the winter soil freezing process of the water-deficient saline-alkali area, a large amount of water migrates from deep soil or underground water to the surface layer. After the soil freezing layer melts in the spring, the water content of the surface soil is significantly increased. The soil water and salt dynamic law in the soil freezing and thawing process is used to press the land by using a presser before the soil freezes in the winter, to improve the tightness of the soil and increase the proportion of soil pores of the rising water. The soil freezing process in the winter is used to promote the migration of deep soil water to the surface layer. In the early spring of the next year, a large plowing machine is used to plow the land deeply in the soil freezing layer melting and returning to the slurry period, to keep the high water content and low salt content of the plough layer. Combined with the micro-sowing of spring crops such as sorghum, oil sunflower and oat, the normal emergence and growth of the spring crops are ensured.

Description

Technical Field

[0001] This invention relates to the field of soil improvement technology, specifically to a method for controlling salinity in saline-alkali land by autumn and winter compaction and early spring tillage to improve soil moisture. Background Technology

[0002] The Bohai Rim region is one of the main distribution areas of coastal saline-alkali land in my country. This region has shallow groundwater levels and high mineralization, resulting in frequent and recurring soil salinization. The shallow topsoil has weak salt control capabilities, severely limiting crop growth. In the fields, salt patches are evident in spring, and the distribution of soil salinity is extremely uneven, leading to low land productivity.

[0003] The core objective of saline-alkali land improvement is to reduce soil salinity and improve soil quality, thereby reducing salt stress on plants while meeting their needs for water and nutrients. However, the regional climate and hydrogeological conditions of the Bohai Rim region make soil salinity a persistent and recurring problem, and the shallow topsoil further restricts agricultural production. Soil water and salinity in this region exhibit significant seasonal variations: summer brings abundant and concentrated rainfall, resulting in significant leaching of soil salinity, known as the salt leaching period; while spring, autumn, and winter see high evaporation and low rainfall, leading to a period of soil salinization, with spring being the most severe. Spring is a salt-sensitive and critical period for crop growth; excessively high soil salinity in spring severely impacts crop growth, resulting in low yields.

[0004] Currently, the key to improving and utilizing saline-alkali land lies in sufficient freshwater resources. Freshwater dissolution and leaching remove soil salts from farmland or deeper soil layers, reducing the damage to crops. Based on this, soil fertility and crop yield can be improved through soil enrichment. However, the Bohai Rim region faces a shortage of freshwater resources. Apart from rainfall, there are almost no freshwater sources available for irrigation, and agricultural practices mainly rely on rainfed dryland farming. Although the region receives 520-600 mm of annual rainfall, over 70% is concentrated in summer (June-September), with spring rainfall less than 100 mm, while evaporation is nearly 1000 mm. This high evaporation-to-fall ratio leads to rapid surface accumulation of soil salts in spring, severely affecting crop emergence and growth, thus limiting productivity.

[0005] Given such severe constraints on water and soil resources, it is particularly important to coordinate regional water, soil, and atmospheric resources and develop a fertile topsoil layer in saline-alkali land. The Bohai Sea water-scarce saline-alkali area is a typical continental monsoon climate zone, where precipitation is the main source of freshwater, but its distribution is extremely uneven throughout the year and fluctuates greatly from year to year. Local planting patterns rely heavily on rainfed agriculture; in wet years, winter wheat and summer maize are grown twice a year, while in dry years, spring maize, sweet sorghum, and sunflowers are planted depending on rainfall. Therefore, local agricultural production is highly dependent on rainfall, resulting in significant annual fluctuations in crop yields and farmers' income, which is the main reason why agricultural production is difficult to steadily improve.

[0006] Besides the influence of precipitation year patterns, cultivating the topsoil layer is also a key measure to mitigate the impact of precipitation year patterns on agricultural production. However, current field tillage practices do not fully consider the dynamic patterns of soil water and salt, and supporting measures such as tillage time and tillage depth are insufficient. This results in weak salt control and moisture retention capacity of the topsoil layer in the region, affecting crop yields. Therefore, it is urgent to adopt appropriate tillage and fertilization measures based on local climate conditions and soil water and salt transport patterns to improve the salt control capacity of cultivated land and achieve optimized regulation of water and salt in the topsoil layer of saline-alkali land, thereby increasing productivity. Summary of the Invention

[0007] The purpose of this invention is to provide a method for controlling salinity in saline-alkali land by autumn and winter compaction and early spring plowing. This method utilizes winter compaction to reduce the proportion of large pores in the soil and the winter freeze-thaw process to promote the migration of deep water to the surface. During the early spring soil thawing period, deep plowing and deep tilling are used to maintain low salinity and high water conditions, thereby improving the emergence and growth of subsequent spring-sown crops and achieving a synergistic improvement in the quality and productivity of the topsoil in saline-alkali land.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] This invention provides a method for soil compaction in autumn and winter and early spring plowing to improve soil moisture and control salinity in saline-alkali land. The method includes the following steps: deep soil compaction in autumn and winter, deep plowing in early spring after the thawing of the frozen layer, shallow rotary tillage and fertilization in spring, micro-furrow sowing of crops, and water and fertilizer management during the crop growth period.

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

[0011] Furthermore, the aforementioned field land preparation involves leveling the land and establishing plots and ridges.

[0012] Furthermore, the aforementioned deep soil compaction in autumn and winter involves repeatedly compacting the land using a compactor to ensure that the soil bulk density is higher than 1.5 g / cm³. 3 above.

[0013] Furthermore, the deep tillage after the thawing of the frozen layer in early spring of the following year refers to deep tillage of the land after the thawing of the frozen soil layer in the following spring, with a tillage depth of more than 20cm.

[0014] Furthermore, the spring shallow rotary tillage and fertilization refers to using a rotary tiller to perform shallow rotary tillage on the soil, with a tillage depth of 15cm. Before rotary tillage, apply 3 cubic meters / acre of cow manure, 20 kg / acre of diammonium phosphate, and 20 kg / acre of superphosphate.

[0015] Furthermore, the crop micro-furrow sowing is performed by using a micro-furrow seeder to sow the crop in micro-furrows, with a micro-furrow depth of 5-8 cm.

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

[0017] Furthermore, the sorghum sowing rate is 1.5-2.5 kg / mu, and the sunflower sowing rate is 0.5-0.8 kg / mu; the sorghum plant spacing is 20 cm and the row spacing is 25 cm, and the 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 involves spraying 1.5 kg / mu of potassium dihydrogen phosphate during the seedling stage and applying 15 kg / mu of urea during the rainy season.

[0019] This invention fully utilizes the dynamic law of soil water and salt during the winter freezing process in water-scarce and saline-alkali areas, during which a large amount of water migrates from deep soil or groundwater to the surface. After the soil freezes in spring, the surface soil moisture content increases significantly. This invention utilizes the soil water and salt dynamic law during the freeze-thaw process to compact the land with a roller before the soil freezes in winter, increasing the soil compaction and the proportion of soil pores for rising water. By utilizing the winter soil freezing process, it promotes the migration of deep soil moisture to the surface. In early spring of the following year, during the thawing and thawing period, a large tillage machine is used to deeply till the land, maintaining high moisture and low salinity in the topsoil. Combined with the micro-furrow sowing of spring crops such as sorghum, sunflower, and oats, it ensures the normal emergence and growth of spring crops.

[0020] The beneficial effects of this invention are as follows:

[0021] (1) It increased soil moisture in spring, ensuring stable yields of spring-sown crops such as sorghum and sunflower. Autumn and winter soil compaction improved soil compaction, reduced water evaporation, and increased surface soil moisture content during the winter freezing period, thus improving the emergence rate and yield of crops the following year. (2) It reduced soil salinity in the topsoil, improved soil structure, and fully utilized the dynamic process of soil water and salt during the freeze-thaw period. Early spring plowing blocked the migration of salt from the lower soil and groundwater to the surface, retained moisture, reduced salinity, and improved soil structure. (3) It is simple to operate, pollution-free, low-cost, and suitable for large-scale mechanized operation: This invention does not require the development or purchase of new agricultural machinery. It can be achieved through mechanical compaction, plowing, rotary tillage, and micro-furrow sowing, resulting in significant economic and ecological benefits. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a comparison of sorghum growth in a heavily saline-alkali area according to Example 1 of the present invention. Detailed Implementation

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

[0025] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0026] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0027] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

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

[0029] The method for improving soil moisture and controlling salinity in saline-alkali land according to the present invention includes the following steps:

[0030] (1) Field land preparation: In autumn (October), the land is leveled. Based on the strip field model established in the coastal area, a field with a length of 250m and a width of 40m is established. A ridge machine is used to build a field ridge with a width of 0.4m and a height of 0.3m around the field. A laser leveling instrument is 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 roller attached is used to repeatedly compact the land to ensure that the soil bulk density is higher than 1.5 g / cm³. 3In summary, reducing the proportion of large pores decreases water loss, while increasing the proportion of small and medium pores 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 frozen soil layer melts (around mid to late February), use a high-horsepower tractor with a reversible plow to plow the land deeply to a depth of more than 20cm to maintain high soil moisture and low salinity.

[0033] (4) Spring shallow rotary tillage and fertilization: During the spring crop sowing period (around mid-to-late April), use a rotary tiller to perform shallow rotary tillage on the soil. The tillage depth is 15cm. Before rotary tillage, apply 3 cubic meters of cow manure per mu, 20 kg of diammonium per mu, and 20 kg of superphosphate per mu.

[0034] (5) Crop micro-furrow sowing: After rotary tillage and fertilization, use a micro-furrow seeder to sow crops (such as sunflower or sorghum) in micro-furrows. The sowing rate of sorghum is 1.5-2.5 kg / mu, and the sowing rate of sunflower is 0.5-0.8 kg / mu. The depth of the micro-furrow is 5-8 cm. The plant spacing of sorghum is 20 cm and the row spacing is 25 cm. The plant spacing of sunflower is 25 cm and the row spacing is 40 cm. The sowing rate and row spacing of the above crops can be achieved by adjusting the row spacing of the micro-furrow seeder.

[0035] (6) Crop water and fertilizer management: After the crop emerges, during the seedling stage (around early to mid-June), use drones to spray 1.5 kg / mu of potassium dihydrogen phosphate for foliar fertilization. During the peak rainfall season (August-September), use drones to spread 15 kg / mu of urea according to the rainfall.

[0036] The following example, from the Agricultural Resources Research Center of the Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, illustrates the invention in detail: the autumn and winter compaction and early spring plowing technique for improving soil moisture and controlling salinity in the coastal saline-alkali land high-efficiency utilization base.

[0037] Example 1

[0038] The geographical environment of the saline-alkali land involved in this embodiment is located in Haixing County, Hebei Province, which has a warm temperate continental monsoon climate. The average annual temperature is 12.1℃, the average temperature in January is -4.6℃, the extreme minimum temperature is -19.9℃, and the frost-free period is 217 days. The annual sunshine duration is 2718.8 hours, and the average annual precipitation is 582mm, mainly concentrated in August and September, accounting for 75% of the annual precipitation. This area is a coastal plain, low-lying and flat, with an elevation of 1.3-3.6 meters. The soil type is mainly coastal saline soil, with NaCl as the dominant ionic component. The average soil salinity is above 0.8%, reaching 0.4% during the summer leaching period and 1.2% during the peak spring salt return period. The salinity level is typical of heavily saline-alkali coastal land. Extreme low temperatures exist in winter, with the deepest frozen layer reaching 50 cm and the shallowest 28 cm. The average water content of the frozen soil is approximately 28.97%, and the average soil salinity is approximately 3.21 g / kg. Furthermore, the groundwater level in this saline-alkali land is shallow, averaging around 1 meter, and has high mineralization, with a salt content ranging from 7 to 20 g / L. -1 .

[0039] This embodiment selected a typical saline-alkali plot in 2021 and conducted research on salt control through deep rolling in autumn and winter and deep plowing in early spring. The selected plot was prepared under the previous strip field model, and the surrounding drainage ditches, land leveling and field ridge construction were repaired. In autumn, land leveling preparation work was carried out for the plot. The specific steps are as follows:

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

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

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

[0043] (4) From April 20 to April 25, the plots were shallowly tilled using a rotary tiller to a depth of 15cm. During the tillage, fertilizer was spread and organic fertilizer was applied. Sorghum and sunflowers were sown using a local micro-furrow seeder. Seeds were treated with pesticides to control underground pests such as mole crickets and grubs. Herbicides were sprayed during the seedling stage to control weeds. During the plant growth period, leaf-eating pests such as aphids and armyworms were prevented.

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

[0045] Experimental results:

[0046] The comparison chart of sorghum growth in the field obtained using the above method is shown below. Figure 1 As shown in Table 1, the specific experimental data are as follows.

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

[0048]

[0049] Note: Soil data testing was conducted in mid-to-late April, before sorghum or sunflower planting.

[0050] As shown in Table 1, from 2021 to 2022, the soil salinity in the top 20cm layer was controlled at 0.36-0.39% from March to May, and the soil moisture content was not less than 22%. The sorghum emergence rate reached over 75%, and the soil salinity in the top layer was controlled below 0.4% throughout the sorghum growing season. The sorghum grain yield reached 395 kg / mu, and the sunflower grain yield reached 120 kg / mu. In the dry year of the coastal saline-alkali area, compared with the traditional winter wheat-summer corn double cropping model, 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 productivity of saline-alkali farmland in the coastal area. Through three years of trials and demonstrations in coastal saline-alkali land, this invention showed a gradual decrease in the average soil salinity during the spring sorghum sowing period, from an initial 0.56% to 0.36% after three years. Soil moisture content increased by more than 25%, soil salinization was rapidly alleviated, and the proportion of saline-alkali patches in the field decreased from an initial 45% to below 6%. Furthermore, the topsoil structure was significantly improved, with soil porosity and organic matter increasing by more than 12% and 9%, respectively. This invention has significant economic, social, and ecological benefits and broad application prospects.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for controlling salinity in saline-alkali land by autumn and winter compaction and early spring plowing to improve soil moisture, characterized in that... The method includes the steps of deep soil compaction in autumn and winter, deep plowing in early spring after the thawing of the frozen layer, shallow rotary tillage and fertilization in spring, crop micro-furrow sowing, and water and fertilizer management during the crop growth period. It also includes the step of preparing the field land before deep soil compaction in autumn and winter; The aforementioned field land preparation involves leveling the land and establishing field plots and ridges; The aforementioned autumn and winter soil deep compaction involves repeatedly compacting the land using a compactor to ensure that the soil bulk density is higher than 1.5 g / cm³. 3 above; The deep tillage after the thawing of the frozen layer in early spring of the following year refers to deep tillage of the land after the thawing of the frozen layer in the following spring, with a tillage depth of more than 20cm. The spring shallow rotary tillage and fertilization method involves using a rotary tiller to perform shallow rotary tillage on the soil to a depth of 15cm. Before rotary tillage, apply 3 cubic meters of cow manure per mu, 20 kg of diammonium phosphate per mu, and 20 kg of superphosphate per mu. The crop micro-furrow sowing refers to sowing crops in micro-furrows using a micro-furrow seeder, with a micro-furrow depth of 5-8cm; The crops include sunflowers or sorghum.

2. The method according to claim 1, characterized in that, The sorghum sowing rate is 1.5-2.5 kg / mu, and the sunflower sowing rate is 0.5-0.8 kg / mu; the sorghum plant spacing is 20 cm and the row spacing is 25 cm, and the sunflower plant spacing is 25 cm and the row spacing is 40 cm.

3. The method according to claim 1, characterized in that, The water and fertilizer management during the crop growth period is as follows: during the seedling stage, spray 1.5 kg / mu of potassium dihydrogen phosphate, and during the rainy season, apply 15 kg / mu of urea.

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